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Larrieu D, Baroncini A, Assi A, Roscop C, Boissiere L, Obeid I. Validation of a new method for the radiological measurement of rod curvature in patients with spine deformity. Spine Deform 2024:10.1007/s43390-024-00905-z. [PMID: 38814381 DOI: 10.1007/s43390-024-00905-z] [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: 04/04/2024] [Accepted: 05/21/2024] [Indexed: 05/31/2024]
Abstract
PURPOSE The relationship between rod curvature and postoperative radiographic results is a debated topic. One of the reasons of the heterogeneity of the observed results might reside in the lack of a validated and widely employed method to measure the curvature of the rods. Aim of this study was to present and validate a novel method for rod measurement, which is based on routine X-rays and utilizes a regression algorithm that limits manual measurements and the related errors. METHODS Data from 20 adolescent idiopathic scoliosis/Scheuermann kyphosis (AIS/SK) patients and 35 adult spine deformity (ASD) patients for analysis, with 112 rods in total. An orthogonal reference grid was overlaid on the lateral X-ray; seven points were then marked along each rod and their coordinates recorded in a table. Using these coordinates, a third-order polynomial regression was applied to obtain the rod curvature equation (correlation coefficients > 0.97). Three observers (one surgeon, one experienced and one inexperienced observer) independently applied the developed method to measure the rod angulation of the included patients and performed the measurements twice. The reliability of the method was evaluated in terms of intraclass correlation coefficient (ICC), Bland-Altmann plot and 2SR. RESULTS The intra-observer ICCs for all measurements exceed 0.85, indicating an excellent correlation. For the AIS/SK group, the surgeon showed a slightly lower reliability compared to the other two evaluators (0.93 vs 0.98 and 0.98). However, the surgeon showed a higher reliability in measurements of the rods at the lumbar level, both for L1-S1 and L4-S1 (0.98 vs 0.96 and 0.89; 0.97 vs. 0.85 and 0.91, respectively). The variability also showed excellent results, with a mean variability ranging from 1.09° to 3.76°. The inter-observer ICCs for the three measurement groups showed an excellent reliability for the AIS/SK group (0.98). The reliability was slightly lower but still excellent for the lumbar measurements in ASD patients at L1-S1 (0.89) and L4-S1 (0.83). The results of the 2SR for each measured segment were 4.4° for T5-T11, 5.4° for L1-S1 and 5.5° for L4-S1. CONCLUSION The described method represents a reliable and reproducible way to measure rod curvature. This method is based on routine X-rays and utilizes a regression algorithm that limits manual measurements and the related errors.
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Affiliation(s)
- Daniel Larrieu
- Spine Surgery Unit 1, Bordeaux University Pellegrin Hospital, Bordeaux, France
- ELSAN, Polyclinique Jean Villar, Brugge Cedex, France
| | | | - Ayman Assi
- Saint Joseph University of Beirut, Beirut, Lebanon
| | - Cecile Roscop
- Spine Surgery Unit 1, Bordeaux University Pellegrin Hospital, Bordeaux, France
- ELSAN, Polyclinique Jean Villar, Brugge Cedex, France
| | - Louis Boissiere
- Spine Surgery Unit 1, Bordeaux University Pellegrin Hospital, Bordeaux, France
- ELSAN, Polyclinique Jean Villar, Brugge Cedex, France
| | - Ibrahim Obeid
- Spine Surgery Unit 1, Bordeaux University Pellegrin Hospital, Bordeaux, France
- ELSAN, Polyclinique Jean Villar, Brugge Cedex, France
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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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Sawa AGU, Wangsawatwong P, Lehrman JN, Hostetler T, de Andrada Pereira B, Godzik J, Hlubek RJ, Uribe JS, Turner JD, Kelly BP. Rod Attachment Induces Significant Strain in Lumbosacral Fixation. Clin Spine Surg 2023; 36:E247-E251. [PMID: 36788442 DOI: 10.1097/bsd.0000000000001438] [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: 05/18/2022] [Accepted: 12/01/2022] [Indexed: 02/16/2023]
Abstract
STUDY DESIGN This was a laboratory investigation. OBJECTIVE Rod attachment can induce significant pedicle screw-and-rod pre- strain that may predispose the instrumentation to failure. This study investigated how in vitro L5-S1 rod strain and S1 screw strain during rod-screw attachment (pre-strain) compared with strains recorded during pure-moment bending ( test- strain). SUMMARY OF BACKGROUND DATA The lumbosacral junction is highly vulnerable to construct failure due to rod fatigue fracture, sacral screw pull-out, and screw fatigue fracture. MATERIALS AND METHODS Twelve cadaveric specimens were instrumented with L2-ilium pedicle screws and rod. Strain gauges on contoured rods and sacral screws recorded strains during sequential rod-to-screw tightening (pre-strains). The same instrumented constructs were immediately tested in a 6-degree-of-freedom apparatus under continuous loading to 7.5 Nm in multidirectional bending while recording instrumentation test-strains. Rod and screw pre-strains and test-strains were compared using 1-way repeated-measures analysis of variance followed by Holm-Šidák paired analysis (significant at P <0.05). RESULTS The mean first (171±192 µE) and second (322±269 µE) rod attachment pre-strains were comparable to mean test-strains during flexion (265±109 µE) and extension (315±125 µE, P ≥0.13). The mean rod attachment pre-strain was significantly greater than mean test-strains during bidirectional lateral bending (40±32 µE ipsilateral and 39±32 µE contralateral, P <0.001) and axial rotation (72±60 µE ipsilateral and 60±57 µE contralateral, P <0.001). The mean first and second sacral screw pre-strains during rod attachment (1.03±0.66 and 1.39±1.00 Nm, respectively) did not differ significantly ( P =0.41); however, the mean sacral screw pre-strain during final (second) rod attachment was significantly greater than screw test-strains during all directions of movement (≤0.81 Nm, P ≤0.03). CONCLUSIONS Instrumentation pre-strains imposed during in vitro rod-screw attachment of seemingly well-contoured rods in L2-ilium fixation are comparable to, and at times greater than, strains experienced during in vitro bending. Spine surgeons should be aware of the biomechanical consequences of rod contouring and attachment on construct vulnerability.
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Affiliation(s)
- Anna G U Sawa
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ
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Urbanski W, Markowski P, Zaluski R, Kokaveshi A, Morasiewicz P. Direct Vertebral Rotation (DVR) Does Not Improve Clinical and Radiological Results Compared to Differential Rod Contouring (DRC) in Patients Treated Surgically for Idiopathic Scoliosis. J Clin Med 2023; 12:4091. [PMID: 37373784 DOI: 10.3390/jcm12124091] [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: 02/18/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Direct vertebral rotation (DVR) is the most widespread method to correct axial vertebral rotation. Differential rod contouring (DRC) also includes derotation, but not to the same extent as DVR. DVR requires additional surgical effort with potential consequences, which are absent in DRC; moreover, the data concerning the clinical benefits of apical derotation are not convincing. In the present study, clinical and radiological outcomes were compared in patients who underwent surgery for adolescent idiopathic scoliosis (AIS), having DVR and DRC vs. DRC only. In total, 73 AIS patients with curves of 40-85°, consecutively operated on by one surgeon, participated in this study and were followed up over 2 years. Scores from the SRS-22 questionnaire were analysed, the angles of trunk rotation (ATR) were measured with an inclinometer and a radiographic assessment of coronal and sagittal spinal profiles was conducted. In 38 cases, only DRC was performed, and in 35 DRC was performed and followed by DVR; the groups did not differ from an epidemiological point of view. Total SRS-22 scores after 2 years were similar in both groups (4.23 (±0.33) in DRC vs. 4.06 (±0.33) in DRC/DVR, p = 0.1). In all components of SRS-22, the differences were minor, with p being way above 0.05. The mean ATR in the DRC/DVR group was slightly smaller (8 ± 4°) than that of the DRC group (10 ± 5°), p = 0.16. Radiographic analysis did not show significant differences. The coronal curve was corrected by 66 ± 12% for DRC and 63 ± 15% for DVR, p = 0.28. Thoracic kyphosis in the DRC/DVR group increased by 1°, whereas in the DRC group the average kyphosis increased by 5° with a p value of 0.07. The complication rates were similar in both groups. This investigation did not show any advantages of the combination of DRC and DVR in scoliosis correction over DRC only, both radiologically and clinically, yet it affected intraoperative parameters, extending the operation time with only a minor increase in blood loss.
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Affiliation(s)
- Wiktor Urbanski
- Department of Neurosurgery, Wroclaw Medical University, 50-367 Wroclaw, Poland
| | | | - Rafal Zaluski
- Department of Neurosurgery, Wroclaw Medical University, 50-367 Wroclaw, Poland
| | | | - Piotr Morasiewicz
- Department of Orthopedics and Traumatology, Institute of Medical Sciences, University of Opole, 45-040 Opole, Poland
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Kumar N, Alathur Ramakrishnan S, Lopez KG, Wang N, Madhu S, Vellayappan BA, Tpd Hallinan J, Fuh JYH, Kumar AS. Design and 3D printing of novel titanium spine rods with lower flexural modulus and stiffness profile with optimised imaging compatibility. 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 2023; 32:1953-1965. [PMID: 37052651 DOI: 10.1007/s00586-023-07674-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 03/07/2023] [Accepted: 03/18/2023] [Indexed: 04/14/2023]
Abstract
PURPOSE To manufacture and test 3D printed novel design titanium spine rods with lower flexural modulus and stiffness compared to standard solid titanium rods for use in metastatic spine tumour surgery (MSTS) and osteoporosis. METHODS Novel design titanium spine rods were designed and 3D printed. Three-point bending test was performed to assess mechanical performance of rods, while a French bender was used to assess intraoperative rod contourability. Furthermore, 3D printed spine rods were tested for CT & MR imaging compatibility using phantom setup. RESULTS Different spine rod designs generated includes shell, voronoi, gyroid, diamond, weaire-phelan, kelvin, and star. Tests showed 3D printed rods had lower flexural modulus with reduction ranging from 2 to 25% versus standard rod. Shell rods exhibited highest reduction in flexural modulus of 25% (~ 77.4 GPa) and star rod exhibited lowest reduction in flexural modulus of 2% (100.8GPa). 3D printed rod showed reduction in stiffness ranging from 40 to 59%. Shell rod displayed highest reduction in stiffness of 59% (179.9 N/mm) and gyroid had least reduction in stiffness of 40% (~ 259.2 N/mm). Rod bending test showed that except gyroid, other rod designs demonstrated lesser bending difficulty versus standard rod. All 3D printed rods demonstrated improved CT/MR imaging compatibility with reduced artefacts versus standard rod. CONCLUSION By utilising novel design approach, we successfully generated a spine rod design portfolio with lower flexural modulus/stiffness profile and better CT/MR imaging compatibility for potential use in MSTS/other conditions such as osteoporosis. Thus, exploration of new rod designs in surgical application could enhance treatment outcome and improve quality of life for patients.
