1
|
Xi Z, Xie Y, Sun S, Wang N, Chen S, Kang X, Li J. Stepwise reduction of bony density in patients induces a higher risk of annular tears by deteriorating the local biomechanical environment. Spine J 2024; 24:831-841. [PMID: 38232914 DOI: 10.1016/j.spinee.2023.12.007] [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: 09/10/2023] [Revised: 11/15/2023] [Accepted: 12/27/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND CONTEXT The relationship between osteoporosis and intervertebral disc degeneration (IDD) remains unclear. Considering that annular tear is the primary phenotype of IDD in the lumbar spine, the deteriorating local biomechanical environment may be the main trigger for annular tears. PURPOSE To investigate whether poor bone mineral density (BMD) in the vertebral bodies may increase the risk of annular tears via the degradation of the local biomechanical environment. STUDY DESIGN This study was a retrospective investigation with relevant numerical mechanical simulations. PATIENT SAMPLE A total of 64 patients with low back pain (LBP) and the most severe IDD in the L4-L5 motion segment were enrolled. OUTCOME MEASURES Annulus integration status was assessed using diffusion tensor fibre tractography (DTT). Hounsfield unit (HU) values of adjacent vertebral bodies were employed to determine BMD. Numerical simulations were conducted to compute stress values in the annulus of models with different BMDs and body positions. METHODS The clinical data of the 64 patients with low back pain were collected retrospectively. The BMD of the vertebral bodies was measured using the HU values, and the annulus integration status was determined according to DTT. The data of the patients with and without annular tears were compared, and regression analysis was used to identify the independent risk factors for annular tears. Furthermore, finite element models of the L4-L5 motion segment were constructed and validated, followed by estimating the maximum stress on the post and postlateral interfaces between the superior and inferior bony endplates (BEPs) and the annulus. RESULTS Patients with lower HU values in their vertebral bodies had significantly higher incidence rates of annular tears, with decreased HU values being an independent risk factor for annular tears. Moreover, increased stress on the BEP-annulus interfaces was associated with a stepwise reduction of bony density (ie, elastic modulus) in the numerical models. CONCLUSIONS The stepwise reduction of bony density in patients results in a higher risk of annular tears by deteriorating the local biomechanical environment. Thus, osteoporosis should be considered to be a potential risk factor for IDD biomechanically.
Collapse
Affiliation(s)
- Zhipeng Xi
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China; Department of Orthopedics, Traditional Chinese Medicine Hospital of Ili Kazak Autonomous Prefecture, 2th. Jiankang Street, Yining, 835000, Xinjiang Uighur Autonomous Region, P.R. China
| | - Yimin Xie
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shenglu Sun
- Department of Imaging, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Nan Wang
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shuang Chen
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Xiong Kang
- Department of Orthopedics, Traditional Chinese Medicine Hospital of Ili Kazak Autonomous Prefecture, 2th. Jiankang Street, Yining, 835000, Xinjiang Uighur Autonomous Region, P.R. China
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, No.182, Chunhui Rd, Longmatan District, Luzhou, 646000, Sichuan Province, P.R. China.
| |
Collapse
|
2
|
Huang F, Huang G, Jia J, Lu S, Li J. Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically: an in silico study. J Orthop Surg Res 2024; 19:143. [PMID: 38365801 PMCID: PMC10870541 DOI: 10.1186/s13018-024-04550-0] [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: 11/02/2023] [Accepted: 01/09/2024] [Indexed: 02/18/2024] Open
Abstract
BACKGROUND The capsule of the zygapophyseal joint plays an important role in motion segmental stability maintenance. Iatrogenic capsule injury is a common phenomenon in posterior approach lumbar interbody fusion operations, but whether this procedure will cause a higher risk of adjacent segment degeneration acceleration biomechanically has yet to be identified. METHODS Posterior lumbar interbody fusion (PLIF) with different grades of iatrogenic capsule injury was simulated in our calibrated and validated numerical model. By adjusting the cross-sectional area of the capsule, different grades of capsule injury were simulated. The stress distribution on the cranial motion segment was computed under different loading conditions to judge the potential risk of adjacent segment degeneration acceleration. RESULTS Compared to the PLIF model with an intact capsule, a stepwise increase in the stress value on the cranial motion segment can be observed with a step decrease in capsule cross-sectional areas. Moreover, compared to the difference between models with intact and slightly injured capsules, the difference in stress values was more evident between models with slight and severe iatrogenic capsule injury. CONCLUSION Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically, and iatrogenic capsule damage on the cranial motion segment should be reduced to optimize patients' long-term prognosis.
