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Liu F, Feng X, Deng G, Leung F, Wang C, Chen B. Biomechanical comparison of a new undercut thread design vs the V-shape thread design for pedicle screws. Spine J 2024; 24:1993-2001. [PMID: 38843954 DOI: 10.1016/j.spinee.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 07/01/2024]
Abstract
BACKGROUND CONTEXT Thread shape is regarded as an important factor influencing the fixation strength and osseointegration of bone screws. However, commercial pedicle screws with a V-shaped thread are prone to generating stress concentration at the bone-screw interface, thereby increasing the risk of screw loosening. Thus, modification of the pedicle-screw thread is imperative. PURPOSE This study aimed to investigate the fixation stability of pedicle screws with the new undercut thread design in comparison to pedicle screws with a V-shaped thread. STUDY DESIGN In vitro cadaveric biomechanical test and finite element analysis (FEA). METHODS Pedicle screws with the undercut thread (characterized by a flat crest feature and a tip-facing undercut feature) were custom-manufactured, whereas those with the V-shaped thread were procured from a commercial supplier. Fixation stability was assessed by the cyclic nonpullout compressive biomechanical testing on cadaveric female osteoporotic vertebrae. The vertical displacement and rotation angle of the 2 types of pedicle screws were calculated every 100 cycles to evaluate their resistance to migration and rotation. FEA was conducted to investigate the stress distribution and bone damage at the bone-screw interface for both types of pedicle screws. RESULTS Biomechanical testing revealed that the pedicle screws with the undercut thread exhibited significantly lower vertical displacement and rotation angles than the pedicle screws with the V-shape thread (p<0.05). FEA results demonstrated a more uniform stress distribution in the bone surrounding the thread in the undercut design than in the V-shape design. Additionally, bone damage resulting from the pedicle screw was lower in the undercut design than in the V-shape design. CONCLUSIONS Pedicle screws with an undercut thread are less prone to migration and rotation and thus more stable in the bone than those with a V-shape thread. CLINICAL SIGNIFICANCE The undercut thread design may reduce the incidence of pedicle-screw loosening.
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Affiliation(s)
- Fei Liu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoreng Feng
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, Yangjiang, China
| | - Geyang Deng
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Frankie Leung
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China
| | - Chengyong Wang
- Guangdong Provincial Key Laboratory of Minimally Invasive Surgical Instruments and Manufacturing Technology, Guangdong University of Technology, Guangzhou, China
| | - Bin Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Sulpis B, Neri T, Klasan A, Castel X, Vassal F, Tetard MC. Isolated posterior stabilization in type B and C thoracolumbar fractures associated with ankylosing spine disorders: A single center experience with clinical and radiological outcomes. SICOT J 2024; 10:26. [PMID: 39137794 PMCID: PMC11323833 DOI: 10.1051/sicotj/2024022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 05/19/2024] [Indexed: 08/15/2024] Open
Abstract
INTRODUCTION Fractures in ankylosing spine disorders (ASD) are associated with high complication and mortality rates. During the posterior stabilization of these fractures, reduction is often partial, resulting in the persistence of a significant anterior diastasis. Our objective was to evaluate the safety and efficiency of isolated posterior stabilization in elderly ASD patients, without direct reduction of the anterior diastasis, in terms of clinical and radiological outcomes, complications, and mortality. METHODS This retrospective study included 46 patients, mean age 79.3 years, with ASD, who underwent isolated posterior stabilization, open or percutaneous, for thoracolumbar fractures. The average follow-up was 21.7 months, with a minimum follow-up of 6 months. Autonomy (Parker score) and radiological results (lordotic angulation) were analyzed pre-and post-operatively. RESULTS Autonomy was maintained at the last follow-up, with no significant difference in Parker's score. The consolidation rate was 94.6%. No implant failure was recorded. Despite the absence of an anterior procedure, lordotic angulation was significantly reduced by 2.6° at 6 months (p = 0.02). The rate of surgical complications following open surgeries was 10.9% (n = 5), of which 6.5% were infections. No surgical complications were reported in percutaneous surgeries. The rate of medical complications was 67.4% (n = 31), with a rate of 88.2% in the open surgery group, compared to 55.2% in the percutaneous surgery group. An open approach was associated with a five-fold higher risk of complications (p = 0.049). Nine patients died during follow-up (19.6%). CONCLUSIONS Isolated posterior stabilization in the treatment of thoracolumbar spine fractures in elderly ASD patients is a safe technique promoting autonomy preservation, and high radiological bony healing with acceptable complication and mortality rates. The persistent anterior gap is partially reduced when the spine is loaded and does not seem to require an anterior procedure, thus decreasing complications. Percutaneous surgery should be the technique of choice to reduce surgical complications.
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Affiliation(s)
- Benoit Sulpis
- Jacques Lisfranc Faculty of Medicine, Jean Monnet University 10 Rue de la Marandière 42270 Saint-Priest-en-Jarez France
- Department of Neuro Surgery, University Hospital of Saint Etienne Hôpital Nord 42055 Saint-Étienne Cedex 2 France
- Department of Orthopaedic Surgery, University Hospital of Saint Etienne Saint Etienne France
| | - Thomas Neri
- Department of Orthopaedic Surgery, University Hospital of Saint Etienne Saint Etienne France
- EA 7424 - Inter-University Laboratory of Human Movement Science, University of Lyon - Jean Monnet University Saint-Étienne Cedex 2 France
| | - Antonio Klasan
- Department for Orthopedics and Traumatology, Kepler University Hospital GmbH Krankenhausstrasse 9 4020 Linz Austria
- Johannes Kepler University Linz Altenberger Strasse 69 4040 Linz Austria
| | - Xavier Castel
- Department of Neuro Surgery, University Hospital of Saint Etienne Hôpital Nord 42055 Saint-Étienne Cedex 2 France
| | - François Vassal
- Department of Neuro Surgery, University Hospital of Saint Etienne Hôpital Nord 42055 Saint-Étienne Cedex 2 France
| | - Marie Charlotte Tetard
- Department of Neuro Surgery, University Hospital of Saint Etienne Hôpital Nord 42055 Saint-Étienne Cedex 2 France
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Mulvaney G, Sowah MN, DeCarlo R, Drossopoulos P, Holland CM, Bohl MA. Biomechanical Analysis of Pedicle Screw Reinsertion Along the Same Trajectory in a Validated 3D-Printed Synthetic Bone Model. World Neurosurg 2024:S1878-8750(24)01342-1. [PMID: 39103047 DOI: 10.1016/j.wneu.2024.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 08/07/2024]
Abstract
OBJECTIVE To investigate the biomechanical properties of pedicle screw reinsertion along the same trajectory in a previously validated synthetic bone model. METHODS Twenty identical acrylonitrile butadiene styrene models of lumbar vertebrae were three-dimensional-printed. Screws were placed in the standard fashion into each pedicle. Models were separated into 2 equal groups, control and experimental. Experimental group screws were completely removed from their testing block and reinserted once. All screws in both groups were then forcibly removed. Continuous torque monitoring was collected on screw insertion torque (IT), removal torque, and reinsertion torque. Pullout strength (PO), screw stiffness (STI), and strain energy (STR) were calculated. RESULTS There was no significant difference between control and experimental groups for PO (P = 0.26), STI (P = 0.55), STR (P = 0.50), or IT (P = 0.24). There was a significant decrease in reinsertion torque (54.5 N-cm ± 8.2 N-cm) from control IT (62.9 N-cm ± 8.4 N-cm, P = 0.045) and experimental IT (67.5 N-cm ± 7.6 N-cm, P = 0.0026). Strong correlations (Pearson's r > 0.80) were seen between control IT against STR and PO, between each of the experimental torque measurements, and between experimental PO and STI. CONCLUSIONS Despite a significant decrease in insertion torque, there is no significant loss of pedicle screw performance when a screw is removed and reinserted along the same trajectory.
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Affiliation(s)
- Graham Mulvaney
- Department of Neurosurgery, Atrium Health Carolinas Medical Center, Charlotte, North Carolina, USA.
| | - Mareshah N Sowah
- University of South Carolina School of Medicine Greenville, Greenville, South Carolina, USA
| | - Rebecca DeCarlo
- Department of Neurosurgery, Atrium Health Carolinas Medical Center, Charlotte, North Carolina, USA
| | - Peter Drossopoulos
- University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | | | - Michael A Bohl
- Carolina Neurosurgery and Spine Associates, Charlotte, North Carolina, USA
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Kernich N, Heck VJ, Ott N, Prescher A, Eysel P, Vinas-Rios JM. Technical aspects of rod-insertion forceps (persuader) application in reducing construct failure after lumbar spine fusion surgery: a biomechanical cadaveric study in Germany. Asian Spine J 2024; 18:493-499. [PMID: 39113480 PMCID: PMC11366558 DOI: 10.31616/asj.2024.0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 09/03/2024] Open
Abstract
STUDY DESIGN A prospective experimental study. PURPOSE This biomechanical in vitro study aimed to examine the extent to which the use of a rod persuader (RP) leads to additional mechanical stress on the screw-rod system and determine its influence on the bony anchoring of primary pedicle screws. OVERVIEW OF LITERATURE Degenerative spine diseases and deformities are the most common indications for the stabilization and fusion of spinal segments. The pedicle screw-rod system is considered the gold standard for dorsal stabilization, and an RP is also increasingly being considered to fit the spondylodesis material. METHODS Ten lumbar spines from body donors were examined. Bisegmental dorsal spinal lumbar interbody fusion of the L3-L5 segments was performed using a pedicle screw-rod system (ROCCIA Multi-LIF Cage; Silony Medical, Germany). In group 1, the titanium rod was inserted without tension, whereas in group 2, the rod was attached to the pedicle screws at the L4 and L5 levels, creating a 5-mm gap. To attach the rod, the RP was used to press the rod into the pedicle screw. The rod was left in place for 30 minutes and then removed. RESULTS The rod reduction technique significantly increased the mechanical load on the overall construct measured by strain gauges (p<0.05) and resulted in outright implant failure with pedicle screw pullout in 88.9%. CONCLUSIONS In cases where the spondylodesis material is not fully attached within the pedicle screw, an RP can be used with extreme caution, particularly in osteoporotic bones, to avoid pedicle screw avulsion and screw anchor failure.
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Affiliation(s)
- Nikolaus Kernich
- Department of Orthopaedics and Traumatology, University of Cologne Faculty of Medicine, Cologne,
Germany
| | - Vincent J. Heck
- Department of Orthopaedics and Traumatology, University of Cologne Faculty of Medicine, Cologne,
Germany
- Department of Spine Surgery, Sana Klinikum Offenbach, Offenbach am Main,
Germany
| | - Nadine Ott
- Department of Orthopaedics and Traumatology, University of Cologne Faculty of Medicine, Cologne,
Germany
| | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy (MOCA), Aachen,
Germany
| | - Peer Eysel
- Department of Orthopaedics and Traumatology, University of Cologne Faculty of Medicine, Cologne,
Germany
| | - Juan Manuel Vinas-Rios
- Department of Orthopaedics and Traumatology, University of Cologne Faculty of Medicine, Cologne,
Germany
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Wang D, Chen X, Han D, Wang W, Kong C, Lu S. Radiographic and surgery-related predictive factors for increased segmental lumbar lordosis following lumbar fusion surgery in patients with degenerative lumbar spondylolisthesis. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2024; 33:2813-2823. [PMID: 38637404 DOI: 10.1007/s00586-024-08248-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/04/2024] [Accepted: 03/28/2024] [Indexed: 04/20/2024]
Abstract
OBJECTIVE This study aimed to evaluate preoperative (pre-op) radiographic characteristics and specific surgical interventions in patients with degenerative lumbar spondylolisthesis (DLS) who underwent lumbar fusion surgery (LFS), with a focus on analyzing predictors of postoperative restoration of segmental lumbar lordosis (SLL). METHODS A retrospective review at a single center identified consecutive single-level DLS patients who underwent LFS between 2016 and 2022. Radiographic measures included disc angle (DA), SLL, lumbar lordosis (LL), anterior/posterior disc height (ADH/PDH), spondylolisthesis percentage (SP), intervertebral disc degeneration, and paraspinal muscle quality. Surgery-related measures included cage position, screw insertion depth, spondylolisthesis reduction rate, and disc height restoration rate. A change in SLL ≥ 4° indicated increased segmental lumbar lordosis (ISLL), and unincreased segmental lumbar lordosis (UISLL) < 4°. Propensity score matching was employed for a 1:1 match between ISLL and UISLL patients based on age, gender, body mass index, smoking status, and osteoporosis condition. RESULTS A total of 192 patients with an average follow-up of 20.9 months were enrolled. Compared to UISLL patients, ISLL patients had significantly lower pre-op DA (6.78° vs. 11.84°), SLL (10.73° vs. 18.24°), LL (42.59° vs. 45.75°), and ADH (10.09 mm vs. 12.21 mm) (all, P < 0.05). ISLL patients were predisposed to more severe intervertebral disc degeneration (P = 0.047) and higher SP (21.30% vs. 19.39%, P = 0.019). The cage was positioned more anteriorly in ISLL patients (67.00% vs. 60.08%, P = 0.000), with more extensive reduction of spondylolisthesis (- 73.70% vs. - 56.16%, P = 0.000) and higher restoration of ADH (33.34% vs. 8.11%, P = 0.000). Multivariate regression showed that lower pre-op SLL (OR 0.750, P = 0.000), more anterior cage position (OR 1.269, P = 0.000), and a greater spondylolisthesis reduction rate (OR 0.965, P = 0.000) significantly impacted SLL restoration. CONCLUSIONS Pre-op SLL, cage position, and spondylolisthesis reduction rate were identified as significant predictors of SLL restoration after LFS for DLS. Surgeons are advised to meticulously select patients based on pre-op SLL and strive to position the cage more anteriorly while minimizing spondylolisthesis to maximize SLL restoration.