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Affiliation(s)
- Naresh Kumar
- Department of Orthopaedic Surgery, National University Health System, Level 11 Tower Block, 1E, Lower Kent Ridge Road, Singapore, 119228, Singapore.
| | - Sridharan Alathur Ramakrishnan
- Department of Orthopaedic Surgery, National University Health System, Level 11 Tower Block, 1E, Lower Kent Ridge Road, Singapore, 119228, Singapore
| | - Keith Gerard Lopez
- Department of Orthopaedic Surgery, National University Health System, Level 11 Tower Block, 1E, Lower Kent Ridge Road, Singapore, 119228, Singapore
| | - Niyou Wang
- Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Sirisha Madhu
- Department of Orthopaedic Surgery, National University Health System, Level 11 Tower Block, 1E, Lower Kent Ridge Road, Singapore, 119228, Singapore
| | - Balamurugan A Vellayappan
- Department of Radiation Oncology, National University Health System, Level 7 Tower Block, 1E, Lower Kent Ridge Road, Singapore, 119228, Singapore
| | - James Tpd Hallinan
- Department of Diagnostic Imaging, National University Hospital, Level 2 National University Hospital Main Building, 5 Lower Kent Ridge Rd, Singapore, 119074, Singapore
| | - Jerry Ying Hsi Fuh
- Department of Mechanical Engineering, National University of Singapore, #04-18 Block EA, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - A Senthil Kumar
- Department of Mechanical Engineering, National University of Singapore, #05-26 Block EA, 9 Engineering Drive 1, Singapore, 117575, Singapore
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Raso J, Chi J, Labaran LA, Frank C, Shen FH. Carbon fiber lumbopelvic reconstruction following sacral giant cell tumor resection: illustrative case. JOURNAL OF NEUROSURGERY. CASE LESSONS 2023; 5:CASE22555. [PMID: 36916526 PMCID: PMC10550644 DOI: 10.3171/case22555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/14/2023] [Indexed: 03/14/2023]
Abstract
BACKGROUND The use of carbon fiber or polyetheretherketone spine constructs has proven to be a safe and effective alternative to standard metal alloy. The mechanical properties of carbon fiber while unique provide a construct that is comparable in strength to previous titanium-based constructs and have additionally shown greater fatigue resistance. These constructs have been especially useful for the mechanical stabilization of the spine following tumor resection. The subsequent interference seen when imaging a patient with a traditional metallic construct is reduced and allows for improved tumor surveillance after the procedure, and a more accurate delivery of radiotherapy when indicated. OBSERVATIONS This case report details the treatment of a 25-year-old female diagnosed with a sacral giant cell tumor. The authors discuss the use of a carbon fiber-reinforced polyetheretherketone for lumbopelvic reconstruction. LESSONS Carbon fiber-reinforced polyetheretherketone with its radiolucency and rigidity is a reliable option for complex spinal reconstruction after tumor resection.
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Ruffilli A, Fiore M, Viroli G, Barile F, Manzetti M, Martikos K, Greggi T, Faldini C. 5.5-mm Cobalt-Chrome vs 6-mm Titanium Alloy Rods in Surgical Treatment of Lenke 1 Adolescent Idiopathic Scoliosis With High-Density Pedicle Screws and Direct Vertebral Rotation on Differently Shaped Rods: A Retrospective Comparative Cohort Study. Int J Spine Surg 2023; 17:25-31. [PMID: 36220777 PMCID: PMC10025857 DOI: 10.14444/8381] [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 gold standard of surgical treatment of adolescent idiopathic scoliosis (AIS) consists of a posterior approach requiring complex 3-dimensional correction with multisegmental pedicle screws and 2 contoured rods. The substantial corrective forces and the ability of the rod to withstand these forces rely on its biomechanical properties. The aim of this study is to compare outcomes of 5.5-mm cobalt-chrome (CoCr) and 6-mm titanium alloy (TiAl) rods in surgical correction in Lenke 1 AIS patients. TiAl has greater elasticity, which may facilitate the correction maneuver, whereas the stiffness of CoCr may result in stronger correction forces. The literature provides no clear indications about which rod may allow better correction and safety. METHODS A total of 64 consecutive patients (30 CoCr vs 34 TiAl) with Lenke 1 AIS <100°, with 2 years minimum follow-up, requiring correction and posterior fusion at our institution were included. The primary outcome measure was coronal and sagittal correction and loss of correction at 2-year follow-up. Secondary outcome measures compared peri- and postoperative complications. RESULTS The mean coronal correction was higher in the CoCr group: -73.6% ± 7.4 vs -65.5% ± 11 (P = 0.001). Mean T5-T12 kyphosis did not change significantly after surgery. In patients with hypokyphosis (<10°), an improvement in thoracic kyphosis was observed in both groups, but the improvement was significantly higher in the TiAl group (P = 0.038). In patients with hyperkyphosis (>40°), a similar reduction in thoracic kyphosis was observed in both groups. At follow-up, no coronal correction loss occurred. The sagittal correction loss was slight (0.5° ± 1.5 for the CoCr group, 1.5° ± 3 for the TiAl group) but statistically higher in the TiAl group (P = 0.032). There were no mechanical complications. One revision was required for infection in the CoCr group. CONCLUSION In this series of Lenke 1 AIS, with the limitations of the study, 5.5-mm CoCr rods have provided better correction in the coronal plane than 6-mm TiAl rods. However, TiAl rods have been found to be associated with higher increase of thoracic kyphosis in hypokyphotic curves, although the clinical relevance of this finding could be questionable. CLINICAL RELEVANCE This article provides surgeons with more information regarding rod material options when correcting Lenke 1 AIS. LEVEL OF EVIDENCE: 3
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Affiliation(s)
| | - Michele Fiore
- IRCCS Istituto Ortopedico Rizzoli (IOR), Bologna, Italy
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Bowden D, Michielli A, Merrill M, Will S. Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adolescent idiopathic scoliosis. Spine Deform 2022; 10:1245-1263. [PMID: 35737287 PMCID: PMC9579082 DOI: 10.1007/s43390-022-00537-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/28/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE To assess surgical and safety outcomes associated with different rod materials and diameters in adolescent idiopathic scoliosis (AIS) surgery. METHODS A systematic literature review and meta-analysis evaluated the surgical management of AIS patients using pedicle screw fixation systems (i.e., posterior rods and pedicle screws) with rods of different materials and sizes. Postoperative surgical outcomes (e.g., kyphosis and coronal correction) and complications (i.e., hyper/hypo-lumbar lordosis, proximal junctional kyphosis, revisions, reoperations, and infections) were assessed. Random-effects models (REMs) pooled data for outcomes reported in ≥ 2 studies. RESULTS Among 75 studies evaluating AIS surgery using pedicle screw fixation systems, 46 described rod materials and/or diameters. Two studies directly comparing titanium (Ti) and cobalt-chromium (CoCr) rods found that CoCr rods provided significantly better postoperative kyphosis angle correction vs. Ti rods during a shorter follow-up (0-3 months, MD = - 2.98°, 95% CI - 5.79 to - 0.17°, p = 0.04), and longer follow-up (≥ 24 months, MD = - 3.99°, 95% CI - 6.98 to - 1.00, p = 0.009). Surgical infection varied from 2% (95% CI 1.0-3.0%) for 5.5 mm rods to 4% (95% CI 2.0-7.0%) for 6 mm rods. Reoperation rates were lower with 5.5 mm rods 1% (95% CI 0.0-3.0%) vs. 6 mm rods [6% (95% CI 2.0-9.0%); p = 0.04]. Differences in coronal angle, lumbar lordosis, proximal junctional kyphosis, revisions, and infections did not differ significantly (p > 0.05) among rods of different materials or diameters. CONCLUSION For AIS, CoCr rods provided better correction of thoracic kyphosis compared to Ti rods. Patients with 5.5 mm rods had fewer reoperations vs. 6.0 and 6.35 mm diameter rods. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Dawn Bowden
- DePuy Synthes Spine, Johnson & Johnson Medical Devices, 325 Paramount Drive, Raynham, MA, 02767, USA.
| | - Annalisa Michielli
- DePuy Synthes Spine, Johnson & Johnson Medical Devices, 325 Paramount Drive, Raynham, MA, 02767, USA
| | - Michelle Merrill
- DePuy Synthes Spine, Johnson & Johnson Medical Devices, 325 Paramount Drive, Raynham, MA, 02767, USA
| | - Steven Will
- DePuy Synthes Spine, Johnson & Johnson Medical Devices, 325 Paramount Drive, Raynham, MA, 02767, USA
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Boeckenfoerde K, Schulze Boevingloh A, Gosheger G, Bockholt S, Lampe LP, Lange T. Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis-The Spinous Processes and Proximal Rod Contouring. J Clin Med 2022; 11:jcm11206098. [PMID: 36294418 PMCID: PMC9604587 DOI: 10.3390/jcm11206098] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/10/2022] [Accepted: 10/15/2022] [Indexed: 11/05/2022] Open
Abstract
Proximal junctional kyphosis (PJK), as one of the most discussed problems after corrective surgery in adolescent idiopathic scoliosis (AIS), is still not fully clarified and seems to be multifactorial. Biomechanical and a few clinical studies have shown the influence of destruction of posterior ligaments by resection of spinous processes and some parameters concerning rod contouring as risk factors for PJK. To verify these results, 192 patients with AIS and corrective surgery via a posterior approach between 2009 and 2017 were included. Radiographic parameters were analyzed preoperatively (preOP), postoperatively (postOP), and with a mean follow up (FU) of 27 months. The participants were divided into two groups (PJK group and non-PJK group). The incidence of PJK was 15.6%. Contrary to the results of biomechanical studies, we could not find any significant influence of the spinous process resection. However, the PJK group had significantly larger preOP T4-T12 kyphosis (31.1° ± 13.93° vs. 23.3° ± 14.93°, p = 0.016). Furthermore, the PJK group showed a significantly larger rod contour angle (RCA) (8.0° ± 4.44° vs. 5.9° ± 3.28°, p = 0.003) and mismatch of postOP proximal junctional angle (PJA) and RCA (3.5° ± 5.72° vs. 0.9° ± 4.86°, p = 0.010) compared to the non-PJK group. An increase in the mismatch of postOP PJA and RCA (OR = 1.14, p = 0.008) and a high RCA are risk factors for PJK and need to be focused on by surgeons.
