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Calek AK, Cornaz F, Suter M, Fasser MR, Farshad M, Widmer J. Endplate weakening during cage bed preparation significantly reduces endplate load capacity. 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 2024:10.1007/s00586-024-08289-4. [PMID: 38733400 DOI: 10.1007/s00586-024-08289-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024]
Abstract
PURPOSE To analyze the effect of endplate weakness prior to PLIF or TLIF cage implantation and compare it to the opposite intact endplate of the same vertebral body. In addition, the influence of bone quality on endplate resistance was investigated. METHODS Twenty-two human lumbar vertebrae were tested in a ramp-to-failure test. One endplate of each vertebral body was tested intact and the other after weakening with a rasp (over an area of 200 mm2). Either a TLIF or PLIF cage was then placed and the compression load was applied across the cage until failure of the endplate. Failure was defined as the first local maximum of the force measurement. Bone quality was assessed by determining the Hounsfield units (HU) on CT images. RESULTS With an intact endplate and a TLIF cage, the median force to failure was 1276.3N (693.1-1980.6N). Endplate weakening reduced axial endplate resistance to failure by 15% (0-23%). With an intact endplate and a PLIF cage, the median force to failure was 1057.2N (701.2-1735.5N). Endplate weakening reduced axial endplate resistance to failure by 36.6% (7-47.9%). Bone quality correlated linearly with the force at which endplate failure occurred. Intact and weakened endplates showed a strong positive correlation: intact-TLIF: r = 0.964, slope of the regression line (slope) = 11.8, p < 0.001; intact-PLIF: r = 0.909, slope = 11.2, p = 5.5E-05; weakened-TLIF: r = 0.973, slope = 12.5, p < 0.001; weakened-PLIF: r = 0.836, slope = 6, p = 0.003. CONCLUSION Weakening of the endplate during cage bed preparation significantly reduces the resistance of the endplate to subsidence to failure: endplate load capacity is reduced by 15% with TLIF and 37% with PLIF. Bone quality correlates with the force at which endplate failure occurs.
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Affiliation(s)
- Anna-Katharina Calek
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
| | - Frédéric Cornaz
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
| | - Mauro Suter
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Calek AK, Cornaz F, Suter M, Fasser MR, Baumgartner S, Sager P, Farshad M, Widmer J. Load distribution on intervertebral cages with and without posterior instrumentation. Spine J 2024; 24:889-898. [PMID: 37924848 DOI: 10.1016/j.spinee.2023.10.017] [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: 05/10/2023] [Revised: 09/18/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND CONTEXT Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) are well-established procedures for spinal fusion. However, little is known about load sharing between cage, dorsal construct, and biological tissue within the instrumented lumbar spine. PURPOSE The aim of this study was to quantify the forces acting on cages under axial compression force with and without posterior instrumentation. STUDY DESIGN Biomechanical cadaveric study. METHODS Ten lumbar spinal segments were tested under uniaxial compression using load cell instrumented intervertebral cages. The force was increased in 100N increments to 1000N or a force greater than 500N on one load cell. Each specimen was tested after unilateral PLIF (uPLIF), bilateral PLIF (bPLIF) and TLIF each with/without posterior instrumentation. Dorsal instrumentation was performed with 55N of compression per side. RESULTS Cage insertion resulted in median cage preloads of 16N, 29N and 35N for uPLIF, bPLIF, and TLIF. The addition of compressed dorsal instrumentation increased the median preload to 224N, 328N, and 317N, respectively. With posterior instrumentation, the percentage of the external load acting on the intervertebral cage was less than 25% at 100N (uPLIF: 14.2%; bPLIF: 16%; TLIF: 11%), less than 45% at 500N (uPLIF: 31.8%; bPLIF: 41.1%; TLIF: 37.9%) and less than 50% at 1000N (uPLIF: 40.3%; bPLIF: 49.7%; TLIF: 43.4%). Without posterior instrumentation, the percentage of external load on the cages was significantly higher with values above 50% at 100N (uPLIF: 55.6%; bPLIF: 75.5%; TLIF: 66.8%), 500N (uPLIF: 71.7%; bPLIF: 79.2%; TLIF: 65.4%), and 1000N external load (uPLIF: 73%; bPLIF: 80.5%; TLIF: 66.1%). For absolute loads, preloads and external loads must be added together. CONCLUSIONS Without posterior instrumentation, the intervertebral cages absorb more than 50% of the axial load and the load distribution is largely independent of the loading amplitude. With posterior instrumentation, the external load acting on the cages is significantly lower and the load distribution becomes load amplitude dependent, with a higher proportion of the load transferred by the cages at high loads. The bPLIF cages tend to absorb more force than the other two cage configurations. CLINICAL SIGNIFICANCE Cage instrumentation allows some of the compression force to be transmitted through the cage to the screws below, better distributing and reducing the overall force on the pedicle screws at the end of the construct and on the rods.