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Affiliation(s)
- Dongfan Wang
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China
| | - Xiaolong Chen
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China
| | - Di Han
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China
| | - Wei Wang
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China
| | - Chao Kong
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China
| | - Shibao Lu
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University, No.45 Changchun Street, Xicheng District, Beijing, China.
- National Center for Clinical Research on Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China.
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Çelik T, Taş ZC. Biomechanical Evaluation of a Newly Developed Functional-Grade Composite Material for Pedicle Screws. World Neurosurg 2024; 187:e525-e533. [PMID: 38677644 DOI: 10.1016/j.wneu.2024.04.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024]
Abstract
OBJECTIVE Pedicle screw and rod systems are widely employed in spine surgeries and loosening due to insufficient mechanical stimulation on the bone is frequently encountered in pedicle screws. This mechanical stimulation problem also arises due to the high rigidity of the implant material. This study aimed to develop new pedicle screws with composite material to solve the pedicle screw loosening problem. METHODS The vertebrae and vertebral disk were modeled in three dimension using computerized tomography images obtained from a patient. A commercially available pedicle screw was modeled using Fusion software, and all models were assembled in accordance with the surgical procedure. Pedicle screw models were also divided radially and longitudinally to resemble functionally graded materials, which are composite materials. The load was applied to the top of the T12 vertebra and the screw-vertebral system was fixed to the bottom of the L1 vertebra. RESULTS The strain results on the vertebrae were examined according to the mechanostat theorem. According to the results, functionally graded material (FGM) pedicle screw decreased the strain on the vertebral bones, and the positive effects on the bone were determined when using the radially functionally graded screws. The maximum stress values were also examined to determine the strengths of all the models. CONCLUSION In conclusion, FGM pedicle screw decreased the strain on the bone which is an important parameter for the loosening failure according to the study. The other important conclusion is that FGM pedicle screw can be the solution to the loosening of the screw but not in all vertebrae.
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Affiliation(s)
- Talip Çelik
- Faculty of Technology, Biomedical Engineering Department, Kocaeli University, Kocaeli, Turkey.
| | - Zeliha Coşkun Taş
- Faculty of Technology, Biomedical Engineering Department, Kocaeli University, Kocaeli, Turkey
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Zhan X, Gao F, Yang Y, Tsai T, Wan Z, Yu Y. Effect of Insertional Direction of Pedicle Screw on Screw Loosening: A Biomechanical Study on Synthetic Bone Vertebra under a Physiology-like Load. Orthop Surg 2024; 16:1461-1472. [PMID: 38714346 PMCID: PMC11144517 DOI: 10.1111/os.14080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/06/2024] [Accepted: 04/09/2024] [Indexed: 05/09/2024] Open
Abstract
OBJECTIVES It is now understood that pedicle screw loosening at the implant-bone interface can lead to poor screw-bone interface purchase and decreased fixation stability. Previous biomechanical tests used cadaveric vertebrae and pull-out or torque loads to assess the effect of the insertional direction of pedicle screws on screw loosening. However, these tests faced challenges in matching biomechanical differences among specimens and simulating in vivo loads applied on pedicle screws. This study aimed to evaluate the effect of the insertional direction of pedicle screws on screw loosening using tension-compression-bending loads and synthetic bone vertebrae. METHODS Polyaxial pedicle screws were inserted into nine synthetic bone vertebrae in three directions (three samples per group): cranial, parallel, and caudad (-10°, 0°, +10° of the pedicle screw rod to the upper plane of the vertebra, respectively). Pedicle screws in the vertebrae were loaded using a polyethylene block connected to a material testing machine. Tension-compression-bending loads (100N-250N) with 30,000 cycles were applied to the pedicle screws, and displacements were recorded and then cycle-displacement curve was drawn based on cycle number. Micro-CT scans were performed on the vertebrae after removing the pedicle screws to obtain images of the screw hole, and the screw hole volume was measured using imaging analysis software. Direct comparison of displacements was conducted via cycle-displacement curve. Screw hole volume was analyzed using analysis of variance. The correlation between the displacement, screw hole volume and the direction of pedicle screw was assessed by Spearman correlation analysis. RESULTS The smallest displacements were observed in the caudad group, followed by the parallel and cranial groups. The caudad group had the smallest screw hole volume (p < 0.001 and p = 0.009 compared to the cranial and parallel groups, respectively), while the volume in the parallel group was greater than that in the cranial group (p = 0.003). Correlation analysis revealed that the insertional direction of the pedicle screw was associated with the displacement (p = -0.949, p < 0.001) and screw hole volume (p = -0.944, p < 0.001). CONCLUSION Strong correlations were found between the insertional direction of the pedicle screw and relevant parameters, including displacement and screw hole volume. Pedicle screw insertion in the caudad direction resulted in the least pedicle screw loosening.
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Affiliation(s)
- Xuqiang Zhan
- Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
| | - Feng Gao
- Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Yuyao Maternity and Child Health Care Hospital (Yuyao Second People's Hospital)ZhejiangChina
| | - Yangyang Yang
- School of Biomedical Engineering & Med‐X Research Institute, Shanghai Jiao Tong UniversityShanghaiChina
| | - Tsung‐Yuan Tsai
- School of Biomedical Engineering & Med‐X Research Institute, Shanghai Jiao Tong UniversityShanghaiChina
| | - Zongmiao Wan
- The First Affiliated Hospital of NanChang UniversityNanchangChina
| | - Yan Yu
- Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Spine SurgeryTongji Hospital, School of Medicine, Tongji UniversityShanghaiChina
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Grabala P, Kowalski P, Grabala M. The Influence of Increased Pedicle Screw Diameter and Thicker Rods on Surgical Results in Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis. J Clin Med 2024; 13:2174. [PMID: 38673447 PMCID: PMC11051082 DOI: 10.3390/jcm13082174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/06/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Background: Modern surgical techniques allow for the correction of spinal deformity, stopping its progression and improving pain relief and social and physical functioning. These instruments have different implant designs, screws, and rod diameters and can be composed of different metal alloys with different hardnesses, which can have a significant impact on the effect of correcting spinal deformities. We designed a retrospective cohort study based on the same surgical technique and spine system using different implant sizes, and compared the results across them. Methods: This is a retrospective review of adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF) between 2016 and 2022 with a minimum two-year follow-up (FU) using two spinal implant systems: 5.5 and 6.0 mm diameter screws with double 5.5 mm titanium rods (Group 1 (G1)), and 6.0 and 6.5 mm diameter pedicle screws with double 6.0 mm cobalt-chromium rods (Group 2 (G2)). The evaluated data were as follows: preoperative personal data, radiographic outcomes, complications, and health-related quality of life questionnaire (HRQoL). The parameters were reviewed preoperatively, after the final fusion, and during the FU. Results: The mean age of all 260 patients at surgery was 14.8 years. The average BMI was also similar in both groups and was noted as 21. The mean levels of fusion and screw density were similar in both groups. The mean preoperative major curves (MCs) were 57.6° and 62.5° in G1 and G2, respectively. The mean flexibility of the curves was noted as 35% in G1 and 33% in G2. After definitive surgery, the mean percentage correction of the MC was better in G2 vs. G1, with 74.5% vs. 69.8%, respectively (p < 0.001). At the final FU, the average loss of correction was 5.9° for G1 and 3.2° for G2 (p < 0.001). The mean preoperative (TK) thoracic kyphosis (T2-T5) was 12.2° in G1 and 10.8° in G2. It was corrected to 15.2° in G1 and to 13° in G2. At the FFU, we noted a significant difference in the TK (T2-T5) between the groups, with 16.7° vs. 9.6° for G1 vs. G2, respectively (p < 0.001). Statistical significance was observed between the preoperative sagittal balance and the final follow-up for both groups (p < 0.001). Conclusions: AIS patients surgically treated with screws with a larger diameter and thicker and stiffer rods showed greater correction and postoperative thoracic kyphosis without implant failure. The complication rates, implant density, and clinical outcomes remained similar. The radiographic benefits reported in this cohort study suggest that large-sized screws and stiffer rods for the correction of pediatric spinal deformities are safe and very effective.
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Affiliation(s)
- Pawel Grabala
- Department of Pediatric Orthopedic Surgery and Traumatology, Medical University of Bialystok and Medical University of Bialystok Children’s Clinical Hospital, ul. Waszyngtona 17, 15-274 Bialystok, Poland
- Paley European Institute, Al. Rzeczypospolitej 1, 02-972 Warsaw, Poland
- Department of Neurosurgery with Department of Interventional Neurology, Medical University of Bialystok and Medical University of Bialystok Clinical Hospital, ul. M. Sklodowskiej-Curie 24A, 15-276 Bialystok, Poland
| | - Piotr Kowalski
- Department of Neurosurgery, Regional Specialized Hospital, ul. Dekerta 1, 66-400 Gorzow, Poland;
| | - Michal Grabala
- 2nd Clinical Department of General and Gastroenterogical Surgery, Medical University of Bialystok and Medical University of Bialystok Clinical Hospital, ul. M. Skłodowskiej-Curie 24A, 15-276 Bialystok, Poland;
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Bennie S, Crowley JD, Wang T, Pelletier MH, Walsh WR. Pedicle screw pull-out testing in polyurethane foam blocks: Effect of block orientation and density. Proc Inst Mech Eng H 2024; 238:455-460. [PMID: 38480483 DOI: 10.1177/09544119241236873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Synthetic bone models such as polyurethane (PU) foam are a well-established substitute to cadaveric bone for screw pull-out testing; however, little attention has been given to the effect of PU foam anisotropy on orthopaedic implant testing. Compressive and screw pull-out performance in three PU foam densities; 0.16 g/cm3 (PCF 10), 0.32 g/cm3 (PCF 20) and 0.64 g/cm3 (PCF 40) were performed in each of the X, Y or Z orientations. The maximum compressive force, stiffness in the linear region, maximum stress and modulus were determined for all compression tests. Pedicle screws were inserted and pulled out axially to determine maximum pull-out force, energy to failure and stiffness. One-way ANOVA and post hoc tests were used to compare outcome variables between PU foam densities and orientations, respectively. Compression tests demonstrated the maximum force was significantly different between all orientations for PCF 20 (X, Y and Z) while stiffness and maximum stress were different between X versus Y and X versus Z. Maximum pull-out force was significantly different between all orientations for PCF 10 foam. No significant differences were noted for other foam densities. There is potential for screw pull-out testing results to be significantly affected by orientation in lower density PU foams. It is recommended that a single, known orientation of the PU foam block be used for experimental testing.
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Affiliation(s)
- Stephen Bennie
- Surgical & Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - James Douglas Crowley
- Surgical & Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - Tian Wang
- Surgical & Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - Matthew Henry Pelletier
- Surgical & Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - William Robert Walsh
- Surgical & Orthopaedic Research Laboratories (SORL), Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
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Matsukawa K, Konomi T, Matsubayashi K, Yamane J, Yato Y. Influence of Pedicle Screw Insertion Depth on Posterior Lumbar Interbody Fusion: Radiological Significance of Deeper Screw Placement. Global Spine J 2024; 14:470-477. [PMID: 35713986 PMCID: PMC10802553 DOI: 10.1177/21925682221110142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
STUDY DESIGN Retrospective case series. OBJECTIVES To investigate the influence of screw size on achieving bone fusion in posterior lumbar interbody fusion (PLIF). METHODS In total, 137 consecutive patients with L4 degenerative spondylolisthesis who underwent single-level PLIF at L4-L5 were evaluated. Factors investigated for their contribution to bone fusion included: 1) age, 2) sex, 3) body mass index, 4) bone mineral density, 5) intervertebral mobility, 6) screw diameter, 7) screw length, 8) screw fitness in the pedicle (%fill), 9) screw depth in the vertebra (%depth), 10) screw angle, 11) facetectomy, 12) crosslink connector, and 13) cage material. RESULTS Bone fusion was confirmed in 88.2% of patients. The comparison between fusion (+) and fusion (-) groups showed no significant differences in screw size. The %fill and %length were significantly greater in the fusion (+) group than in the fusion (-) group (%fill: 58.5% ± 7.5% vs 52.3% ± 7.3%, respectively, P = .005; %depth: 59.8% ± 9.7% vs 50.3% ± 13.8%, respectively, P = .025). Multivariate logistic regression analysis revealed that %fill (odds ratio [OR]= 1.11, P = .025) and %depth (OR = 1.09, P = .003) were significant independent factors affecting bone fusion. Receiver operating characteristic curve analyses identified a %fill of 60.0% and a %depth of 54.2% as optimal cutoff values for achieving bone fusion. CONCLUSIONS Screw size should be determined based on the screw fitness in the pedicle (%fill > 60%) and screw insertion depth in the vertebral body (%depth > 54.2%) according to individual vertebral anatomy in L4-L5 PLIF.
