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Park S, Hwang CJ, Lee DH, Kim NY, Nam HW, Kang HW, Lee CS, Ok CH, Cho JH. Risk factors of revision operation and early revision for adjacent segment degeneration after lumbar fusion surgery: a case-control study. Spine J 2024:S1529-9430(24)00183-9. [PMID: 38663482 DOI: 10.1016/j.spinee.2024.04.013] [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: 09/26/2023] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND CONTEXT Adjacent segment degeneration (ASD) following lumbar fusion operation is common and can occur at varying timepoints after index surgery. An early revision operation for ASD, however, signifies a short symptom-free period and might increase the risk of successive surgeries. PURPOSE We aimed to elucidate the overall risk factors associated with revision surgeries for ASD with distinct attention to early revisions. STUDY DESIGN/SETTING Retrospective, case-control study. PATIENT SAMPLE The study included 86 patients who underwent revision operations for ASD after lumbar fusion in the revision group and 166 patients who did not for at least 5 years after index surgery. OUTCOME MEASURES Sagittal parameters, Pfirrmann grading, facet degeneration grading, and disc space height (DSH) of adjacent segments were assessed. METHODS Revision operations within 5 years postsurgery were defined as early revision. We compared the revision and no-revision groups as well as the early- and late-revision groups. RESULTS The revision group demonstrated a significantly greater preoperative C7-S1 sagittal vertical axis (SVA) (p=.001), postoperative C7-S1 SVA (p<.001), and postoperative pelvic incidence (PI)-lumbar lordosis (LL) (p<.001) than those in the no-revision group. Preoperative DSH of the proximal adjunct segment (p=.001), postoperative PI-LL (p=.014), and postoperative C7-S1 SVA (p=.037) exhibited significant association with ASD in logistic regression analysis. The early-revision group had a significantly higher patient age (p=.001) and a greater number of levels fused (p=.030) than those in the late-revision group. Multivariate Cox regression analysis demonstrated that old age (p=.045), a significant number of levels fused (p=.047), and a narrow preoperative DSH of the proximal adjacent level (p=.011) were risk factors for early revision. CONCLUSIONS Postoperative sagittal imbalance, including significant PI-LL and C7-S1 SVA were risk factors for revision operation for ASD but not for early revision. These factors are likely to affect the long-term risk of revision operation due to ASD and thus are not considered risk factors for early revision. Narrow DSH of the proximal adjacent level increased the risks of both revision and early revision surgeries. Moreover, old age and a significant number of levels fused further increased the risk for early revision for ASD.
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Affiliation(s)
- Sehan Park
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Chang Ju Hwang
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Dong-Ho Lee
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Nam Yeop Kim
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Hyun Wook Nam
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Hyun Wook Kang
- Department of Spine Surgery, St.Peter's Hospital, 2649, Nambusunhwan-ro, Gangnam-gu, Seoul, Republic of Korea
| | - Choon Sung Lee
- Department of Spine Surgery, St.Peter's Hospital, 2649, Nambusunhwan-ro, Gangnam-gu, Seoul, Republic of Korea
| | - Cha Hyeong Ok
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea
| | - Jae Hwan Cho
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea.