Collapse
Affiliation(s)
- Fei Huang
- Department of Orthopedics, Meishan Hospital of Traditional Chinese Medicine, Meishan, China
| | - Gang Huang
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Junpengli Jia
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Shihao Lu
- Department of Orthopedics, Changzheng Hospital Affiliated to the Naval Medical University, Xiangyin Road, Shanghai, 200433, People's Republic of China.
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, No. 182, Chunhui Road, Longmatan District, Luzhou, 646000, Sichuan Province, People's Republic of China.
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China.
| |
Collapse
|
3
|
Xi Z, Xie Y, Chen S, Sun S, Zhang X, Yang J, Li J. The cranial vertebral body suffers a higher risk of adjacent vertebral fracture due to the poor biomechanical environment in patients with percutaneous vertebralplasty. Spine J 2023; 23:1764-1777. [PMID: 37611873 DOI: 10.1016/j.spinee.2023.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/08/2023] [Accepted: 08/15/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND CONTEXT Adjacent vertebral fracture (AVF), a frequent complication of PVP, is influenced by factors such as osteoporosis progression, increased intervertebral cement leakage (ICL), and biomechanical deterioration. Notably, the risk of AVF is notably elevated in the cranial vertebral body compared with the caudal counterpart. Despite this knowledge, the underlying pathological mechanism remains elusive. PURPOSE This study delves into the role of biomechanical deterioration as a pivotal factor in the heightened risk of AVF in the cranial vertebral body following PVP. By isolating this variable, we aim to unravel its prominence relative to other potential risk factors. STUDY DESIGN A retrospective study and corresponding numerical mechanical simulations. PATIENT SAMPLE Clinical data from 101 patients treated by PVP were reviewed in this study. OUTCOME MEASURES Clinical assessments involved measuring Hounsfield unit (HU) values of adjacent vertebral bodies as a representation of patients' bone mineral density (BMD). Additionally, the rates of ICL were compared among these patients. Numerical simulations were conducted to compute stress values in the cranial and caudal vertebral bodies under various body positions. METHODS In a retrospective analysis of PVP patients spanning July 2016 to August 2019, we scrutinized the HU values of adjacent vertebral bodies to discern disparities in BMD between cranial and caudal regions. Additionally, we compared ICL rates on both cranial and caudal sides. To augment our investigation, well-validated numerical models simulated the PVP procedure, enabling the computation of maximum stress values in cranial and caudal vertebral bodies across varying body positions. RESULTS The incidence rate of cranial AVF was significantly higher than the caudal side. No notable distinctions in HU values or ICL rates were observed between the cranial and caudal sides. The incidence of AVF showed no significant elevation in patients with ICL in either region. However, numerical simulations unveiled heightened stress values in the cranial vertebral body. CONCLUSIONS In patients postPVP, the cranial vertebral body faces a heightened risk of AVF, primarily attributed to biomechanical deterioration rather than lower BMD or an elevated ICL rate.
Collapse
Affiliation(s)
- Zhipeng Xi
- Department of Spine Surgery, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, P.R. China
| | - Yimin Xie
- Department of Spine Surgery, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shuang Chen
- Department of Spine Surgery, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shenglu Sun
- Department of Imaging, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine for Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, P.R. China
| | - Xiaoyu Zhang
- Department of Spine Surgery, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, P.R. China
| | - Jiexiang Yang
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, No.182, Chunhui Rd, Longmatan District, Luzhou, Sichuan Province, 646000, P.R. China
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, No.182, Chunhui Rd, Longmatan District, Luzhou, Sichuan Province, 646000, P.R. China.
