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Son JI, Lee YS, Ko MJ, Wui SH, Park SW. Effect of Mixture of Recombinant Human Bone Morphogenic Protein-2 and Demineralized Bone Matrix in Lateral Lumbar Interbody Fusion. J Korean Neurosurg Soc 2024; 67:354-363. [PMID: 37850225 PMCID: PMC11079555 DOI: 10.3340/jkns.2023.0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/21/2023] [Accepted: 10/11/2023] [Indexed: 10/19/2023] Open
Abstract
OBJECTIVE This study aims to determine the optimal dose of recombinant-human bone morphogenic protein-2 (rhBMP-2) for successful bone fusion in minimally invasive lateral lumbar interbody fusion (MIS LLIF). Previous studies show that rhBMP is an effective alternative to autologous iliac crest bone graft, but the optimal dose remains uncertain. The study analyzes the fusion rates associated with different rhBMP doses to provide a recommendation for the optimal dose in MIS LLIF. METHODS Ninety-three patients underwent MIS LLIF using demineralized bone matrix (DBM) or a mixture of rhBMP-2 and DBM as fusion material. The group was divided into the following three groups according to the rhBMP-2 usage : group A, only DBM was used (n=27); group B, 1 mg of rhBMP-2 per 5 mL of DBM paste (n=41); and group C, 2 mg of rhBMP-2 per 5 mL of DBM paste (n=25). Demographic data, clinical outcomes, postoperative complication and fusion were assessed. RESULTS At 12 months post-surgery, the overall fusion rate was 92.3% according to Bridwell fusion grading system. Groups B and C, who received rhBMP-2, had significantly higher fusion rates than group A, who received only DBM. However, there was no significant increase in fusion rate when the rhBMP-2 dosage was increased from group B to group C. The groups B and C showed significant improvement in back pain and Oswestry disability index compared to the group A. The incidence of screw loosening was decreased in groups B and C, but there was no significant difference in the occurrence of other complications. CONCLUSION Usage of rhBMP-2 in LLIF surgery leads to early and increased final fusion rates, which can result in faster pain relief and return to daily activities for patients. The benefits of using rhBMP-2 were not significantly different between the groups that received 1 mg/5 mL and 2 mg/5 mL of rhBMP-2. Therefore, it is recommended to use 1 mg of rhBMP-2 with 5 mL of DBM, taking both economic and clinical aspects into consideration.
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Affiliation(s)
- Jun Ik Son
- Department of Neurosurgery, Chung-Ang University Hospital, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Young-seok Lee
- Department of Neurosurgery, Chung-Ang University Hospital, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Myeong Jin Ko
- Department of Neurosurgery, Chung-Ang University Hospital, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Seong-Hyun Wui
- Department of Neurosurgery, Chung-Ang University Gwangmyeong Hospital, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Seung Won Park
- Department of Neurosurgery, Chung-Ang University Gwangmyeong Hospital, College of Medicine, Chung-Ang University, Seoul, Korea
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Tan H, Yamamoto EA, Smith S, Yoo J, Kark J, Lin C, Orina J, Philipp T, Ross DA, Wright C, Wright J, Ryu WHA. Characterizing utilization patterns and reoperation risk factors of interspinous process devices: analysis of a national claims database. PAIN MEDICINE (MALDEN, MASS.) 2024; 25:283-290. [PMID: 38065695 DOI: 10.1093/pm/pnad159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/13/2023] [Accepted: 11/21/2023] [Indexed: 04/04/2024]
Abstract
INTRODUCTION Interspinous process devices (IPDs) were developed as minimally invasive alternatives to open decompression surgery for spinal stenosis. However, given high treatment failure and reoperation rates, there has been minimal adoption by spine surgeons. This study leveraged a national claims database to characterize national IPD usage patterns and postoperative outcomes after IPD implantation. METHOD Using the PearlDiver database, we identified all patients who underwent 1- or 2-level IPD implantation between 2010 and 2018. Univariate and multivariable logistic regression was performed to identify predictors of the number of IPD levels implanted and reoperation up to 3 years after the index surgery. Right-censored Kaplan-Meier curves were plotted for duration of reoperation-free survival and compared with log-rank tests. RESULTS Patients (n = 4865) received 1-level (n = 3246) or 2-level (n = 1619) IPDs. Patients who were older (adjusted odds ratio [aOR] 1.02, 95% confidence interval [CI] 1.01-1.03, P < .001), male (aOR 1.31, 95% CI 116-1.50, P < .001), and obese (aOR 1.19, 95% CI 1.05-1.36, P < .01) were significantly more likely to receive a 2-level IPD than to receive a 1-level IPD. The 3-year reoperation rate was 9.3% of patients when mortality was accounted for during the follow-up period. Older age decreased (aOR 0.97, 95% CI 0.97-0.99, P = .0039) likelihood of reoperation, whereas 1-level IPD (aOR 1.37, 95% CI 1.01-1.89, P = .048), Charlson Comorbidity Index (aOR 1.07, 95% CI 1.01-1.14, P = .018), and performing concomitant open decompression increased the likelihood of reoperation (aOR 1.68, 95% CI 1.35-2.09, P = .0014). CONCLUSION Compared with 1-level IPDs, 2-level IPDs were implanted more frequently in older, male, and obese patients. The 3-year reoperation rate was 9.3%. Concomitant open decompression with IPD placement was identified as a significant risk factor for subsequent reoperation and warrants future investigation.
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Affiliation(s)
- Hao Tan
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - Erin A Yamamoto
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - Spencer Smith
- Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239, United States
| | - Jung Yoo
- Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239, United States
| | - Jonathan Kark
- Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239, United States
| | - Clifford Lin
- Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239, United States
| | - Josiah Orina
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - Travis Philipp
- Department of Orthopedics and Rehabilitation, Oregon Health & Science University, Portland, OR 97239, United States
| | - Donald A Ross
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - Christina Wright
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - James Wright
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
| | - Won Hyung A Ryu
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, United States
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Liu R, He T, Wu X, Tan W, Yan Z, Deng Y. Biomechanical response of decompression alone in lower grade lumbar degenerative spondylolisthesis--A finite element analysis. J Orthop Surg Res 2024; 19:209. [PMID: 38561837 PMCID: PMC10983632 DOI: 10.1186/s13018-024-04681-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Previous studies have demonstrated the clinical efficacy of decompression alone in lower-grade spondylolisthesis. A higher rate of surgical revision and a lower rate of back pain relief was also observed. However, there is a lack of relevant biomechanical evidence after decompression alone for lower-grade spondylolisthesis. PURPOSE Evaluating the biomechanical characteristics of total laminectomy, hemilaminectomy, and facetectomy for lower-grade spondylolisthesis by analyzing the range of motion (ROM), intradiscal pressure (IDP), annulus fibrosus stress (AFS), facet joints contact force (FJCF), and isthmus stress (IS). METHODS Firstly, we utilized finite element tools to develop a normal lumbar model and subsequently constructed a spondylolisthesis model based on the normal model. We then performed total laminectomy, hemilaminectomy, and one-third facetectomy in the normal model and spondylolisthesis model, respectively. Finally, we analyzed parameters, such as ROM, IDP, AFS, FJCF, and IS, for all the models under the same concentrate force and moment. RESULTS The intact spondylolisthesis model showed a significant increase in the relative parameters, including ROM, AFS, FJCF, and IS, compared to the intact normal lumbar model. Hemilaminectomy and one-third facetectomy in both spondylolisthesis and normal lumbar models did not result in an obvious change in ROM, IDP, AFS, FJCF, and IS compared to the pre-operative state. Moreover, there was no significant difference in the degree of parameter changes between the spondylolisthesis and normal lumbar models after undergoing the same surgical procedures. However, total laminectomy significantly increased ROM, AFS, and IS and decreased the FJCF in both normal lumbar models and spondylolisthesis models. CONCLUSION Hemilaminectomy and one-third facetectomy did not have a significant impact on the segment stability of lower-grade spondylolisthesis; however, patients with LDS undergoing hemilaminectomy and one-third facetectomy may experience higher isthmus stress on the surgical side during rotation. In addition, total laminectomy changes the biomechanics in both normal lumbar models and spondylolisthesis models.