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Fan W, Yang S, Chen J, Guo LX, Zhang M. A Biomechanical Comparison of 2 Different Topping-off Devices and Their Influence on the Sacroiliac Joint Following Lumbosacral Fusion Surgery. Neurospine 2024; 21:244-252. [PMID: 38317555 PMCID: PMC10992661 DOI: 10.14245/ns.2347108.554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 02/07/2024] Open
Abstract
OBJECTIVE Interspinous spacer (ISS)-based and pedicle screw-rod dynamic fixator (PDF)-based topping-off devices have been applied in lumbar/lumbosacral fusion surgeries for preventing the development of proximal adjacent segment degeneration. However, little attention has been paid to sacroiliac joint (SIJ), which belongs to the adjacent joints. Accordingly, the objective of this study was to compare how these 2 topping-off devices affect the SIJ biomechanics. METHODS A validated, normal finite-element lumbopelvic model (L3-pelvis) was initially adjusted to simulate interbody fusion with rigid fixation at the L5-S1 level, and then the DIAM or BioFlex system was instrumented at the L4-5 level to establish the ISS-based or PDF-based topping-off model, respectively. All the developed models were loaded with moments of 4 physiological motions using hybrid loading protocol. RESULTS Compared with the rigid fusion model (without topping-off devices), range of motion and von-Mises stress at the SIJs were increased by 23.1%-64.1% and 23.6%-62.8%, respectively, for the ISS-based model and by 51.2%-126.7% and 50.4%-108.7%, respectively, for the PDF-based model. CONCLUSION The obtained results suggest that the PDF-based topping-off device leads to higher increments in SIJ motion and stress than ISS-based topping-off device following lumbosacral fusion, implying topping-off technique could be linked to an increased risk of SIJ degeneration, especially when using PDF-based device.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Song Yang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Jie Chen
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Ming Zhang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
- Research Institute for Sports Science and Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Guan J, Liu T, Yu X, Li W, Feng N, Jiang G, Zhao H, Yang Y. Biomechanical and clinical research of Isobar semi-rigid stabilization devices for lumbar degenerative diseases: a systematic review. Biomed Eng Online 2023; 22:95. [PMID: 37742006 PMCID: PMC10518087 DOI: 10.1186/s12938-023-01156-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 09/15/2023] [Indexed: 09/25/2023] Open
Abstract
While lumbar spinal fusion using rigid rods is a prevalent surgical technique, it can lead to complications such as adjacent segment disease (ASDis). Dynamic stabilization devices serve to maintain physiological spinal motion and alleviate painful stress, yet they are accompanied by a substantial incidence of construct failure and subsequent reoperation. Compared to traditional rigid devices, Isobar TTL semi-rigid stabilization devices demonstrate equivalent stiffness and effective stabilization capabilities. Furthermore, when contrasted with dynamic stabilization techniques, semi-rigid stabilization offers improved load distribution, a broader range of motion within the fixed segment, and reduced mechanical failure rates. This paper will review and evaluate the clinical and biomechanical performance of Isobar TTL semi-rigid stabilization devices. A literature search using the PubMed, EMBASE, CNKI, Wanfang, VIP, and Cochrane Library databases identified studies that met the eligibility criteria. Twenty-eight clinical studies and nine biomechanical studies were included in this systematic review. The VAS, the ODI, and Japanese Orthopedic Association scoring improved significantly in most studies. UCLA grading scale, Pfirrmann grading, and modified Pfirrmann grading of the upper adjacent segments improved significantly in most studies. The occurrence rate of ASD was low. In biomechanical studies, Isobar TTL demonstrated a superior load sharing distribution, a larger fixed segment range of motion, and reduced stress at the rod-screw/screw-bone interfaces compared with titanium rods. While findings from mechanical studies provided promising results, the clinical studies exhibited low methodological quality. As a result, the available evidence does not possess sufficient strength to substantiate superior outcomes with Isobar semi-rigid system in comparison to titanium rods. To establish more conclusive conclusions, further investigations incorporating improved protocols, larger sample sizes, and extended follow-up durations are warranted.
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Affiliation(s)
- Jianbin Guan
- Department of Spine Surgery, Honghui-Hospital, Xi'an Jiaotong University, Xi'an, 710054, China.
| | - Tao Liu
- Department of Spine Surgery, Honghui-Hospital, Xi'an Jiaotong University, Xi'an, 710054, China
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Xing Yu
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China.