| |
Collapse
|
4
|
Hsieh MK, Tai CL, Li YD, Lee DM, Lin CY, Tsai TT, Lai PL, Chen WP. Finite element analysis of optimized novel additively manufactured non-articulating prostheses for cervical total disc replacement. Front Bioeng Biotechnol 2023; 11:1182265. [PMID: 37324423 PMCID: PMC10267663 DOI: 10.3389/fbioe.2023.1182265] [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: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Ball-and-socket designs of cervical total disc replacement (TDR) have been popular in recent years despite the disadvantages of polyethylene wear, heterotrophic ossification, increased facet contact force, and implant subsidence. In this study, a non-articulating, additively manufactured hybrid TDR with an ultra-high molecular weight polyethylene core and polycarbonate urethane (PCU) fiber jacket, was designed to mimic the motion of normal discs. A finite element (FE) study was conducted to optimize the lattice structure and assess the biomechanical performance of this new generation TDR with an intact disc and a commercial ball-and-socket Baguera®C TDR (Spineart SA, Geneva, Switzerland) on an intact C5-6 cervical spinal model. The lattice structure of the PCU fiber was constructed using the Tesseract or the Cross structures from the IntraLattice model in the Rhino software (McNeel North America, Seattle, WA) to create the hybrid I and hybrid II groups, respectively. The circumferential area of the PCU fiber was divided into three regions (anterior, lateral and posterior), and the cellular structures were adjusted. Optimal cellular distributions and structures were A2L5P2 in the hybrid I and A2L7P3 in the hybrid II groups. All but one of the maximum von Mises stresses were within the yield strength of the PCU material. The range of motions, facet joint stress, C6 vertebral superior endplate stress and path of instantaneous center of rotation of the hybrid I and II groups were closer to those of the intact group than those of the Baguera®C group under 100 N follower load and pure moment of 1.5 Nm in four different planar motions. Restoration of normal cervical spinal kinematics and prevention of implant subsidence could be observed from the FE analysis results. Superior stress distribution in the PCU fiber and core in the hybrid II group revealed that the Cross lattice structure of a PCU fiber jacket could be a choice for a next-generation TDR. This promising outcome suggests the feasibility of implanting an additively manufactured multi-material artificial disc that allows for better physiological motion than the current ball-and-socket design.
Collapse
Affiliation(s)
- Ming-Kai Hsieh
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ching-Lung Tai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Yun-Da Li
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - De-Mei Lee
- Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Yi Lin
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Po-Liang Lai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Weng-Pin Chen
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
| |
Collapse
|
5
|
Wang QD, Guo LX. Biomechanical role of cement augmentation in the vibration characteristics of the osteoporotic lumbar spine after lumbar interbody fusion. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2022; 33:52. [PMID: 35657438 PMCID: PMC9166889 DOI: 10.1007/s10856-022-06671-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
Under whole body vibration, how the cement augmentation affects the vibration characteristic of the osteoporotic fusion lumbar spine, complications, and fusion outcomes is unclear. A L1-L5 lumbar spine finite element model was developed to simulate a transforaminal lumbar interbody fusion (TLIF) model with bilateral pedicle screws at L4-L5 level, a polymethylmethacrylate (PMMA) cement-augmented TLIF model (TLIF-PMMA) and an osteoporotic TLIF model. A 40 N sinusoidal vertical load at 5 Hz and a 400 N preload were utilized to simulate a vertical vibration of the human body and the physiological compression caused by muscle contraction and the weight of human body. The results showed that PMMA cement augmentation may produce a stiffer pedicle screw/rod construct and decrease the risk of adjacent segment disease, subsidence, and rod failure under whole-body vibration(WBV). Cement augmentation might restore the disc height and segmental lordosis and decrease the risk of poor outcomes, but it might also increase the risk of cage failure and prolong the period of lumbar fusion under WBV. The findings may provide new insights for performing lumbar interbody fusion in patients affected by osteoporosis of the lumbar spine. Graphical abstract.