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Affiliation(s)
- Renfeng Liu
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China
| | - Tao He
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China
| | - Xin Wu
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China
| | - Wei Tan
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China
| | - Zuyun Yan
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China
| | - Youwen Deng
- Department of Spine Surgery, Central South University Third Xiangya Hospital, Changsha, China.
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Chung HW, Park KH, Lee HD, Jeon CH, Jeon JM, Chung NS. Risk factors for nonunion in oblique lateral interbody fusion. J Orthop Sci 2024; 29:59-63. [PMID: 36411226 DOI: 10.1016/j.jos.2022.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/21/2022] [Accepted: 10/30/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Compared with posterior interbody fusion techniques, oblique lateral interbody fusion (OLIF) offers a larger fusion bed with greater intervertebral space access, use of larger cages, more sufficient discectomy, and better end-plate preparation. However, the fusion rate of OLIF is similar to that of other interbody fusions. This study aimed to examine the factors associated with nonunion in OLIF. METHODS This study examined 201 disc levels from 124 consecutive patients who underwent OLIF for lumbar degenerative diseases with 1-year regular follow-up. Demographic and surgical factors were reviewed from the medical records. Radiological factors measured were sagittal parameters, intervertebral disc angle (DA) before surgery and at the final follow-up, presence of vertebral end-plate lesions, and cage subsidence. Multivariable logistic regression analysis was performed to identify the factors associated with nonunion. RESULTS Among the 201 discs, 185 (92.0%) achieved union at 1-year followed up. Smoking, surgery at the L5-S1 level, not performing laminectomy, and a large intervertebral DA were factors associated with nonunion in OLIF (all P < 0.05). Multivariable logistic regression analysis showed two independent variables (surgery at L5-S1 level and not performing laminectomy) as risk factors for nonunion in OLIF. CONCLUSIONS Not performing laminectomy and surgery at the L5-S1 level were risk factors for nonunion in OLIF. To reduce the nonunion rate, surgeons should consider additional stabilization strategies for the L5-S1 OLIF and perform laminectomy.
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Affiliation(s)
- Hee-Woong Chung
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea
| | - Ki-Hoon Park
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea
| | - Han-Dong Lee
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea
| | - Chang-Hoon Jeon
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea
| | - Jong-Min Jeon
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea
| | - Nam-Su Chung
- Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, South Korea.
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The effect of various options for decompression of degenerated lumbar spine motion segments on the range of motion: a biomechanical in vitro study. 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; 32:1358-1366. [PMID: 36826599 DOI: 10.1007/s00586-023-07587-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 01/16/2023] [Accepted: 02/05/2023] [Indexed: 02/25/2023]
Abstract
BACKGROUND Lumbar spinal stenosis is a common disease in the aging population. Decompression surgery represents the treatment standard, however, a risk of segmental destabilization depending on the approach and extent of decompression is discussed. So far, biomechanical studies on techniques were mainly conducted on non-degenerated specimens. This biomechanical in vitro study aimed to investigate the increase in segmental range of motion (ROM) depending on the extent of decompression in degenerated segments. METHODS Ten fresh frozen lumbar specimens were embedded in polymethyl methacrylate (PMMA) and loaded in a spine tester with pure moments of ± 7.5 Nm. The specimens were tested in their intact state for lateral bending (LB), flexion/extension (FE) and axial rotation (AR). Subsequently, four different decompression techniques were performed: unilateral interlaminar decompression (DC1), unilateral with "over the top" decompression (DC2), bilateral interlaminar decompression (DC3) and laminectomy (DC4). The ROM of the index segment was reported as percent (%) of the native state. RESULTS Specimens were measured in their intact state prior to decompression. The mean ROM was defined as 100% (FE:6.3 ± 2.3°; LB:5.4 ± 2.8°; AR:3.0 ± 1.6°). Interventions showed a continuous ROM increase: FE (DC1: + 4% ± 4.3; DC2: + 4% ± 4.5; DC3: + 8% ± 8.3;DC4: + 20% ± 15.9), LB(DC1: + 4% ± 6.0; DC2: + 5% ± 7.3; DC3: + 8% ± 8.3; DC4: + 11% ± 9.9), AR (DC1: + 7% ± 6.0; DC2: + 9% ± 7.9; DC3: + 15% ± 11.5; DC4: + 19% ± 10.5). Significant increases in ROM for all motion directions (p < 0.05) were only obtained after complete laminectomy (DC4). CONCLUSION Unilateral and/or bilateral decompressive surgery resulted in a statistically insignificant ROM increase, whereas complete laminectomy showed statistically significant ROM increase. If this ROM increase also has an impact on the clinical outcome and how to identify segments at risk for secondary lumbar instability should be evaluated in further studies.
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Awaya T, Nishimura Y, Eguchi K, Nagashima Y, Ando R, Akahori S, Yoshikawa S, Haimoto S, Hara M, Takayasu M, Saito R. Radiological Analysis of Minimally Invasive Microscopic Laminectomy for Lumbar Canal Stenosis with a Focus on Multilevel Stenosis and Spondylolisthesis. World Neurosurg 2022; 164:e224-e234. [PMID: 35483569 DOI: 10.1016/j.wneu.2022.04.079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 10/18/2022]
Abstract
OBJECTIVE We retrospectively compared the radiological and clinical outcomes of two different surgical techniques (lumbar spinous process splitting laminectomy [LSPSL] and unilateral laminotomy for bilateral decompression [ULBD]) to treat lumbar spinal canal stenosis (LCS). METHODS We performed a retrospective comparative study of 141 consecutive patients with an average age of 70.8 ± 9.4 years who had undergone LSPSL or ULBD for LCS between April 2015 and April 2019. None of the patients had developed remote fractures of the spinous processes using either technique. These cases were divided into 2 groups: group L, 73 patients who had undergone LSPSL from April 2015 to April 2017; and group U, 68 patients who had undergone ULBD from May 2017 to April 2019. The clinical and radiological outcomes and surgical complications at the 1-year postoperative follow-up period were evaluated. RESULTS We found no significant differences in the operative time between the 2 groups. However, group U had had significantly less blood loss than group L. The facet joints were significantly well preserved in group U. We examined the multilevel and spondylolisthesis cases separately and found that both surgical procedures were equally effective and that the visual analog scale scores for back or leg pain and Japanese Orthopaedic Association scores had significantly improved postoperatively in each group. Group U showed better outcomes in terms of LCS recurrence, with 3 patients in the group L requiring repeat surgery. CONCLUSIONS We found both ULBD and LSPSL to be safe and effective techniques for LCS, even for patients with spondylolisthesis and multilevel disease. ULBD was superior in terms of recurrence prevention, preservation of the facet joints, and less blood loss.