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Affiliation(s)
- Kathrin Boeckenfoerde
- Department of Orthopedics and Tumor Orthopedics, Muenster University Hospital, 48149 Muenster, Germany
| | - Albert Schulze Boevingloh
- Department of Orthopedics and Tumor Orthopedics, Muenster University Hospital, 48149 Muenster, Germany
| | - Georg Gosheger
- Department of Orthopedics and Tumor Orthopedics, Muenster University Hospital, 48149 Muenster, Germany
| | - Sebastian Bockholt
- Department of Orthopedics and Tumor Orthopedics, Muenster University Hospital, 48149 Muenster, Germany
| | - Lukas Peter Lampe
- Department of Orthopedics and Trauma Surgery, St. Josef-Hospital, Ruhr-University Bochum, 44791 Bochum, Germany
| | - Tobias Lange
- Department of Orthopedics and Trauma Surgery, St. Josef-Hospital, Ruhr-University Bochum, 44791 Bochum, Germany
- Correspondence: ; Tel.: +49-234-509-6502
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Pareatumbee P, Zainul-Abidin S, Yew A, Chou SM, Howe TS, Koh JSB, Tan MH. Effect of implant length variations on stress shielding in proximal humeral replacement after tumor excision under torsion: Finite element study. J Orthop Res 2022; 41:1139-1147. [PMID: 36200541 DOI: 10.1002/jor.25456] [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: 06/19/2022] [Revised: 09/01/2022] [Accepted: 10/01/2022] [Indexed: 02/04/2023]
Abstract
The proximal humerus is the most common site of occurrence of primary bone tumors in the upper limb. Endoprosthetic replacement is deemed as the preferred reconstructive option following primary resection of bone tumors. However, it has been also associated with complications such as stress shielding and aseptic loosening compromising prosthetic survival. Our objective was to conduct a finite element (FE) study to investigate the effect of varying endoprosthesis length on bone stresses as well as to quantify the extent of stress shielding across the bone length (BL) in a humerus-prosthesis assembly for proximal humeral replacement after tumor excision thereby allowing us to identify the optimal implant length with best biomechanical performance. FE models of the intact humerus and humerus-prosthesis assemblies were established where they were loaded at the elbow joint under torsion with the glenohumeral joint fixed to represent twisting. After dividing the bone into individual slices consisting of 5% BL, the maximum cortical and cancellous principal, von Mises and shear bone stresses were calculated. To measure the level of stress shielding, the percentage stress change from the intact state was evaluated across each slice. Similar stress patterns were observed between the intact state and shorter endoprosthesis compared to the longer endoprostheses. Our findings illustrated the possibility of stress shielding occurring under torsional forces with its effect increasing with implant lengthening. To conclude, we believe that using a shorter prosthesis may substantially diminish the risk of potential implant failure due to stress shielding.
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Affiliation(s)
- Pivatidevi Pareatumbee
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore
| | - Suraya Zainul-Abidin
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore.,Department of Orthopedic Surgery, Singapore General Hospital, Singapore, Singapore.,Division of Musculoskeletal Sciences, Singapore General Hospital, Singapore, Singapore
| | - Andy Yew
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore.,Division of Musculoskeletal Sciences, Singapore General Hospital, Singapore, Singapore
| | - Siaw M Chou
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore
| | - Tet Sen Howe
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore.,Department of Orthopedic Surgery, Singapore General Hospital, Singapore, Singapore.,Division of Musculoskeletal Sciences, Singapore General Hospital, Singapore, Singapore
| | - Joyce S B Koh
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore.,Department of Orthopedic Surgery, Singapore General Hospital, Singapore, Singapore.,Division of Musculoskeletal Sciences, Singapore General Hospital, Singapore, Singapore
| | - Mann Hong Tan
- Singhealth-Duke NUS Musculoskeletal Sciences Academic Clinical Program, Singapore General Hospital, Singapore, Singapore.,Department of Orthopedic Surgery, Singapore General Hospital, Singapore, Singapore.,Division of Musculoskeletal Sciences, Singapore General Hospital, Singapore, Singapore
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11
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Suominen EN, Saarinen AJ, Syvänen J, Ahonen M, Helenius L, Helenius IJ. Beam-Like rods do not Provide Additional Improvement to Thoracic Kyphosis Restoration when Compared to Sagittal Reinforced rods in Adolescents Undergoing Spinal Fusion with Pedicle Screw Instrumentation for Idiopathic Scoliosis. World Neurosurg 2022; 168:e555-e561. [DOI: 10.1016/j.wneu.2022.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/07/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022]
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12
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Metallic Implants Used in Lumbar Interbody Fusion. MATERIALS 2022; 15:ma15103650. [PMID: 35629676 PMCID: PMC9146470 DOI: 10.3390/ma15103650] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/07/2023]
Abstract
Over the last decade, pedicle fixation systems have evolved and modifications in spinal fusion techniques have been developed to increase fusion rates and improve clinical outcomes after lumbar interbody fusion (LIF). Regarding materials used for screw and rod manufacturing, metals, especially titanium alloys, are the most popular resources. In the case of pedicle screws, that biomaterial can be also doped with hydroxyapatite, CaP, ECM, or tantalum. Other materials used for rod fabrication include cobalt-chromium alloys and nitinol (nickel-titanium alloy). In terms of mechanical properties, the ideal implant used in LIF should have high tensile and fatigue strength, Young's modulus similar to that of the bone, and should be 100% resistant to corrosion to avoid mechanical failures. On the other hand, a comprehensive understanding of cellular and molecular pathways is essential to identify preferable characteristics of implanted biomaterial to obtain fusion and avoid implant loosening. Implanted material elicits a biological response driven by immune cells at the site of insertion. These reactions are subdivided into innate (primary cellular response with no previous exposure) and adaptive (a specific type of reaction induced after earlier exposure to the antigen) and are responsible for wound healing, fusion, and also adverse reactions, i.e., hypersensitivity. The main purposes of this literature review are to summarize the physical and mechanical properties of metal alloys used for spinal instrumentation in LIF which include fatigue strength, Young's modulus, and corrosion resistance. Moreover, we also focused on describing biological response after their implantation into the human body. Our review paper is mainly focused on titanium, cobalt-chromium, nickel-titanium (nitinol), and stainless steel alloys.
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13
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Burke CA, Speirs JN, Nelson SC. Maximizing mechanical advantage: surgical technique increases stiffness in spinal instrumentation. Spine Deform 2022; 10:295-299. [PMID: 34748141 DOI: 10.1007/s43390-021-00425-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/08/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE While there has been a great improvement in the treatment of adolescent idiopathic scoliosis, sagittal deformity correction has remained challenging. Increased rod stiffness has been shown to reduce thoracic flattening. We propose that the surgical technique can increase rod stiffness. A mechanical study was created to quantify the effect this has on construct stiffness. METHODS The sagittal bending stiffness of a constrained over contoured rod was measured using four different commonly used instrumentation systems. Pedicle screws were secured into custom printed blocks. One block was completely immobilized, while the other block was subject to four levels of constraint. This includes no constraint, mild constraint, moderate constraint, and maximal constraint with both blocks immobilized. The rod apex was loaded until 1 cm of displacement occurred. The stiffness was then calculated and compared between groups. RESULTS All four rod types showed increased bending stiffness as the construct became more constrained. The moderately constrained and the maximally constrained groups had a significantly higher stiffness compared to the unconstrained groups in all rod types (p < 0.05). The 6.0 mm titanium circular rods showed the highest increase in stiffness between maximal and no constraint, which became 3.02 × stiffer. CONCLUSIONS Rod stiffness is not only determined by size, shape, and metal alloy, but also by surgical technique. Constraining the spinal instrumentation by first locking the rod to the proximal and distal anchors significantly increases the sagittal bending stiffness. In a mechanical model this technique increases rod bending stiffness regardless of the material or shape.