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Affiliation(s)
- Anna-Katharina Calek
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, Zurich CH-8008, Switzerland.
| | - Frédéric Cornaz
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, Zurich CH-8008, Switzerland
| | - Mauro Suter
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Sina Baumgartner
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Philipp Sager
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, Zurich CH-8008, Switzerland; University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
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Sircar K, Weber M, Walter SG, Ott N, Prescher A, Eysel P, Kernich N. Torque forces of expandable titanium vertebral body replacement cages during expansion and subsidence in the osteoporotic lumbar spine. Clin Biomech (Bristol, Avon) 2024; 114:106239. [PMID: 38599132 DOI: 10.1016/j.clinbiomech.2024.106239] [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: 07/15/2023] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND The application of expandable titanium-cages has gained widespread use in vertebral body replacement for indications such as burst fractures, tumors and infectious destruction. However, torque forces necessary for a satisfactory expansion of these implants and for subsidence of them into the adjacent vertebrae are unknown within the osteoporotic spine. METHODS Six fresh-frozen human, osteoporotic, lumbar spines were dorsally instrumented with titanium implants (L2-L4) and a partial corpectomy of L3 was performed. An expandable titanium-cage was inserted ventrally and expanded by both residents and senior surgeons until fixation was deemed sufficient, based on haptic feedback. Torque forces for expansion were measured in Nm. Expansion was then continued until cage subsidence occurred. Torque forces necessary for subsidence were recorded. Strain of the dorsal rods during expansion was measured with strain gauges. FINDINGS The mean torque force for fixation of cages was 1.17 Nm (0.9 Nm for residents, 1.4 Nm for senior surgeons, p = .06). The mean torque force for subsidence of cages was 3.1 Nm (p = .005). Mean peak strain of the dorsal rods was 970 μm/m during expansion and 1792 μm/m at subsidence of cages (p = .004). INTERPRETATION The use of expandable titanium-cages for vertebral body replacement seems to be a primarily safe procedure even within the osteoporotic spine as torque forces required for subsidence of cages are nearly three times higher than those needed for fixation. Most of the expansion load is absorbed by straining of the dorsal instrumentation. Rod materials other than titanium may alter the torque forces found in this study.
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Affiliation(s)
- Krishnan Sircar
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany.
| | - Maximilian Weber
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany
| | - Sebastian G Walter
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany
| | - Nadine Ott
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany
| | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University Hospital, Wendlingweg 2, 52070 Aachen, Germany
| | - Peer Eysel
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany
| | - Nikolaus Kernich
- Department of Orthopedic and Trauma Surgery, University of Cologne, Faculty of Medicine and University Hospital Cologne, Kerpener-Strasse 62, 50937 Cologne, Germany
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Wu J, Miao J, Chen G, Xu H, Wen W, Xu H, Liu L. Finite element biomechanical analysis of 3D printed intervertebral fusion cage in osteoporotic population. BMC Musculoskelet Disord 2024; 25:129. [PMID: 38347518 PMCID: PMC10860281 DOI: 10.1186/s12891-024-07221-7] [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: 08/10/2023] [Accepted: 01/21/2024] [Indexed: 02/15/2024] Open
Abstract
OBJECTIVE To study the biomechanical characteristics of each tissue structure when using different 3D printing Cage in osteoporotic patients undergoing interbody fusion. METHODS A finite element model of the lumbar spine was reconstructed and validated with regarding a range of motion and intervertebral disc pressure from previous in vitro studies. Cage and pedicle screws were implanted and part of the lamina, spinous process, and facet joints were removed in the L4/5 segment of the validated mode to simulate interbody fusion. A 280 N follower load and 7.5 N·m moment were applied to different postoperative models and intact osteoporotic model to simulate lumbar motion. The biomechanical characteristics of different models were evaluated by calculating and analyzing the range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment. RESULTS After rigid fixation, the range of motion of the fixed segment of model A-C decreased significantly, which was much smaller than that of the osteoporotic model. And with the increase of the axial area of the interbody fusion cages, the fixed segment of model A-C tended to be more stable. The range of motion and intradiscal pressure of the spinal models with different interbody fusion cages were higher than those of the complete osteoporosis model, but there was no significant difference between the postoperative models. On the other hand, the L5 upper endplate stress and screw-rod system stress of model A-C show a decreasing trend in different directions of motion. The stress of the endplate is the highest during flexion, which can reach 40.5 MPa (model A). The difference in endplate stress between models A-C was the largest during lateral bending. The endplate stress of models A and B was 150.5% and 140.9% of that of model C, respectively. The stress of the screw-rod system was the highest during lateral bending (model A, 102.0 MPa), which was 108.4%, 102.4%, 110.4%, 114.2% of model B and 158.5%, 110.1%, 115.8%, 125.4% of model C in flexion, extension, lateral bending, and rotation, respectively. CONCLUSIONS For people with osteoporosis, no matter what type of cage is used, good immediate stability can be achieved after surgery. Larger cage sizes provide better fixation without significantly increasing ROM and IDP in adjacent segments, which may contribute to the development of ASD. In addition, larger cage sizes can disperse endplate stress and reduce stress concentration, which is of positive significance in preventing cage subsidence after operation. The cage and screw rod system establish a stress conduction pathway on the spine, and a larger cage greatly enhances the stress-bearing capacity of the front column, which can better distribute the stress of the posterior spine structure and the stress borne by the posterior screw rod system, reduce the stress concentration phenomenon of the nail rod system, and avoid exceeding the yield strength of the material, resulting in the risk of future instrument failure.