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Affiliation(s)
- Takayuki Awaya
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | - Yusuke Nishimura
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan.
| | - Kaoru Eguchi
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | | | - Ryo Ando
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | - Sho Akahori
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | - Satoshi Yoshikawa
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | - Shoichi Haimoto
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
| | - Masahito Hara
- Department of Neurosurgery, Aichi Medical University Hospital, Nagakute, Japan
| | - Masakazu Takayasu
- Department of Neurosurgery, Inazawa Municipal Hospital, Inazawa, Japan
| | - Ryuta Saito
- Department of Neurosurgery, Nagoya University Hospital, Nagoya, Japan
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Bokov A, Pavlova S, Bulkin A, Aleynik A, Mlyavykh S. Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine: An observational study. World J Orthop 2021; 12:310-319. [PMID: 34055588 PMCID: PMC8152435 DOI: 10.5312/wjo.v12.i5.310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/15/2021] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The majority of published data report the results of biomechanical tests of various design pedicle screw performance. The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied.
AIM To estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine.
METHODS This study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments. Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion. Follow-up was for 18 mo. Patients with signs of pedicle screw loosening on computed tomography were registered; logistic regression analysis was used to identify the factors that influenced the rate of loosening.
RESULTS Parameters included in the analysis were screw geometry, type of thread, external and internal screw diameter and helical pitch, bone density in Hounsfield units, number of levels fused, instrumentation without anterior support, laminectomy, and unilateral and bilateral total facet joint resection. The rate of screw loosening decreased with the increment in outer diameter, decrease in core diameter and helical pitch. The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density. Bilateral facet joint removal significantly favored pedicle screw loosening. The influence of other factors was insignificant.
CONCLUSION Screw parameters had a significant impact on the loosening rate along with bone quality characteristics, the number of levels fused and the extensiveness of decompression. The significance of the influence of screw parameters was comparable to those of patient- and surgery-related factors. Pedicle screw loosening was influenced by helical pitch, inner and outer diameter, but screw geometry and thread type were insignificant factors.
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Affiliation(s)
- Andrey Bokov
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Svetlana Pavlova
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Anatoliy Bulkin
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Alexandr Aleynik
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
| | - Sergey Mlyavykh
- Department of Oncology and Neurosurgery, Federal State Budgetary Educational Institution of Higher Education “Privolzhsky Research Medical University” of the Ministry of Health of the Russian Federation, Nizhniy Novgorod 603000, Russia
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Müther M, Lüthge S, Gerwing M, Stummer W, Schwake M. Management of Spinal Dumbbell Tumors via a Minimally Invasive Posterolateral Approach and Carbon Fiber-Reinforced Polyether Ether Ketone Instrumentation: Technical Note and Surgical Case Series. World Neurosurg 2021; 151:277-283.e1. [PMID: 33915306 DOI: 10.1016/j.wneu.2021.04.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Stand-alone minimally invasive approaches for the surgical management of spinal dumbbell tumors carry the risk of incomplete resections and impaired hemostasis. More-extensive approaches require subsequent instrumentation with metal artifacts impairing follow-up imaging. Here, we present a technical note on percutaneous instrumentation using carbon fiber-reinforced polyether ether ketone (CFR-PEEK) hardware combined with a minimally invasive posterolateral approach for tumor resection. METHODS We present a Technical Note and according case series of 7 patients with dumbbell tumors in the lumbar and thoracolumbar spine operated on between 2017 and 2020. CFR-PEEK pedicle screws and rods were inserted percutaneously. Afterwards, a dedicated self-standing retractor for posterolateral approaches was connected to the screws. Following a unilateral facetectomy, the tumor was resected in a microsurgical fashion. Clinical data are reported with respect to the Preferred Reporting Of CasE Series in Surgery (PROCESS) guidelines. RESULTS Four patients presented with de novo tumors. Three patients were treated for residual tumor mass after previous surgeries. Gross total resection was achieved in all 7 cases, as demonstrated by early postoperative magnetic resonance imaging. Histopathology demonstrated 5 World Health Organization grade I schwannomas, 1 grade II hemangiopericytoma, and 1 cavernous hemangioma. No postoperative complications were observed. CFR-PEEK hardware allowed unambiguous visualization of the resection cavity on follow-up imaging. CONCLUSIONS Resection of dumbbell tumors via a minimally invasive posterolateral approach and instrumentation with CFR-PEEK hardware allows maximal and safe resection. Due to lack of major metal artifacts, carbon fiber hardware improves the interpretation of follow-up imaging as well as planning of radiation if required for tumor recurrence.
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Affiliation(s)
- Michael Müther
- Department of Neurosurgery, University Hospital Münster, Münster, Germany.
| | - Swenja Lüthge
- Department of Neurosurgery, University Hospital Münster, Münster, Germany
| | - Mirjam Gerwing
- Department of Radiology, University Hospital Münster, Münster, Germany
| | - Walter Stummer
- Department of Neurosurgery, University Hospital Münster, Münster, Germany
| | - Michael Schwake
- Department of Neurosurgery, University Hospital Münster, Münster, Germany
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Matsumoto K, Shah A, Kelkar A, Parajuli D, Sudershan S, Goel VK, Sairyo K. Biomechanical evaluation of a novel decompression surgery: Transforaminal full-endoscopic lateral recess decompression (TE-LRD). NORTH AMERICAN SPINE SOCIETY JOURNAL (NASSJ) 2021; 5:100045. [PMID: 35141612 PMCID: PMC8819954 DOI: 10.1016/j.xnsj.2020.100045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 11/28/2022]
Abstract
Background Transforaminal full endoscopic lateral recess decompression (TE-LRD) can decompress lateral recess stenosis transforaminally under the endoscopy procedure. However, the biomechanical effects of the TE-LRD compared to the conventional decompression techniques are not reported. The purpose of this study is to compare the biomechanical effects of TE-LRD with conventional decompression techniques using finite element method. Methods Three finite element models of lumbar functional spinal unit (FSU) of the L4-L5 levels were created: 1) normal disc 2) moderate grade disc degeneration 3) severe grade disc degeneration. For each of these three models, the following decompression techniques were simulated, 1) 50% TE-LRD, 2) 100% TE-LRD, 3) Unilateral laminectomy, 4) Bilateral laminectomy. The lower endplate of the fifth lumbar vertebra was fixed and 10Nm of moment in flexion/extension, left/right bending and axial rotation was applied to the upper endplate of the fourth lumbar vertebra, under a follower load of 400N. The range of motion, intervertebral disc stress, and facet joint stress were compared. Results 50% TE-LRD was found to be the most stable decompression technique in all intervertebral disc models. Though the increase in the range of motion of 100% TE-LRD was higher than other decompression techniques in the normal disc model, it was not significantly different from 50% TE-LRD or unilateral laminectomy techniques in the degenerated disc models. The increase in the intervertebral disc stress was lowest for the 50% TE-LRD surgery in all intervertebral disc models. The increase in the facet stresses for 50% TE-LRD was lower than in the conventional decompression techniques for all intervertebral disc models. Conclusions 50% TE-LRD was the decompression surgical technique with the least effect on spinal instability. 100% TE-LRD showed to be effective for cases with degenerative discs. 50% TE-LRD may decrease the risk of postoperative intervertebral disc and facet joint degeneration.