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Affiliation(s)
- Keitaro Matsukawa
- Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Japan
| | - Tsunehiko Konomi
- Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Japan
| | - Kohei Matsubayashi
- Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Japan
| | - Junichi Yamane
- Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Japan
| | - Yoshiyuki Yato
- Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Musashimurayama, Japan
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11
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Kojima K, Asamoto S, Hori T, Endo T, Fukui Y. Lateral Mass Intrapedicular Screw Fixation for Subaxial Cervical Spines: A Short- to Medium-Term Retrospective Follow-Up Study of 20 Cases. J Neurol Surg A Cent Eur Neurosurg 2024; 85:132-136. [PMID: 37127040 DOI: 10.1055/s-0043-1767723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND Lateral mass intrapedicular screw(LMIS) fixation was introduced in 2021 as an alternative method for the fixation of subaxial cervical spines for the treatment of various cervical spine disease. The objective of this study is to provide a short- to medium-term result of the 20 patients who underwent cervical spine fixation using LMIS. METHODS Twenty patients with varying cervical spine pathology who underwent cervical spine fixation using LMIS in a 21-month period were included in the study. Postoperative computed tomography (CT) imaging was used to evaluate the screw placement. RESULTS A total of 105 screws were used. The average screw size used was 3.5 × 14 mm. The average screw angle in the axial plane was 18 degrees. Five screws had breached the inner cortex of the vertebral canal. None of the patients had any postsurgical neurologic deficit. Fifteen screws did not reach the pedicle. Intraoperative fixation was excellent and no screw showed signs of loosening in the subsequent follow-up imaging. CONCLUSION LMIS is a good alternative to the commonly used methods for subaxial cervical spine fixation and is worth considering in many patients.
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Affiliation(s)
- Kota Kojima
- Department of Spine and Spinal Cord Surgery, Makita General Hospital, Tokyo, Japan
| | - Shunji Asamoto
- Department of Spine and Spinal Cord Surgery, Makita General Hospital, Tokyo, Japan
| | - Takahiro Hori
- Department of Neurosurgery, Makita General Hospital, Tokyo, Japan
| | - Takahiro Endo
- Department of Spine and Spinal Cord Surgery, Makita General Hospital, Tokyo, Japan
| | - Yasuyuki Fukui
- Department of Spine and Spinal Cord Surgery, Makita General Hospital, Tokyo, Japan
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12
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Oberthür S, Roch PJ, Klockner F, Jäckle KB, Viezens L, Lehmann W, Sehmisch S, Weiser L. Can You Feel it? - Correlation Between Intraoperatively Perceived Bone Quality and Objectively Measured Bone Mineral Density. Global Spine J 2024; 14:631-638. [PMID: 35993490 PMCID: PMC10802517 DOI: 10.1177/21925682221120398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
STUDY DESIGN clinical study. OBJECTIVES Loosening of pedicle screws is a frequent complication in patients with osteoporosis. The indication for additional stabilization, such as cement augmentation, is more often based on the subjective intraoperative feeling of the surgeon than on a preoperative bone mineral density (BMD) measurement. Aim was to evaluate the correlation of the intraoperative perceived bone quality in comparison to the objectively measured BMD. METHODS A total of 62 patients undergoing dorsal stabilization using pedicle screws at a level-1 trauma center were analyzed. The preoperative CT scan measured each instrumented vertebra's pedicle size and BMD. During the surgery, the perceived screw stability was graded by the respective surgeon for each screw. RESULTS 204 vertebral bodies were evaluated. Looking at all implanted screws a significant correlation between the measured BMD and the perceived screw stability was found (Resident r = .450; R2 = .202; P < .001/Attending r = .364; R2 = .133; P < .001), but there was no significant correlation in the osteoporotic patients (Resident P = .148 / Attending P = .907). The evaluation of the screws implanted in osteoporotic vertebrae showed that the surgeons considered a total of 31% of these screws to be sufficiently stable. CONCLUSIONS There was no significant correlation between the measured BMD and the perceived pedicle screw stability in the group with osteopenic / osteoporotic bone (<100 mg/cm³). The results indicate that it is not possible to reliably determine the bone quality and the resulting screw stability in patients with reduced BMD. The preoperative measurement of the BMD should become a crucial part of preoperative planning.
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Affiliation(s)
- Swantje Oberthür
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
- Department of Trauma Surgery, Medical School Hannover, Hannover, Germany
| | - Paul Jonathan Roch
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Friederike Klockner
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Katharina Blanka Jäckle
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Lennart Viezens
- Department of Trauma and Orthopaedic Surgery, Division of Spine Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wolfgang Lehmann
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Stephan Sehmisch
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
- Department of Trauma Surgery, Medical School Hannover, Hannover, Germany
| | - Lukas Weiser
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
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13
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Hwang CJ, Lee JY, Lee DH, Cho JH, Lee CS, Lee MY, Yoon SJ. Novel Screw Placement Method for Extremely Small Lumbar Pedicles in Scoliosis. J Clin Med 2024; 13:1115. [PMID: 38398428 PMCID: PMC10888630 DOI: 10.3390/jcm13041115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/23/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Study Design: Consecutive case series. Objective: To propose a screw placement method in patients with extremely small lumbar pedicles (ESLPs) (<2 mm) to maintain screw density and correction power, without relying on the O-arm navigation system. Summary of Background Data: In scoliosis surgery, ESLPs can hinder probe passage, resulting in exclusion or substitution of the pedicle screws with a hook. Screw density affects correction power, making it necessary to maximize the number of screw placements, especially in the lumbar curve. Limited studies provide technical guidelines for screw placement in patients with ESLPs, independent of the O-arm navigation system. Methods: We enrolled 19 patients who underwent scoliosis correction surgery using our novel screw placement method for ESLPs. Clinical, radiological, and surgical parameters were assessed. After posterior exposure of the spine, the C-arm fluoroscope was rotated to obtain a true posterior-anterior view and both pedicles were symmetrically visualized. An imaginary pedicle outline was presumed based on the elliptical or linear shadow from the pedicle. The screw entry point was established at a 2 (or 10) o'clock position in the presumed pedicle outline. After adjusting the gear-shift convergence, both cortices of the transverse process were penetrated and the tip was advanced towards the lateral vertebral body wall, where an extrapedicular screw was placed with tricortical fixation. Results: Out of 90 lumbar screws in 19 patients, 33 screws were inserted using our novel method, without correction loss or complications during an average follow-up period of 28.44 months, except radiological loosening of one screw. Conclusions: Our new extrapedicular screw placement method into the vertebral body provides an easy, accurate, and safe alternative for scoliosis patients with ESLPs without relying on the O-arm navigation system. Surgeons must consider utilizing this method to enhance correction power in scoliosis surgery, regardless of the small size of the lumbar pedicle.
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Affiliation(s)
- Chang-Ju Hwang
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
| | - Joo-Young Lee
- Department of Orthopedic Surgery, Dong-A Medical Center, University of Dong-A College of Medicine, Busan 49201, Republic of Korea
| | - Dong-Ho Lee
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
| | - Jae-Hwan Cho
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
| | - Choon-Sung Lee
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
| | - Mi-Young Lee
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
| | - So-Jung Yoon
- Department of Orthopedic Surgery, Scoliosis Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea (J.-H.C.)
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14
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Boucas P, Mamdouhi T, Rizzo SE, Megas A. Cement Augmentation of Pedicle Screw Instrumentation: A Literature Review. Asian Spine J 2023; 17:939-948. [PMID: 37788974 PMCID: PMC10622820 DOI: 10.31616/asj.2022.0216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 10/05/2023] Open
Abstract
This literature review aimed to review the current understanding, indications, and limitations of pedicle screw instrumentation cement augmentation. Since they were first reported in the 1980s, pedicle screw cement augmentation rates have been increasing. Several studies have been published to date that describe various surgical techniques and the biomechanical changes that occur when cement is introduced through the screw-bone interface. This article provides a concise review of the uses, biomechanical properties, cost analysis, complications, and surgical techniques used for pedicle screw cement augmentation to help guide physician practices. A comprehensive review of the current literature was conducted, with key studies, and contributions from throughout history being highlighted. Patients with low bone mineral density are the most well-studied indication for pedicle screw cement augmentation. Many studies show that cement augmentation can improve pullout strength in patients with low bone mineral density; however, the benefit varies inversely with pathology severity and directly with technique. The various screw types are discussed, with each having its own mechanical advantages. Cement distribution is largely dependent on the filling method and volume of cement used. Cement composition and timing of cement use after mixing are critical considerations in practice because they can significantly alter the bone-cement and screw-cement interfaces. Overall, studies have shown that pedicle screw cement augmentation has a low complication rate and increased pullout strength, justifying its universal use in patients with a suboptimal bone-implant interface.
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Affiliation(s)
- Peter Boucas
- Department of Orthopaedic Surgery, Huntington Hospital Northwell Health, Huntington, NY,
USA
- Department of Orthopaedic Surgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY,
USA
| | - Tania Mamdouhi
- Department of Orthopaedic Surgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY,
USA
| | - Sarah E. Rizzo
- Department of Orthopaedic Surgery, Huntington Hospital Northwell Health, Huntington, NY,
USA
- Department of Orthopaedic Surgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY,
USA
| | - Andrew Megas
- Department of Orthopaedic Surgery, Grewal Orthopaedic and Spine Care, East Meadow, NY,
USA
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Gao S, Hu Y, Mamat F, Liang W, Mamat M, Xun C, Zhang J, Sheng W. Application of cement-augmented pedicle screws in elderly patients with spinal tuberculosis and severe osteoporosis: a preliminary study. J Orthop Surg Res 2023; 18:624. [PMID: 37626361 PMCID: PMC10463792 DOI: 10.1186/s13018-023-04099-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
OBJECTIVE Surgical management of elderly patients with spinal tuberculosis and severe osteoporosis is challenging. Cement-augmented pedicle screws (CAPS) have been specifically designed for elderly patients with osteoporotic spines. Herein, we investigated the feasibility of CAPS applied in elderly patients with spinal tuberculosis and severe osteoporosis. METHODS We retrospectively analyzed data of patients with spinal tuberculosis and severe osteoporosis between January 2017 and January 2021. Surgical data, including surgical duration and intraoperative blood loss, were recorded. Radiological parameters, such as correction of regional kyphotic angle and screw loosening, were also evaluated. Additionally, visual analog scores (VAS) and Oswestry disability index (ODI) were used to evaluate back pain and functional recovery, respectively. Erythrocyte sedimentation (ESR) and C-reactive protein (CRP) concentrations were detected to assess tuberculosis activity. The presence of complications and fusion rate was also assessed. RESULTS A total of 15 patients were included in this study. The surgical duration was 263.0 ± 56.2 min, with an average blood loss of 378.7 ± 237.0 ml. The correction of regional kyphotic angle was 12.4° ± 15.0°, and it was well maintained until the final follow-up. The mean VAS decreased from 6.0 ± 1.2 points to 0.5 ± 0.6 points, and ODI reduced from 37.8% ± 7.6% to 8.3% ± 2.8% (P < 0.01). At the final follow-up, ESR and CRP levels were within normal range. Bony fusion occurred in all patients, with an average fusion duration of 8.8 ± 1.5 months. No cases of pedicle screw pullout, screw loosening, or pseudoarthrosis occurred. Tuberculosis recurrence and dissemination were not observed during the follow-ups. CONCLUSIONS CAPS fixation is an effective and safe technique to achieve solid fixation and favorable clinical outcomes in elderly patients with spinal tuberculosis and severe osteoporosis.
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Affiliation(s)
- Shutao Gao
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Yukun Hu
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Fulati Mamat
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Weidong Liang
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Mardan Mamat
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Chuanhui Xun
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Jian Zhang
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
| | - Weibin Sheng
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan Avenue, Xinshi District, Ürümqi, 830054 Xinjiang China
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Grabala P, Helenius IJ, Grabala M, Shah SA. Influences of Increasing Pedicle Screw Diameter on Widening Vertebral Pedicle Size during Surgery in Spinal Deformities in Children and Adolescents without Higher Risk of Pedicle and Vertebral Breaches. J Clin Med 2023; 12:5368. [PMID: 37629410 PMCID: PMC10455094 DOI: 10.3390/jcm12165368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND A very common technique for treating spinal deformities in children and adolescents is the use of segmental screws. In order to obtain proper stability and the best possible correction, the screws must first be precisely inserted. Additional factors influencing the quality and success of the operation are the size and quality of the bone, the skills of the surgeon, and biomechanical factors, i.e., the width and length of the screws used during surgery. Our study was focused on evaluating the effect of increasing the diameter of the instrumented pedicles by pedicle screws and assessing the safety of expanding these pedicles with screws of various sizes in children with spinal deformities during the growth period, using preoperative magnetic resonance imaging and postoperative computed tomography (CT) to assess and compare preoperative size measurements from MRI to postoperative CT measurements. METHODS We obtained data for evaluation from the available medical records and treatment histories of patients aged 2 to 18 who underwent surgical treatment of spinal deformities in the years 2016-2023. In 230 patients (28 male and 202 female), 7954 vertebral bodies were scanned by preoperative MRI, and 5080 pedicle screws were inserted during surgery, which were then assessed by postoperative CT scan. For the most accurate assessment, patients were classified into three age groups: 2-5 years (Group 1), 6-10 years (Group 2), and 11-18 years (Group 3). In addition, we studied implant subgroups: vertebral bodies with inserted pedicles of screw sizes 5.0 mm and 5.5 mm (Group S), and pedicles of screw sizes 6.0 mm, 6.5 mm, and 7.0 mm (Group L). RESULTS The morphology of pedicles (Lenke classification) analyzed before surgery using MRI was 55.2% type A, 33.8% type B, 4.7% type C, and 6.3% type D. The postoperative lateral and medial breaches were noted, and these did not cause any complications requiring revision surgery. The mean pedicle diameter before surgery for T1-L5 vertebral pedicles was between 3.79 (1.44) mm and 5.68 (1.64) mm. The mean expanding diameter of pedicles after surgery for T1-L5 vertebral pedicles ranged from 1.90 (0.39) mm to 2.92 (0.28) mm, which corresponds to the extension of the pedicle diameter in the mean range of 47% (4.1)-71% (3.0). We noted that the mean vertebral pedicle expansion was 49% in Group 1, 52% in Group 2, and 62% in Group 3 (N.S.), and the mean expansion for 7.0 mm screw pedicles was 78%. CONCLUSIONS Our study confirms that there is a wide range of expansion of the vertebral pedicle during screw insertion (up to 78%) with a low risk of lateral or medial breaches and without an increased risk of complications. The larger the diameter of the screw inserted into the pedicle, the more the pedicle expands. Pedicle measurements by preoperative MRI may be helpful for sufficient reliability in preoperative planning.
