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Lee JW, Song MJ, Lee SJ, Song HS, Jung YS, Kim H. Biomechanical comparison between low profile 2.7 mm distal locking hook plate and 3.5 mm distal locking hook plate for acromioclavicular joint injury: A finite element analysis. Injury 2024; 55:111657. [PMID: 39002321 DOI: 10.1016/j.injury.2024.111657] [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: 03/02/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 07/15/2024]
Abstract
PURPOSE Although hook plate fixation is popularly used, concerns exist regarding periprosthetic fractures and the necessity to remove the plate to prevent subacromial erosion and subsequent acromion fracture, due to its non-anatomical design. We hypothesized that a low profile 2.7 mm distal locking hook plate would provide comparable stability to a properly used 3.5 mm distal locking hook plate MATERIALS AND METHODS: A 3.5 mm distal locking plate (type 1) and a low profile 2.7 mm plate (type 2) were assessed by finite element analysis. Peak von Mises stress (PVMS) was calculated on the acromion's undersurface, clavicle shaft, and hook, focusing on how these stresses varied with the number and placement of distal locking screws. RESULTS Increased distal screws in both types led to lower PVMS on the acromion's undersurface and the hook, with the lowest acromion PVMS observed in type 2 with three distal screws, and on the hook in type 1 with two distal screws. Increasing the number of distal screws similarly reduced PVMS on the clavicle shaft, with the lowest in type 1 with two distal screws. In both plate types, the most posterior distal locking screw played a crucial role in distributing stress across the acromion and the hook. CONCLUSION The low profile 2.7 mm distal locking hook plate showed comparable biomechanical results to the 3.5 mm distal locking hook plate. Increasing the number of distal locking screws showed less stress concentration on the bone and hook in both models. The most posterior distal locking screw showed an essential role in stress distribution.
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Affiliation(s)
- Jeong-Woo Lee
- Department of Biomedical Engineering, Inje University, Gimhae, Korea
| | - Min-Jun Song
- Department of Biomedical Engineering, Inje University, Gimhae, Korea
| | - Sung-Jae Lee
- Department of Biomedical Engineering, Inje University, Gimhae, Korea
| | - Hyun Seok Song
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Youn-Sung Jung
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hyungsuk Kim
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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Hu Y, Chen X, Chu Z, Luo L, Gan Z, Zhong J, Yuan Z, Zhu B, Dong W. Biomechanical Properties of Novel Porous Scaffold Core and Hollow Lateral Hole Pedicle Screws: A Comparative Study in Bama Pigs. Orthop Surg 2024; 16:1718-1725. [PMID: 38766934 PMCID: PMC11216838 DOI: 10.1111/os.14091] [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: 12/12/2023] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 05/22/2024] Open
Abstract
OBJECTIVE Screw loosening is a common complication of internal fixation of pedicle screw. Therefore, the development of a pedicle screw with low loosening rate and high biosafety is of great clinical significance. This study aimed to investigate whether the application of a porous scaffold structure can improve the stability of pedicle screws by comparing the biomechanical properties of novel porous scaffold core pedicle screws (PSCPSs) with those of hollow lateral hole pedicle screws (HLHPSs) in a porcine lumbar spine. METHODS Thirty-two pedicle screws of both types were implanted bilaterally into the L1-4 vertebrae of four Bama pigs, with our newly designed PSCPSs on the right and HLHPSs on the left. All the Bama pigs were sacrificed 16 weeks postoperatively, and the lumbar spine was freed into individual vertebrae. Biomechanical properties of both the pedicle screws were evaluated using pull-out tests, as well as cyclic bending and pull-out tests, while the mechanical properties were assessed using three-point bending tests. The data generated were statistically analyzed using paired-sample t-tests and two independent sample t-tests. RESULTS We found that the maximal pull-out forces before and after cyclic bending of the PSCPSs (1161.50 ± 337.98 N and 1075.25 ± 223.33 N) were significantly higher than those of the HLHPSs (948.38 ± 194.32 N and 807.13 ± 242.75 N) (p < 0.05, p < 0.05). In 800 cycles of the bending tests, neither PSCPS nor HLHPS showed loosening or visible detachment, but their maximal pull-out forces after cyclic bending tests decreased compared to those in cycles without cyclic bending tests (7.43% and 14.89%, respectively), with no statistical significance (p > 0.05 and p > 0.05, respectively). Additionally, both screws buckled rather than broke in the three-point bending tests, with no statistically significant differences between the maximal bending load and modulus of elasticity of the two screws (p > 0.05 and p > 0.05, respectively). CONCLUSIONS Compared with the HLHPSs, the PSCPSs have greater pull-out resistance and better fatigue tolerance with appropriate mechanical properties. Therefore, PSCPSs theoretically have significant potential for clinical applications in reducing the incidence of loosening after pedicle screw implantation.