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Affiliation(s)
- Koji Matsumoto
- Department of Orthopaedic Surgery, Nihon University Itabashi Hospital, 30-1 Oyaguchikamimati Itabashi-ku, Tokyo, 173-8610, Japan
| | - Anoli Shah
- Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedics surgery, Colleges of Engineering and Medicine, University of Toledo, OH, 43606, USA
| | - Amey Kelkar
- Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedics surgery, Colleges of Engineering and Medicine, University of Toledo, OH, 43606, USA
| | - Dikshya Parajuli
- Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedics surgery, Colleges of Engineering and Medicine, University of Toledo, OH, 43606, USA
| | - Sushil Sudershan
- Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedics surgery, Colleges of Engineering and Medicine, University of Toledo, OH, 43606, USA
| | - Vijay K. Goel
- Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Bioengineering and Orthopaedics surgery, Colleges of Engineering and Medicine, University of Toledo, OH, 43606, USA
- Corresponding author.
| | - Koichi Sairyo
- Department of Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan
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Combined Effects of Graded Foraminotomy and Annular Defect on Biomechanics after Percutaneous Endoscopic Lumbar Decompression: A Finite Element Study. JOURNAL OF HEALTHCARE ENGINEERING 2020; 2020:8820228. [PMID: 32908657 PMCID: PMC7474753 DOI: 10.1155/2020/8820228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/30/2020] [Accepted: 08/03/2020] [Indexed: 12/03/2022]
Abstract
Percutaneous endoscopic technology has been widely used in the treatment of lumbar disc stenosis and herniation. However, the quantitative influence of percutaneous endoscopic lumbar decompression on spinal biomechanics of the L5–S1 lumbosacral segment remains poorly understood. Hence, the objective of this study is to investigate the combined effects on the biomechanics of different grades of foraminotomy and annular defect for the L5–S1 segment. A 3D, nonlinear, detailed finite element model of L4–S1 was established and validated. Changes in biomechanical responses upon stimulation to the intact spine during different degrees of resection were analyzed. Measurements included intervertebral rotation, intradiscal pressure, and the strain of disc structure under flexion, extension, left/right lateral bending, and left/right axial rotation under pure bending moments and physiological loads. Compared with the intact model, under prefollower load, annular defect slightly decreased intervertebral rotation by −5.0% in extension and 2.2% in right axial rotation and significantly increased the mean strain of the exposed disc by 237.7% in all loading cases. For right axial rotation, unilateral total foraminotomy with an annular detect increased intervertebral rotation by 29.5% and intradiscal pressure by 57.6% under pure bending moment while the maximum corresponding values were 9.8% and 6.6% when the degree of foraminotomy was below 75%, respectively. These results indicate that percutaneous endoscopic lumbar foraminotomy highly maintains spinal stability, even if the effect of annular detect is taken into account, when the unilateral facet is not totally removed. Patients should avoid excessive extension and axial rotation after surgery on L5–S1. The postoperative open annular defect may substantially increase the risk of recurrent disc herniation.
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Ahuja S, Moideen AN, Dudhniwala AG, Karatsis E, Papadakis L, Varitis E. Lumbar stability following graded unilateral and bilateral facetectomy: A finite element model study. Clin Biomech (Bristol, Avon) 2020; 75:105011. [PMID: 32335473 DOI: 10.1016/j.clinbiomech.2020.105011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 04/02/2020] [Accepted: 04/08/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Excision of excessive amount of facet joint during lumbar discectomy or decompression can cause segmental instability of the lumbar spine. This study was performed to assess the segmental instability, facet joint loading and intradiscal pressure following graded lumbar facetectomy. This biomechanical study was performed using a verified and validated L3-S1 finite element model. METHODS Nine scenarios were analysed. Intact model as control, 30%, 45%, 60% and complete facet joint excision in unilateral and bilateral setting. The effect of progressive graded facetectomy of L4-L5 on the segmental mobility, facet loading and intradiscal pressure was assessed. FINDINGS In comparison with control 30% excision of the facet joint mainly caused increase in mediolateral mobility. With 45% excision of the facet joint there was increase in both anteroposterior and mediolateral mobility, this was worse in bilateral and unilateral models respectively. This worsened with larger facet excision scenarios. Facet load increased significantly on extension with excision of 45% & 60% unilaterally and 100% bilaterally. Flexion produced rise in intradiscal pressure in all scenarios. INTERPRETATION The increased spinal mobility, facet loading and intradiscal pressure with more than 30% facetectomy highlights the importance of preserving the facets during decompression thereby safeguarding accelerated degeneration of these segments and iatrogenic segmental instability. The findings from this study could also potentially explain the correlation between spinal instability, disc degeneration and facet joint arthrosis as noted in clinical studies.
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Affiliation(s)
- S Ahuja
- Wales Centre for Spinal Surgery and Trauma, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, United Kingdom
| | - A N Moideen
- Wales Centre for Spinal Surgery and Trauma, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, United Kingdom.
| | - A G Dudhniwala
- Wales Centre for Spinal Surgery and Trauma, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, United Kingdom
| | - E Karatsis
- Group Leader of Biomechanics, BETA CAE Systems S.A., 54005 Thessaloniki, Greece.
| | - L Papadakis
- Laboratory for Biomaterials and Computational Mechanics, Department of Mechanical Engineering, University of Western Macedonia, Kozani, Greece
| | - E Varitis
- Laboratory for Biomaterials and Computational Mechanics, Department of Mechanical Engineering, University of Western Macedonia, Kozani, Greece.
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Jia S, Li Y, Xie J, Tian T, Zhang S, Han L. Differential response to vibration of three forms of scoliosis during axial cyclic loading: a finite element study. BMC Musculoskelet Disord 2019; 20:370. [PMID: 31409412 PMCID: PMC6693133 DOI: 10.1186/s12891-019-2728-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/17/2019] [Indexed: 02/07/2023] Open
Abstract
Background Scoliosis is a serious disease that can affect all segments of society. Few studies have investigated the response to vibration of differing sinusoidal axial cyclic loading frequencies for different forms of scoliosis in the lumbar spine. Methods In this study, four finite element models, comprising a healthy spine, Lenke-A, Lenke-B and Lenke-C scoliosis of the lumbar S1-L1 region were developed. Modal analysis extracted resonant frequencies of the FE models with an upper body mass of 40 kg and 400 N preload. A transient dynamic analysis was performed to obtain the response to vibration of models under a sinusoidal axial loading of ± 40N at frequencies of 3, 5, 7, 9, 11 and 13 Hz using an upper body mass of 40 kg and 400 N preload. Results The first-order resonant frequencies of healthy, Lenke-A, Lenke-B and Lenke-C spines were 9.2, 3.9, 4.6 and 5.7 Hz, respectively. A Lenke-A lumbar spine was more likely to deform at a lower vibration frequency and Lenke-C deformed more easily at a higher vibration frequency. Furthermore, the vibration amplitude in the Y-direction (left-right) was greatest and least in the Z-direction (top-bottom). The frequency of cyclic loading closest to the resonant frequency resulted in a maximum value of peak-to-peak vibrational displacement. Furthermore, the vibrational amplitudes in patients with scoliosis were larger than they were in healthy subjects. In addition, axial displacement of the vertebrae in the healthy spine changed steadily whereas fluctuations in the scoliotic vertebrae in scoliosis patients were greater than that of other vertebrae. Conclusions Different forms of scoliosis may have different vibrational characteristics, the scoliotic vertebrae being the weak link in scoliosis under loading condition of whole body vibration. Scoliosis was more sensitive to this form of vibration. Where the frequency of axial cyclic vibrational loading of the lumbar spine was closer to its resonant frequency, the vibrational amplitude was larger. These results suggest that vibration will exacerbate the degree of scoliosis and so such patients should reduce their exposure to vibration. Clinical treatment should pay attention to the scoliotic vertebrae and reduce their vibration. These findings may assist in the clinical prevention and treatment of scoliosis.