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Affiliation(s)
- Corey A Burke
- Department of Orthopaedic Surgery, Loma Linda University, 11406 Loma Linda Drive, Suite 213, Loma Linda, CA, 02354, USA
| | - Joshua N Speirs
- Department of Orthopaedic Surgery, Loma Linda University, 11406 Loma Linda Drive, Suite 213, Loma Linda, CA, 02354, USA.
| | - Scott C Nelson
- Department of Orthopaedic Surgery, Loma Linda University, 11406 Loma Linda Drive, Suite 213, Loma Linda, CA, 02354, USA
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14
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Eltes PE, Turbucz M, Fayad J, Bereczki F, Szőke G, Terebessy T, Lacroix D, Varga PP, Lazary A. A Novel Three-Dimensional Computational Method to Assess Rod Contour Deformation and to Map Bony Fusion in a Lumbopelvic Reconstruction After En-Bloc Sacrectomy. Front Surg 2022; 8:698179. [PMID: 35071306 PMCID: PMC8766313 DOI: 10.3389/fsurg.2021.698179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: En-bloc resection of a primary malignant sacral tumor with wide oncological margins impacts the biomechanics of the spinopelvic complex, deteriorating postoperative function. The closed-loop technique (CLT) for spinopelvic fixation (SPF) uses a single U-shaped rod to restore the spinopelvic biomechanical integrity. The CLT method was designed to provide a non-rigid fixation, however this hypothesis has not been previously tested. Here, we establish a computational method to measure the deformation of the implant and characterize the bony fusion process based on the 6-year follow-up (FU) data. Materials and Methods: Post-operative CT scans were collected of a male patient who underwent total sacrectomy at the age of 42 due to a chordoma. CLT was used to reconstruct the spinopelvic junction. We defined the 3D geometry of the implant construct. Using rigid registration algorithms, a common coordinate system was created for the CLT to measure and visualize the deformation of the construct during the FU. In order to demonstrate the cyclical loading of the construct, the patient underwent gait analysis at the 6th year FU. First, a region of interest (ROI) was selected at the proximal level of the construct, then the deformation was determined during the follow-up period. In order to investigate the fusion process, a single axial slice-based voxel finite element (FE) mesh was created. The Hounsfield values (HU) were determined, then using an empirical linear equation, bone mineral density (BMD) values were assigned for every mesh element, out of 10 color-coded categories (1st category = 0 g/cm3, 10th category 1.12 g/cm3). Results: Significant correlation was found between the number of days postoperatively and deformation in the sagittal plane, resulting in a forward bending tendency of the construct. Volume distributions were determined and visualized over time for the different BMD categories and it was found that the total volume of the elements in the highest BMD category in the first postoperative CT was 0.04 cm3, at the 2nd year, FU was 0.98 cm3, and after 6 years, it was 2.30 cm3. Conclusion: The CLT provides a non-rigid fixation. The quantification of implant deformation and bony fusion may help understate the complex lumbopelvic biomechanics after sacrectomy.
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Affiliation(s)
- Peter Endre Eltes
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
- Department of Spine Surgery, Semmelweis University, Budapest, Hungary
- *Correspondence: Peter Endre Eltes
| | - Mate Turbucz
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
- School of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Jennifer Fayad
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
- Department of Industrial Engineering, Alma Mater Studiorum, Universita di Bologna, Bologna, Italy
| | - Ferenc Bereczki
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
- School of PhD Studies, Semmelweis University, Budapest, Hungary
| | - György Szőke
- Department of Orthopaedics, Semmelweis University, Budapest, Hungary
| | - Tamás Terebessy
- Department of Orthopaedics, Semmelweis University, Budapest, Hungary
| | - Damien Lacroix
- INSIGNEO Institute for In Silico Medicine, Department of Mechanical Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - Peter Pal Varga
- National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
| | - Aron Lazary
- Department of Spine Surgery, Semmelweis University, Budapest, Hungary
- National Center for Spinal Disorders, Buda Health Center, Budapest, Hungary
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15
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Hong YG, Kim HC, Jeon H, An SB, Lee JY, Lee JJ, Kim KJ, Kim CO, Shin DA, Yi S, Kim KN, Yoon DH, Kim TW, Ha Y. Association of frailty with regional sagittal spinal alignment in the elderly. J Clin Neurosci 2021; 96:172-179. [PMID: 34836786 DOI: 10.1016/j.jocn.2021.10.008] [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: 05/21/2020] [Revised: 07/14/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022]
Abstract
The degenerative changes in the spine of the frail elderly gradually exacerbate the alignment of the spine as the degeneration progresses. This study was conducted to assess the relationship between frailty and spine sagittal alignment measured in terms of global, cervical, thoracic, and lumbo-pelvic parameters. In total, 101 patients aged 75 years and older hospitalized for spine surgery were prospectively enrolled. We evaluated spinal sagittal parameters by dividing them into global (C7 sagittal vertical axis [SVA] and T1 pelvic angle [T1PA]), cervical (the C2-7 Cobb angle, Jackson line, and C2-7 plumb line), thoracic (thoracic kyphosis [TK]), and lumbo-pelvic (pelvic tilt [PT] and pelvic incidence minus lumbar lordosis value [PI-LL]). Patient characteristics; the Fatigue, Resistance, Ambulation, Illness, Loss of Weight (FRAIL) scale; and sagittal spinal parameters were included in the analysis. Multiple regression analysis was performed to identify associations between the FRAIL scale and sagittal spinal parameters. The FRAIL scale showed correlations with global sagittal parameters (C7 SVA [β = 0.225, p = 0.029] and T1PA [β = 0.273, p = 0.008]) and lumbo-pelvic parameters (PT [β = 0.294, p = 0.004] and PI-LL [β = 0.323, p = 0.001). Cervical and thoracic parameters were not directly associated with the FRAIL scale. LL and PI-LL were associated with TK, and TK was associated with cervical parameters (the C2-7 Cobb angle, Jackson line and C2-7 plumb line). In conclusion, frailty status could be an important factor that influences sagittal spinal alignment in the elderly. In this study, it was found that frailty mainly affected the balance of lumbo-pelvic alignment, and consequently affected the balance of the whole spine.
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Affiliation(s)
- Yun Gi Hong
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Hyung-Cheol Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Hyeongseok Jeon
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Seong Bae An
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Ji Yeon Lee
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Jong Joo Lee
- Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University College of Medicine, Seoul, Republic of Korea
| | - Kwang Joon Kim
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Chang Oh Kim
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Dong Ah Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Seong Yi
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Keung Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Do Heum Yoon
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Tae Woo Kim
- Department of Medicine, Yonsei University Graduate School, Seoul, Republic of Korea; Department of Neurosurgery, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea.
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Republic of Korea.
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16
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Prost S, Pesenti S, Farah K, Tropiano P, Fuentes S, Blondel B. Sagittal reduction of spinal deformity: Superior versus lateral screw-rod connection. Orthop Traumatol Surg Res 2021; 107:102954. [PMID: 33951541 DOI: 10.1016/j.otsr.2021.102954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/28/2020] [Accepted: 11/16/2020] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Spinal malalignment can greatly impact a patient's quality of life. Various sagittal parameters are used as realignment goals; however, about 50% of patients end up being under-corrected postoperatively. To improve the correction, prebent rods are available with a radius of curvature corresponding to the patient's "ideal" sagittal alignment. But no studies have been done on how the radius of curvature changes according to the type of connection between the pedicle screws and rods. The goal of this experimental study was to quantify how much prebent rods flatten based on the method used to connect the screw and rod: top-loading screw vs. dome screw with lateral connector. METHODS The experiment was done on a material testing system in axial compression on three constructs consisting of two rods secured with top-loading screws and three other constructs consisting of two rods secured with dome screws and lateral connector. The maximum angle of the construct was measured during loading and after removing the load. The primary outcome measure was the mean angle in each construct at each step. RESULTS The mean angle of the constructs with top-loading screws when subjected to 500 N load was significantly less than in the constructs with dome screws and lateral connector: 18.6° vs. 24.5° respectively (p<0.0003). The mean angle of the constructs with top-loading screws after removing the load was significantly less than in the constructs with dome screws and lateral connector: 25.7° vs. 32.3° respectively, (p<0.0005). CONCLUSION In vitro, top-loading screws produced significantly greater flattening than dome screws with lateral connector. These findings must be confirmed in vivo. Understanding the behavior of rods as a function of the type of screw connection can be an important factor to minimize the risk of under-correction in the sagittal plane. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Solène Prost
- Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Unité de chirurgie rachidienne, 264, rue Saint-Pierre, 13005 Marseille, France
| | - Sébastien Pesenti
- Service de chirurgie orthopédique pédiatrique, Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, 264, rue Saint-Pierre, 13005 Marseille, France
| | - Kaissar Farah
- Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Unité de chirurgie rachidienne, 264, rue Saint-Pierre, 13005 Marseille, France
| | - Patrick Tropiano
- Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Unité de chirurgie rachidienne, 264, rue Saint-Pierre, 13005 Marseille, France
| | - Stéphane Fuentes
- Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Unité de chirurgie rachidienne, 264, rue Saint-Pierre, 13005 Marseille, France
| | - Benjamin Blondel
- Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Unité de chirurgie rachidienne, 264, rue Saint-Pierre, 13005 Marseille, France.
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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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18
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de Andrada Pereira B, Lehrman JN, Sawa AGU, Lindsey DP, Yerby SA, Godzik J, Waguespack AM, Uribe JS, Kelly BP. Biomechanical effects of a novel posteriorly placed sacroiliac joint fusion device integrated with traditional lumbopelvic long-construct instrumentation. J Neurosurg Spine 2021; 35:320-329. [PMID: 34144523 DOI: 10.3171/2020.11.spine201540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/24/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE S2-alar-iliac (S2AI) screw fixation effectively ensures stability and enhances fusion in long-segment constructs. Nevertheless, pelvic fixation is associated with a high rate of mechanical failure. Because of the transarticular nature of the S2AI screw, adding a second point of fixation may provide additional stability and attenuate strains. The objective of the study was to evaluate changes in stability and strain with the integration of a sacroiliac (SI) joint fusion device, implanted through a novel posterior SI approach, supplemental to posterior long-segment fusion. METHODS L1-pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests in the following conditions: 1) intact, 2) L2-S1 pedicle screw and rod fixation with L5-S1 interbody fusion, 3) added S2AI screws, and 4) added bilateral SI joint fixation (SIJF). The range of motion (ROM), rod strain, and screw bending moments (S1 and S2AI) were analyzed. RESULTS S2AI fixation decreased L2-S1 ROM in flexion-extension (p ≤ 0.04), L5-S1 ROM in flexion-extension and compression (p ≤ 0.004), and SI joint ROM during flexion-extension and lateral bending (p ≤ 0.03) compared with S1 fixation. SI joint ROM was significantly less with SIJF in place than with the intact joint, S1, and S2AI fixation in flexion-extension and lateral bending (p ≤ 0.01). The S1 screw bending moment decreased following S2AI fixation by as much as 78% in extension, but with statistical significance only in right axial rotation (p = 0.03). Extending fixation to S2AI significantly increased the rod strain at L5-S1 during flexion, axial rotation, and compression (p ≤ 0.048). SIJF was associated with a slight increase in rod strain versus S2AI fixation alone at L5-S1 during left lateral bending (p = 0.048). Compared with the S1 condition, fixation to S2AI increased the mean rod strain at L5-S1 during compression (p = 0.048). The rod strain at L5-S1 was not statistically different with SIJF compared with S2AI fixation (p ≥ 0.12). CONCLUSIONS Constructs ending with an S2AI screw versus an S1 screw tended to be more stable, with reduced SI joint motion. S2AI fixation decreased the S1 screw bending moments compared with fixation ending at S1. These benefits were paired with increased rod strain at L5-S1. Supplementation of S2AI fixation with SIJF implants provided further reductions (approximately 30%) in the sagittal plane and lateral bending SI joint motion compared with fixation ending at the S2AI position. This stability was not paired with significant changes in rod or screw strains.