Collapse
Affiliation(s)
- Qing-Dong Wang
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China.
| |
Collapse
|
6
|
Kamenova M, Li E, Soleman J, Fiebig O, Mehrkens A, Schaeren S. Posterior stabilization with polyetheretherketone (PEEK) rods and transforaminal lumbar interbody fusion (TLIF) with titanium rods for single-level lumbar spine degenerative disease in patients above 70 years of age. Arch Orthop Trauma Surg 2022; 143:2831-2843. [PMID: 35511354 DOI: 10.1007/s00402-022-04448-8] [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: 11/24/2021] [Accepted: 04/09/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND Given the lack of guidelines regarding the operative management of elderly patients needing lumbar spine fusion for degenerative disease, it is often difficult to balance between invasiveness respecting the fragile spine and geriatric comorbidities. AIM To compare reoperation rates and clinical outcome in patients above 70 years of age undergoing Transforaminal Lumbar Interbody Fusion (TLIF) with titanium rods or posterior stabilization with Polyetheretherketone (PEEK) rods for the treatment of one-level lumbar spine degenerative disease. METHODS Retrospective review of baseline characteristics, reoperation rates as well as the clinical and radiological outcomes of patients, older than 70 years, undergoing posterolateral fusion with PEEK rods (n = 76, PEEK group) or TLIF with titanium rods (n = 67, TLIF group) for a single-level lumbar degenerative disease from 2014 to 2020. Additional subanalysis on the patients above 80 years of age was performed. RESULTS Our results showed similar reoperation rates and outcomes in the TLIF and PEEK groups. However, intraoperative blood loss, administration of tranexamic acid, and operation time were significantly higher in the TLIF group. In patients older than 80 years, reoperation rates at first follow-up were significantly higher in the TLIF group, too. CONCLUSION According to our results, posterior stabilization with PEEK rods is less invasive and was associated with significantly lower blood loss, administration of blood products and shorter operation time. Moreover, in patients above 80 years of age reoperations rates were lower with PEEK rods, as well. Nevertheless, the benefits of PEEK rods for foraminal stenosis still have to be investigated.
Collapse
Affiliation(s)
- M Kamenova
- Department of Spine Surgery, University Hospital of Basel, Spitalstrasse 21, 4051, Basel, Switzerland. .,Department of Neurosurgery, University Hospital of Basel, Basel, Switzerland.
| | - E Li
- Department of Spine Surgery, University Hospital of Basel, Spitalstrasse 21, 4051, Basel, Switzerland.,Department of Orthopedic Surgery and Traumatology, University Hospital of Basel, Basel, Switzerland
| | - J Soleman
- Department of Neurosurgery, University Hospital of Basel, Basel, Switzerland.,Faculty of Medicine, University of Basel, Basel, Switzerland
| | - O Fiebig
- Department of Spine Surgery, University Hospital of Basel, Spitalstrasse 21, 4051, Basel, Switzerland
| | - A Mehrkens
- Department of Spine Surgery, University Hospital of Basel, Spitalstrasse 21, 4051, Basel, Switzerland
| | - S Schaeren
- Department of Spine Surgery, University Hospital of Basel, Spitalstrasse 21, 4051, Basel, Switzerland
| |
Collapse
|
7
|
Yuan F, Zhao H, Sun H, Sun Y, Zhao J, Xia T. Investigation of microplastics in sludge from five wastewater treatment plants in Nanjing, China. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113793. [PMID: 34601347 DOI: 10.1016/j.jenvman.2021.113793] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 08/07/2021] [Accepted: 09/18/2021] [Indexed: 06/13/2023]
Abstract
Municipal wastewater treatment plants (WWTPs) have been regarded as the main receptors of microplastics in industrial and domestic wastewater. The excess sludge they generate is an important carrier for the microplastics to enter the environment. In China, relevant regional studies are still in an initial phase. In this work, microplastics in the sewage sludges at different sampling points of five WWTPs in Nanjing City (an important city in the Yangtze River basin) were investigated, including their abundance, morphology and chemical composition. Furthermore, the influence factors such as population density, economic development level, wastewater source and treatment process were also discussed. The analysis results through optical microscope and FT-IR showed that the detected microplastics were divided into fragments, films, fibers and granules. Their chemical component reached up to 19 species, including small amounts of petroleum resins which was scarcely detected in other studies. Wastewater source was the primary factor influencing the microplastic abundance and size in sludge. And the microplastic shape and chemical components were closely related to the industrial type. Furthermore, because the removal effect on the microplastics with different morphologies were varied with the treatment process, the preliminary suggestions on the technology for particular wastewater were proposed. This study provides partial regional data and analysis for the microplastics contained in the sludge of WWTPs, expecting to provide a certain theoretical support for the operations management of WWTPs and standardized sludge treatment.