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Affiliation(s)
- Shaowei Jia
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Ye Li
- Department of Orthopedics, Peking Union Medical College Hospital, PUMC&CAMS, Beijing, China
| | - Junde Xie
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Tian Tian
- School of Medical Imaging, Tianjin Medical University, Tianjin, China
| | - Shunxin Zhang
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Li Han
- School of Medical Imaging, Tianjin Medical University, Tianjin, China.
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Bokov A, Bulkin A, Aleynik A, Kutlaeva M, Mlyavykh S. Pedicle Screws Loosening in Patients With Degenerative Diseases of the Lumbar Spine: Potential Risk Factors and Relative Contribution. Global Spine J 2019; 9:55-61. [PMID: 30775209 PMCID: PMC6362557 DOI: 10.1177/2192568218772302] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
STUDY DESIGN Retrospective cohort study. OBJECTIVE To determine risk factors that may affect the rate of pedicle screws loosening in patients with degenerative diseases of the lumbar spine. METHODS A total of 250 patients with a low-grade spondylolisthesis and lumbar instability associated with degenerative diseases were enrolled. Preoperatively patients underwent computed tomography (CT) and cancellous bone radiodensity of a vertebral body was measured in Hounsfield units (HU). Pedicle screw fixation was used to treat patients either with a posterior fusion only or in combination with transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), and direct lateral interbody fusion (D-LIF). Minimal follow-up period accounted for 18 months. Cases with screw loosening were registered assessing association with risk factors using logistic regression. RESULTS The rate of screw loosening was in positive correlation with the number fused levels and decreasing bone radiodensity. Fusion with a greater load-bearing surface cage was associated with the decrease in rate of pedicle screws loosening. Incomplete reduction in case of spondylolisthesis, bilateral facet joints removal, and laminectomy performed without anterior support favored pedicle screws loosening development. The estimated model classifies correctly 79% of cases with the specificity and sensitivity accounting for 87% and 66% respectively. CONCLUSIONS The decreasing bone radiodensity in Hounsfield units has a considerable correlation with the rate of pedicle screws loosening. On the other hand, the length of fixation and applied surgical technique including fusion type also have a significant impact on complication rate. Spinal instrumentations should be planned by taking into account all potential risk factors and not characteristics relevant to bone quality assessment alone.
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Affiliation(s)
- Andrey Bokov
- Privolzhskiy Research Medical University, Nizhny Novgorod, Russia,Andrey Bokov, Privolzhskiy Research Medical University, Nizhny Novgorod, 603115, Russia.
| | - Anatoliy Bulkin
- Privolzhskiy Research Medical University, Nizhny Novgorod, Russia
| | | | - Marina Kutlaeva
- Privolzhskiy Research Medical University, Nizhny Novgorod, Russia
| | - Sergey Mlyavykh
- Privolzhskiy Research Medical University, Nizhny Novgorod, Russia
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Effect of Graded Facetectomy on Lumbar Biomechanics. JOURNAL OF HEALTHCARE ENGINEERING 2017; 2017:7981513. [PMID: 29065645 PMCID: PMC5337791 DOI: 10.1155/2017/7981513] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/08/2017] [Accepted: 01/23/2017] [Indexed: 12/22/2022]
Abstract
Facetectomy is an important intervention for spinal stenosis but may lead to spinal instability. Biomechanical knowledge for facetectomy can be beneficial when deciding whether fusion is necessary. Therefore, the aim of this study was to investigate the biomechanical effect of different grades of facetectomy. A three-dimensional nonlinear finite element model of L3–L5 was constructed. The mobility of the model and the intradiscal pressure (IDP) of L4-L5 for standing were inside the data from the literature. The effect of graded facetectomy on intervertebral rotation, IDP, facet joint forces, and maximum von Mises equivalent stresses in the annuli was analyzed under flexion, extension, left/right lateral bending, and left/right axial rotation. Compared with the intact model, under extension, unilateral facetectomy increased the range of intervertebral rotation (IVR) by 11.7% and IDP by 10.7%, while the bilateral facetectomy increased IVR by 40.7% and IDP by 23.6%. Under axial rotation, the unilateral facetectomy and the bilateral facetectomy increased the IVR by 101.3% and 354.3%, respectively, when turned to the right and by 1.1% and 265.3%, respectively, when turned to the left. The results conclude that, after unilateral and bilateral facetectomy, care must be taken when placing the spine into extension and axial rotation posture from the biomechanical point of view.
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Theologis AA, Jain D, Ames CP, Pekmezci M. Circumferential fusion for degenerative lumbar spondylolisthesis complicated by distal junctional grade 4 spondylolisthesis in the sub-acute post-operative setting. 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 2017; 26:3075-3081. [PMID: 28204925 DOI: 10.1007/s00586-017-4976-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/13/2016] [Accepted: 01/23/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Surgical management for lumbar stenosis is generally safe and provides significant improvements in pain, disability, and function. Successful lumbar decompression hinges on removing an appropriate amount of lamina and other compressive pathology in the lateral recess. Too little bony decompression can result in persistent pain and disability, while over resection of the pars and/or facets may jeopardize spinal stability. CASE REPORT In this unique report, we present for the first time an acute iatrogenic grade 4 L5-S1 spondylolisthesis distal to a L3-5 laminectomy and circumferential instrumented fusion due to bilateral iatrogenic L5 pars fractures and its management and clinical outcomes after revision operation. The patient presented with worsening pain, neurologic compromise, and severe sagittal imbalance. The iatrogenic, high-grade spondylolisthesis was urgently addressed with a L5-S1 anterior lumbar interbody fusion and extension of posterior instrumentation to the pelvis, which resulted in considerable pain relief, resolution of neurologic deficits, and reconstitution of acceptable sagittal imbalance. CONCLUSION All attempts during a lumbar decompression should be made to prevent iatrogenic pars fractures, as they may result in severe sagittal imbalance, neurologic compromise, and persistent disability. Iatrogenic, high-grade L5-S1 spondylolisthesis can be successfully treated with reduction using circumferential fusion of the lumbosacral junction.
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Affiliation(s)
- Alexander A Theologis
- Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU West 3rd Floor, San Francisco, CA, 94143, USA.
| | - Deeptee Jain
- Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU West 3rd Floor, San Francisco, CA, 94143, USA
| | | | - Murat Pekmezci
- Department of Orthopaedic Surgery, University of California-San Francisco (UCSF), 500 Parnassus Avenue, MU West 3rd Floor, San Francisco, CA, 94143, USA
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Quadrantectomy for resection of spinal ependymomas with a new classification of unilateral approaches regarding bone drilling and the use of a new tool: The Balak ball-tipped water jet dissector. INTERDISCIPLINARY NEUROSURGERY-ADVANCED TECHNIQUES AND CASE MANAGEMENT 2016. [DOI: 10.1016/j.inat.2016.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Biomechanical analysis of press-extension technique on degenerative lumbar with disc herniation and staggered facet joint. Saudi Pharm J 2016; 24:305-11. [PMID: 27275119 PMCID: PMC4880949 DOI: 10.1016/j.jsps.2016.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study investigates the effect of a new Chinese massage technique named “press-extension” on degenerative lumbar with disc herniation and facet joint dislocation, and provides a biomechanical explanation of this massage technique. Self-developed biomechanical software was used to establish a normal L1–S1 lumbar 3D FE model, which integrated the spine CT and MRI data-based anatomical structure. Then graphic technique is utilized to build a degenerative lumbar FE model with disc herniation and facet joint dislocation. According to the actual press-extension experiments, mechanic parameters are collected to set boundary condition for FE analysis. The result demonstrated that press-extension techniques bring the annuli fibrosi obvious induction effect, making the central nucleus pulposus forward close, increasing the pressure in front part. Study concludes that finite element modelling for lumbar spine is suitable for the analysis of press-extension technique impact on lumbar intervertebral disc biomechanics, to provide the basis for the disease mechanism of intervertebral disc herniation using press-extension technique.