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Affiliation(s)
| | | | - Anna G U Sawa
- 1Department of Neurosurgery, Spinal Biomechanics Laboratory, and
| | | | | | - Jakub Godzik
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | | | - Juan S Uribe
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Brian P Kelly
- 1Department of Neurosurgery, Spinal Biomechanics Laboratory, and
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Wang B, Feng C, Pan J, Zhou S, Sun Z, Shao Y, Qu Y, Bao S, Li Y, Yang T. The Effect of 3D Printing Metal Materials on Osteoporosis Treatment. BIOMED RESEARCH INTERNATIONAL 2021; 2021:9972867. [PMID: 34239938 PMCID: PMC8233068 DOI: 10.1155/2021/9972867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/09/2021] [Indexed: 12/27/2022]
Abstract
3D printing has been in use for a long time and has continued to contribute to breakthroughs in the fields of clinical, physical, and rehabilitation medicine. In order to evaluate the role of 3D printing technology in treating spinal disorders, this paper presents a systematic review of the relevant literature. 3D printing is described in terms of its adjunctive function in various stages of spinal surgery and assistance in osteoporosis treatment. A review of metal 3D printed materials and applications of the technology is also provided.
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Affiliation(s)
- Bing Wang
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Chuwen Feng
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, 26 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Jianyu Pan
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Shuoyan Zhou
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Zhongren Sun
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Yuming Shao
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Yuanyuan Qu
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Shengyong Bao
- Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, Department of Rehabilitation Medicine, Shenzhen 518120, China
| | - Yang Li
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, 26 Heping Road, Xiangfang District, Harbin 8615-0040, China
| | - Tiansong Yang
- Heilongjiang University of Chinese Medicine, 24 Heping Road, Xiangfang District, Harbin 8615-0040, China
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, 26 Heping Road, Xiangfang District, Harbin 8615-0040, China
- Shenzhen People's Hospital, Second Clinical Medical College of Jinan University, Department of Rehabilitation Medicine, Shenzhen 518120, China
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Sakai D, Tanaka M, Takahashi J, Taniguchi Y, Schol J, Hiyama A, Misawa H, Kuraishi S, Oba H, Matsubayashi Y, Kato S, Sugawara R, Sato M, Watanabe M, Takeshita K. Cobalt-chromium versus titanium alloy rods for correction of adolescent idiopathic scoliosis based on 1-year follow-up: a multicenter randomized controlled clinical trial. J Neurosurg Spine 2021; 34:897-906. [PMID: 33740765 DOI: 10.3171/2020.9.spine201486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/21/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE For instrumented correction surgery for adolescent idiopathic scoliosis (AIS), surgeons are increasingly switching from titanium (Ti) alloy rods to stiffer cobalt-chromium (CoCr) rods. The authors conducted the first multicenter randomized controlled clinical trial to investigate whether these materials affect the outcomes in terms of spine correction and quality of life (QOL). This trial was registered at UMIN Clinical Trials Registry on September 3, 2012, under the identifier UMIN000008838 (level of evidence 1). METHODS Female AIS patients (Lenke types 1-3, patient age 10-19 years) were recruited at 5 Japanese institutions and randomized into two cohorts: 6.0-mm-diameter Ti rods were placed in one group, and 6.0-mm-diameter CoCr rods were placed in the other. Patients were followed up at 2 weeks and 3, 6, and 12 months with radiographic examination to quantify the sagittal and coronal correction (Cobb angle, thoracic kyphosis, rib hump, and apical vertebral rotation). Patients completed questionnaires (Scoliosis Research Society-22r, 12-Item Short-Form Health Survey, and Scoliosis Japanese Questionnaire-27) at 6 and 12 months to assess QOL. RESULTS A total of 69 AIS patients were randomized to the demographically similar Ti (n = 37) or CoCr (n = 32) cohort. Four adverse events were recorded, two in each cohort, but these were not related to the rod material. At the final follow-up, both Ti and CoCr cohorts showed significant improvement in spinal correction, including the Cobb angle, thoracic kyphosis, and rib hump size. The correction rates were 68.4% and 67.1% for the Ti and CoCr cohorts, respectively. No parameters differed significantly between the cohorts at any time. Survey data showed improved but similar outcomes in both cohorts. CONCLUSIONS Both treatments (Ti and CoCr) produced similar results and were efficient in engendering clinically significant spine corrections. Clinical trial registration no.: UMIN000008838 (UMIN Clinical Trials Registry).
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Affiliation(s)
- Daisuke Sakai
- 1Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa
| | - Masato Tanaka
- 2Department of Orthopaedic Surgery, Okayama Rosai Hospital, Okayama
| | - Jun Takahashi
- 3Department of Orthopaedic Surgery, Shinshu University School of Medicine, Nagano
| | - Yuki Taniguchi
- 4Department of Orthopaedic Surgery, The University of Tokyo
| | - Jordy Schol
- 1Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa
| | - Akihiko Hiyama
- 1Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa
| | - Haruo Misawa
- 5Department of Orthopaedic Surgery, Okayama University School of Medicine, Okayama; and
| | - Shugo Kuraishi
- 3Department of Orthopaedic Surgery, Shinshu University School of Medicine, Nagano
| | - Hiroki Oba
- 3Department of Orthopaedic Surgery, Shinshu University School of Medicine, Nagano
| | | | - So Kato
- 4Department of Orthopaedic Surgery, The University of Tokyo
| | - Ryo Sugawara
- 6Department of Orthopaedics, Jichi Medical University, Tochigi, Japan
| | - Masato Sato
- 1Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa
| | - Masahiko Watanabe
- 1Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa
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La Barbera L, Larson AN, Aubin CE. How do spine instrumentation parameters influence the 3D correction of thoracic adolescent idiopathic scoliosis? A patient-specific biomechanical study. Clin Biomech (Bristol, Avon) 2021; 84:105346. [PMID: 33848703 DOI: 10.1016/j.clinbiomech.2021.105346] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/24/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Patient-specific models promises to support the surgical decision-making process, particularly in adolescent idiopathic scoliosis. The present computational biomechanical study investigates how specific instrumentation parameters impact 3D deformity correction in thoracic scoliosis. METHODS 1080 instrumentation simulations of a representative patient were run. The independent instrumentation parameters were: screw pattern, upper and lower instrumented vertebrae, rod curvature and rod stiffness. ANOVA and correlation analyses analyzed how the instrumentation parameters influenced the 3D correction. FINDINGS Coronal plane correction was affected by the lower instrumented vertebra and rod stiffness (explaining 84% and 11%, respectively, of its overall variance). The sagittal profile was controlled by rod curvature and the upper vertebra (56% and 36%). The transverse plane vertebral rotation was influenced by lower, upper instrumented vertebra and screw pattern (35%, 32% and 19%). The Cobb angle correction was strongly correlated with the number of fused vertebrae, particularly when grouped by the upper instrumented vertebra (r = -0.91) and rod stiffness (r = -0.73). Thoracic kyphosis was strongly correlated with the number of fused vertebrae grouped by rod curvature (r = 0.84). Apical vertebral rotation was moderately correlated with the number of fused vertebrae grouped by upper/lower instrumented vertebra (r = 0.55/0.58), although variations were minimal. INTERPRETATION Instrumenting the last vertebra touching the central sacral vertical line improves 3D correction. A trade-off between a more cranial vs. caudal upper instrumented vertebra, respectively beneficial for coronal/sagittal vs. transverse plane correction, is required. High rod stiffness, differential rod contouring, and screw pattern were effective for coronal correction, thoracic kyphosis, and axial vertebral derotation, respectively.