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Affiliation(s)
- Yong Hu
- Department of Spine SurgeryNingbo No. 6 HospitalNingboChina
| | - Xijiong Chen
- Health Science CenterNingbo UniversityNingboChina
| | - Zhentao Chu
- Health Science CenterNingbo UniversityNingboChina
| | - Linwei Luo
- Health Science CenterNingbo UniversityNingboChina
| | - Zhiwei Gan
- Health Science CenterNingbo UniversityNingboChina
| | - Jianbin Zhong
- Department of Spine SurgeryNingbo No. 6 HospitalNingboChina
| | - Zhenshan Yuan
- Department of Spine SurgeryNingbo No. 6 HospitalNingboChina
| | - Bingke Zhu
- Department of Spine SurgeryNingbo No. 6 HospitalNingboChina
| | - Weixin Dong
- Department of Spine SurgeryNingbo No. 6 HospitalNingboChina
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Weber M, Lenz M, Egenolf P, Prescher A, Walter S, Heck VJ, Eysel P, Scheyerer MJ. Increased stability due to symmetric cement volume in augmented pedicle screws? A biomechanical study. J Biomed Mater Res B Appl Biomater 2024; 112:e35339. [PMID: 37955803 DOI: 10.1002/jbm.b.35339] [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: 12/19/2022] [Revised: 08/01/2023] [Accepted: 10/02/2023] [Indexed: 11/14/2023]
Abstract
Pedicle screw instrumentation has become "state of the art" in surgical treatment of many spinal disorders. Loosening of pedicle screws due to poor bone mineral density is a frequent complication in osteoporotic patients. As prevalence of osteoporosis and spinal disorders are increasing with an aging demographic, optimizing the biomechanical properties of pedicle screw constructions and therefore outcome after spinal surgery in osteoporotic patients is a key factor in future surgical therapy. Therefore, this biomechanical study investigated the stability of polymethylmethacrylate (PMMA)-augmented pedicle screw-rod constructions under a deviating distribution of PMMA applied to the instrumentation in osteoporotic human cadaveric vertebrae. We showed that PMMA-augmented pedicle screw-rod constructions tend to be more stable than those with non-augmented pedicle screws. Further, there appears to be a larger risk of screw loosening in unilateral augmented pedicle screws than in non-augmented, therefore a highly asymmetrically distributed PMMA should be avoided.
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Affiliation(s)
- Maximilian Weber
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Maximilian Lenz
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Philipp Egenolf
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Andreas Prescher
- University Hospital RWTH, Institute of Molecular and Cellular Anatomy (MOCA), Aachen, Germany
| | - Sebastian Walter
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Vincent J Heck
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Peer Eysel
- Center for Orthopedic and Trauma Surgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Max Joseph Scheyerer
- Department of Trauma and Spine Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
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Sarwahi V, Hasan S, Koutsogiannis P, Visahan K, Rao H, Patil A, Lo Y, Amaral T, DiMauro JP. Effect of Pedicle Screw Size on Surgical Outcomes Following Surgery for 412 Adolescent Idiopathic Scoliosis Patients. Spine (Phila Pa 1976) 2023; 48:1544-1551. [PMID: 37134132 DOI: 10.1097/brs.0000000000004700] [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] [Received: 01/18/2023] [Accepted: 04/12/2023] [Indexed: 05/04/2023]
Abstract
STUDY DESIGN Retrospective Review. OBJECTIVE The objective of this study was to determine differences in surgical and post-operative outcomes in AIS patients undergoing spinal deformity correction surgery using standard or large pedicle screw size. SUMMARY OF BACKGROUND Use of pedicle screw fixation in spinal deformity correction surgery is considered safe and effective. Still, the small size of the pedicle and the complex 3D anatomy of the thoracic spine makes screw placement challenging, with improper pedicle screw fixation leading to catastrophic complications including injuries to nerve roots, spinal cord, and major vessels. Thus, insertion of larger diameter screw sizes has raised concerns amongst surgeons, especially in the pediatric population. MATERIALS AND METHODS AIS patients undergoing PSF between 2013 and 2019 were included. Demographic, radiographic, and operative outcomes collected. Patients in the large screw size group (GpI) received 6.5 mm diameter screw sizes at all levels while standard screw size group (GpII) received 5.0 to 5.5 mm diameter screw sizes at all levels. Kruskall-Wallis and Fisher's exact test performed for continuous and categorical variables respectively.Subanalyses included (1) screw accuracy in patients with available CT scans, (2) stratified analysis of large- and standard-screw patients with ≥60% flexibility rate, (3) stratified analysis of large- and standard-screw patients with <60% flexibility rate, and (4) matched analysis of large- and standard-screw patients by surgeon and year of surgery. RESULTS GpI patients experienced significantly higher overall curve correction ( P <0.001), with 87.6% experiencing at least one grade reduction of apical vertebral rotation from preoperative to postoperative visit( P =0.008).Patients with larger screws displayed higher postoperative kyphosis. No patient experienced medial breaching. CONCLUSION Large screw sizes have similar safety profiles to standard screws without negatively impacting surgical and perioperative outcomes in AIS patients undergoing PSF. Additionally, coronal, sagittal, and rotational correction is superior for larger-diameter screws in AIS patients.