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Amirouche F, Solitro GF, Siemionow K, Drucker D, Upadhyay A, Patel P. Role of posterior elements in the disc bulging of a degenerated cervical spine. Int J Spine Surg 2015; 9:13. [PMID: 26056628 DOI: 10.14444/2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Many studies have been developed to characterize the mechanical behavior of the intervertebral disc specifically for the lumbar spine and there have been limited studies done on the cervical spine with the goal to evaluate the strength of the cervical spine under compression without any information on the bulging of the intervertebral discs. The goal of the current study is to examine the deformation response of the cervical intervertebral disc classified with grade III or greater degeneration and analyze the relationship between axial deformation and anterior and posterior bulge under compression up to 550 N. METHODS Each specimen was compressed for 3 cycles to a maximum load of 550N in steps of 50 N. The bulge was measured using Linear Variable Differential Transformers (LVDTs on an intact spinal segment, spinal segment with post laminectomy, and spinal segment post facetectomy. RESULTS The anterior budge for an intact spinal segment shows a change of slope at loads of 262N±66N. For a physiological load of 250N the vertical displacement or spine segment height was reduced by 10.1% for an intact segment and 8.78% for the laminectomy and facetectomy configurations with F = 0.159 (Fcrit = 3.89) with no statistical difference observed. For the post laminectomy there was a decrease of 35% in anterior bulge compared to the intact specimen. CONCLUSIONS Our results show that for grade III disc degeneration the cervical segments bulging for both the laminectomy and facetectomy procedures are not significantly different. In post laminectomy the average anterior and posterior bulges are similar to the average anterior and posterior bulge post facetectomy.
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Affiliation(s)
- Farid Amirouche
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Giovanni F Solitro
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Kris Siemionow
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - David Drucker
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ashish Upadhyay
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Priyesh Patel
- Department of Orthopaedics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Nanda A, Kukreja S, Ambekar S, Bollam P, Sin AH. Surgical Strategies in the Management of Spinal Nerve Sheath Tumors. World Neurosurg 2015; 83:886-99. [DOI: 10.1016/j.wneu.2015.01.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 01/05/2015] [Accepted: 01/19/2015] [Indexed: 12/01/2022]
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Melnyk AD, Kelly A, Chak JD, Wen TL, Cripton PA, Dvorak MF, Oxland TR. The effect of disc degeneration on anterior shear translation in the lumbar spine. J Orthop Res 2015; 33:450-7. [PMID: 25418948 DOI: 10.1002/jor.22792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 11/17/2014] [Indexed: 02/04/2023]
Abstract
Many pathologies involving disc degeneration are treated with surgery and spinal implants. It is important to understand how the spine behaves mechanically as a function of disc degeneration. Shear loading is especially relevant in the natural and surgically stabilized lumbar spine. The objective of our study was to determine the effect of disc degeneration on anterior translation of the lumbar spine under shear loading. We tested 30 human cadaveric functional spinal units (L3-4 and L4-5) in anterior shear loading. First, the specimens were imaged in a 1.5 T magnetic resonance scanner. The discs were graded according to the Pfirrmann classification. The specimens were then loaded up to 250 N in anterior shear with an axial compression force of 300 N. Motion of the vertebrae was captured with an optoelectronic camera system. Inter- and intra-observer reliability for disc grading was determined (Cohen's and Fleiss' Kappa), and a non-parametric test was performed on the translation data to characterize the effect of disc degeneration on this parameter. We found fair to moderate agreement between and within observers for the disc grading. We found no significant effect of disc degeneration on anterior shear translation (Kruskal-Wallis ANOVA). Our results indicate that disc degeneration, as classified with the Pfirrmann scale, does not predict lumbar spinal motion in shear.
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Affiliation(s)
- Angela D Melnyk
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia, Canada; Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada; International Collaboration on Repair Discoveries, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
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Poureisa M, Soltani S, Fouladi DF, Hagigi A. Etiologies of Recurrent Low Back Pain after Laminectomy with Emphasis on Segmental Instability. JOURNAL OF MEDICAL SCIENCES 2014. [DOI: 10.3923/jms.2014.241.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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González-Darder JM. [Excessive fusion in cervical post-facetectomy arthrodesis]. Neurocirugia (Astur) 2014; 25:244-5. [PMID: 25086733 DOI: 10.1016/j.neucir.2014.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 06/13/2014] [Indexed: 10/25/2022]
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Abstract
Minimally invasive spine surgery (MISS) techniques were developed to address morbidities associated with open spinal surgery approaches. MISS was initially applied for indications such as the microendoscopic decompression of stenosis (MEDS)-an operation that has become widely implemented in modern spine surgery practice. Minimally invasive surgery for MEDS is an excellent example of how an MISS technique has improved outcomes compared with the use of traditional open surgical procedures. In parallel with reports of surgeon experience, accumulating clinical evidence suggests that MISS is favoured over open surgery, and one could argue that the role of MISS techniques will continue to expand. As the field of minimally invasive surgery has developed, MISS has been implemented for the treatment of increasingly difficult and complex pathologies, including trauma, spinal malignancies and spinal deformity in adults. In this Review, we present the accumulating evidence in support of minimally invasive techniques for established MISS indications, such as lumbar stenosis, and discuss the need for additional level I and level II data to demonstrate the benefit of MISS over traditional open surgery. The expanding utility of MISS techniques to address an increasingly broad range of spinal pathologies is also highlighted.
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Bisschop A, Mullender MG, Kingma I, Jiya TU, van der Veen AJ, Roos JC, van Dieën JH, van Royen BJ. The impact of bone mineral density and disc degeneration on shear strength and stiffness of the lumbar spine following laminectomy. 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 2011; 21:530-6. [PMID: 21863461 PMCID: PMC3296849 DOI: 10.1007/s00586-011-1968-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/01/2011] [Accepted: 07/31/2011] [Indexed: 11/25/2022]
Abstract
Purpose Laminectomy is a standard surgical procedure for elderly patients with symptomatic degenerative lumbar stenosis. The procedure aims at decompression of the affected nerves, but it also causes a reduction of spinal shear strength and shear stiffness. The magnitude of this reduction and the influence of bone mineral density (BMD) and disc degeneration are unknown. We studied the influence of laminectomy, BMD, and disc degeneration on shear force to failure (SFF) and shear stiffness (SS). Methods Ten human cadaveric lumbar spines were obtained (mean age 72.1 years, range 53–89 years). Laminectomy was performed either on L2 or L4, equally divided within the group of ten spines. BMD was assessed by dual X-ray absorptiometry (DXA). Low BMD was defined as a BMD value below the median. Intervertebral discs were assessed for degeneration by MRI (Pfirrmann) and scaled in mild and severe degeneration groups. Motion segments L2–L3 and L4–L5 were isolated from each spine. SFF and SS were measured, while loading simultaneously with 1,600 N axial compression. Results Low BMD had a significant negative effect on SFF. In addition, a significant interaction between low BMD and laminectomy was found. In the high BMD group, SFF was 2,482 N (range 1,678–3,284) and decreased to 1,371 N (range 940–1,886) after laminectomy. In the low BMD group, SFF was 1,339 N (range 909–1,628) and decreased to 761 N (range 561–1,221). Disc degeneration did not affect SFF, nor did it interact with laminectomy. Neither low BMD nor the interaction of low BMD and laminectomy did affect SS. Degeneration and its interaction with laminectomy did not significantly affect SS. Conclusions In conclusion, low BMD significantly decreased SFF before and after lumbar laminectomy. Therefore, DXA assessment may be an important asset to preoperative screening. Lumbar disc degeneration did not affect shear properties of lumbar segments before or after laminectomy.