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Affiliation(s)
- Pawel Grabala
- Department of Pediatric Orthopedic Surgery and Traumatology, University Children’s Hospital, Waszyngtona 17, 15-274 Bialystok, Poland
| | - Ilkka J. Helenius
- Department of Orthopedics and Traumatology, Helsinki University Hospital, 00260 Helsinki, Finland;
| | - Michal Grabala
- 2nd Clinical Department of General and Gastroenterogical Surgery, Medical University of Bialystok, ul. M. Skłodowskiej-Curie 24a, 15-276 Bialystok, Poland;
| | - Suken A. Shah
- Department of Orthopaedic Surgery, Nemours Children’s Health, Delaware Valley, 1600 Rockland Road, Wilmington, DE 19803, USA;
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Costăchescu B, Niculescu AG, Grumezescu AM, Teleanu DM. Screw Osteointegration-Increasing Biomechanical Resistance to Pull-Out Effect. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5582. [PMID: 37629873 PMCID: PMC10456840 DOI: 10.3390/ma16165582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Spinal disorders cover a broad spectrum of pathologies and are among the most prevalent medical conditions. The management of these health issues was noted to be increasingly based on surgical interventions. Spinal fixation devices are often employed to improve surgery outcomes, increasing spinal stability, restoring structural integrity, and ensuring functionality. However, most of the currently used fixation tools are fabricated from materials with very different mechanical properties to native bone that are prone to pull-out effects or fail over time, requiring revision procedures. Solutions to these problems presently exploited in practice include the optimal selection of screw shape and size, modification of insertion trajectory, and utilization of bone cement to reinforce fixation constructs. Nevertheless, none of these methods are without risks and limitations. An alternative option to increasing biomechanical resistance to the pull-out effect is to tackle bone regenerative capacity and focus on screw osteointegration properties. Osteointegration was reportedly enhanced through various optimization strategies, including use of novel materials, surface modification techniques (e.g., application of coatings and topological optimization), and utilization of composites that allow synergistic effects between constituents. In this context, this paper takes a comprehensive path, starting with a brief presentation of spinal fixation devices, moving further to observations on how the pull-out strength can be enhanced with existing methods, and further focusing on techniques for implant osteointegration improvement.
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Affiliation(s)
- Bogdan Costăchescu
- “Gr. T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- “Prof. Dr. N. Oblu” Emergency Clinical Hospital, 700309 Iasi, Romania
| | - Adelina-Gabriela Niculescu
- Research Institute of the University of Bucharest—ICUB, University of Bucharest, 050657 Bucharest, Romania;
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, 011061 Bucharest, Romania
| | - Alexandru Mihai Grumezescu
- Research Institute of the University of Bucharest—ICUB, University of Bucharest, 050657 Bucharest, Romania;
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, 011061 Bucharest, Romania
- Academy of Romanian Scientists, Ilfov No. 3, 050044 Bucharest, Romania
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Kaiser R, Kantorová L, Langaufová A, Slezáková S, Tučková D, Klugar M, Klézl Z, Barsa P, Cienciala J, Hajdúk R, Hrabálek L, Kučera R, Netuka D, Prýmek M, Repko M, Smrčka M, Štulík J. Decompression alone versus decompression with instrumented fusion in the treatment of lumbar degenerative spondylolisthesis: a systematic review and meta-analysis of randomised trials. J Neurol Neurosurg Psychiatry 2023; 94:657-666. [PMID: 36849239 PMCID: PMC10359551 DOI: 10.1136/jnnp-2022-330158] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 01/16/2023] [Indexed: 03/01/2023]
Abstract
OBJECTIVE To determine the efficacy of adding instrumented spinal fusion to decompression to treat degenerative spondylolisthesis (DS). DESIGN Systematic review with meta-analysis. DATA SOURCES MEDLINE, Embase, Emcare, Cochrane Library, CINAHL, Scopus, ProQuest Dissertations & Theses Global, ClinicalTrials.gov and WHO International Clinical Trials Registry Platform from inception to May 2022. ELIGIBILITY CRITERIA FOR STUDY SELECTION Randomised controlled trials (RCTs) comparing decompression with instrumented fusion to decompression alone in patients with DS. Two reviewers independently screened the studies, assessed the risk of bias and extracted data. We provide the Grading of Recommendations, Assessment, Development and Evaluation assessment of the certainty of evidence (COE). RESULTS We identified 4514 records and included four trials with 523 participants. At a 2-year follow-up, adding fusion to decompression likely results in trivial difference in the Oswestry Disability Index (range 0-100, with higher values indicating greater impairment) with mean difference (MD) 0.86 (95% CI -4.53 to 6.26; moderate COE). Similar results were observed for back and leg pain measured on a scale of 0 to 100, with higher values indicating more severe pain. There was a slightly increased improvement in back pain (2-year follow-up) in the group without fusion shown by MD -5·92 points (95% CI -11.00 to -0.84; moderate COE). There was a trivial difference in leg pain between the groups, slightly favouring the one without fusion, with MD -1.25 points (95% CI -6.71 to 4.21; moderate COE). Our findings at 2-year follow-up suggest that omitting fusion may increase the reoperation rate slightly (OR 1.23; 0.70 to 2.17; low COE). CONCLUSIONS Evidence suggests no benefits of adding instrumented fusion to decompression for treating DS. Isolated decompression seems sufficient for most patients. Further RCTs assessing spondylolisthesis stability are needed to determine which patients would benefit from fusion. PROSPERO REGISTRATION NUMBER CRD42022308267.
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Affiliation(s)
- Radek Kaiser
- Department of Neurosurgery and Neurooncology, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Military University Hospital Prague, Prague, Czech Republic
| | - Lucia Kantorová
- Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC: JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Masaryk University Faculty of Medicine, Brno, Czech Republic
- Czech Health Research Council, Prague, Czech Republic
| | - Alena Langaufová
- Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC: JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Masaryk University Faculty of Medicine, Brno, Czech Republic
- Institute of Health Information and Statistics of the Czech Republic, Prague, Czech Republic
| | - Simona Slezáková
- Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC: JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Masaryk University Faculty of Medicine, Brno, Czech Republic
- Institute of Health Information and Statistics of the Czech Republic, Prague, Czech Republic
| | - Dagmar Tučková
- Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC: JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Masaryk University Faculty of Medicine, Brno, Czech Republic
- Czech Health Research Council, Prague, Czech Republic
| | - Miloslav Klugar
- Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC: JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Masaryk University Faculty of Medicine, Brno, Czech Republic
- Institute of Health Information and Statistics of the Czech Republic, Prague, Czech Republic
| | - Zdeněk Klézl
- Department of Spinal Surgery, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Motol University Hospital, Prague, Czech Republic
| | - Pavel Barsa
- Department of Neurosurgery, Regional Hospital Liberec, Liberec, Czech Republic
| | - Jan Cienciala
- Department of Orthopaedic Surgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- University Hospital Brno, Brno, Czech Republic
| | - Richard Hajdúk
- Department of Spinal Surgery, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Motol University Hospital, Prague, Czech Republic
| | - Lumír Hrabálek
- Department of Neurosurgery, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
- University Hospital Olomouc, Olomouc, Czech Republic
| | - Roman Kučera
- Department of Neurosurgery, Na Homolce Hospital, Prague, Czech Republic
| | - David Netuka
- Department of Neurosurgery and Neurooncology, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Military University Hospital Prague, Prague, Czech Republic
| | - Martin Prýmek
- Department of Orthopaedic Surgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- University Hospital Brno, Brno, Czech Republic
| | - Martin Repko
- Department of Orthopaedic Surgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- University Hospital Brno, Brno, Czech Republic
| | - Martin Smrčka
- University Hospital Brno, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jan Štulík
- Department of Spinal Surgery, First Faculty of Medicine, Charles University, Prague, Czech Republic
- Motol University Hospital, Prague, Czech Republic
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19
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Mandelka E, Gierse J, Zimmermann F, Gruetzner PA, Franke J, Vetter SY. Implications of navigation in thoracolumbar pedicle screw placement on screw accuracy and screw diameter/pedicle width ratio. BRAIN & SPINE 2023; 3:101780. [PMID: 38020982 PMCID: PMC10668071 DOI: 10.1016/j.bas.2023.101780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/22/2023] [Accepted: 07/10/2023] [Indexed: 12/01/2023]
Abstract
Introduction There is ample evidence that higher accuracy can be achieved in thoracolumbar pedicle screw placement by using spinal navigation. Still, to date, the evidence regarding the influence of the use of navigation on the screw diameter to pedicle width ratio remains limited. Research question The aim of this study was to investigate the implications of navigation in thoracolumbar pedicle screw placement not only on screw accuracy, but on the screw diameter to pedicle width ratio as well. Material and methods In this single-center single-surgeon study, 45 Patients undergoing navigated thoracolumbar pedicle screw placement were prospectively included. The results were compared with a matched comparison group of patients in which screw placement was performed under fluoroscopic guidance. The screw accuracy and the screw diameter to pedicle width ratio of every screw were compared between the groups. Results Screw accuracy was significantly higher in the navigation group compared to the fluoroscopic guidance group, alongside with a significant increase of the screw diameter to pedicle width ratio by approximately 10%. In addition, both the intraoperative radiation dose and the operating time tended to be lower in the study group. Conclusion This study was able to show that navigated thoracolumbar pedicle screw placement not only increases the accuracy of screw placement but also facilitates the selection of the adequate screw sizes, which according to the literature has positive effects on fixation strength. Meanwhile, the use of navigation did not negatively affect the time needed for surgery or the patient's intraoperative exposure to radiation.
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Affiliation(s)
- Eric Mandelka
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
| | - Jula Gierse
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
| | - Felix Zimmermann
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
| | - Paul A. Gruetzner
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
| | - Jochen Franke
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
| | - Sven Y. Vetter
- Research group Medical Imaging and Navigation in Trauma and Orthopedic Surgery (MINTOS), Department of Orthopedics and Trauma Surgery, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, 67071, Ludwigshafen, Germany
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20
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Wang TY, Tabarestani TQ, Mehta VA, Sankey EW, Karikari IO, Goodwin CR, Than KD, Abd-El-Barr MM. A Comparison of Percutaneous Pedicle Screw Accuracy Between Robotic Navigation and Novel Fluoroscopy-Based Instrument Tracking for Patients Undergoing Instrumented Thoracolumbar Surgery. World Neurosurg 2023; 172:e389-e395. [PMID: 36649859 DOI: 10.1016/j.wneu.2023.01.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
BACKGROUND The accuracy of pedicle screws placed with instrument tracking and robotic navigation are individually comparable or superior to placement using standard fluoroscopy, however head-to-head comparisons between these adjuncts in a similar surgical population have yet to be performed. METHODS Consecutive patients undergoing percutaneous thoracic and lumbosacral spinal instrumentation were retrospectively enrolled. Instrumentation was performed using either fluoroscopy-based instrument tracking system (TrackX, TrackX Technologies) or robotic-navigation (ExcelsiusGPS, Globus Medical). Postinstrumentation computed tomography scans were graded for breach according to the Gertzbein-Robbins scale, with "acceptable" screws deemed as Grade A or B and "unacceptable" screws deemed as Grades C through E. Accuracy data was compared between both instrumentation modalities. RESULTS Fifty-three patients, comprising a total of 250 screws (167 robot, 83 instrument tracking) were included. The overall accuracy between both modalities was similar, with 96.4% and 97.6% of screws with acceptable accuracy between instrument tracking and robotic navigation, respectively (I-squared 0.30, df = 1, P = 0.58). Between instrument tracking and robotic navigation, 92.8% and 95.8% of screws received Grade A, 3.6% and 1.8% a Grade B, 1.2% and 1.2% a Grade C, 1.2% and 0.6% a Grade D, and 1.2% and 0.6% a Grade E, respectively. The robot was abandoned intraoperatively in 2 cases due to unrecoverable registration inaccuracy or software failure, leading to abandonment of 8 potential screws (4.8%). CONCLUSIONS In a similar patient population, there is a similarly high degree of instrumentation accuracy between fluoroscopy-based instrument tracking and robotic navigation. There is a rare chance for screw breach with either surgical adjunct.
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Affiliation(s)
- Timothy Y Wang
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
| | | | - Vikram A Mehta
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
| | - Eric W Sankey
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
| | - Isaac O Karikari
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
| | - C Rory Goodwin
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
| | - Khoi D Than
- Duke University Department of Neurological Surgery, Durham, North Carolina, USA
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21
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Schömig F, Becker L, Schönnagel L, Völker A, Disch AC, Schnake KJ, Pumberger M. Avoiding Spinal Implant Failures in Osteoporotic Patients: A Narrative Review. Global Spine J 2023; 13:52S-58S. [PMID: 37084355 PMCID: PMC10177307 DOI: 10.1177/21925682231159066] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
STUDY DESIGN Narrative review. OBJECTIVES With an aging population, the prevalence of osteoporosis is continuously rising. As osseous integrity is crucial for bony fusion and implant stability, previous studies have shown osteoporosis to be associated with an increased risk for implant failure and higher reoperation rates after spine surgery. Thus, our review's purpose was to provide an update of evidence-based solutions in the surgical treatment of osteoporosis patients. METHODS We summarize the existing literature regarding changes associated with decreased bone mineral density (BMD) and resulting biomechanical implications for the spine as well as multidisciplinary treatment strategies to avoid implant failures in osteoporotic patients. RESULTS Osteoporosis is caused by an uncoupling of the bone remodeling cycle based on an unbalancing of bone resorption and formation and resulting reduced BMD. The reduction in trabecular structure, increased porosity of cancellous bone and decreased cross-linking between trabeculae cause a higher risk of complications after spinal implant-based surgeries. Thus, patients with osteoporosis require special planning considerations, including adequate preoperative evaluation and optimization. Surgical strategies aim towards maximizing screw pull-out strength, toggle resistance, as well as primary and secondary construct stability. CONCLUSIONS As osteoporosis plays a crucial role in the fate of patients undergoing spine surgery, surgeons need to be aware of the specific implications of low BMD. While there still is no consensus on the best course of treatment, multidisciplinary preoperative assessment and adherence to specific surgical principles help reduce the rate of implant-related complications.