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Affiliation(s)
- Luigi La Barbera
- Department of Mechanical Engineering, Polytechnique Montréal, Montréal, Québec, Canada; Sainte-Justine University Hospital Centre, Montréal, Québec, Canada; Department of Chemistry, Materials and Chemical Engineering, Politecnico di Milano, Milan, Italy.
| | - A Noelle Larson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Carl-Eric Aubin
- Department of Mechanical Engineering, Polytechnique Montréal, Montréal, Québec, Canada; Sainte-Justine University Hospital Centre, Montréal, Québec, Canada
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22
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Jung JM, Hyun SJ, Kim KJ. Surgical Impacts of Metastatic Non-small Cell Lung Cancer to the Thoracic and Lumbar Spine. J Korean Med Sci 2021; 36:e52. [PMID: 33619918 PMCID: PMC7900527 DOI: 10.3346/jkms.2021.36.e52] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/06/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Surgery for spinal metastasis is rapidly increasing in frequency with procedures ranging from laminectomy to spondylectomy combined with stabilization. This study investigated the effect of various surgical procedures for spinal metastasis of non-small cell lung cancer (NSCLC). METHODS A single-center consecutive series of patients who underwent surgery for spinal metastasis of NSCLC were retrospectively reviewed. Patients' characteristics, radiographic parameters, operative data, clinical outcomes, and complications were analyzed. Surgical outcomes were assessed according to pain and performance status before and after surgery. Overall survival (OS) rate was estimated using the Kaplan-Meier method. Multivariate analysis was performed to detect factors independently associated with OS using a Cox proportional hazards model. RESULTS Twenty-one patients were treated with laminectomy, 24 with corpectomy, 13 with spondylectomy (piecemeal or total en bloc fashion), and all procedures were combined with stabilization. Back pain and performance status improved significantly after surgical treatment among the three groups. Revision surgery due to tumor progression at the index level or spinal metastasis at another level were four patients (19.0%) in the laminectomy group, six patients (25.0%) in the corpectomy group, and one patient (7.7%) in the spondylectomy group. A Charlson comorbidity index and the number of spinal metastasis negatively affected OS (hazard ratio [HR], 19.613 and 2.244). Postoperative chemotherapy, time to metastasis, spondylectomy, and corpectomy had favorable associations with OS (HR, 0.455, 0.487, 0.619, and 0.715, respectively). CONCLUSION Postoperative chemotherapy was the most critical factor in OS of patients with metastatic NSCLC to the spine. An extensive surgical procedure (corpectomy/spondylectomy) with stabilization also could be beneficial for limited patients with spinal metastasis of NSCLC.
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Affiliation(s)
- Jong Myung Jung
- Department of Neurosurgery, Spine Center, Gachon University Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
| | - Seung Jae Hyun
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
| | - Ki Jeong Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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La Barbera L, Larson AN, Rawlinson J, Aubin CE. In silico patient-specific optimization of correction strategies for thoracic adolescent idiopathic scoliosis. Clin Biomech (Bristol, Avon) 2021; 81:105200. [PMID: 33317937 DOI: 10.1016/j.clinbiomech.2020.105200] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND With modelling and simulation (or in silico) techniques, patient-specific optimization algorithms represent promising tools to support the surgical decision-making process, particularly in 3D correction of adolescent idiopathic scoliosis, where the best intraoperative instrumentation strategy and the correction goals are debated. METHODS 1080 biomechanical intraoperative simulations of a representative pediatric thoracic curve were run according to a full-factorial design approach. Widely accepted instrumentation configurations (5 screw patterns, 4 upper and 3 lower instrumented vertebrae, 6 rod curvatures and 3 rod stiffnesses) were analyzed, assuming concave rod rotation and en bloc derotation as main correction maneuvers. Results in terms of 3D correction and mobility were rated using an objective function for thoracic scoliosis also including surgeon-dependent correction objectives. An extensive sensitivity analysis on correction objectives was performed. FINDINGS Multiple optimal strategies were identified, depending on the selected correction objective. They provided significantly better coronal (67% vs. 55%) correction, using comparable instrumented levels (9.9 ± 1.6 vs. 10.7 ± 2.1), screw patterns and significantly higher implant density (1.6 ± 0.3 vs. 1.4 ± 0.2 screws/vertebra) compared to worst ones. Optimal strategies typically included the neutral and the last touching vertebrae in the construct and high stiffness (CoCr, 6 mm) differentially/highly contoured rods. INTERPRETATION The computerized algorithm determined the best instrumentation parameters to achieve optimal correction for the considered thoracic case. Multiple clinically equivalent strategies may be used, as supported by the variety of considered correction objectives. The current approach could be translated to any scoliotic curves, including surgeon preferences in terms of instrumentation parameters, intraoperative correction maneuvers and correction objectives.
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Affiliation(s)
- Luigi La Barbera
- Department of Mechanical Engineering, Polytechnique Montréal, Montréal, Québec, Canada; Sainte-Justine University Hospital Centre, Montréal, Québec, Canada.
| | - A Noelle Larson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Jeremy Rawlinson
- Department of Mechanical Engineering, Polytechnique Montréal, Montréal, Québec, Canada; Medtronic, Spinal Applied Research, Memphis, TN, USA
| | - Carl-Eric Aubin
- Department of Mechanical Engineering, Polytechnique Montréal, Montréal, Québec, Canada; Sainte-Justine University Hospital Centre, Montréal, Québec, Canada
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24
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Boddapati V, Lombardi JM, Urakawa H, Lehman RA. Intraoperative image guidance for the surgical treatment of adult spinal deformity. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:91. [PMID: 33553384 PMCID: PMC7859785 DOI: 10.21037/atm-20-2765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 06/11/2020] [Indexed: 01/02/2023]
Abstract
Operative management of adult spinal deformity (ASD) has been increasing in recent years secondary to an aging society. The advance of intraoperative image guidance, such as the development of navigation and robotics systems has contributed to the growth and safety of ASD surgery. Currently, intraoperative image guidance is mainly used for pedicle screw placement and the evaluation of alignment correction in ASD surgery. Though it is expected that the use of navigation and robotics would result in increasing pedicle screw accuracy as reported in other spine surgeries, there are no well-powered studies specifically focusing on ASD surgery. Currently, deformity correction relies heavily on preoperative planning, however, a few studies have shown the possibility that intraoperative image modalities may accurately predict postoperative spinopelvic parameters. Future developments of intraoperative image guidance are needed to overcome the remaining challenges in ASD surgery such as radiation exposure to patient and surgeon. More novel imaging modalities may result in evolution in ASD surgery. Overall there is a paucity of literature focusing on intraoperative image guidance in ASD surgery, therefore, further studies are warranted to assess the efficacy of intraoperative image guidance in ASD surgery. This narrative review sought to provide the current role and future perspectives of intraoperative image guidance focusing on ASD surgery.
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Affiliation(s)
- Venkat Boddapati
- The Spine Hospital, New York-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
| | - Joseph M. Lombardi
- The Spine Hospital, New York-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
| | | | - Ronald A. Lehman
- The Spine Hospital, New York-Presbyterian/Columbia University Irving Medical Center, New York, NY, USA
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25
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Liao C, Li Y, Tjong SC. Polyetheretherketone and Its Composites for Bone Replacement and Regeneration. Polymers (Basel) 2020; 12:E2858. [PMID: 33260490 PMCID: PMC7760052 DOI: 10.3390/polym12122858] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 12/18/2022] Open
Abstract
In this article, recent advances in the development, preparation, biocompatibility and mechanical properties of polyetheretherketone (PEEK) and its composites for hard and soft tissue engineering are reviewed. PEEK has been widely employed for fabricating spinal fusions due to its radiolucency, chemical stability and superior sterilization resistance at high temperatures. PEEK can also be tailored into patient-specific implants for treating orbital and craniofacial defects in combination with additive manufacturing process. However, PEEK is bioinert, lacking osseointegration after implantation. Accordingly, several approaches including surface roughening, thin film coating technology, and addition of bioactive hydroxyapatite (HA) micro-/nanofillers have been adopted to improve osseointegration performance. The elastic modulus of PEEK is 3.7-4.0 GPa, being considerably lower than that of human cortical bone ranging from 7-30 GPa. Thus, PEEK is not stiff enough to sustain applied stress in load-bearing orthopedic implants. Therefore, HA micro-/nanofillers, continuous and discontinuous carbon fibers are incorporated into PEEK for enhancing its stiffness for load-bearing applications. Among these, carbon fibers are more effective than HA micro-/nanofillers in providing additional stiffness and load-bearing capabilities. In particular, the tensile properties of PEEK composite with 30wt% short carbon fibers resemble those of cortical bone. Hydrophobic PEEK shows no degradation behavior, thus hampering its use for making porous bone scaffolds. PEEK can be blended with hydrophilic polymers such as polyglycolic acid and polyvinyl alcohol to produce biodegradable scaffolds for bone tissue engineering applications.
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Affiliation(s)
- Chengzhu Liao
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Yuchao Li
- Department of Materials Science and Engineering, Liaocheng University, Liaocheng 252000, China
| | - Sie Chin Tjong
- Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
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26
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Shaw KA, Devito DP, Schmitz ML, Murphy JS. Are precontoured cobalt-chromium spinal rods mechanically superior to manually contoured rods? Spine Deform 2020; 8:871-877. [PMID: 32424695 DOI: 10.1007/s43390-020-00133-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/04/2020] [Indexed: 11/29/2022]
Abstract
STUDY DESIGN Laboratory based study. OBJECTIVE To compare reduction force and plastic deformation of cobalt-chromium (Co-Cr) spinal rods using a rigid, thoracolumbar spinal deformity model. Pre-contoured spinal rods are growing in their utilization for spinal deformity. Although there are theoretical advantages to pre-contouring rods, no previous studies have compared pre-contoured and manually contoured rods for their ability to maintain sagittal contour and resist mechanical load. METHODS A spinal deformity model was utilized, simulating a rigid, thoracolumbar spinal deformity fixated with pedicle screws. Roll-formed pre-contoured and manually contoured 5.5 mm and 6.0 mm Co-Cr rods were reduced to the model with a load cell attached to the apical screw to measure corrective force. Rods remained reduced in the model for 20 min and change in contour was assessed to characterize plastic deformation. RESULTS Twenty-four rods were tested with six rods per group (Table 1). The load to reduction was significantly lower in the 5.5 mm rods compared to the 6.0 mm rods (95% CI -254.0 to -61.42; p = 0.008). Although there was no difference in the corrective forces for manual and pre-contoured 5.5 mm rods (p = 0.722), the 6.0 mm rod produced significantly less corrective force compared to the manually contoured 6.0 mm rods (95% CI -134.42 to -5.317; p = 0.039). Additionally, rod contour for the manual group showed significantly less plastic deformation than the pre-contoured group in both 5.5 mm and 6.0 mm rods (5.5 mm: 57.1% vs. 61.6%, p = 0.006; 6.0 mm: 54.3% vs. 62.28%, p = 0.003). CONCLUSIONS Roll formed, pre-contoured Co-Cr rods demonstrated significantly greater plastic deformation when compared with manually contoured rods of the same diameter. Furthermore, 6.0 mm pre-contoured rods required significantly lower load for rod reduction, the equivalent of 15 lb-force. Post-manufacturing, roll-formed pre-contouring of larger diameter Co-Cr may impair the rods mechanical properties.