| | - Wenhao Li
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Ningning Feng
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Guozheng Jiang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
| | - He Zhao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Yongdong Yang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 100700, China
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Fan W, Zhang C, Wang QD, Guo LX, Zhang M. The effects of topping-off instrumentation on biomechanics of sacroiliac joint after lumbosacral fusion. Comput Biol Med 2023; 164:107357. [PMID: 37586205 DOI: 10.1016/j.compbiomed.2023.107357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 08/02/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Lumbar/lumbosacral fusion supplemented with topping-off devices has been proposed with the aim of avoiding adjacent segment degeneration proximal to the fusion construct. However, it remains unclear how the biomechanics of the sacroiliac joint (SIJ) are altered after topping-off surgery. The objective of this study was to investigate the biomechanical effects of topping-off instrumentation on SIJ after lumbosacral fusion. METHODS The validated finite element model of an intact lumbar spine-pelvis segment was modified to simulate L5-S1 interbody fusion fixed with a pedicle screw system. An interspinous spacer, Device for Intervertebral Assisted Motion (DIAM), was used as a topping-off device and placed between interspinous processes of the L4 and L5 segments. Range of motion (ROM), von-Mises stress distribution, and ligament strain at SIJ were compared between fusion (without DIAM) and topping-off (fusion with DIAM) models under moments of four physiological motions. RESULTS ROM at the left and right SIJs in the topping-off model was higher by 26.9% and 27.5% in flexion, 16.8% and 16.1% in extension, 18.8% and 15.8% in lateral bending, and 3.7% and 7.4% in axial rotation, respectively, compared to those in the fusion model. The predicted stress and strain data showed that under all physiological loads, the topping-off model exhibited higher stress and ligament strain at the SIJs than the fusion model. CONCLUSIONS Motion, stress, and ligament strain at SIJ increase when supplementing lumbosacral fusion with topping-off devices, suggesting that topping-off surgery may be associated with higher risks of SIJ degeneration and pain than fusion alone.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China.
| | - Chi Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Qing-Dong Wang
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Ming Zhang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Institute for Sports Science and Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Lee JW, Kim HC, Kim SI, Min HK, Ha KY, Park HY, Cho CH, Sung HS, Lim JH, Kim YH. Effects of bone cement augmentation for uppermost instrumented vertebra on adjacent disc segment degeneration in lumbar fusions. World Neurosurg 2023; 171:e31-e37. [PMID: 36528321 DOI: 10.1016/j.wneu.2022.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 12/23/2022]
Abstract
OBJECTIVE We investigated the long-term effects of bone cement-augmented instrumentation in multilevel lumbar fusions in a retrospective cohort study. The use of cement-augmented screws is one of the techniques used to reduce early mechanical failure in treating multilevel lumbar fusion, especially in the elderly. However, little information is available regarding the long-term effects. METHODS A total of 51 patients who had undergone ≥3 levels of lumbar fusion were divided into two groups according to the use of bone cement-augmented screw fixation involving the upper instrumented vertebra: 22 patients in the cement-augmented group (group I) and 29 patients in the non-cement-augmented group (group II). Analysis of radiographic adjacent disc segment degeneration (ASD) revealed patients with lumbosacral fusion with a similar degree of osteoporosis. Radiologic ASD was defined as progression of >2 UCLA (University of California, Los Angeles) grades at 2 years postoperatively. Other sagittal parameters and the preoperative magnetic resonance imaging Pfirrmann grades at the adjacent levels, possibly related to ASD, were also analyzed. RESULTS No significant differences were present in the preoperative demographic and radiographic parameters between the 2 groups. However, the postoperative kyphotic changes at 3 months were greater for the non-cement-augmented group. In terms of the long-term effects, the incidence of radiologic ASD (group I, n = 20 [95.2%]; vs group II, n = 15 [53.6%]) was significantly higher in the cement-augmented group. Logistic regression analysis of radiologic ASD, including other clinical and radiologic parameters, postoperative pelvic incidence-lumbar lordosis mismatch (odds ratio, 5.201; 95% confidence interval, 1.123-24.090; P = 0.035), and cement augmentation (odds ratio, 20.193; 95% confidence interval, 2.195-185.729; P = 0.008) showed a significant correlation with the development of radiologic ASD at 2 years postoperatively. CONCLUSIONS Although bone cement-augmented screw implantation can prevent kyphotic deformation at the proximal junction of upper instrumented vertebra in the early postoperative stages of multilevel lumbar fusion, a careful selection of patients is required because of possibly accelerated degeneration of adjacent segments.