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Affiliation(s)
- Friederike Schömig
- Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Luis Becker
- Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lukas Schönnagel
- Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Anna Völker
- Department of Orthopaedic, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany
| | - Alexander C Disch
- University Comprehensive Spine Center, University Center for Orthopedics, Traumatology and Plastic Surgery, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Klaus John Schnake
- Center for Spinal and Scoliosis Surgery, Malteser Waldkrankenhaus St Marien gGmbH, Erlangen, Germany
- Department of Orthopedics and Traumatology, Paracelsus Private Medical University Nuremberg, Nuremberg, Germany
| | - Matthias Pumberger
- Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany
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22
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Chatelain LS, Kourilsky A, Lot G, Rogers A. Airo® navigation versus freehand fluoroscopy technique: A comparative study of accuracy and radiological exposure for thoracolumbar screws placement. Neurochirurgie 2023; 69:101437. [PMID: 36967084 DOI: 10.1016/j.neuchi.2023.101437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 04/14/2023]
Abstract
PURPOSE The aim was to compare the accuracy of freehand fluoroscopy and CT based navigation on thoracolumbar screws placement and their respective effects on radiological exposure to the patient. No previous study directly compared the Airo® navigation system to freehand technique. METHODS In this monocentric retrospective study, 156 consecutive patients who underwent thoracolumbar spine surgery were included. Epidemiological data and surgical indications were noted. Heary classification was used for thoracic screws and Gertzbein-Robbins classification for lumbar screws. Radiological exposure was collected for each surgery. RESULTS A total of 918 screws were implanted. We analyzed 725 lumbar screws (Airo® 287; freehand fluoroscopy 438) and 193 thoracic screws (Airo® 49; freehand fluoroscopy 144). Overall, lumbar screws accuracy (Gertzbein-Robbins grade A and B) was good in both groups (freehand fluoroscopy 91.3%; Airo® 97.6%; P<0.05). We found significantly less Grade B and C in the Airo® group. Thoracic accuracy was also good in both groups (Heary 1 and 2; freehand fluoroscopy 77.8%; Airo® 93.9%), without reaching statistical significance. Radiological exposure was significantly higher in the Airo® group with a mean effective dose of 9.69 mSv versus 0.71mSv for freehand fluoroscopy. CONCLUSION Our study confirmed that the use of Airo® navigation yielded good accuracy. It however exposed the patient to higher radiological exposure compared with freehand fluoroscopy technique. LEVEL OF EVIDENCE Level 3.
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Affiliation(s)
- L S Chatelain
- Fondation Rothschild, Department of Neurosurgery, 25-29, rue Manin, 75019 Paris, France.
| | - A Kourilsky
- Fondation Rothschild, Department of Neurosurgery, 25-29, rue Manin, 75019 Paris, France
| | - G Lot
- Fondation Rothschild, Department of Neurosurgery, 25-29, rue Manin, 75019 Paris, France
| | - A Rogers
- Fondation Rothschild, Department of Neurosurgery, 25-29, rue Manin, 75019 Paris, France; American Hospital of Paris, 55, boulevard du Château, 92200 Neuilly-sur-Seine, France
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23
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K H Ho B, Jackson L, Farsakh A, Kam J, Ball J. The relationship of the posterior iliac interval and the S1 screw trajectory. J Clin Neurosci 2023; 111:32-36. [PMID: 36931065 DOI: 10.1016/j.jocn.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 03/17/2023]
Abstract
INTRODUCTION Surgical fixation is widely practised in the management of spinal deformity. S1 screws are commonly incorporated in lumbosacral fusions and can be performed in both open and percutaneous techniques. However, their entry point is determined by the position of the pedicle as well as the posterior iliac interval (PII), as it creates an impedance for screw angulation. A wider angle screw has the potential to achieve a greater length and thus strength versus a narrow screw angle insertion due to risk of anterior breach. METHODS A retrospective analysis of 50 consecutive patients between July 2018 andDecember 2021 undergoing lumbo-sacral fusion with include S1 screw insertion from a single institution and surgeon. The age, screw angles, and the posterior iliac intervals were measured. RESULTS The patients ranged from age 27 to 83 years old (mean 64.7) with a posterior iliac interval (PII) ranging from 7.76 to 12.62 cm (mean 10.24) and the average S1 screw angle on the right was 76.01 degrees (range 59.37 to 88.48) and on the left 74.37 degrees (range 59.75 to 87.47 degrees). Applying the Pearson Correlation co-efficient, a wider PII correlated with a more angulated screw entry (P < 0.05). CONCLUSION As expected, a wider PPI is significantly associated with a more angulated S1 screw trajectory and may have implication on patient biomechanics in lumbo-sacral fusion constructs.
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Affiliation(s)
- Benjamin K H Ho
- Department of Neurosurgery, Royal North Shore Hospital, New South Wales, Australia
| | - Lachlan Jackson
- Department of Neurosurgery, Royal North Shore Hospital, New South Wales, Australia
| | - Ameen Farsakh
- Department of Neurosurgery, Monash Medical Centre, Victoria, Australia
| | - Jeremy Kam
- Department of Neurosurgery, Monash Medical Centre, Victoria, Australia
| | - Jonathon Ball
- Department of Neurosurgery, Royal North Shore Hospital, New South Wales, Australia
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24
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Hsu FC, Chen CS, Yao YC, Lin HH, Wang ST, Chang MC, Liu CL, Chou PH. Shorter screw lengths in dynamic Dynesys fixation have less screw loosening: From clinical investigation to finite-element analysis. J Chin Med Assoc 2023; 86:330-337. [PMID: 36729417 DOI: 10.1097/jcma.0000000000000864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND The dynamic Dynesys Stabilization System preserves lumbar mobility at instrumented levels. This study investigated the effect of screw length on screw loosening (SL) after dynamic Dynesys fixation and screw displacement during lumbar motion, using clinical investigation and finite-element (FE) analysis. METHODS Clinical data of 50 patients with degenerative spondylolisthesis treated with decompression and Dynesys fixation in 2011 were analyzed retrospectively. Horizontal sliding displacement and vertical displacement of screw tips at L4 were analyzed postoperatively using displacement-controlled FE analysis at the L4-L5 level with screw lengths 45 (long screw), 36 (median screw), and 27 (short screw), and 6.4 mm in diameter, under flexion, extension, lateral bending, and rotation. RESULTS In 13 patients (13/50, 26%), 40 screws (40/266, 15%) were loose at mean follow-up of 101.3 ± 4.4 months. Radiographic SL at 35, 40, 45, and 50 mm were 7.7%, 10.7%, 12.1%, and 37.5%, respectively, regardless of the fixation level ( p = 0.009). FE analysis revealed that the long screw model with corresponding longer lever arm had maximal horizontal sliding displacement under all directions and maximal vertical displacement, except for lateral bending. CONCLUSION Shorter screws in Dynesys fixation may help avoid dynamic SL. Clinically, 50 mm screws showed the greatest SL and median screw screws demonstrated the least displacement biomechanically.
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Affiliation(s)
- Fang-Chi Hsu
- Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Chen-Sheng Chen
- Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Yu-Cheng Yao
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Hsi-Hsien Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Shih-Tien Wang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Ming-Chau Chang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chien-Lin Liu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Po-Hsin Chou
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
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25
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Shiber M, Kimchi G, Knoller N, Harel R. The Evolution of Minimally Invasive Spine Tumor Resection and Stabilization: From K-Wires to Navigated One-Step Screws. J Clin Med 2023; 12:jcm12020536. [PMID: 36675466 PMCID: PMC9865379 DOI: 10.3390/jcm12020536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/03/2023] [Accepted: 01/07/2023] [Indexed: 01/11/2023] Open
Abstract
Minimization of the surgical approaches to spinal extradural metastases resection and stabilization was advocated by the 2012 Oncological Guidelines for Spinal Metastases Management. Minimally invasive approaches to spine oncology surgery (MISS) are continually advancing. This paper will describe the evolution of minimally invasive surgical techniques for the resection of metastatic spinal lesions and stabilization in a single institute. A retrospective analysis of patients who underwent minimally invasive extradural spinal metastases resection during the years 2013-2019 by a single surgeon was performed. Medical records, imaging studies, operative reports, rates of screw misplacement, operative time and estimated blood loss were reviewed. Detailed description of the surgical technique is provided. Of 138 patients operated for extradural spinal tumors during the study years, 19 patients were treated in a minimally invasive approach and met the inclusion criteria for this study. The mortality rate was significantly improved over the years with accordance of improve selection criteria to better prognosis patients. The surgical technique has evolved over the study years from fluoroscopy to intraoperative 3D imaging and navigation guidance and from k-wire screw insertion technique to one-step screws. Minimally invasive spinal tumor surgery is an evolving technique. The adoption of assistive devices such as intraoperative 3D imaging and one-step screw insertion systems was safe and efficient. Oncologic patients may particularly benefit from the minimization of surgical decompression and fusion in light of the frailty of this population and the mitigated postoperative outcomes associated with MIS oncological procedures.
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Affiliation(s)
- Mai Shiber
- Department of Neurological Surgery, Sheba Medical Center, Ramat Gan 52621, Israel
- Sackler Medical School, Tel-Aviv University, Tel Aviv 69978, Israel
- Adelson School of Medicine, Ariel University, Ariel 40700, Israel
| | - Gil Kimchi
- Department of Neurological Surgery, Sheba Medical Center, Ramat Gan 52621, Israel
- Sackler Medical School, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Nachshon Knoller
- Department of Neurological Surgery, Sheba Medical Center, Ramat Gan 52621, Israel
- Sackler Medical School, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Ran Harel
- Department of Neurological Surgery, Sheba Medical Center, Ramat Gan 52621, Israel
- Sackler Medical School, Tel-Aviv University, Tel Aviv 69978, Israel
- Correspondence: ; Tel.: +972-3-5302650
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Butler AJ, Colman MW, Lynch J, Phillips FM. Augmented reality in minimally invasive spine surgery: early efficiency and complications of percutaneous pedicle screw instrumentation. Spine J 2023; 23:27-33. [PMID: 36182070 DOI: 10.1016/j.spinee.2022.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND CONTEXT Augmented reality (AR) employs an optical projection directly onto the user's retina, allowing complex image overlay on the natural visual field. In general, pedicle screw accuracy rates have improved with increasingly use of technology, with navigation-based instrumentation described as accurate in 89%-100% of cases. Emerging AR technology in spine surgery builds upon current spinal navigation to provide 3-dimensional imaging of the spine and powerfully reduce the impact of inherent ergonomic and efficiency difficulties. PURPOSE This publication describes the first known series of in vivo pedicle screws placed percutaneously using AR technology for MIS applications. STUDY DESIGN / SETTING After IRB approval, 3 senior surgeons at 2 institutions contributed cases from June, 2020 - March, 2022. 164 total MIS cases in which AR used for placement of percutaneous pedicle screw instrumentation with spinal navigation were identified prospectively. PATIENT SAMPLE 155 (94.5%) were performed for degenerative pathology, 6 (3.6%) for tumor and 3 (1.8%) for spinal deformity. These cases amounted to a total of 606 pedicle screws; 590 (97.3%) were placed in the lumbar spine, with 16 (2.7%) thoracic screws placed. OUTCOME MEASURES Patient demographics and surgical metrics including total posterior construct time (defined as time elapsed from preincision instrument registration to final screw placement), clinical complications and instrumentation revision rates were recorded in a secure and de-identified database. METHODS The AR system used features a wireless headset with transparent near-eye display which projects intra-operative 3D imaging directly onto the surgeon's retina. After patient positioning, 1 percuntaneous and 1 superficial reference marker are placed. Intra-operative CT data is processed to the headset and integrates into the surgeon's visual field creating a "see-through" 3D effect in addition to 2D standard navigation images. MIS pedicle screw placement is then carried out percutaneously through single line of sight using navigated instruments. RESULTS Time elapsed from registration and percutaneous approach to final screw placement averaged 3 minutes and 54 seconds per screw. Analysis of the learning curve revealed similar surgical times in the early cases compared to the cases performed with more experience with the system. No instrumentation was revised for clinical or radiographic complication at final available follow-up ranging from 6-24 months. A total of 3 screws (0.49%) were replaced intra-operatively. No clinical effects via radiculopathy or neurologic deficit postoperatively were noted. CONCLUSIONS This is the first report of the use of AR for placement of spinal pedicle screws using minimally invasive techniques. This series of 164 cases confirmed efficiency and safety of screw placement with the inherent advantages of AR technologies over legacy enabling technologies.