Collapse
Affiliation(s)
- Fang Yuan
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China.
| | - Han Zhao
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China
| | - Haibing Sun
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China
| | - Yongjun Sun
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China
| | - Jinhui Zhao
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China
| | - Ting Xia
- College of Urban Construction, Nanjing Tech University, Puzhu Road 30, Nanjing, 211816, PR China.
| |
Collapse
|
8
|
Doodkorte RJP, Vercoulen TFG, Roth AK, de Bie RA, Willems PC. Instrumentation techniques to prevent proximal junctional kyphosis and proximal junctional failure in adult spinal deformity correction-a systematic review of biomechanical studies. Spine J 2021; 21:842-854. [PMID: 33482379 DOI: 10.1016/j.spinee.2021.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Correction of adult spinal deformity (ASD) by long segment instrumented spinal fusion is an increasingly common surgical intervention. However, it is associated with high rates of complications and revision surgery, especially in the elderly patient population. The high construct stiffness of instrumented thoracolumbar spinal fusion has been postulated to lead to a higher incidence of proximal junctional kyphosis (PJK) and failure (PJF). Several cadaveric biomechanical studies have reported on surgical techniques to reduce the incidence of PJF/PJK. As yet, no overview has been made of these biomechanical studies. PURPOSE To summarize the evidence of all biomechanical studies that have assessed techniques to reduce PJK/PJF following long segment instrumented spinal fusion in the ASD patient population. STUDY DESIGN A systematic review. METHODS EMBASE and MEDLINE databases were searched for human and animal cadaveric biomechanical studies investigating the effect of various surgical techniques to reduce PJK/PJF following long segment instrumented thoracolumbar spinal fusion in the adult patient population. Studied techniques, biomechanical test methods, range of motion (ROM), intervertebral disc pressure (IDP) and other relevant outcome parameters were documented. RESULTS Twelve studies met the inclusion criteria. Four of these studies included non-human cadaveric material. One study investigated the prophylactic application of cement augmentation (vertebroplasty), whereas the remaining studies investigated semi-rigid junctional fixation techniques to achieve a gradual transition zone of forces at the proximal end of a fusion construct, so-called topping-off. An increased gradual transition zone in terms of ROM compared to pedicle screw constructs was demonstrated for sublaminar tethers, sublaminar tape, pretensioned suture loops, transverse hooks and laminar hooks. Furthermore, reduced IDP was found after the application of sublaminar tethers, suture loops, sublaminar tapes and laminar hooks. Finally, two-level prophylactic vertebroplasty resulted in a lower incidence of vertebral compression fractures in a flexion-compression experiment. CONCLUSIONS A variety of techniques, involving either posterior semi-rigid junctional fixation or the reinforcement of vertebral bodies, has been biomechanically assessed. However, the low number of studies and variation in study protocols hampers direct comparison of different techniques. Furthermore, determination of what constitutes an optimal gradual transition zone and its translation to clinical practice, would aid comparison and further development of different semi-rigid junctional fixation techniques. Even though biomechanics are extremely important in the development of PJK/PJF, patient-specific factors should always be taken into account on a case-by-case basis when considering to apply a semi-rigid junctional fixation technique.