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Affiliation(s)
- K Aaron Shaw
- Department of Orthopedic Surgery, Dwight D. Eisenhower Army Medical Center, 300 East Hospital Road, Fort Gordon, GA, 30905, USA.
| | - Dennis P Devito
- Department of Pediatric Orthopedic Surgery, Children's Healthcare of Atlanta, Scottish Rite Campus, Atlanta, GA, USA
| | - Michael L Schmitz
- Department of Pediatric Orthopedic Surgery, Children's Healthcare of Atlanta, Scottish Rite Campus, Atlanta, GA, USA
| | - Joshua S Murphy
- Department of Pediatric Orthopedic Surgery, Children's Healthcare of Atlanta, Scottish Rite Campus, Atlanta, GA, USA
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27
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Lee JJ, Oh SH, Jeong YH, Park SM, Jeon HS, Kim HC, An SB, Shin DA, Yi S, Kim KN, Yoon DH, Shin JJ, Ha Y. Surgical Strategies for Cervical Deformities Associated With Neuromuscular Disorders. Neurospine 2020; 17:513-524. [PMID: 33022156 PMCID: PMC7538346 DOI: 10.14245/ns.2040464.232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/22/2020] [Indexed: 12/26/2022] Open
Abstract
Neuromuscular disorders (NMDs) are diseases involving the upper and lower motor neurons and muscles. In patients with NMDs, cervical spinal deformities are a very common issue; however, unlike thoracolumbar spinal deformities, few studies have investigated these disorders. The patients with NMDs have irregular spinal curvature caused by poor balance and poor coordination of their head, neck, and trunk. Particularly, cervical deformity occurs at younger age, and is known to show more rigid and severe curvature at high cervical levels. Muscular physiologic dynamic characteristics such as spasticity or dystonia combined with static structural factors such as curvature flexibility can result in deformity and often lead to traumatic spinal cord injury. In addition, postoperative complication rate is higher due to abnormal involuntary movement and muscle tone. Therefore, it is important to control abnormal involuntary movement perioperatively along with strong instrumentation for correction of deformity. Various methods such as botulinum toxin injection, physical therapy, muscle division technique, or intrathecal baclofen pump implant may help control abnormal involuntary movements and improve spinal stability. Surgical management for cervical deformities associated with NMDs requires a multidisciplinary effort and a customized strategy.
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Affiliation(s)
- Jong Joo Lee
- Department of Neurosurgery, Bundang Jesaeng Hospital, Seongnam, Korea
| | - Sung Han Oh
- Department of Neurosurgery, Bundang Jesaeng Hospital, Seongnam, Korea
| | - Yeong Ha Jeong
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Man Park
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hyeong Seok Jeon
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Hyung-Cheol Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Bae An
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Dong Ah Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Yi
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Keung Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Do Heum Yoon
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jun Jae Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Seoul, Korea
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28
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Park BJ, Hyun SJ, Wui SH, Jung JM, Kim KJ, Jahng TA. Surgical Outcomes and Complications Following All Posterior Approach for Spinal Deformity Associated with Neurofibromatosis Type-1. J Korean Neurosurg Soc 2020; 63:738-746. [PMID: 32512989 PMCID: PMC7671774 DOI: 10.3340/jkns.2019.0218] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/19/2020] [Indexed: 12/27/2022] Open
Abstract
Objectives The purpose of this study was to evaluate surgical outcomes and complications of spinal deformity associated with neurofibromatosis type-1 (NF-1).
Methods From 2012 to 2018, patients suffering from spinal deformity associated with NF-1 who underwent surgical correction were identified. Demographic data and radiographic measures were retrospectively reviewed. Pre- and postoperative whole spine radiograph images were used to determine both coronal and sagittal Cobb angles. All of patients underwent 3-dimentional computed tomographic scan and magnetic resonance imaging scan to confirm dystrophic features. For evaluation of clinical outcomes, we surveyed the pre- and postoperative scoliosis research society-22r (SRS-22r) score.
Results Seven patients with spinal deformity associated with NF-1 were enrolled in this study. The mean age of patients was 29.5±1.2 years old. The mean follow-up period was 2.8±1.4 years. The apex of the deformity was located in cervicothoracic (n=1), thoracic (n=4), and lumbar region (n=2). Most patients have poor bone quality and decreased bone mineral density with average T-score of -3.5±1.0. All patients underwent surgical correction via posterior approach. The pre- and postoperative mean coronal and sagittal Cobb angle was 61.6±22.6° and 34.6±38.1°, 56.8±18.5° and 40.2±9.1°, respectively. Mean correction rate of coronal and sagittal angle was 44.7% and 23.1%. Ultimate follow-up SRS-22r score (average score, 3.9±0.4) improved comparing to preoperative score (average score, 3.3±0.9). Only one patient received revision surgery due to rod fracture. No serious complication occurred, such as neurological deficit, and viscerovascular injury.
Conclusion The surgical correction of patients having spinal deformity associated with NF-1 is challenging, however the radiographic and clinical outcomes are satisfactory. The all posterior approach can be a safe and effective surgical option for patients having dystrophic curves associated with NF-1.
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Affiliation(s)
- Byoung-Joo Park
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Seung-Jae Hyun
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Seong-Hyun Wui
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Jong-Myung Jung
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Ki-Jeong Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Tae-Ahn Jahng
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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29
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Kim TW, Oh JK, Lee JY, Cho SK, An SB, Jeon HS, Kim HC, Kim KJ, Shin DA, Yi S, Kim KN, Yoon DH, Kim CO, Ha Y. Association of Frailty and Self-Care Activity With Sagittal Spinopelvic Alignment in the Elderly. World Neurosurg 2020; 138:e759-e766. [PMID: 32201289 DOI: 10.1016/j.wneu.2020.03.071] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To assess the relationship between frailty, activities of daily living (ADL), instrumental ADL (IADL), and sagittal spinopelvic parameters in the elderly. METHODS To compare the characteristics based on the FRAIL scale status (robust, prefrail, frail), continuous variables were analyzed using ANOVA with Tukey post hoc tests, and categorical variables were analyzed using χ2 and Fisher's exact test. Multivariate linear regression was used to investigate cross-sectional association between sagittal alignment and FRAIL status. RESULTS Comparison analysis of the 3 groups (robust, prefrail, frail) demonstrated that frailty scale had significant correlations with T1 pelvic angle (T1PA, P = 0.019), pelvic tilt (PT, P = 0.004), pelvic incidence minus lumbar lordosis (PI-LL, P = 0.004) and ADL (P = 0.017). Multiple regression analysis that controlled for confounding factors confirmed the correlations between frailty scale and spinopelvic parameters (C7 sagittal vertical axis [SVA], B = 17.49, P = 0.028; T1PA, B = 4.83, P = 0.029; PT, B = 4.62, P = 0.003; PI-LL value, B = 7.11, P = 0.005). In addition, the ADL was associated with T1PA (B = 4.06, P = 0.006); whereas the IADL was correlated with C7 SVA (B = 11.38, P = 0.005), T1PA (B = 3.36, P = 0.003), and PI-LL (B = 3.13, P = 0.018). CONCLUSIONS Higher frailty score was associated with higher grades of sagittal spinopelvic malalignment and ADL in the elderly. Furthermore, higher ADL and IADL scores were associated with higher grades of sagittal spinopelvic malalignment. Frailty, ADL, IADL, and sagittal spinopelvic parameters were closely related to each other in the elderly.
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Affiliation(s)
- Tae Woo Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea; Department of Neurosurgery, Inje University Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea
| | - Jae Keun Oh
- Department of Neurosurgery, Spine Center, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Ji Yeon Lee
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Samuel K Cho
- Department of Orthopedics, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Seong Bae An
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Hyeong Seok Jeon
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Hyung Cheol Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Kwang Joon Kim
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong Ah Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Seong Yi
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Keung Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Do Heum Yoon
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Chang Oh Kim
- Division of Geriatrics, Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, College of Medicine, Yonsei University, Seoul, Korea.
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Jung JM, Hyun SJ, Kim KJ, Jahng TA. Rod fracture after multiple-rod constructs for adult spinal deformity. J Neurosurg Spine 2020; 32:407-414. [PMID: 31783347 DOI: 10.3171/2019.9.spine19913] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/11/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE This study investigated the incidence and risk factors of rod fracture (RF) after multiple-rod constructs (MRCs) for adult spinal deformity (ASD) surgery. METHODS A single-center, single-surgeon consecutive series of adult patients who underwent posterior thoracolumbar fusion at 4 or more levels using MRCs after osteotomy with at least 1 year of follow-up were retrospectively reviewed. Patient characteristics, radiological parameters, operative data, and clinical outcomes (on the Scoliosis Research Society-22r questionnaire) were analyzed at baseline and follow-up. RESULTS Seventy-six patients were enrolled in this study. RF occurred in 9 patients (11.8%), with all cases involving partial rod breakage. Seven patients (9.2%) underwent revision surgery. There were no significant differences in baseline demographic characteristics, radiological parameters, and surgical factors between the RF and non-RF groups. Multivariable analysis revealed that interbody fusion at the L5-S1 and L4-S1 levels could significantly reduce the occurrence of RF after MRCs for ASD (adjusted odds ratios 0.070 and 0.035, respectively). The RF group had significantly worse function score (mean 2.9 ± 0.8 vs 3.5 ± 0.7) and pain score (mean 2.8 ± 1.0 vs 3.5 ± 0.8) compared with the non-RF group at last visit. CONCLUSIONS RF occurred in 11.8% of patients with MRCs after ASD surgery. Most RFs occurred at the lumbosacral junction or adjacent level (77%). Interbody fusion at the lumbosacral junction (L5-S1 or L4-S1 level) could significantly prevent the occurrence of RF after MRCs for ASD.