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Affiliation(s)
- Alexander J Butler
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA.
| | - Matthew W Colman
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | | | - Frank M Phillips
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
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27
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Sanjay D, Bhardwaj JS, Kumar N, Chanda S. Expandable pedicle screw may have better fixation than normal pedicle screw: preclinical investigation on instrumented L4-L5 vertebrae based on various physiological movements. Med Biol Eng Comput 2022; 60:2501-2519. [DOI: 10.1007/s11517-022-02625-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/24/2022] [Indexed: 10/17/2022]
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28
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Song F, Feng W, Yang D, Li G, Iqbal K, Liu Y, Yang H. A Novel Screw Modeling Approach to Study the Effects of Screw Parameters on Pullout Strength. J Biomech Eng 2022; 145:1143328. [PMID: 35864784 DOI: 10.1115/1.4055035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Indexed: 11/08/2022]
Abstract
Screw loosening remains a prominent problem for osteoporotic patients undergoing pedicle screw fixation surgeries and is affected by screw parameters (e.g., diameter, pitch and thread angle). However, the individual and interactive effects of these parameters on screw fixation are not fully understood. Furthermore, current finite element modeling of an threaded screw is less computationally efficient. To address these issues, we (1) explored a novel "simulated threaded screw" approach (virtual threads assigned to the contact elements of a simplified screw) and compared its performance with threaded and simplified screws, and (2) examined with this approach the individual and interactive effects of altering screw diameter (5.5-6.5 mm), pitch (1-2 mm) and half-thread angle (20-30°) on pullout strength of normal vertebrae. Results demonstrated that the "simulated threaded screw" approach equivalently predicted pullout strength compared to the "threaded screw" approach (R2 = 0.99, slope = 1). We further found that the pullout strength was most sensitive to the change in screw diameter, followed by thread angle, pitch and interactions of diameter*pitch or diameter*angle. In conclusion, the "simulated threaded screw" approach can achieve the same predictive capability compared to threaded modeling of the screw. The current findings may serve as useful references for planning of screw parameters, so as to improve the complication of screw loosening.
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Affiliation(s)
- Fei Song
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Wentian Feng
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Dongyue Yang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Guanghui Li
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Kamran Iqbal
- Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Yuxuan Liu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
| | - Haisheng Yang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, 100 Pingleyuan, Chaoyang District, Beijing, 100124, China
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Comparison of Affected-Vertebra Fixation of Cortical Bone Trajectory Screw and Pedicle Screw for Lumbar Tuberculosis: A Minimum 3-Year Follow-Up. BIOMED RESEARCH INTERNATIONAL 2022; 2022:6312994. [PMID: 35909489 PMCID: PMC9334104 DOI: 10.1155/2022/6312994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/17/2022] [Accepted: 07/01/2022] [Indexed: 11/23/2022]
Abstract
Purpose This study is aimed at comparing the clinical efficacy of cortical bone trajectory (CBT) screw fixation and pedicle screw (PS) fixation of the affected vertebrae in lumbar tuberculosis. Methods We retrospectively analyzed the outcomes in 52 patients (27 cases in the CBT group, 25 cases in the PS group) with lumbar TB who underwent posterior affected-vertebra fixation combined with anterior debridement and bone grafting. The intraoperative blood loss, operative time, visual analog scale (VAS) scores for incision pain and leg pain, Japanese Orthopedic Association (JOA) score, bone grafting fusion, and complications were recorded. Results All patients were followed up for 35-52 months and achieved good clinical outcomes. There were no differences between the two groups in the operative time, intraoperative blood loss, JOA score, bone grafting fusion, and complications. However, there was a significant difference between the two groups in VAS scores for incision pain on the 1st day and 3rd day after surgery. At the last follow-up, JOA scores were significantly improved in both groups compared to the preoperation. Conclusion This retrospective study confirmed that both the affected-vertebra CBT screw fixation and PS fixation for lumbar TB via posterior and anterior approaches could achieve satisfactory outcomes, while the former resulted in better improvement for postoperative VAS scores.
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Beyond the pedicle screw-a patent review. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2022; 31:1553-1565. [PMID: 35380271 DOI: 10.1007/s00586-022-07193-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE This review provides an overview of the patent literature on posteriorly placed intrapedicular bone anchors. Conventional pedicle screws are the gold standard to create a fixation in the vertebra for spinal fusion surgery but may lack fixation strength, especially in osteoporotic bone. The ageing population demands new bone anchors that have an increased fixation strength, that can be placed safely, and, if necessary, can be removed without damaging the surrounding tissue. METHODS The patent search was conducted using a classification search in the Espacenet patent database. Only patents with a Cooperative Patent Classification of A61B17/70 or A61B17/7001 concerning spinal positioners and stabilizers were eligible for inclusion. The search query resulted in the identification of 731 patents. Based on preset inclusion criteria, a total of 56 unique patents on different anchoring methods were included, reviewed and categorized in this study. RESULTS Five unique fixation methods were identified; (1) anchors that use threading, (2) anchors that utilize a curved path through the vertebra, (3) anchors that (partly) expand, (4) anchors that use cement and (5) anchors that are designed to initiate bone ingrowth. Of the anchor designs included in this study, eight had a corresponding commercial product, six of which were evaluated in clinical trials. CONCLUSION This review provides insights into worldwide patented intrapedicular bone anchors that aim to increase the fixation strength compared to the conventional pedicle screw. The identified anchoring methods and their working principles can be used for clinical decision-making and as a source of inspiration when designing novel bone anchors.
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Weidling M, Heilemann M, Schoenfelder S, Heyde CE. Influence of thread design on anchorage of pedicle screws in cancellous bone: an experimental and analytical analysis. Sci Rep 2022; 12:8051. [PMID: 35577852 PMCID: PMC9110386 DOI: 10.1038/s41598-022-11824-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 04/28/2022] [Indexed: 11/12/2022] Open
Abstract
Threads of modern pedicle screws can vary greatly in design. It is difficult to assess which interplay of design features is particularly advantageous for screw anchorage. This study aims to increase the understanding of the anchorage behaviour between screw and cancellous bone. Pull-out tests of six pedicle screws in two sizes each were performed on three densities of biomechanical test material. More general screw characteristics were derived from the screw design and evaluated using the test data. Selected screws were tested on body donor material. Some screw characteristics, such as compacting, are well suited to compare the different thread designs of screws with tapered core. The combination of two characteristics, one representing bone compacting and one representing thread flank area, appears to be particularly advantageous for assessing anchorage behaviour. With an equation derived from these characteristics, the pull-out strength could be calculated very accurately (mean deviation 1%). Furthermore, findings are corroborated by tests on donor material. For screws with tapered core, the design demands for good anchorage against pull-out from cancellous bone change with material density. With sufficient bone quality, screws with a high compacting effect are advantageous, while with low bone density a high thread flank area also appears necessary for better screw anchorage.
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Affiliation(s)
- Martin Weidling
- Department of Orthopaedic Surgery, Traumatology and Plastic Surgery, ZESBO - Center for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany.
| | - Martin Heilemann
- Department of Orthopaedic Surgery, Traumatology and Plastic Surgery, ZESBO - Center for Research on Musculoskeletal Systems, Leipzig University, Leipzig, Germany
| | - Stephan Schoenfelder
- Faculty of Engineering, University of Applied Sciences Leipzig, Leipzig, Germany
| | - Christoph E Heyde
- Department of Orthopaedic Surgery, Traumatology and Plastic Surgery, Leipzig University Medical Center, Leipzig, Germany
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Cutting Flute and Thread Design on Self-Tapping Pedicle Screws Influence the Insertion Torque and Pullout Strength. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12041956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Self-tapping screws are commonly used in trauma and maxillofacial surgery and are increasingly used for pedicle screw insertions. In order to evaluate how the quantity and length of cutting flutes on self-tapping pedicle screws affect the insertion torque and pullout strength, eight different self-tapping pedicle screw designs were evaluated. All screws had a threaded length of 35 mm and featured variations in the number of leads, as well as the length and quantity of cutting flutes. Five samples of each design were inserted into pre-drilled, untapped holes (ø2.7 mm, length 35 mm) in sawbone blocks of density 20 PCF. The insertion torque and pullout strength were measured according to ASTM F543. The results showed that screws with a longer cutting flute of 9.5 mm had a lower mean maximum insertion torque than screws with shorter 2.9 mm cutting flutes. Pedicle screws with a double-lead thread design had a greater insertion torque than their single-lead counterparts, and the use of three cutting flutes produced a lower torque than two cutting flutes. The results demonstrated a greater pullout strength in screws with a single-lead thread rather than a double-lead, three cutting flutes instead of two, and a longer length for the cutting flute. In conclusion, to provide immediate stability and reduce the surgical insertion time, a single-lead, self-tapping pedicle screw incorporating three long cutting flutes is recommended because of the significantly greater pullout strength. This design could also reduce the risk of implant loosening in comparison to double-lead, self-tapping pedicle screw designs.
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Li D, Sun C, Jiang J, Lu F, Xia X, Wang H, Zou F, Ma X. A study of screw placement to obtain the optimal pull-out resistance of lumbar pedicle screws-analysis of Hounsfield units measurements based on computed tomography. BMC Musculoskelet Disord 2022; 23:124. [PMID: 35130888 PMCID: PMC8819881 DOI: 10.1186/s12891-022-05074-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/25/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE The screw path of lumbar pedicle screws in the vertebral body has certain variability. It is not clear whether the screw paths in different directions can obtain the same pull-out resistance. This study intends to use CT (Computed Tomography) to measure the Hounsfield unit (HU value) around the screw paths in different parts of the lumbar vertebral body to obtain the bone mineral density value of the corresponding parts which will provide some reference for the direction of lumbar pedicle screw placement. METHODS This retrospective study included 200 patients with lumbar degenerative diseases selected randomly from the case base and the patient's basic information was recorded. L1-L5 vertebral body was divided equally into the upper, middle and lower 1/3, which was consistent with the three sagittal entry directions of the pedicle screw head tilt, parallel endplate and caudal tilt, and the HU values were measured by CT cross-sectional scanning to indirectly reflect the local bone density values. The paired t-test (randomized block experiment) was used to compare the HU values of the upper, middle and lower 1 / 3 parts, with P < 0.05 being considered statistically significant. RESULTS Comparison of HU values in different parts of each vertebral body revealed that HU values in the middle 1/3 of the L1,L2 (163.88 ± 58.44 and 152.94 ± 59.45) and in the lower 1/3 of the L4 (149.86 ± 60.18) were higher than in the other two parts of the vertebral body of the same segment(P < 0.0001,P = 0.0069 and P = 0.0024, respectively); According to the results of each stratification, patients with younger age and better bone condition had higher HU values in the middle 1/3 of L1 and L2, and higher HU values in the lower 1/3 of L3, L4 and L5; With the increase of age, the decrease of bone condition and the difference of HU value in each vertebral body gradually decreased. CONCLUSION Although further follow-up studies are needed, based on the analysis of the statistical results, we speculate that from the perspective of obtaining the best pull-out resistance of the lumbar pedicle screws, the placement direction of L1 and L2 in the sagittal position may be as parallel to the endplate as possible; L3, L4, and L5 may be as appropriate as possible to the tail tilt theoretically.
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Affiliation(s)
- Dachuan Li
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Chi Sun
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Jianyuan Jiang
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Feizhou Lu
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Xinlei Xia
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Hongli Wang
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China
| | - Fei Zou
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China.
| | - Xiaosheng Ma
- Department of Orthopedics, Huashan Hospital, Fudan University, No.12, middle Urumqi Road, Jing'an District, Shanghai, 200040, China.
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Ding H, Hai Y, Liu Y, Guan L, Pan A, Zhang X, Han B, Li Y, Yin P. Cortical Trajectory Fixation Versus Traditional Pedicle-Screw Fixation in the Treatment of Lumbar Degenerative Patients with Osteoporosis: A Prospective Randomized Controlled Trial. Clin Interv Aging 2022; 17:175-184. [PMID: 35237030 PMCID: PMC8882472 DOI: 10.2147/cia.s349533] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/31/2022] [Indexed: 12/11/2022] Open
Abstract
Study Design Objective Methods Results Conclusion Trial Registration Number Date of Registration
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Affiliation(s)
- Hongtao Ding
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Yong Hai
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
- Correspondence: Yong Hai; Yuzeng Liu, Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China, Tel +86 10-85231229; +86 13801221889; +86 13811552832, Email ; ;
| | - Yuzeng Liu
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Li Guan
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Aixing Pan
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Xinuo Zhang
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Bo Han
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Yue Li
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
| | - Peng Yin
- Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China
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Pinheiro RP, Miranda RDF, Shimano AC, Chandanson T, George K, Defino HL. A influência da incompatibilidade do macho de rosca na resistência à extração do parafuso pedicular. Rev Bras Ortop 2022; 57:327-333. [PMID: 35652034 PMCID: PMC9142262 DOI: 10.1055/s-0041-1732390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/08/2021] [Indexed: 11/26/2022] Open
Abstract
Objective
We aimed to study the “in vitro” pullout strength of SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct Screw (DSG Screw, SpineGuard Inc, Boulder, Colorado, USA), a screw designed to be inserted using a direct insertion technique.
Methods
Dynamic Surgical Guidance Screws of 5.5 and 6.5 mm were introduced into polyurethane blocks with a density of 10 PCF (0,16g/cm
3
). According to the experimental group, screws were inserted without pilot hole, with pilot without tapping, undertapping and line-to-line tapping. Screw pullout tests were performed using a universal test machine after screw insertion into polyurethane blocks.
Results
Screws inserted directly into the polyurethane blocks without pilot hole and tapping showed a statistically higher pullout strength. Insertion of the screw without tapping or with undertapping increases the pullout screw strength compared with line-to-line tapping.
Conclusion
Dynamic Surgical Guidance Screw showed the highest pullout strength after its insertion without pilot hole and tapping.