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Affiliation(s)
- Jae-Won Lee
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Hun-Chul Kim
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Sang-Il Kim
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Hyung-Ki Min
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Kee-Yong Ha
- Department of Orthopedic Surgery, Kyung-Hee University Hospital at Gangdong, Seoul, Korea
| | - Hyung-Youl Park
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Chang-Hee Cho
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Hoon-Seok Sung
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Jae-Hak Lim
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea
| | - Young-Hoon Kim
- Department of Orthopedic Surgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
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Saghebdoust S, Zare R, Chaurasia B, Vakilzadeh MM, Yousefi O, Boustani MR. Dynamic Rod Constructs as the Preventive Strategy against Adjacent Segment Disease in Degenerative Lumbar Spinal Disorders: A Retrospective Comparative Cohort Study. THE ARCHIVES OF BONE AND JOINT SURGERY 2023; 11:404-413. [PMID: 37404298 PMCID: PMC10314982 DOI: 10.22038/abjs.2022.68498.3239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/17/2022] [Indexed: 07/06/2023]
Abstract
Objectives Adjacent segment degeneration (ASDe) and adjacent segment disease (ASDi) are potential long-term complications after lumbar fusion with rigid instrumentation. Dynamic fixation techniques (Topping-off) adjacent to the fused segments have been developed to curtail the risk of ASDe and ASDi. The current study sought to investigate whether the addition of dynamic rod constructs (DRC) in patients with preoperative degeneration in the adjacent disc was effective in reducing the risk of ASDi. Methods A retrospective analysis was performed on clinical data of 207 patients with degenerative lumbar disorders (DLD) from January 2012 to January 2019, who underwent posterior transpedicular lumbar fusion (without Topping-off, NoT/O), and posterior dynamic instrumentation with DRC. Clinical and radiological outcomes were evaluated using Oswestry Disability Index (ODI), Visual Analogue Scale (VAS), and lumbar radiographs one, three, and 12 months postoperatively and annually. ASDe was defined as disc height collapse > 20% and disc wedging > 5. Patients with confirmed ASDe and aggravation of ODI > 20 or VAS score > 5 at final follow-up were diagnosed as ASDi. The Kaplan-Meier hazard method was used to estimate the cumulative probability of ASDi within 63 months of surgery. Results Over three years of follow-up, 65 patients in the NoT/O (59.6%) and 52 cases (53.1%) in the DRC groups met the diagnostic criteria for ASDe. Furthermore, 27 (24.8%) patients in the NoT/O group showed ASDi during the follow-up, compared to 14 (14.3%) cases in the DRC group (P=0.059). Revision surgery was performed on 19 individuals in the NoT/O and 8 cases in the DRC groups (P=0.048). The Cox regression model identified a significantly decreased risk of ASDi if DRC was used (Hazard ratio: 0.29; 95% CI: 0.13-0.6). Conclusion Dynamic fixation adjacent to the fused segment is an effective strategy for preventing ASDi in carefully selected individuals with preoperative degenerative changes at the adjacent level.
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Affiliation(s)
| | - Reza Zare
- Department of Neurosurgery, Razavi Hospital, Mashhad, Iran
| | - Bipin Chaurasia
- Department of Neurosurgery, Neurosurgery Clinic, Birgunj, Nepal
| | | | - Omid Yousefi
- Trauma Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Chiou K, Chiu YC, Lee CY, Huang TJ, Lai YC, Yang CJ, Hsu JC, Wu MH. Comparison of long-term outcomes of spinal fusion surgeries supplemented with "topping-off" implants in lumbar degenerative diseases: A systematic review and network meta-analysis. NORTH AMERICAN SPINE SOCIETY JOURNAL 2022; 12:100177. [PMID: 36394053 PMCID: PMC9650073 DOI: 10.1016/j.xnsj.2022.100177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/06/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022]
Abstract
Background Context Spinal fusion surgery is a common treatment for lumbar degenerative diseases and has been associated with the long-term complication of adjacent segment disease (ASD). In recent years, the "topping-off" technique has emerged as a new surgical method, combining spinal fusion with a hybrid stabilization device (HSD) or interspinous process device (IPD) proximal to the fused vertebrae. Methods A literature search using the PubMed, Cochrane Central Register of Controlled Trials, EMBASE, and Web of Science databases identified eligible studies comparing topping-off implant(s) with spinal fusion surgery for lumbar degenerative diseases. Risk of bias was assessed using the Cochrane RoB 2.0 tool for randomized controlled trials and the Newcastle-Ottawa scale for retrospective studies. Each outcome was analyzed using the statistical Confidence in NMA (CINeMA) 1.9.0 software. Results 17 RCTs and retrospective studies that included 1255 participants and five interventions were identified. The topping-off implants device for intervertebral assisted motion (DIAM; OR = 0.235, p < 0.001), Dynesys (OR = 0.413, p < 0.001), and Coflex (OR = 0.417, p < 0.01) significantly lowered the incidence of radiographic adjacent segment degeneration (RASDeg) compared with spinal fusion surgery alone. Spinal fusion supplemented with DIAM significantly reduced the incidence of clinical adjacent segment disease (CASD) (OR = 0.358, p = 0.032). Conclusions Spinal fusion supplemented with DIAM substantially reduced the incidence of radiographic and clinical adjacent segment disease. No significant difference was observed between the treatment comparators for reoperation due to ASD and back pain relief score.