Collapse
Affiliation(s)
- Remco J P Doodkorte
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands.
| | - Timon F G Vercoulen
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Alex K Roth
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Rob A de Bie
- Department of Epidemiology, Research School CAPHRI, Faculty of Health, Medicine and Life Sciences, Maastricht University, P. Debyeplein1, 6229 HA, Maastricht, The Netherlands
| | - Paul C Willems
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
| |
Collapse
|
9
|
Auger JD, Frings N, Wu Y, Marty AG, Morgan EF. Trabecular Architecture and Mechanical Heterogeneity Effects on Vertebral Body Strength. Curr Osteoporos Rep 2020; 18:716-726. [PMID: 33215364 PMCID: PMC7891914 DOI: 10.1007/s11914-020-00640-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/24/2020] [Indexed: 12/29/2022]
Abstract
PURPOSE OF REVIEW We aimed to synthesize the recent work on the intra-vertebral heterogeneity in density, trabecular architecture and mechanical properties, its implications for fracture risk, its association with degeneration of the intervertebral discs, and its implications for implant design. RECENT FINDINGS As compared to the peripheral regions of the centrum, the central region of the vertebral body exhibits lower density and more sparse microstructure. As compared to the anterior region, the posterior region shows higher density. These variations are more pronounced in vertebrae from older persons and in those adjacent to degenerated discs. Mixed results have been reported in regard to variation along the superior-inferior axis and to relationships between the heterogeneity in density and vertebral strength and fracture risk. These discrepancies highlight that, first, despite the large amount of study of the intra-vertebral heterogeneity in microstructure, direct study of that in mechanical properties has lagged, and second, more measurements of vertebral loading are needed to understand how the heterogeneity affects distributions of stress and strain in the vertebra. These future areas of study are relevant not only to the question of spine fractures but also to the design and selection of implants for spine fusion and disc replacement. The intra-vertebral heterogeneity in microstructure and mechanical properties may be a product of mechanical adaptation as well as a key determinant of the ability of the vertebral body to withstand a given type of loading.
Collapse
Affiliation(s)
- Joshua D Auger
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Neilesh Frings
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Yuanqiao Wu
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Andre Gutierrez Marty
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Elise F Morgan
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.
| |
Collapse
|
10
|
Warburton A, Girdler SJ, Mikhail CM, Ahn A, Cho SK. Biomaterials in Spinal Implants: A Review. Neurospine 2019; 17:101-110. [PMID: 31694360 PMCID: PMC7136103 DOI: 10.14245/ns.1938296.148] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/27/2019] [Indexed: 01/26/2023] Open
Abstract
The aim to find the perfect biomaterial for spinal implant has been the focus of spinal research since the 1800s. Spinal surgery and the devices used therein have undergone a constant evolution in order to meet the needs of surgeons who have continued to further understand the biomechanical principles of spinal stability and have improved as new technologies and materials are available for production use. The perfect biomaterial would be one that is biologically inert/compatible, has a Young’s modulus similar to that of the bone where it is implanted, high tensile strength, stiffness, fatigue strength, and low artifacts on imaging. Today, the materials that have been most commonly used include stainless steel, titanium, cobalt chrome, nitinol (a nickel titanium alloy), tantalum, and polyetheretherketone in rods, screws, cages, and plates. Current advancements such as 3-dimensional printing, the ProDisc-L and ProDisc-C, the ApiFix, and the Mobi-C which all aim to improve range of motion, reduce pain, and improve patient satisfaction. Spine surgeons should remain vigilant regarding the current literature and technological advancements in spinal materials and procedures. The progression of spinal implant materials for cages, rods, screws, and plates with advantages and disadvantages for each material will be discussed.