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Affiliation(s)
- Rômulo Pedroza Pinheiro
- Setor de Cirurgia da Coluna, Departamento de Ortopedia e Anestesiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - Raffaello de Freitas Miranda
- Setor de Cirurgia da Coluna, Departamento de Ortopedia e Anestesiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - Antonio Carlos Shimano
- Setor de Cirurgia da Coluna, Departamento de Ortopedia e Anestesiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - Thibault Chandanson
- Département Génie Mécanique et Conception, Université de Technologie de Belfort, Montbéliard, França
| | - Keri George
- Departamento de Bacharelado em Enfermagem, University of Calgary, Alberta, Canadá
| | - Helton L.A. Defino
- Setor de Cirurgia da Coluna, Departamento de Ortopedia e Anestesiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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CİNGÖZ İD, GÜRKAN G, KAYA İ, ATAR M, UZUNOGLU I, ŞAHİN MC, YUCEER N. An investigation of the efficiency of pedicle screw simulator software in thoracic. JOURNAL OF HEALTH SCIENCES AND MEDICINE 2022. [DOI: 10.32322/jhsm.1012790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Optimizing Lumbar Pedicle Screw Trajectory Utilizing a 3D Printed Drill Guide to Ensure Placement of Pedicle Screws Into Higher Density Bone May Improve Pedicle Screw Pullout Resistance. World Neurosurg 2021; 158:e459-e464. [PMID: 34763101 DOI: 10.1016/j.wneu.2021.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 10/30/2021] [Accepted: 11/01/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Lower preoperative Hounsfield Unit (HU) values of vertebral body are associated with pedicle screw (PS) loosening after implantation with traditional trans-pedicular trajectory. However, the relationship between trajectory HU value and PS fixation quality remains unknown. This study aimed to investigate if 3D printed guider directed accurate implantation of pedicle screw could increase the anti-pulling properties of screws. METHODS 3D models of cadaveric spines were reconstructed by using CT image and PS trajectories were designed for both sides of vertebra. The designed trajectories were divided into high HU group and low HU group. PS implantation with 3D printed screw guide can be in complementary shape with target vertebra. Throughout 3D finite element analysis and biomechanical tests, the pull-out strength of screws in high or low trajectory HU groups were compared. RESULTS The HU value was 132± 13(mean ± standard deviation) in low HU group and 189± 17 in high HU group. The distance between planned trajectories and actual trajectories was 1.69 ±0.4 mm. Biomechanical tests showed that in high trajectory HU group the pull-out strength of screws was 750.41± 80.65 N, and compared to 655.83 ±74.31 N in low trajectory HU group, the difference was statistically significant. When simulated with finite element method, the pull-out strength of low HU trajectory pedicle screws was lower than that of high HU trajectory. CONCLUSION Pre-operative computer-assisted trajectory design combining 3D printed screw guide may direct more accurate implantation with optimal implantation trajectory, and may provide a new way to improve pedicle screw fixation.
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Implant Microbial Colonization Detected by Sonication as a Cause for Spinal Device Failure: A Prospective Study. Spine (Phila Pa 1976) 2021; 46:1485-1494. [PMID: 34618709 DOI: 10.1097/brs.0000000000004063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A prospective single center observational study. OBJECTIVES The aim of this study was to examine the potential role of sonication in the diagnosis of low-grade infections and its association with pedicle screw (PS) loosening, and to describe risk factors and radiological findings associated with spinal implant infection. SUMMARY OF BACKGROUND DATA Although PS loosening has mainly been attributed to mechanical overload, implant colonization and biofilm formation have recently been suggested. Culturing of sonication fluid implants is promising in the field of spine instrumentation infection, but little data are available. METHODS We prospectively included all patients who were subjected to implant removal. PS loosening was assessed with computed tomography (CT) scan. Different clinical and radiological parameters which could serve as indicators of implant infection were studied. RESULTS Thirty-eight patients were included in the study and 11 of them (29%) had a positive sonication result. Patients with spinal implant infection were associated with screw loosening (P = 0.005). Particularly, those screws with a positive microbiological culture showed signs of screw loosening in the preoperative CT scan (P < 0.001). Our results also showed that radiological screw loosening at L1-L3 level, and loosened larger constructs were associated with screw microbial colonization. The most common isolated microorganisms were coagulase-negative staphylococci and Cutibacterium acnes. An implant-based multivariate analysis indicated that screw loosening, the absence of prophylactic cefazolin, ICU hospitalization, screw breakage, and L1-L3 spine level were independent risk factors for implant-associated infection. Our model exhibited a high predictive power with an area under the curve of 0.937. CONCLUSION As clinical presentation of deep implant chronic infection is unspecific, consideration of these factors enables preoperative prediction and risk stratification of implant colonization, thus helping patient's management.Level of Evidence: 3.
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Tachi H, Kato K, Abe Y, Kokabu T, Yamada K, Iwasaki N, Sudo H. Surgical Outcome Prediction Using a Four-Dimensional Planning Simulation System With Finite Element Analysis Incorporating Pre-bent Rods in Adolescent Idiopathic Scoliosis: Simulation for Spatiotemporal Anatomical Correction Technique. Front Bioeng Biotechnol 2021; 9:746902. [PMID: 34712654 PMCID: PMC8546212 DOI: 10.3389/fbioe.2021.746902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 09/09/2021] [Indexed: 01/15/2023] Open
Abstract
An optimal surgical strategy for adolescent idiopathic scoliosis (AIS) is to provide maximal deformity correction while preserving spinal mobile segments as much as possible and obtaining a balanced posture. From a spatiotemporal deformity correction standpoint, we recently showed that anatomical four-dimensional (4D) spinal correction could be accomplished by curving the rod. In the surgical procedure, two rods are bent identically to confirm spinal anatomical alignment without referring to the intraoperative alignment of the deformity. Therefore, anatomically designed rods have been developed as notch-free, pre-bent rods for easier anatomical reconstruction. In addition to providing the best spinal instrumentation configurations as pre-bent rods, prediction of surgical outcome along with its biomechanical impact can be obtained by simulation of the surgical procedures with computer modeling. However, an objective model that can simulate the surgical outcome in patients with AIS has not been completely elucidated. The present study aimed to compare simulated deformity corrections based on our newly developed spatiotemporal morphological 4D planning simulation system incorporating pre-bent rods and actual deformity corrections in patients with AIS. A consecutive series of 47 patients who underwent anatomical posterior correction for AIS curves were prospectively evaluated. After multilevel facetectomy, except for the lowest instrumented segment, 11 types of pre-bent rods were used. Patient demographic data, radiographic measurements, and sagittal rod angles were analyzed within 1 week of surgery. Our simulation system incorporating pre-bent rods showed a significant correlation with the actual postoperative spinal alignment. The present study demonstrated the feasibility of our simulation system and the ability to simulate the surgical procedure using the pre-bent rods. The simulation system can be used to minimize the differences between the optimal and possible outcomes related to the instrumentation levels and rod shapes. Preoperative assumption of rod shape and length can contribute to a reduction in operative time which decreases blood loss and risk of infection. The results of the finite element analysis in the simulation system measured for each individual patient would also provide a more realistic representation of the surgical procedures.
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Affiliation(s)
- Hiroyuki Tachi
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.,Department of Orthopaedic Surgery, Eniwa Hospital, Eniwa, Japan
| | - Koji Kato
- Department of Systems Information Science, Future University Hakodate, Hakodate, Japan
| | - Yuichiro Abe
- Department of Orthopaedic Surgery, Eniwa Hospital, Eniwa, Japan
| | - Terufumi Kokabu
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Katsuhisa Yamada
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Norimasa Iwasaki
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hideki Sudo
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.,Department of Advanced Medicine for Spine and Spinal Cord Disorders, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Biomechanical Comparison of Fixation Stability among Various Pedicle Screw Geometries: Effects of Screw Outer/Inner Projection Shape and Thread Profile. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11219901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The proper screw geometry and pilot-hole size remain controversial in current biomechanical studies. Variable results arise from differences in specimen anatomy and density, uncontrolled screw properties and mixed screw brands, in addition to the use of different tapping methods. The purpose of this study was to evaluate the effect of bone density and pilot-hole size on the biomechanical performance of various pedicle screw geometries. Six screw designs, involving three different outer/inner projections of screws (cylindrical/conical, conical/conical and cylindrical/cylindrical), together with two different thread profiles (square and V), were examined. The insertional torque and pullout strength of each screw were measured following insertion of the screw into test blocks, with densities of 20 and 30 pcf, predrilled with 2.7-mm/3.2-mm/3.7-mm pilot holes. The correlation between the bone volume embedded in the screw threads and the pullout strength was statistically analyzed. Our study demonstrates that V-shaped screw threads showed a higher pullout strength than S-shaped threads in materials of different densities and among different pilot-hole sizes. The configuration, consisting of an outer cylindrical shape, an inner conical shape and V-shaped screw threads, showed the highest insertional torque and pullout strength at a normal and higher-than-normal bone density. Even with increasing pilot-hole size, this configuration maintained superiority.
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Çetin A, Bircan DA. 3D pull-out finite element simulation of the pedicle screw-trabecular bone interface at strain rates. Proc Inst Mech Eng H 2021; 236:134-144. [PMID: 34479459 DOI: 10.1177/09544119211044560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biomedical experimental studies such as pull-out (PO), screw loosening experience variability mechanical properties of fresh bone, legal procedures of cadaver bone samples and time-consuming problems. Finite Element Method (FEM) could overcome experimental problems in biomechanics. However, material modelling of bone is quite difficult, which has viscoelastic and viscoplastic properties. The study presents a bone material model which is constructed at the strain rates with the Johnson-Cook (JC) material model, one of the robust constitutive material models. The JC material constants of trabecular bone are determined by the curve fitting method at strain rates for the 3D PO finite element simulation, which defines the screw-bone interface relationship. The PO simulation is performed using the Abaqus/CAE software program. Bone fracture mechanisms are simulated with dynamic/explicit solutions during the PO phenomenon. The paper exposes whether the strain rate has effects on the PO performance. Moreover, simulation reveals the relationship between pedicle screw diameter and PO performance. The results obtained that the maximum pull-out force (POF) improves as both the screw diameter and the strain rate increase. For 5.5 mm diameter pedicle screw POFs were 487, 517 and 1708 N at strain rate 0.00015, 0.015 and 0.015 s-1, respectively. The FOFs obtained from the simulation of the other screw were 730, 802 and 2008 N at strain rates 0.00015, 0.0015 and 0.015, respectively. PO phenomenon was also simulated realistically in the finite element analysis (FEA).
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Affiliation(s)
- Ahmet Çetin
- Department of Mechanical Engineering, Cukurova University, Adana, Turkey
| | - Durmuş Ali Bircan
- Department of Mechanical Engineering, Cukurova University, Adana, Turkey
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Abstract
STUDY DESIGN Retrospective observational study of consecutive patients. OBJECTIVE We sought to: (1) clarify the key factors predominantly associated with the insertional torque of pedicle screws; (2) compare the optimal factors for pedicle screw insertion to obtain rigid screw fixation in patients with adult spinal deformity (ASD) and in those with adolescent idiopathic scoliosis (AIS); (3) determine the optimal screw/pedicle ratio (S/P) to obtain rigid pedicle screw fixation. SUMMARY OF BACKGROUND DATA Rigid pedicle screw fixation is mandatory to perform corrections for spinal deformities properly and to allow successful fusion after surgery. The fixation depends mainly on screw position accuracy and patient bone quality. Traditionally, spinal surgeons have decided the screw size, trajectory, and tapping size based on their intuition. Insertional torque has been indicated as useful to predict screw fixation strength, and is correlated with screw pullout strength and frequency of postoperative screw loosening. METHODS We compared insertion torque at L1-L3 levels of 324 screws in 68 patients with ASD and 58 screws in 32 patients with AIS. We assessed the association between screw/pedicle ratio and insertion torque by constructing a spline curve. RESULTS Pedicle and screw diameter correlated positively with insertion torque in patients with either ASD or AIS. The optimal screw/pedicle ratio to obtain rigid pedicle screw fixation in patients with ASD was close to, but less than one, and, by contrast, was about 1 to 1.25 in patients with AIS. CONCLUSION We propose the concept of an optimal S/P ratio for obtaining rigid pedicle screw fixation during spinal corrective surgery, which is different for patients with ASD and patients with AIS. The S/P ratio is useful for deciding the appropriate diameter screw for each case in preoperative planning.Level of Evidence: 4.
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Abstract
BACKGROUND/INTRODUCTION Pedicle screws have long been part of the continued advancements in spine surgery. Despite the many techniques that have been devised for their safe placement, malposition of screws continues to occur. Studies have evaluated the possible safe limits of screw malposition, and have given some insight on anatomic variation in spinal deformity. Review of the literature reveals several cases of deleterious long-term sequelae of malpositioned screws. DISCUSSION With the current experience, proposed recommendations are provided to detect and avoid the potential long-term sequelae. Though the literature has helped to define possible concerning screws, there are no good studies predicting long-term risk. CONCLUSION Improvements in technology and techniques, advancements in intraoperative confirmation and postoperative surveillance, studies that assist risk stratification, and expert consensus evaluations will help guide surgeons in their decision for addressing misplaced screws.