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Affiliation(s)
- Arno Bisschop
- Department of Orthopedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, P.O. Box 7057, 1081 HV, Amsterdam, The Netherlands
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Kuo CS, Hu HT, Lin RM, Huang KY, Lin PC, Zhong ZC, Hseih ML. Biomechanical analysis of the lumbar spine on facet joint force and intradiscal pressure--a finite element study. BMC Musculoskelet Disord 2010; 11:151. [PMID: 20602783 PMCID: PMC2913991 DOI: 10.1186/1471-2474-11-151] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 07/05/2010] [Indexed: 11/16/2022] Open
Abstract
Background Finite element analysis results will show significant differences if the model used is performed under various material properties, geometries, loading modes or other conditions. This study adopted an FE model, taking into account the possible asymmetry inherently existing in the spine with respect to the sagittal plane, with a more geometrically realistic outline to analyze and compare the biomechanical behaviour of the lumbar spine with regard to the facet force and intradiscal pressure, which are associated with low back pain symptoms and other spinal disorders. Dealing carefully with the contact surfaces of the facet joints at various levels of the lumbar spine can potentially help us further ascertain physiological behaviour concerning the frictional effects of facet joints under separate loadings or the responses to the compressive loads in the discs. Methods A lumbar spine model was constructed from processes including smoothing the bony outline of each scan image, stacking the boundary lines into a smooth surface model, and subsequent further processing in order to conform with the purpose of effective finite element analysis performance. For simplicity, most spinal components were modelled as isotropic and linear materials with the exception of spinal ligaments (bilinear). The contact behaviour of the facet joints and changes of the intradiscal pressure with different postures were analyzed. Results The results revealed that asymmetric responses of the facet joint forces exist in various postures and that such effect is amplified with larger loadings. In axial rotation, the facet joint forces were relatively larger in the contralateral facet joints than in the ipsilateral ones at the same level. Although the effect of the preloads on facet joint forces was not apparent, intradiscal pressure did increase with preload, and its magnitude increased more markedly in flexion than in extension and axial rotation. Conclusions Disc pressures showed a significant increase with preload and changed more noticeably in flexion than in extension or in axial rotation. Compared with the applied preloads, the postures played a more important role, especially in axial rotation; the facet joint forces were increased in the contralateral facet joints as compared to the ipsilateral ones at the same level of the lumbar spine.
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Affiliation(s)
- Ching-Sung Kuo
- Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan.
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Strange DGT, Fisher ST, Boughton PC, Kishen TJ, Diwan AD. Restoration of compressive loading properties of lumbar discs with a nucleus implant-a finite element analysis study. Spine J 2010; 10:602-9. [PMID: 20547110 DOI: 10.1016/j.spinee.2010.04.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 02/06/2010] [Accepted: 04/08/2010] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Discectomy is a common procedure for treating sciatica. However, both the operation and preceding herniated disc alter the biomechanical properties of the spinal segment. The disc mechanics are also altered in patients with chronic contained herniation. The biomechanical properties of the disc can potentially be restored with an elastomeric nucleus replacement implanted via minimally invasive surgery. PURPOSE The purpose of this study was to determine whether the compressive characteristics of the intervertebral disc after a nucleotomy can be restored with an elastomeric nucleus replacement. STUDY DESIGN A finite element model of the L4-L5 intervertebral disc was created to investigate the effect of the implantation of an elastomeric nucleus replacement on the biomechanical properties of the disc under axial loading. METHOD A L4-L5 physiologic intervertebral disc model was constructed and then modified to contain a range by volume of nucleotomies and nucleus replacements. The material properties of the nucleus replacement were based on experimental data for an elastomeric implant. The compressive stiffness, radial annular bulge, and stress distribution of the nucleotomy and nucleus replacement models were investigated under displacement-controlled loading. RESULTS Removal of nucleus pulposus from the physiologic disc reduced the force necessary to compress the disc 2 mm by 50%, altered the von Mises stress distribution, and reduced the outward radial annular bulge. Replacing the natural nucleus pulposus of the physiologic disc with an artificial nucleus reduced the force required to compress the disc 2 mm by 10%, indicating a restoration of disc compressive stiffness. The von Mises stress distribution and annular bulge observed in the disc with an artificial nucleus were similar to that observed in the physiologic disc. CONCLUSION This study demonstrates that despite having different material properties, a nucleus replacement implant can restore the axial compressive mechanical properties of a disc after a discectomy. The implant carries compressive load and transfers the load into annular hoop stress.
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Affiliation(s)
- Daniel G T Strange
- Spine Service, Department of Orthopaedic Surgery, St George Hospital, University of New South Wales, Kogarah NSW 2217, Sydney, Australia
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van Solinge GB, van der Veen AJ, van Dieën JH, Kingma I, van Royen BJ. Anterior shear strength of the porcine lumbar spine after laminectomy and partial facetectomy. 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 2010; 19:2130-6. [PMID: 20582709 DOI: 10.1007/s00586-010-1492-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 05/02/2010] [Accepted: 06/11/2010] [Indexed: 01/24/2023]
Abstract
Degenerative lumbar spinal stenosis is the most common reason for lumbar surgery in patients in the age of 65 years and older. The standard surgical management is decompression of the spinal canal by laminectomy and partial facetectomy. The effect of this procedure on the shear strength of the spine has not yet been investigated in vitro. In the present study we determined the ultimate shear force to failure, the displacement and the shear stiffness after performing a laminectomy and a partial facetectomy. Eight lumbar spines of domestic pigs (7 months old) were sectioned to obtain eight L2-L3 and eight L4-L5 motion segments. All segments were loaded with a compression force of 1,600 N. In half of the 16 motion segments a laminectomy and a 50% partial facetectomy were applied. The median ultimate shear force to failure with laminectomy and partial facetectomy was 1,645 N (range 1,066-1,985) which was significantly smaller (p = 0.012) than the ultimate shear force to failure of the control segments (median 2,113, range 1,338-2,659). The median shear stiffness was 197.4 N/mm (range 119.2-216.7) with laminectomy and partial facetectomy which was significantly (p = 0.036) smaller than the stiffness of the control specimens (median 216.5, 188.1-250.2). It was concluded that laminectomy and partial facetectomy resulted in 22% reduction in ultimate shear force to failure and 9% reduction in shear stiffness. Although relatively small, these effects may explain why patients have an increased risk of sustaining shear force related vertebral fractures after spinal decompression surgery.
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Affiliation(s)
- Guido B van Solinge
- Department of Orthopedic Surgery, VU University Medical Center, Amsterdam, The Netherlands
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Ogden AT, Bresnahan L, Smith JS, Natarajan R, Fessler RG. Biomechanical comparison of traditional and minimally invasive intradural tumor exposures using finite element analysis. Clin Biomech (Bristol, Avon) 2009; 24:143-7. [PMID: 19121823 DOI: 10.1016/j.clinbiomech.2008.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/11/2008] [Accepted: 11/12/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND Minimally invasive approaches to intradural pathology have evolved in part in an effort to reduce approach related destabilization of the spine. No biomechanical data exist however evaluating the effects of traditional and minimally invasive exposures. METHODS A finite element model of the lumbar spine was generated, and a simulated open laminectomy and a modified hemilaminectomy at L4 were performed. Forces were applied to assess changes in flexion, extension, axial rotation, and lateral bending. FINDINGS Open laminectomy produced much greater changes in extension, flexion, and axial rotation than the modified hemilaminectomy from the intact. Lateral bending was similarly unaffected for both exposures. INTERPRETATION The results suggest that a minimally invasive hemilaminar exposure preserves the structural integrity of the lumbar spine and minimizes alterations to segmental motion postoperatively.