Collapse
Affiliation(s)
| | | | | | - Amy Ahn
- Mount Sinai Health System, New York, NY, USA
| | | |
Collapse
|
11
|
Fan W, Guo LX, Zhao D. Stress analysis of the implants in transforaminal lumbar interbody fusion under static and vibration loadings: a comparison between pedicle screw fixation system with rigid and flexible rods. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2019; 30:118. [PMID: 31628540 DOI: 10.1007/s10856-019-6320-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
The use of a pedicle screw fixation system with rods made of more compliant materials has become increasingly popular for spine fusion surgery in recent years. The aim of this study was to compare stress responses of the implants in transforaminal lumbar interbody fusion (TLIF) when using flexible and conventional rigid posterior fixation systems. A previously validated intact L1-S1 finite element model was modified to simulate single-level (L4-L5) TLIF with bilateral pedicle screw fixation using two types of connecting rod (rigid and flexible rods). The von Mises stresses in the implants (including TLIF cage, pedicle screws and rods) for the rigid and flexible fixations were analyzed under static and vibration loadings. The results showed that compared with the rigid fixation, the use of flexible fixation decreased the maximum stress in the pedicle screws, but increased the maximum stress in the cage and the ratio of maximum stress in the rods to the yield stress. It was also found that with decreasing diameter of the flexible rod (i.e. increasing flexibility of the rod), the maximum stress was decreased in the pedicle screws but increased in the cage and the rods. The findings imply that compared with the rigid rod, application of the flexible rod in the pedicle screw fixation system for the TLIF might decrease the breakage risk of pedicle screws but increase the risk of cage subsidence and rod breakage. Moreover, flexibility of the rod in the flexible fixation system should be carefully determined.
Collapse
Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China.
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China
| | - Dan Zhao
- Liaoning University of Traditional Chinese Medicine, Shenyang, China
- Liaoning Special Education Teachers College, Shenyang, China
| |
Collapse
|
12
|
Beckmann A, Herren C, Nicolini LF, Grevenstein D, Oikonomidis S, Kobbe P, Hildebrand F, Stoffel M, Markert B, Siewe J. Biomechanical testing of a polycarbonate-urethane-based dynamic instrumentation system under physiological conditions. Clin Biomech (Bristol, Avon) 2019; 61:112-119. [PMID: 30551087 DOI: 10.1016/j.clinbiomech.2018.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/28/2018] [Accepted: 12/04/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Posterior dynamic stabilization systems are developed to maintain the healthy biomechanics of the spine while providing stabilization. Numerous dynamic systems incorporate polycarbonate urethane with temperature- and moisture-dependent material properties. In the underlying study, a novel test rig is used to evaluate the biomechanical performance of a system containing polycarbonate urethane. METHODS The test rig is composed of two hydraulic actuators. An environmental chamber, filled with water vapor at body temperature, is included in the set up. The translational and rotational degrees of freedom of vertebrae and pedicle screws are measured using a magnetic tracking system. The Transition® device is tested in five lumbar spines (L2-L5) of human cadavers. Pure moment tests are performed for flexion-extension, lateral bending, and axial rotation. Three test conditions are compared: 1. native specimens, 2. dynamic instrumentation at L4-L5, 3. dynamic instrumentation with decompression at L4-L5. FINDINGS The ranges of motion, the centers of rotation, and the pedicle screw loosening are calculated and evaluated. During daily motions such as walking, the loads on the lumbar spine differ from the standardized test protocols. To allow a reproducible data evaluation for smaller deformations, all moment-rotation curves are parameterized using sigmoid functions. INTERPRETATION In flexion-extension, the Transition® device provides the highest stiffening of the segment and the largest shift of the center of rotation. No shift in the center of rotation, and the smallest supporting effect on the segment is observed for axial rotation. In lateral bending, a mediate reduction of the range of motion is observed.
Collapse
Affiliation(s)
- Agnes Beckmann
- RWTH Aachen University, Institute of General Mechanics, Germany.
| | - Christian Herren
- Aachen University Hospital, Department for Trauma and Reconstructive Surgery, Aachen, Germany
| | | | - David Grevenstein
- University of Cologne, Centre for Orthopaedic and Trauma Surgery, Germany
| | | | - Philipp Kobbe
- Aachen University Hospital, Department for Trauma and Reconstructive Surgery, Aachen, Germany
| | - Frank Hildebrand
- Aachen University Hospital, Department for Trauma and Reconstructive Surgery, Aachen, Germany
| | - Marcus Stoffel
- RWTH Aachen University, Institute of General Mechanics, Germany
| | - Bernd Markert
- RWTH Aachen University, Institute of General Mechanics, Germany
| | - Jan Siewe
- University of Cologne, Centre for Orthopaedic and Trauma Surgery, Germany
| |
Collapse
|