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Affiliation(s)
- Vishal Sarwahi
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Sayyida Hasan
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Petros Koutsogiannis
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Keshin Visahan
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Himanshu Rao
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY
| | - Aravind Patil
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Yungtai Lo
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Terry Amaral
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
| | - Jon-Paul DiMauro
- Department of Pediatric Orthopaedics, Cohen Children's Medical Center, New Hyde Park, NY
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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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Cao B, Yuan B, Xu G, Zhao Y, Sun Y, Wang Z, Zhou S, Xu Z, Wang Y, Chen X. A Pilot Human Cadaveric Study on Accuracy of the Augmented Reality Surgical Navigation System for Thoracolumbar Pedicle Screw Insertion Using a New Intraoperative Rapid Registration Method. J Digit Imaging 2023; 36:1919-1929. [PMID: 37131064 PMCID: PMC10406793 DOI: 10.1007/s10278-023-00840-x] [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: 01/02/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/04/2023] Open
Abstract
To evaluate the feasibility and accuracy of AR-assisted pedicle screw placement using a new intraoperative rapid registration method of combining preoperative CT scanning and intraoperative C-arm 2D fluoroscopy in cadavers. Five cadavers with intact thoracolumbar spines were employed in this study. Intraoperative registration was performed using anteroposterior and lateral views of preoperative CT scanning and intraoperative 2D fluoroscopic images. Patient-specific targeting guides were used for pedicle screw placement from Th1-L5, totaling 166 screws. Instrumentation for each side was randomized (augmented reality surgical navigation (ARSN) vs. C-arm) with an equal distribution of 83 screws in each group. CT was performed to evaluate the accuracy of both techniques by assessing the screw positions and the deviations between the inserted screws and planned trajectories. Postoperative CT showed that 98.80% (82/83) screws in ARSN group and 72.29% (60/83) screws in C-arm group were within the 2-mm safe zone (p < 0.001). The mean time for instrumentation per level in ARSN group was significantly shorter than that in C-arm group (56.17 ± 3.33 s vs. 99.22 ± 9.03 s, p < 0.001). The overall intraoperative registration time was 17.2 ± 3.5 s per segment. AR-based navigation technology can provide surgeons with accurate guidance of pedicle screw insertion and save the operation time by using the intraoperative rapid registration method of combining preoperative CT scanning and intraoperative C-arm 2D fluoroscopy.
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Affiliation(s)
- Bing Cao
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Bo Yuan
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Guofeng Xu
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Yin Zhao
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Yanqing Sun
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Zhiwei Wang
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Shengyuan Zhou
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Zheng Xu
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China
| | - Yao Wang
- Linyan Medical Technology Company Limited, 528 Ruiqing Road, Pudong New District, Shanghai, China
| | - Xiongsheng Chen
- Spine Center, Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, 415 Fengyang Road, Huangpu District, Shanghai, China.
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Hu Y, Chu Z, Shen S, Zhong J, Zhu B, Wu J, Yuan Z, Dong W. Biomechanical Properties of Novel Lateral Hole Pedicle Screws and Solid Pedicle Screws: A Comparative Study in the Beagle Dogs. Orthop Surg 2022; 15:328-336. [PMID: 36411506 PMCID: PMC9837263 DOI: 10.1111/os.13596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Although pedicle screws are widely used to reconstruct the stability of the spine, screw loosening is a common complication after spine surgery. The main objective of this study was to investigate whether the application of the hollow lateral hole structure had the potential to improve the stability of the pedicle screw by comparing the biomechanical properties of the novel lateral hole pedicle screws (LHPSs) with those of the solid pedicle screws (SPSs) in beagle dogs. METHODS The cancellous bone of the distal femur, proximal femur, distal tibia, and proximal tibia were chosen as implantation sites in beagle dogs. In each of 12 dogs, four LHPSs, and four SPSs were implanted into both lower limbs. At 1, 2, and 3 months after surgery, four dogs were randomly sampled and sacrificed. The LHPS group and SPS group were subdivided into four subgroups according to the length of their duration of implantation (0, 1, 2, 3 months). The biomechanical properties of both pedicle screws were evaluated by pull-out and the cyclic bending tests. RESULTS The results of the study showed that no significant difference was found between LHPSs (276.62 ± 50.11 N) and SPSs (282.47 ± 42.98 N) in pull-out tests at time 0 (P > 0.05). At the same time point after implantations, LHPSs exhibited significantly higher maximal pullout strength than SPSs (month 1: 360.51 ± 25.63 vs 325.87 ± 28.11 N; month 2: 416.59 ± 23.78 vs 362.12 ± 29.27 N; month 3: 447.05 ± 38.26 vs 376.63 ± 32.36 N) (P < 0.05). Moreover, compared with SPSs, LHPSs withstood more loading cycles (month 2: 592 ± 21 vs 534 ± 48 times; month 3: 596 ± 10 vs 543 ± 59 times), and exhibiting less displacement before loosening at month 2 (1.70 ± 0.17 vs 1.96 ± 0.10 mm) and 3 (1.69 ± 0.19 vs 1.92 ± 0.14 mm) (P < 0.05), but no significant difference in time 0 and month 1 (P > 0.05). CONCLUSIONS The pedicle screw with the hollow lateral hole structure could allow bone to grow into the inner architecture, which improved biomechanical properties by extending the contact area between screw and bone tissue after implantation into the cancellous bone. It indicated that LHPS could reduce loosening of the pedicle screws in long term after surgery.