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Affiliation(s)
- Alfred T Ogden
- Department of Neurological Surgery, Columbia University, The Neurological Institute, 710 W. 168th Street, New York, NY 10032, USA.
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A biomechanical evaluation of graded posterior element removal for treatment of lumbar stenosis: comparison of a minimally invasive approach with two standard laminectomy techniques. Spine (Phila Pa 1976) 2009; 34:17-23. [PMID: 19127157 DOI: 10.1097/brs.0b013e318191438b] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A validated finite element model of the intact lumbar spine (L1-S1) was modified to study the biomechanical changes as a result of surgical alteration for treatment of stenosis at L3-L4 and L4-L5 using 2 established techniques and 1 new minimally invasive technique. OBJECTIVE To investigate the impact of graded posterior element removal associated with new surgical techniques on postoperative segmental motion and loading in the annulus. SUMMARY OF BACKGROUND DATA Several studies have shown that laminectomy increases and produces segmental instability unless fusion is performed. However, no data exist comparing the biomechanical impact of completely preserving the contralateral anatomy and what effect this has compared to traditional approaches. METHODS The effect of graded removal of posterior elements because of iatrogenic change associated with the 3 approaches was investigated using an 800 N compressive preload using the follower load technique and application of 8 Nm flexion, 6 Nm extension, 4 Nm torsion, and 6 Nm lateral bending moments. RESULTS This study shows that removal of posterior elements for treatment of stenosis at L3-L4 and L4-L5 results in increased flexion-extension and axial rotation at the surgical site. This study also shows that the segmental motion following a traditional laminectomy is greater than the minimally invasive approach in flexion, extension, left and right axial rotation. Moderate preservation of the posterior elements which occurs in the intralaminar approach generates greater segmental motion that the minimally invasive approach in extension, left and right axial rotation. CONCLUSION Minimization of bone and ligament removal associated with minimally invasive procedures results in greater preservation of the normal motion of the lumbar spine after surgery. This study suggests that preservation of the posterior spinal elements associated with minimally invasive surgery could minimize the risk of developing de novo postoperative changes in spinal alignment and/or acceleration of facet and disc degeneration.
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Chutkan NB, Zhou H, Akins JP, Wenger KH. Effects of facetectomy and crosslink augmentation on motion segment flexibility in posterior lumbar interbody fusion. Spine (Phila Pa 1976) 2008; 33:E906-10. [PMID: 18923306 DOI: 10.1097/brs.0b013e318183bb6d] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Biomechanical assessment using calf lumbar motion segments. OBJECTIVE To determine whether facetectomy affects the primary stability of posterior lumbar interbody fusion. SUMMARY OF BACKGROUND DATA To improve visualization and access to the disc space, the facet joints frequently are removed. Previous biomechanical studies have indicated a fundamental role for the facet joints in maintaining spinal segment stability. METHODS Single motion segments from calf lumbar spines were tested for pure-moment flexibility in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). After testing intact, an interbody cage and pedicle screw system were implanted. Next, a bilateral facetectomy was performed, and finally a crosslink was added. Flexibility testing was repeated at each stage of implantation. Data are reported for range of motion (ROM), neutral zone (NZ), and a new compliance parameter (COM), based on the slopes of the moment-angle curve in the neutral and elastic regions. RESULTS With posterior lumbar interbody fusion implantation, ROM in FE was reduced 82% +/- 4% (mean +/- standard deviation) and NZ 78% +/- 7% over intact (P < 0.015: Wilcoxon). Reduction in LB was slightly more, whereas reduction in AR was considerably less and did not achieve statistical significance for NZ. After facetectomy, ROM in FE increased 0.3 degrees (P < 0.05), on average, and NZ did not change. In LB neither changed significantly. In AR, ROM increased 0.6 degrees (P < 0.05), and NZ increased 0.2 degrees (P < 0.05). The addition of a crosslink changed ROM and NZ less than 0.1 degrees in FE and LB, whereas in AR it restored half of the stability lost due to facetectomy in ROM (P < 0.05), and had a similar trendwise effect on NZ. The new compliance measure, COM, was found to agree with the direction of change in ROM more consistently than did NZ. CONCLUSION Facetectomy causes a nominal increase in ROM and NZ in FE and LB, which are not affected by the addition of a crosslink. Although the effect of facetectomy is greater in AR-and crosslink has a measurable restoring effect-all differences are within a few tenths of a degree under this loading paradigm. Thus, the clinical utility of adding a crosslink may not be justified based on these small biomechanical changes. COM can serve as a complement to ROM and NZ, or even as a surrogate when its 2 components are reported together, as it shows strong agreement with ROM, effectively distinguishes between lax and elastic region behaviors, and provides a measure of flexibility independent of the load range.
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Affiliation(s)
- Norman B Chutkan
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta, GA, USA
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Li H, Wang Z. Intervertebral disc biomechanical analysis using the finite element modeling based on medical images. Comput Med Imaging Graph 2006; 30:363-70. [PMID: 17074465 DOI: 10.1016/j.compmedimag.2006.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this paper, a 3D geometric model of the intervertebral and lumbar disks has been presented, which integrated the spine CT and MRI data-based anatomical structure. Based on the geometric model, a 3D finite element model of an L1-L2 segment was created. Loads, which simulate the pressure from above were applied to the FEM, while a boundary condition describing the relative L1-L2 displacement is imposed on the FEM to account for 3D physiological states. The simulation calculation illustrates the stress and strain distribution and deformation of the spine. The method has two characteristics compared to previous studies: first, the finite element model of the lumbar are based on the data directly derived from medical images such as CTs and MRIs. Second, the result of analysis will be more accurate than using the data of geometric parameters. The FEM provides a promising tool in clinical diagnosis and for optimizing individual therapy in the intervertebral disc herniation.
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Affiliation(s)
- Haiyun Li
- College of Biomedical Engineering, Capital University of Medical Sciences, Beijng 100054, China.
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Qiu TX, Teo EC, Zhang QH. Effect of bilateral facetectomy of thoracolumbar spine T11–L1 on spinal stability. Med Biol Eng Comput 2006; 44:363-70. [PMID: 16937178 DOI: 10.1007/s11517-006-0048-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Accepted: 03/14/2006] [Indexed: 12/11/2022]
Abstract
Spinal stenosis can be found in any part of the spine, though it is most commonly located on the lumbar and cervical areas. It has been documented in the literature that bilateral facetectomy in a lumbar motion segment to increase the space induces an increase in flexibility at the level at which the surgery was performed. However, the result of bilateral facetectomy on the stability of the thoracolumbar spine has not been studied. A nonlinear three-dimensional finite element (FE) model of thoracolumbar T11-L1 was built to explore the influence of bilateral facetectomy. The FE model of T11-L1 was validated against published experimental results under various physiological loadings. The FE model with bilateral facetectomy was evaluated under flexion, extension, lateral bending and axial rotation to determine alterations in kinematics. Results show that bilateral facetectomy causes increase in motion, considerable increase in axial rotation and least increase in lateral bending. Removal of facets did not result in significant change in the sagittal motion in flexion and extension.
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Affiliation(s)
- Tian-Xia Qiu
- School of Mechanical and Aerospace Engineering, Biomedical Engineering Research Center, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798
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