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Banas M, Hore N, Buchfelder M, Brandner S. Assessment of conformity of actual thoraco-lumbar pedicle screw dimensions to manufacturers' specifications. Sci Prog 2021; 104:368504211035035. [PMID: 34398723 PMCID: PMC10358464 DOI: 10.1177/00368504211035035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although correct selection of pedicle screw dimensions is indispensable to achieving optimum results, manufacturer-specified or intended dimensions may differ from actual dimensions. Here we analyzed the reliability of specifications made by various manufacturers by comparing them to the actual lengths and diameters of pedicle screws in a standardized experimental setup. We analyzed the actual length and diameter of pedicle screws of five different manufacturers. Four different screw lengths and for each length two different diameters were measured. Measurements were performed with the pedicle screws attached to a rod, with the length determined from the bottom of the tulip to the tip of the screw and the diameters determined at the proximal and distal threads. Differences in length of > 1 mm were found between the manufacturers' specifications and our actual measurements in 24 different pedicle screws. The highest deviation of the measured length from the manufacturers' specification was 3.2 mm. The difference in length between the shortest and longest screw with identical specifications was 3.4 mm. The highest deviation of the measured proximal thread diameters and the manufacturer's specifications was 0.5 mm. The diameter of the distal thread depends on the shape of the pedicle screw and hence varies between manufacturers in conical screws. We found clear differences in the length of pedicle screws with identical manufacturer specifications. Since differences between the actual dimensions and the dimensions indicated by the manufacturer may vary, this needs to be taken into account during the planning of spine instrumentation.
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Affiliation(s)
- Marian Banas
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
- Department of Neurosurgery, Clinic Hohe Warte, Bayreuth, Germany
| | - Nirjhar Hore
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - Michael Buchfelder
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
| | - Sebastian Brandner
- Department of Neurosurgery, University Hospital Erlangen, Erlangen, Germany
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Viezens L, Sellenschloh K, Püschel K, Morlock MM, Lehmann W, Huber G, Weiser L. Impact of Screw Diameter on Pedicle Screw Fatigue Strength-A Biomechanical Evaluation. World Neurosurg 2021; 152:e369-e376. [PMID: 34087457 DOI: 10.1016/j.wneu.2021.05.108] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/22/2021] [Accepted: 05/24/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Loosening of pedicle screws is a frequently observed complication in spinal surgery. Because additional stabilization procedures such as cement augmentation or lengthening of the instrumentation involve relevant risks, optimal stability of the primarily implanted pedicle screw is of essential importance. The aim of the present study was to investigate the effect of increasing the screw diameter on pedicle screw stability. METHODS A total of 10 human cadaveric vertebral bodies (L4) were included in the present study. The bone mineral density was evaluated using quantitative computed tomography and the pedicle diameter using computed tomography. The vertebrae underwent instrumentation using 6.0-mm × 45-mm pedicle screws on 1 side and screws with the largest possible diameter (8-10-mm × 45-mm) on the other side. Fatigue testing was performed by applying a cyclic loading (craniocaudal sinusoidal 0.5 Hz) with increasing peak force (100 N + 0.1 N/cycle) until screw head displacement of 5.4 mm was reached. RESULTS The mean fatigue load was 334 N for the 6-mm diameter screws and was increased significantly to 454 N (+36%) for the largest possible diameter screws (P < 0.001). With an increase in the fatigue load by 52%, this effect was even more pronounced in vertebrae with reduced bone density (bone mineral density <120 mg/cm3; n = 7; P < 0.001). The stiffness of the construct was significantly greater in the largest diameter screw group compared with the standard screw group during the entire testing period (start, P < 0.001; middle, P < 0.001; end, P = 0.009). CONCLUSIONS Increasing the pedicle screw diameter from a standard 6-mm screw to the largest possible diameter (8-10 mm) led to a significantly greater fatigue load.
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Affiliation(s)
- Lennart Viezens
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany; Division of Spine Surgery, Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kay Sellenschloh
- Institute of Biomechanics, Hamburg University of Technology, Hamburg, Germany
| | - Klaus Püschel
- Institute of Forensic Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael M Morlock
- Institute of Biomechanics, Hamburg University of Technology, Hamburg, Germany
| | - Wolfgang Lehmann
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Gerd Huber
- Institute of Biomechanics, Hamburg University of Technology, Hamburg, Germany
| | - Lukas Weiser
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany.
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Weiser L, Huber G, Sellenschloh K, Püschel K, Morlock MM, Viezens L, Lehmann W. Rescue Augmentation: Increased Stability in Augmentation After Initial Loosening of Pedicle Screws. Global Spine J 2021; 11:679-685. [PMID: 32875910 PMCID: PMC8165920 DOI: 10.1177/2192568220919123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
STUDY DESIGN Biomechanical study. OBJECTIVES Failure of pedicle screws is a major problem in spinal surgery not only postoperatively, but also intraoperatively. The aim of this study was to evaluate whether cement augmentation may restore mounting of initially loosened pedicle screws. METHODS A total of 14 osteoporotic or osteopenic human cadaveric vertebral bodies (L2)-according to quantitative computed tomography (QCT)-were instrumented on both sides by conventional pedicle screws and cement augmented on 1 side. In vitro fatigue loading (cranial-caudal sinusoidal, 0.5 Hz) with increasing peak force (100 N + 0.1 N/cycles) was applied until a screw head displacement of 5.4 mm (∼20°) was reached. After loosening, the nonaugmented screw was rescue augmented, and fatigue testing was repeated. RESULTS The fatigue load reached 207.3 N for the nonaugmented screws and was significantly (P = .009) exceeded because of initial cement augmentation (300.6 N). The rescue augmentation after screw loosening showed a fatigue load of 370.1 N which was significantly higher (P < .001) compared with the nonaugmented screws. The impact of bone density on fatigue strength decreased from the nonaugmented to the augmented to the rescue-augmented screws and shows the greatest effect of cement augmentation on fatigue strength at low bone density. CONCLUSIONS Rescue augmentation leads to similar or higher fatigue strengths compared with those of the initially augmented screws. Therefore, the cement augmentation of initially loosened pedicle screws is a promising option to restore adequate screw stability.
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Affiliation(s)
- Lukas Weiser
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany,Lukas Weiser, Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Robert Koch Str 40, 37099 Göttingen, Germany.
| | - Gerd Huber
- Institute of Biomechanics, TUHH Hamburg University of Technology, Hamburg, Germany
| | - Kay Sellenschloh
- Institute of Biomechanics, TUHH Hamburg University of Technology, Hamburg, Germany
| | - Klaus Püschel
- Institute of Forensic Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael M. Morlock
- Institute of Biomechanics, TUHH Hamburg University of Technology, Hamburg, Germany
| | - Lennart Viezens
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Wolfgang Lehmann
- Department of Trauma Surgery, Orthopaedic Surgery and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
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Yuan L, Zhang X, Zeng Y, Chen Z, Li W. Incidence, Risk, and Outcome of Pedicle Screw Loosening in Degenerative Lumbar Scoliosis Patients Undergoing Long-Segment Fusion. Global Spine J 2021; 13:1064-1071. [PMID: 34018438 DOI: 10.1177/21925682211017477] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
STUDY DESIGN Retrospective study. OBJECTIVE To investigate the incidence, risk factors, and outcomes of pedicle screw loosening in degenerative lumbar scoliosis (DLS) undergoing long-segment spinal fusion surgery. METHODS One hundred and thirty DLS patients who underwent long-segment fusion surgery with at least a 12-month follow-up were studied. The incidence and risk factors of screw loosening were investigated. VAS, SRS-22, and ODI scores were obtained preoperatively and at follow-up. RESULTS One hundred and sixty-eight of 1784 (9.4%) screws showed evidence of loosening in 71 (54.6%) patients. Three patients required revision surgery. Screw loosening rates according to vertebral insertion level were lowest instrumented vertebra (LIV): 45.4%; uppermost instrumented vertebra (UIV):17.7%; one vertebra above the LIV: 0.5%; 2 vertebrae above the LIV: 0.4%. Multiple logistic regression analysis of possible risk factors indicated that preoperative lateral subluxation ≥8 mm (odds ratio [OR]: 2.68, 95% confidence interval [CI]: 1.16-6.20), osteopenia (OR: 5.52, 95% CI: 1.64-18.56), osteoporosis (OR: 8.19, 95% CI: 2.40-27.97), fusion to sacrum (OR: 2.55, 95% CI: 1.12-5.83), postoperative TLK greater than 10° (OR: 2.63, 95% CI: 1.14-6.04) and SVA imbalance (OR: 3.44, 95% CI: 1.17-10.14) were statistically significant. No difference was noted in preoperative, follow-up, and change of VAS, ODI, and SRS-22 scores. CONCLUSIONS Screw loosening in DLS underwent long-segment surgery is common and tends to occur in the LIV or UIV. Lateral subluxation ≥8 mm, osteopenia, osteoporosis, fusion to the sacrum, postoperative TLK greater than 10°, and SVA imbalance were the independent influencing factors. Screw loosening can be asymptomatic, while longer-term follow-up is required.
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Affiliation(s)
- Lei Yuan
- Department of Orthopedics, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Spinal Disease Research, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Xinling Zhang
- Department of Orthopedics, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Spinal Disease Research, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Yan Zeng
- Department of Orthopedics, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Spinal Disease Research, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Zhongqiang Chen
- Department of Orthopedics, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Spinal Disease Research, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Weishi Li
- Department of Orthopedics, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Spinal Disease Research, Peking University Third Hospital, Beijing, China
- Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
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Bokov A, Pavlova S, Bulkin A, Aleynik A, Mlyavykh S. Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine: An observational study. World J Orthop 2021; 12:310-319. [PMID: 34055588 PMCID: PMC8152435 DOI: 10.5312/wjo.v12.i5.310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/15/2021] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The majority of published data report the results of biomechanical tests of various design pedicle screw performance. The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied.
AIM To estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine.
METHODS This study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments. Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion. Follow-up was for 18 mo. Patients with signs of pedicle screw loosening on computed tomography were registered; logistic regression analysis was used to identify the factors that influenced the rate of loosening.
RESULTS Parameters included in the analysis were screw geometry, type of thread, external and internal screw diameter and helical pitch, bone density in Hounsfield units, number of levels fused, instrumentation without anterior support, laminectomy, and unilateral and bilateral total facet joint resection. The rate of screw loosening decreased with the increment in outer diameter, decrease in core diameter and helical pitch. The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density. Bilateral facet joint removal significantly favored pedicle screw loosening. The influence of other factors was insignificant.
CONCLUSION Screw parameters had a significant impact on the loosening rate along with bone quality characteristics, the number of levels fused and the extensiveness of decompression. The significance of the influence of screw parameters was comparable to those of patient- and surgery-related factors. Pedicle screw loosening was influenced by helical pitch, inner and outer diameter, but screw geometry and thread type were insignificant factors.
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Affiliation(s)
- Andrey Bokov
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Svetlana Pavlova
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Anatoliy Bulkin
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Alexandr Aleynik
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Sergey Mlyavykh
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
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49
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Rocos B, Harding I. Lordosis Restoration With Midline Minimally Invasive Cortical Trajectory Screws (MidLF) and Transforaminal Interbody Fusion: A Safe Technique With a Short Stay. Int J Spine Surg 2021; 15:436-440. [PMID: 33963030 DOI: 10.14444/8065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The minimally invasive cortical trajectory screw (MidLF) technique has been described accompanied with posterolateral interbody fusion (PLIF). We present our 2-year results of a hybrid technique to show that using transforaminal interbody fusion (TLIF) rather than PLIF in conjunction with MidLF is a less invasive and safe technique. METHODS We retrospectively identified 25 patients who underwent MidLF with TLIF from July 2015 through September 2017. The surgical technique was the same for each, with radiological, clinical, and patient-reported outcome data collected and analyzed at a 2-year follow-up. RESULTS The cohort showed a mean age of 55 (35-85) years. The length of hospital stay was between 1 and 4 days, with an average of 2.7 days. Postoperatively, lordosis across the motion segment fused increased by a mean of 7.3° (0°-24°), mean pelvic incidence was 53°(31°-80°), and pelvic tilt reduced by an average of 3.5° (0°-11°). The Oswestry Disability Index improved from 34 preoperatively to 19 postoperatively. Visual analogue pain score-leg improved by 4.7 points, from 6 down to 1. One patient showed delayed wound healing. There were no incidences of neurological injury or durotomy. CONCLUSIONS Our data suggests that MidLF with TLIF is both less invasive than traditional techniques and safe. It restores lordosis, requires less exposure and retraction of neural elements than the more widely used PLIF, and shows early discharge and satisfactory medium-term patient-reported outcomes. LEVEL OF EVIDENCE 3. CLINICAL RELEVANCE The MidLF technique with PLIF is less invasive than traditional techniques, restores alignment and shows satisfactory medium term results.
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Affiliation(s)
- Brett Rocos
- Avon Orthopaedic Centre, Brunel Building, Southmead Hospital, Westbury-on-Trym, Bristol, United Kingdom
| | - Ian Harding
- Avon Orthopaedic Centre, Brunel Building, Southmead Hospital, Westbury-on-Trym, Bristol, United Kingdom
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50
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Çetin A, Bircan DA. Experimental investigation of pull-out performance of pedicle screws at different polyurethane (PU) foam densities. Proc Inst Mech Eng H 2021; 235:709-716. [PMID: 33730935 DOI: 10.1177/09544119211002587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Pedicle bone screws are one of the most critical materials used in spinal orthopaedic operations. Screw loosening and pull-out (PO) are basic complications encountered during or after surgery. Pull-out Strength (POS) of the bone is one of the significant parameters to understand the mechanical behaviour of a screw fixed to poor quality or osteoporotic bone. This study investigates how the POS of a pedicle screw is affected by the factors of the screw diameter and the polyurethane (PU) foam density by experimental analysis. In the experiments, two different diameter (5.5 and 6.5 mm) of conical pedicle screws and five different density (0.08, 0.16, 0.24, 0.32 and 0.48 g·cm-3) PU foams were used. According to the force-displacement curves obtained from experimental results, the POS increased with the increases in screw diameter and PU foam density.
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Affiliation(s)
- Ahmet Çetin
- Department of Mechanical Engineering, Çukurova University, Adana, Turkey
| | - Durmuş Ali Bircan
- Department of Mechanical Engineering, Çukurova University, Adana, Turkey
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