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Affiliation(s)
- Yong Hu
- Department of Spine SurgeryThe Ningbo No. 6 HospitalNingboChina
| | | | | | - Jian‐bin Zhong
- Department of Spine SurgeryThe Ningbo No. 6 HospitalNingboChina
| | - Bing‐ke Zhu
- Department of Spine SurgeryThe Ningbo No. 6 HospitalNingboChina
| | - Jia‐da Wu
- School of MedicineNingbo UniversityNingboChina
| | - Zhen‐shan Yuan
- Department of Spine SurgeryThe Ningbo No. 6 HospitalNingboChina
| | - Wei‐xin Dong
- Department of Spine SurgeryThe Ningbo No. 6 HospitalNingboChina
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Cornaz F, Farshad M, Widmer J. Location of pedicle screw hold in relation to bone quality and loads. Front Bioeng Biotechnol 2022; 10:953119. [PMID: 36118575 PMCID: PMC9478651 DOI: 10.3389/fbioe.2022.953119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/21/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction: Sufficient screw hold is an indispensable requirement for successful spinal fusion, but pedicle screw loosening is a highly prevalent burden. The aim of this study was to quantify the contribution of the pedicle and corpus region in relation to bone quality and loading amplitude of pedicle screws with traditional trajectories. Methods: After CT examination to classify bone quality, 14 pedicle screws were inserted into seven L5. Subsequently, Micro-CT images were acquired to analyze the screw’s location and the vertebrae were split in the midsagittal plane and horizontally along the screw’s axis to allow imprint tests with 6 mm long sections of the pedicle screws in a caudal direction perpendicular to the screw’s surface. Force-displacement curves in combination with the micro-CT data were used to reconstruct the resistance of the pedicle and corpus region at different loading amplitudes. Results: Bone quality was classified as normal in three specimens, as moderate in two and as bad in two specimens, resulting in six, four, and four pedicle screws per group. The screw length in the pedicle region in relation to the inserted screw length was measured at an average of 63%, 62%, and 52% for the three groups, respectively. At a calculated 100 N axial load acting on the whole pedicle screw, the pedicle region contributed an average of 55%, 58%, and 58% resistance for the normal, moderate, and bad bone quality specimens, respectively. With 500 N load, these values were measured at 59%, 63%, and 73% and with 1000 N load, they were quantified at 71%, 75%, and 81%. Conclusion: At lower loading amplitudes, the contribution of the pedicle and corpus region on pedicle screw hold are largely balanced and independent of bone quality. With increasing loading amplitudes, the contribution of the pedicle region increases disproportionally, and this increase is even more pronounced in situations with reduced bone quality. These results demonstrate the importance of the pedicle region for screw hold, especially for reduced bone quality.
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Affiliation(s)
- Frédéric Cornaz
- Department of Orthopedics, Balgrist University Hospital, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
- *Correspondence: Frédéric Cornaz,
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, Zurich, Switzerland
| | - Jonas Widmer
- Department of Orthopedics, Balgrist University Hospital, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
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Yoon TH, Choi CH, Choi YR, Ju HJ, Chun YM. Relation between diameter of a lateral screw and pull-out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study. J Orthop Res 2022; 40:1577-1583. [PMID: 34664322 DOI: 10.1002/jor.25194] [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: 05/25/2021] [Revised: 09/26/2021] [Accepted: 09/30/2021] [Indexed: 02/04/2023]
Abstract
Plate fixation has recently gained popularity among the various surgical methods used to treat Neer type II distal clavicle fractures. The use of a low-profile distal clavicle locking plate is logically considered a better option when there is no significant difference in the fixation strength between insertions of 3.5- and 2.7-mm diameter screws. Therefore, the purpose of this biomechanical study was to investigate any differences in fixation strength among varying sizes of screws that are used to treat distal clavicle fractures. The study was performed with 20 paired shoulder girdles from 10 fresh frozen cadavers. To create a type IIA fracture of Neer classification, osteotomy was performed perpendicularly to the longitudinal axis of the clavicle at the medial end point of the conoid ligament. Two custom-made fixtures designed to be attached to both upper and lower sides of the Instron were fabricated for the evaluation. The mean maximum pull-out strength for fixation using 3.5-mm diameter screws was 241.9 ± 67.8 N, whereas the mean pull-out strength in fixation with 2.7-mm diameter screws was 228.1 ± 63.0 N. There was no statistically significant difference between the two groups. Distal fragment fixation with distal clavicle locking plates using two 2.7-mm diameter screws showed comparable biomechanical pull-out strength at the time-zero setting to fixations with a hook plate using two 3.5-mm diameter screws. Therefore, the fixation of the distal fragment with a low-profile plate and 2.7-mm screws may be preferred as an alternative option if the distal fragment of the fractured clavicle is not extremely small.