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Affiliation(s)
- Katie Chiou
- College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Chia Chiu
- College of Business Administration, Shoochow University, Taipei, Taiwan
| | - Ching-Yu Lee
- Department of Orthopedics, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsung-Jen Huang
- Department of Orthopedics, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Ching Lai
- Graduate Institute of Health and Biotechnology Law, Taipei Medical University, Taipei, Taiwan
| | - Chia-Ju Yang
- Medical and Pharmaceutical Industry of Technology and Development Center, National Taipei University of Technology, Taipei, Taiwan
| | - Jason C. Hsu
- International PhD Program of Biotech and Healthcare Management, College of Management, Taipei Medical University, Taipei, Taiwan
- Clinical Data Center, Office of Data Science, Taipei Medical University, Taipei, Taiwan
- Research Center of Data Science on Healthcare Industry, College of Management, Taipei Medical University, Taipei, Taiwan
- Clinical Big Data Research Center, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan
| | - Meng-Huang Wu
- Department of Orthopedics, Taipei Medical University Hospital, Taipei, Taiwan
- Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Biodesign Center, Taipei Medical University, Taipei, Taiwan
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Guo Z, Liu G, Wang L, Zhao Y, Zhao Y, Lu S, Cheng C. Biomechanical effect of Coflex and X-STOP spacers on the lumbar spine: a finite element analysis. Am J Transl Res 2022; 14:5155-5163. [PMID: 35958508 PMCID: PMC9360861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVE To explore the biomechanical differences between Coflex and X-STOP devices by finite element analysis. METHODS Based on the normal lumbar CT images from a healthy adult volunteer, four finite element models including the healthy lumbar segment model, the mild degenerated lumbar segment model, a Coflex fixed lumbar segment model and X-STOP fixed lumbar segment model were constructed. A simulation analysis under the conditions of flexion, extension, lateral bending, and rotation was performed to compare range of motion (ROM), intradiscal pressure, the facet joint force, the maximum Von Mises stress and the peak facet contact forces, between Coflex and X-STOP devices. RESULTS Compared to the mild degenerated lumbar segment model at surgical level L4-L5, Coflex and X-STOP could reduce ROM in extension by 98.34% and 95.86%, respectively, decrease peak stress of intervertebral discs in extension by 59.4% and 66.17%, respectively, and release peak force of facet joint in extension by 97.09% and 95.42%, respectively. Both devices had no significant impact on adjacent levels. The maximum Von Mises stress in Coflex device was 637.56 Mpa in flexion, 528.86 Mpa in extension, while the maximum Von Mises stress in X-STOP device was 476.65 Mpa at extension position. The peak facet contact forces of Coflex and X-STOP devices appeared in extension and were 19.76 Mpa and 49.28 Mpa, respectively. CONCLUSIONS Coflex and X-STOP devices can effectively decrease the ROM and intradiscal pressure in extension, without affecting the adjacent levels.
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Affiliation(s)
- Zhiyuan Guo
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Guangfei Liu
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Lu Wang
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Yuejiang Zhao
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Ye Zhao
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Shouliang Lu
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
| | - Cai Cheng
- Department of Orthopedics, Cangzhou Central Hospital Cangzhou, Hebei, China
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