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Choi HY, Hyun SJ, Kim KJ, Jahng TA, Kim HJ. Radiographic and Clinical Outcomes Following Pedicle Subtraction Osteotomy : Minimum 2-Year Follow-Up Data. J Korean Neurosurg Soc 2019; 63:99-107. [PMID: 31658806 PMCID: PMC6952730 DOI: 10.3340/jkns.2018.0170] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 01/26/2019] [Indexed: 11/27/2022] Open
Abstract
Objective The purpose of this study was to report the results of pedicle subtraction osteotomy (PSO) for fixed sagittal imbalance with a minimum 2-year follow-up. Besides, authors evaluated the effect of adjunctive multi-level posterior column osteotomy (PCO) on achievement of additional lumbar lordosis (LL) during PSO.
Methods A total of 31 consecutive patients undergoing PSO for fixed sagittal imbalance were enrolled and analyzed. Correction angle of osteotomized vertebra (PSO angle) and other radiographic parameters including pelvic incidence (PI), thoracic kyphosis, LL, and sagittal vertical axis (SVA) were evaluated. Clinical outcomes and surgical complications were also assessed.
Results The mean age was 66.0±9.3 years with a mean follow-up period of 33.2±10.5 months. The mean number of fused segments was 9.6±3.5. The mean operative time and surgical bleeding were 475.9±160.5 minutes and 1406.1±932.1 mL, respectively. The preoperative SRS-22 score was 2.3±0.7 and improved to 3.2±0.8 at the final follow-up. The mean PI was 54.5±9.5°. LL was changed from 7.0±28.9° to -50.2±13.2°. The PSO angle was 33.7±13.5° (15.6±20.1° preoperatively, -16.1±19.4° postoperatively). The difference of correction angle of LL (57.3°) was greater about 23.6° than which of PSO angle (33.7°). SVA was improved from 189.5±93.0 mm, preoperatively to 12.4±40.8 mm, postoperatively. There occurred six, eight, and 14 cases of complications at intraoperative, early (<2 weeks) postoperative, and late (≥2 weeks) postoperative period, respectively. Additional operations were needed in nine patients due to the complications.
Conclusion PSO could provide satisfactory results for patients with fixed sagittal imbalance regarding clinical and radiographic outcomes. Additional correction of LL could be achieved with conduction of adjunctive multi-level PCOs during PSO.
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Affiliation(s)
- Ho Yong Choi
- Department of Neurosurgery, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea
| | - Seung-Jae Hyun
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Ki-Jeong Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Tae-Ahn Jahng
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Hyun-Jib Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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Knez D, Nahle IS, Vrtovec T, Parent S, Kadoury S. Computer‐assisted pedicle screw trajectory planning using CT‐inferred bone density: A demonstration against surgical outcomes. Med Phys 2019; 46:3543-3554. [DOI: 10.1002/mp.13585] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/28/2019] [Accepted: 05/03/2019] [Indexed: 12/19/2022] Open
Affiliation(s)
- Dejan Knez
- Faculty of Electrical Engineering University of Ljubljana Tržaška c. 25 Ljubljana 1000Slovenia
| | - Imad S. Nahle
- CHU Sainte‐Justine Hospital Research Center 3175 Cote‐Sainte‐Catherine Rd. Montréal H3T 1C5QuébecCanada
| | - Tomaž Vrtovec
- Faculty of Electrical Engineering University of Ljubljana Tržaška c. 25 Ljubljana 1000Slovenia
| | - Stefan Parent
- CHU Sainte‐Justine Hospital Research Center 3175 Cote‐Sainte‐Catherine Rd. Montréal H3T 1C5QuébecCanada
| | - Samuel Kadoury
- CHU Sainte‐Justine Hospital Research Center 3175 Cote‐Sainte‐Catherine Rd. Montréal H3T 1C5QuébecCanada
- Department of Computer and Software Engineering Polytechnique Montreal P.O. Box 6079, Succ. Centre‐ville Montréal H3C 3A7QuébecCanada
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Jung JM, Hyun SJ, Kim KJ, Jahng TA, Kim HJ, Choi Y. Anatomic Trajectory Screw Fixation at Upper Instrumented Vertebra Is a Substantial Risk Factor for Proximal Junctional Kyphosis. World Neurosurg 2019; 129:e522-e529. [PMID: 31152888 DOI: 10.1016/j.wneu.2019.05.198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND This study aimed to investigate the risk of proximal junction kyphosis (PJK) and proximal junction failure (PJF) associated with screw trajectory (straightforward vs. mixed vs. anatomic) at upper instrumented vertebra (UIV). METHODS A single-center, single-surgeon consecutive series of adult patients who underwent lumbar fusion for ≥4 levels (the UIV of the thoracolumbar spine, T9-L2, and the lower instrumented vertebra at the sacrum or pelvis) was retrospectively reviewed. Patients were divided into 3 groups according to UIV screw trajectory: group S, 2 straightforward screws; group M, 1 straightforward screw and 1 anatomic trajectory screw; and group A, 2 anatomic trajectory screws. RESULTS A total of 83 patients were included in this study, including 51 in group S, 16 in group M, and 16 in group A. The incidence of PJK in group S (12 patients, 23.5%), group M (7 patients, 43.8%), and group A (9 patients, 56.3%) significantly increased in sequence by group (P = 0.044). Anatomic trajectory screw fixation increased the risk for PJF requiring revision surgery compared with straightforward screw fixation (3 patients [18.8%] vs. 1 patient [2.0%]; P = 0.040). Multivariable analysis identified that anatomic trajectory screw fixation was a significant risk factor for PJK (P = 0.008; adjusted odds ratio = 7.591; 95% confidence interval, 1.69-34.093). CONCLUSION Anatomic trajectory screw fixation at the UIV is a substantial risk factor for PJK and PJF. To reduce PJK and PJF, straightforward screw fixation at the UIV is recommended in adult spinal deformity correction surgery.
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Affiliation(s)
- Jong-Myung Jung
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Seung-Jae Hyun
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea.
| | - Ki-Jeong Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Tae-Ahn Jahng
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Hyun-Jib Kim
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea
| | - Yunhee Choi
- Division of Medical Statistics, Medical Research Collaborating Center, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
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Effect of Vertebroplasty at the Upper Instrumented Vertebra and Upper Instrumented Vertebra +1 for Prevention of Proximal Junctional Failure in Adult Spinal Deformity Surgery: A Comparative Matched-Cohort Study. World Neurosurg 2019; 124:e436-e444. [PMID: 30610979 DOI: 10.1016/j.wneu.2018.12.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 01/05/2023]
Abstract
BACKGROUND This study aimed to compare radiographic outcomes of adult spinal deformity (ASD) surgery with or without 2-level prophylactic vertebroplasty (PVP) at the uppermost instrumented vertebra (UIV) and the vertebra 1 level proximal to the UIV. METHODS This retrospective 1:2 matched-cohort comparative study enrolled 2 groups of patients undergoing ASD surgery, including 28 patients with PVP (PVP group) and 56 patients without PVP (non-PVP group), in 3 institutes between 2012 and 2015. The primary outcome measure was the incidence of proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and proximal junctional fracture (PJFX). The secondary outcome measure were radiologic outcomes between PVP segments and non-PVP segments. RESULTS Between the PVP group and non-PVP group, no significant differences were found in the incidence of PJK (13 [46.4%] vs. 26 [46.4%]; P = 1.000), PJF (11 [39.3%] vs. 18 [32.1%]; P = 0.516), and PJFX (11 [39.3%] vs. 18 [32.1%]; P = 0.516). The number of the PJFX segments was 16 and 33 in PVP segments and non-PVP segments, respectively. Until revision surgery or final follow-up, the PJFX had progressed in 24 non-PVP segments (82.7%), but not in PVP segments. The PJFX progression in all PVP segments stopped near the PVP mass at the final follow-up. Reoperation as a result of PJFX was performed in 1 patient (3.6%) and 8 patients (14.3%) in the PVP and non-PVP groups, respectively. CONCLUSIONS PVP at UIV and vertebra 1 level proximal to the UIV cannot prevent PJK, PJF, and PJFX; however, it plays a positive role by delaying their progression. Furthermore, PVP tends to lower the reoperation rate after PJFX in ASD surgery.
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Musapoor A, Nikkhoo M, Haghpanahi M. A finite element study on intra-operative corrective forces and evaluation of screw density in scoliosis surgeries. Proc Inst Mech Eng H 2018; 232:1245-1254. [DOI: 10.1177/0954411918810707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Scoliosis is an abnormal sideways curvature of the spine and rib cage, which may need surgical treatments. Most of the corrective maneuvers in scoliosis surgeries are based on surgeon’s experience; hence, there is great interest of understanding how the correction ratio can be influenced by the magnitude of forces and moments. Therefore, the objective of this study was to develop and validate a detailed finite element model of the thoracolumbar which can be used to simulate the scoliosis surgeries based on patient-specific clinical images. The validated models of five patients were carefully developed, and the surgery procedures were simulated and the corrective forces were estimated using inverse finite element analysis during the surgery. Furthermore, parametric studies including the influences of the corrective force magnitude and screw density were evaluated. The results showed that the maximum estimated correction force and moment were 173 (±55.43) N and 10.67 (±2.02) N m, respectively, which were aligned with measured clinical observations. The sensitivity analysis on the magnitude of applied force to the screws showed that correction ratio was slightly increased in level 1 (i.e. FB = 1.3 × F) but decreased in level 2 (i.e. FB = 1.6 × F). In addition, the parametric study on increasing the number of pedicle screws showed that there was no significant difference between lower and higher screw density. However, the stress distribution was significantly greater using higher screw density during correction maneuvers. In conclusion, this study shows a direct relationship between the applied force/moment and screw density and the correction ratio up to a border line which should be defined accurately. This detailed computational modeling can be used in clinic in hope of achieving the optimum outcome of scoliosis surgery using individual patient-specific characterization.
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Affiliation(s)
- Ameneh Musapoor
- School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
| | - Mohammad Nikkhoo
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Mohammad Haghpanahi
- School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
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