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Affiliation(s)
- Tae-Hwan Yoon
- Department of Orthopaedic Surgery, Arthroscopy and Joint Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Chong-Hyuk Choi
- Department of Orthopaedic Surgery, Arthroscopy and Joint Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Yun-Rak Choi
- Department of Orthopaedic Surgery, Arthroscopy and Joint Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hun-Jin Ju
- Department of Orthopaedic Surgery, Arthroscopy and Joint Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Yong-Min Chun
- Department of Orthopaedic Surgery, Arthroscopy and Joint Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Liu JB, Zuo R, Zheng WJ, Li CQ, Zhang C, Zhou Y. The accuracy and effectiveness of automatic pedicle screw trajectory planning based on computer tomography values: an in vitro osteoporosis model study. BMC Musculoskelet Disord 2022; 23:165. [PMID: 35189892 PMCID: PMC8862578 DOI: 10.1186/s12891-022-05101-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/08/2022] [Indexed: 05/31/2023] Open
Abstract
Background Pedicle screw placement in patients with osteoporosis is a serious clinical challenge. The bone mineral density (BMD) of the screw trajectory has been positively correlated with the screw pull-out force, while the computer tomography (CT) value has been linearly correlated with the BMD. The purpose of this study was to establish an in vitro osteoporosis model and verify the accuracy and effectiveness of automated pedicle screw planning software based on CT values in this model. Methods Ten vertebrae (L1-L5) of normal adult pigs were randomly divided into decalcification and control groups. In the decalcification group, the vertebral bodies were decalcified with Ethylenediaminetetraacetic acid (EDTA) to construct an in vitro osteoporosis model. In the decalcification group, automatic planning (AP) and conventional manual planning (MP) were used to plan the pedicle screw trajectory on the left and right sides of the pedicle, respectively, and MP was used on both sides of the control group. CT values of trajectories obtained by the two methods were measured and compared. Then, 3D-printed guide plates were designed to assist pedicle screw placement. Finally, the pull-out force of the trajectory obtained by the two methods was measured. Results After decalcification, the BMD of the vertebra decreased from − 0.03 ± 1.03 to − 3.03 ± 0.29 (P < 0.05). In the decalcification group, the MP trajectory CT value was 2167.28 ± 65.62 Hu, the AP trajectory CT value was 2723.96 ± 165.83 Hu, and the MP trajectory CT value in the control group was 2242.94 ± 25.80 Hu (P < 0.05). In the decalcified vertebrae, the screw pull-out force of the MP group was 48.6% lower than that of the control group (P < 0.05). The pull-out force of the AP trajectory was 44.7% higher than that of the MP trajectory (P < 0.05) and reached 97.4% of the MP trajectory in the control group (P > 0.05). Conclusion Automatic planning of the pedicle screw trajectory based on the CT value can obtain a higher screw pull-out force, which is a valuable new method of pedicle screw placement in osteoporotic vertebre. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-022-05101-6.
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Affiliation(s)
- Jia Bin Liu
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China
| | - Rui Zuo
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China
| | - Wen Jie Zheng
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China
| | - Chang Qing Li
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China
| | - Chao Zhang
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China.
| | - Yue Zhou
- Department of Orthopaedics, Xinqiao Hospital, Amy Medical University (Third Military Medical University), Chongqing, 400037, People's Republic of China.
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Seng DW, Chou SM, Liang BZ, Tan AC. Revising a loosened cancellous screw with a larger screw does not restore original pull-out strength - A biomechanical study. Clin Biomech (Bristol, Avon) 2021; 89:105460. [PMID: 34461520 DOI: 10.1016/j.clinbiomech.2021.105460] [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: 02/19/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cancellous screw fixation is often used in fracture fixation. When this screw is over-tightened, damage to the bone and other non-linear processes such as fracture and construct failure would be involved. The objectives of this study were (1) to determine the reduction in pull-out strength when a cancellous screw spins and (2) to determine how much pull-out strength can be restored by revising with a larger diameter screw. METHODS A biomechanical study using synthetic polyurethane foam (320 kg/m3) was performed to assess (1) the pull-out strength of a 6.5 mm cancellous screw, (2) the pull-out strength of a loosened 6.5 mm cancellous screw and (3) the pull-out strength of a loosened 6.5 mm cancellous screw revised with a 7.3 mm cancellous screw. FINDINGS The baseline pull-out strength of the 6.5 mm cancellous screw was 2213.91 ± 200.51 N. There was a 79.1% (463.79 ± 99.95 N) reduction in pull-out strength once spinning occurs (p = 0.027). When a spinning 6.5 mm cancellous screw was revised to a 7.3 mm cancellous screw, the pull-out strength increased to 1313.65 ± 93.23 N, 59.3% of the baseline pull-out strength (2213.91 ± 200.51 N) (p = 0.027). INTEPRETATION A loosened 6.5 mm cancellous screw results in a 79.1% reduction in pull-out strength. Revising a loosened cancellous screw by inserting a larger 7.3 mm diameter screw partially improves the pull-out strength to 59.3% of the baseline. Surgeons should consider the use of "two-finger tight" torque when inserting a screw to avoid stripping.
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Affiliation(s)
- Daniel Wr Seng
- Department of Orthopaedic Surgery, Woodlands Health, Singapore.
| | - Siaw Meng Chou
- School of Mechanical & Aerospace Engineering, College of Engineering, Nanyang Technological University, Singapore
| | - Benjamin Zr Liang
- Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, Singapore
| | - Alvin Ck Tan
- Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, Singapore
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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: 7] [Impact Index Per Article: 2.3] [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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Matsukawa K, Yato Y, Imabayashi H. Impact of Screw Diameter and Length on Pedicle Screw Fixation Strength in Osteoporotic Vertebrae: A Finite Element Analysis. Asian Spine J 2020; 15:566-574. [PMID: 33355846 PMCID: PMC8561163 DOI: 10.31616/asj.2020.0353] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/22/2020] [Indexed: 11/23/2022] Open
Abstract
Study Design Biomechanical study. Purpose To quantitatively investigate the effect of screw size on screw fixation in osteoporotic vertebrae with finite element analysis (FEA) Overview of Literature Osteoporosis poses a challenge in spinal instrumentation; however, the selection of screw size is directly related to fixation and is closely dependent on each surgeon’s experience and preference. Methods Total 1,200 nonlinear FEA with various screw diameters (4.5–7.5 mm) and lengths (30–50 mm) were performed on 25 patients (seven men and 18 women; mean age, 75.2±10.8 years) with osteoporosis. The axial pullout strength, and the vertebral fixation strength of a paired-screw construct against flexion, extension, lateral bending, and axial rotation were examined. Thereafter, we calculated the equivalent stress of the bone-screw interface during nondestructive loading. Then, using diameter parameters (screw diameter or screw fitness in the pedicle [%fill]), and length parameters (screw length or screw depth in the vertebral body [%length]), multiple regression analyses were performed in order to evaluate the factors affecting various fixations. Results Larger diameter and longer screws significantly increased the pullout strength and vertebral fixation strength; further, they decreased the equivalent stress around the screws. Multiple regression analyses showed that the actual screw diameter and %length were factors that had a stronger effect on the fixation strength than %fill and the actual screw length. Screw diameter had a greater effect on the resistance to screw pullout and flexion and extension loading (β=0.38–0.43, p<0.01); while the %length had a greater effect on resistance to lateral bending and axial rotation loading (β=0.25–0.36, p<0.01) as well as mechanical stress of the bone-screw interface (β=−0.42, p<0.01). Conclusions The screw size should be determined based on the biomechanical behavior of the screws, type of mechanical force applied on the corresponding vertebra, and anatomical limitations.
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Affiliation(s)
- Keitaro Matsukawa
- 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
| | - Hideaki Imabayashi
- Department of Orthopaedic Surgery, Tokyo Saiseikai Central Hospital, Tokyo, Japan
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Murata K, Fujibayashi S, Otsuki B, Shimizu T, Masamoto K, Matsuda S. Accuracy of fluoroscopic guidance with the coaxial view of the pedicle for percutaneous insertion of lumbar pedicle screws and risk factors for pedicle breach. J Neurosurg Spine 2020; 34:52-59. [PMID: 32858519 DOI: 10.3171/2020.5.spine20291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/18/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In this study the authors aimed to evaluate the rate of malposition, including pedicle breach and superior facet violation, after percutaneous insertion of pedicle screws using the coaxial fluoroscopic view of the pedicle, and to assess the risk factors for pedicle breach. METHODS In total, 394 percutaneous screws placed in 85 patients using the coaxial fluoroscopic view of the pedicle between January 2014 and September 2017 were assessed, and 445 pedicle screws inserted in 116 patients using conventional open procedures were used for reference. Pedicle breach and superior facet violation were evaluated by postoperative 0.4-mm slice CT. RESULTS Superior facet violation was observed in 0.5% of the percutaneous screws and 1.8% of the conventionally inserted screws. Pedicle breach occurred more frequently with percutaneous screws (28.9%) than with conventionally inserted screws (11.9%). The breaches in percutaneous screws were minor and did not reduce the interbody fusion rate. The angle difference between the percutaneous and conventionally inserted screws was comparable. Insertion at the L3 or L4 level, right-sided insertion, placement around a trefoil canal, smaller pedicle angle, and a small difference between the screw and pedicle diameters were found to be risk factors for pedicle breach by percutaneous pedicle screws. CONCLUSIONS Percutaneous pedicle screw placement using the coaxial fluoroscopic view of the pedicle carries a low risk of superior facet violation. The screws should be placed carefully considering the level and side of insertion, canal shape, and pedicle angle.
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Use of longer sized screws is a salvage method for broken pedicles in osteoporotic vertebrae. Sci Rep 2020; 10:10441. [PMID: 32591573 PMCID: PMC7320151 DOI: 10.1038/s41598-020-67489-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/05/2020] [Indexed: 11/09/2022] Open
Abstract
Screw loosening due to broken pedicles is a common complication resulting from the insertion of screws either with inadequate diameters or into an osteoporotic pedicle. In this novel in vitro study, we tried to clarify the contribution of the pedicle to screw fixation and subsequent salvage strategies using longer or larger-diameter screws in broken pedicles. Sixty L4 fresh-frozen lumbar vertebrae harvested from mature pigs were designed as the normal-density group (n = 30) and decalcified as the osteoporosis group (n = 30). Three modalities were randomly assigned as intact pedicle (n = 30), semi-pedicle (n = 15), and non-pedicle (n = 15) in each group. Three sizes of polyaxial screws (diameter × length of 6.0 mm × 45 mm, 6.0 mm × 50 mm, and 6.5 mm × 45 mm) over five trials were used in each modality. The associations between bone density, pedicle modality and screw pullout strength were analyzed. After decalcification for 4 weeks, the area bone mineral density decreased to approximately 56% (p < 0.05) of the normal-density group, which was assigned as the osteoporosis group. An appropriate screw trajectory and insertional depth were confirmed using X-ray imaging prior to pullout testing in both groups. The pullout forces of larger-diameter screws (6.5 mm × 45 mm) and longer screws (6.0 mm × 50 mm) were significantly higher (p < 0.05) in the semi- and non-pedicle modalities in the normal-density group, whereas only longer screws (6.0 mm × 50 mm) had a significantly higher (p < 0.05) pullout force in the non-pedicle modalities in the osteoporosis group. The pedicle plays an important role in both the normal bone density group and the osteoporosis group, as revealed by analyzing the pullout force percentage contributed by the pedicle. Use of a longer screw would be a way to salvage a broken pedicle of osteoporotic vertebra.
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A novel parameter for the prediction of pedicle screw fixation in cancellous bone - A biomechanical study on synthetic foam. Med Eng Phys 2020; 79:44-51. [DOI: 10.1016/j.medengphy.2020.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/17/2020] [Accepted: 03/01/2020] [Indexed: 11/21/2022]
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17
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Zhang W, Zhao J, Li L, Yu C, Zhao Y, Si H. Modelling tri-cortical pedicle screw fixation in thoracic vertebrae under osteoporotic condition: A finite element analysis based on computed tomography. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 187:105035. [PMID: 31443980 DOI: 10.1016/j.cmpb.2019.105035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/05/2019] [Accepted: 08/11/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE The technique of tri-cortical pedicle screw (TCPS) has been used to improve the anchoring strength in the sacral vertebrae. However, no studies have reported their application in the thoracic vertebrae. Our research is aimed to assess the stability and strength of the TCPS in thoracic vertebrae under osteoporotic condition by three dimensional (3D) finite element method on the basis of medical image reconstruction using computed tomography (CT), and verifying its effectiveness in clinical application. MATERIALS AND METHODS The 3D finite element models were constructed using Mimcs to transfer two dimensional CT images into 3D models by marching cubes algorithm of six-partition. Six physiological activities were simulated in 3D finite element models. Compared with the strength and stability of the uni-cortical pedicle screw (UCPS) and bi-cortical pedicle screw (BCPS), the effectiveness of TCPS was assessed. The stress distribution and maximum stress were measured to evaluate the strength. The maximum displacement and the range of motion were analysed to assessed the stability. EXPERIMENTAL RESULTS Four geometrically accurate and nonlinear T7-T9 finite element models were constructed successfully by 3D finite element method based on the CT images. Three kinds of internal fixation methods in the osteoporotic thoracic vertebral body can improved the maximum stress, decrease the maximum displacement and range of motion in six physiological activities. The range of motion and maximum displacement of TCPS decreased more significantly than that of UCPS and BCPS. The maximum von Mises stress of TCPS was minimum and UCPS was maximum under the condition of extension, right lateral bending, left rotation and right rotation. CONCLUSIONS Effectively, TCPS can provide better stability and strength than that of UCPS and BCPS techniques in the osteoporotic thoracic vertebrae. In practice, the technique of TCPS can be applied in the osteoporotic thoracic vertebral body to enhance the griping strength of the screws and reduce the risk of pedicle screw loosening. However, further cadaver experiments and more biomechanical analysis are necessary to confirmed our findings.
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Affiliation(s)
- Wencan Zhang
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Junyong Zhao
- College of Physics and Electronic Sciences, Shandong Normal University, Jinan 250000, China
| | - Le Li
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Chenxiao Yu
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Yuefeng Zhao
- College of Physics and Electronic Sciences, Shandong Normal University, Jinan 250000, China
| | - Haipeng Si
- Qilu Hospital, Shandong University, Jinan 250012, China.
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Utility of Thoracolumbar Low-Dose CT With Model-Based Iterative Reconstruction for Measuring Pedicle Diameter Using a Radiation Dose Less Than a One-Time Lumbar X-Ray. Spine (Phila Pa 1976) 2020; 45:38-47. [PMID: 31425432 DOI: 10.1097/brs.0000000000003210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective. OBJECTIVE To evaluate the image quality of low-radiation-dose computed tomography (LD-CT) of the thoracolumbar spine, using model-based iterative reconstruction (MBIR) for measuring pedicle diameter. SUMMARY OF BACKGROUND DATA MBIR can drastically reduce radiation dose but its utility in spine surgery planning is unknown. METHODS We identified patients (mean age, 70.5 ± 13.3 yrs) who incidentally underwent both standard-radiation-dose CT (SD-CT) with hybrid iterative reconstruction and LD-CT with MBIR of the thoracolumbar spine within 2 years. We compared radiation dose, subjective image sharpness, signal-to-noise ratio, and contrast-to-noise ratio for the two tests. Additionally, inner pedicle diameters were measured on SD-CT (DSD) and LD-CT (DLD), and statistically compared. RESULTS We included 24 CT and 84 pedicles for each CT group. The radiation dose of LD-CT estimated by volume CT dose index was 1.21 ± 0.42 mGy, one-sixth the dose of SD-CT. The effective dose of LD-CT was 0.58 ± 0.31 mSv, equivalent to or less than that of a one-time lumbar X-ray in a previous report. LD-CT was significantly inferior in subjective image sharpness for the contour of vertebrae and trabecular structure, but superior for signal-to-noise ratio and contrast-to-noise ratio. The intra-rater reliability (intra-RR) and inter-RR for DLD were 0.985 and 0.892, respectively, comparable to those of DSD. DLD was consistently 0.30 mm smaller than DSD when compared within the same pedicle, regardless of pedicle diameter. CONCLUSION LD-CT with MBIR produced a radiation dose equivalent to a one-time lumbar X-ray and provided excellent images for measuring pedicle diameter. LD-CT can be a substitute for SD-CT when planning spine surgery if the relationship between DSD and DLD is sufficiently understood. LEVEL OF EVIDENCE 3.
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Effect of surgical factors on the augmentation of cement-injectable cannulated pedicle screw fixation by a novel calcium phosphate-based nanocomposite. Front Med 2019; 13:590-601. [PMID: 31555965 DOI: 10.1007/s11684-019-0710-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 06/25/2019] [Indexed: 10/25/2022]
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Burkhart TA, Sadashivaiah M, Reeves J, Rasounlinejad P. The Evaluation of a Novel Three-Dimensional Printed Expandable Pedicle Screw Sleeve Insert. J Med Device 2019. [DOI: 10.1115/1.4043762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
When used in combination with decompression, spinal fusion is a successful procedure for treating patients with spinal stenosis and degenerative spondylolisthesis. While a number of auxiliary devices have been proposed to enhance the fixation of the screw within the pedicle and vertebral body, there is conflicting information regarding the efficacy of their use. Therefore, the aim of this study was to determine the ability of a novel expandable pedicle screw to improve the fixation of the pedicle screw within the pedicle and vertebral body. A three-dimensional (3D) printed, screw sleeve was designed that expanded within the pedicle and vertebral body when a standard pedicle screw was inserted into it. The left and right pedicle of ten (N = 10) cadaveric lumbar spine specimens (L3–L5) were randomly assigned to be instrumented with either a pedicle screw and the sleeve or a pedicle screw only. Following instrumentation, the screws were exposed to tensile load at 5 mm/min until failure. The failure force, failure deformation, and area under the force–deformation curve were determined and compared between screw conditions. There were no significant differences between the screws and sleeve, and the screw only conditions for the failure force (p = 0.24), failure displacement (p = 0.10), and area under the curve (p = 0.38). While the novel screw sleeve presented here performed as well as a screw without a sleeve, it was better than other screw augmentation devices reported previously. In addition, it is likely that this device would prove useful as an enhancement to revision.
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Affiliation(s)
- Timothy A. Burkhart
- Department Mechanical and Materials Engineering, Lawson Health Research Institute, Western University, 1151 Richmond Road, London, ON N6A 5B9, Canada e-mail:
| | - Manjunath Sadashivaiah
- Department of Mechanical and Material Engineering, Western University, London, ON N6A 5B9, Canada e-mail:
| | - Jacob Reeves
- Department of Mechanical and Materials Engineering, Western University, London, ON N6A 5B9, Canada e-mail:
| | - Paraham Rasounlinejad
- Department of Surgery, Victoria Hospital, Western University, London, ON N6A 5W9, Canada e-mail:
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Biswas JK, Sahu TP, Rana M, Roy S, Karmakar SK, Majumder S, Roychowdhury A. Design factors of lumbar pedicle screws under bending load: A finite element analysis. Biocybern Biomed Eng 2019. [DOI: 10.1016/j.bbe.2018.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Gibby JT, Swenson SA, Cvetko S, Rao R, Javan R. Head-mounted display augmented reality to guide pedicle screw placement utilizing computed tomography. Int J Comput Assist Radiol Surg 2018; 14:525-535. [PMID: 29934792 DOI: 10.1007/s11548-018-1814-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/13/2018] [Indexed: 02/06/2023]
Abstract
PURPOSE Augmented reality has potential to enhance surgical navigation and visualization. We determined whether head-mounted display augmented reality (HMD-AR) with superimposed computed tomography (CT) data could allow the wearer to percutaneously guide pedicle screw placement in an opaque lumbar model with no real-time fluoroscopic guidance. METHODS CT imaging was obtained of a phantom composed of L1-L3 Sawbones vertebrae in opaque silicone. Preprocedural planning was performed by creating virtual trajectories of appropriate angle and depth for ideal approach into the pedicle, and these data were integrated into the Microsoft HoloLens using the Novarad OpenSight application allowing the user to view the virtual trajectory guides and CT images superimposed on the phantom in two and three dimensions. Spinal needles were inserted following the virtual trajectories to the point of contact with bone. Repeat CT revealed actual needle trajectory, allowing comparison with the ideal preprocedural paths. RESULTS Registration of AR to phantom showed a roughly circular deviation with maximum average radius of 2.5 mm. Users took an average of 200 s to place a needle. Extrapolation of needle trajectory into the pedicle showed that of 36 needles placed, 35 (97%) would have remained within the pedicles. Needles placed approximated a mean distance of 4.69 mm in the mediolateral direction and 4.48 mm in the craniocaudal direction from pedicle bone edge. CONCLUSION To our knowledge, this is the first peer-reviewed report and evaluation of HMD-AR with superimposed 3D guidance utilizing CT for spinal pedicle guide placement for the purpose of cannulation without the use of fluoroscopy.
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Affiliation(s)
- Jacob T Gibby
- School of Medicine and Health Sciences, George Washington University, 2300 I St NW, Washington, DC, 200052, USA
| | - Samuel A Swenson
- School of Medicine and Health Sciences, George Washington University, 2300 I St NW, Washington, DC, 200052, USA
| | - Steve Cvetko
- Novarad Corporation, 752 East 1180 South, Suite 200, American Fork, UT, 84003, USA
| | - Raj Rao
- School of Medicine and Health Sciences, George Washington University, 2300 I St NW, Washington, DC, 200052, USA.,Department of Orthopedic Surgery, George Washington University Hospital, 900 23rd St NW, Washington, DC, 20037, USA
| | - Ramin Javan
- School of Medicine and Health Sciences, George Washington University, 2300 I St NW, Washington, DC, 200052, USA. .,Department of Neuroradiology, George Washington University Hospital, 900 23rd St NW, Suite G2092, Washington, DC, 20037, USA.
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The Effects of Geometrical Parameters of the Pedicle Screw on Its Pullout Strength: In-Vitro Animal Tests. JOURNAL OF ORTHOPEDIC AND SPINE TRAUMA 2017. [DOI: 10.5812/jost.74189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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