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Affiliation(s)
- Jincheng Wu
- Department of Emergency Trauma Surgery, The Second Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China, 48 Baishuitang Road, Longhua District, 571700
| | - Jun Miao
- Tianjin Hospital, Tianjin University, Tianjin, China
| | | | - Hanpeng Xu
- Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wangqiang Wen
- The First Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China
| | - Haoxiang Xu
- The Second People's Hospital of Hefei, Hefei, Anhui, China
| | - Lizhu Liu
- Department of Emergency Trauma Surgery, The Second Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China, 48 Baishuitang Road, Longhua District, 571700.
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Zhao G, He S, Chen E, Ma T, Wu K, Wu J, Li W, Song C. Biomechanical effects of osteoporosis severity on the occurrence of proximal junctional kyphosis following long-segment posterior thoracolumbar fusion. Clin Biomech (Bristol, Avon) 2023; 110:106132. [PMID: 37924756 DOI: 10.1016/j.clinbiomech.2023.106132] [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: 07/26/2023] [Revised: 10/17/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Proximal junctional kyphosis is a common long-term complication in adult spinal deformity surgery that involves long-segment posterior spinal fusion. However, the underlying biomechanical mechanisms of the impact of osteoporosis on proximal junctional kyphosis remain unclear. The present study was to evaluate adjacent segment degeneration and spine mechanical instability in osteoporotic patients who underwent long-segment posterior thoracolumbar fusion. METHODS Finite element models of the thoracolumbar spine T1-L5 with posterior long-segment T8-L5 fusion under different degrees of osteoporosis were constructed to analyze intervertebral disc stress characterization, vertebrae mechanical transfer, and pedicle screw system loads during various motions. FINDINGS Compared with normal bone mass, the maximum von Mises stresses of T7 and T8 were increased by 20.32%, 22.38%, 44.69%, 4.49% and 29.48%, 17.84%, 40.95%, 3.20% during flexion, extension, lateral bending, and axial rotation in the mild osteoporosis model, and by 21.21%, 18.32%, 88.28%, 2.94% and 37.76%, 15.09%, 61.47%, -0.04% in severe osteoporosis model. The peak stresses among T6/T7, T7/T8, and T8/T9 discs were 14.77 MPa, 11.55 MPa, and 2.39 MPa under lateral bending conditions for the severe osteoporosis model, respectively. As the severity of osteoporosis increased, stress levels on SCR8 and SCR9 intensified during various movements. INTERPRETATION Osteoporosis had an adverse effect on proximal junctional kyphosis. The stress levels in cortical bone, intervertebral discs and screws were increased with bone mass loss, which can easily lead to intervertebral disc degeneration, bone destruction as well as screw pullout. These factors have significantly affected or accelerated the occurrence of proximal junctional kyphosis.
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Affiliation(s)
- Gaiping Zhao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
| | - Shenglan He
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Eryun Chen
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Tong Ma
- Department of Bone and Joint Surgery, Yangpu Hospital, School of Medicine, Tongji University, Shanghai 200090, China
| | - Kunneng Wu
- Shanghai Institute of Medical Device Testing, Shanghai 201318, China
| | - Jie Wu
- Key Laboratory of Hydrodynamics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Weiqi Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
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Weber M, Kernich N, Scheyerer MJ, Prescher A, Walter S, Heck VJ, Eysel P, Sircar K. Does index-level pedicle screw instrumentation affect cage subsidence after vertebral body replacement? - A biomechanical study in human cadaveric osteoporotic specimens. Clin Biomech (Bristol, Avon) 2023; 109:106075. [PMID: 37651900 DOI: 10.1016/j.clinbiomech.2023.106075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/18/2023] [Accepted: 08/18/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND Vertebral body replacement is a common surgical procedure for treatment of disorders associated with spinal instability. Therefore, pedicle screws are usually inserted in adjacent vertebrae for stabilization of the posterior column, however, there is lack of evidence whether implantation of index-level pedicle screws is beneficial or not. This biomechanical study aims to investigate the effect of pedicle screw instrumentation on axial stability following vertebral body replacement. METHODS Unstable fracture at L3 level was simulated in lumbar spines from six human cadaveric specimens. Then instrumentation was performed one level above / one level below index level in three specimens and further, three specimens were instrumented at index-level (L3) additionaly. Then we used a testing protocol for biomechanical evaluation of axial loading on human cadaveric lumbar spines until cage subsidence occurred. FINDINGS Our results show that index-level instrumented spines endured significantly higher load until cage subsidence occurred compared to non-index-level instrumented specimens (p = 0.05). INTERPRETATION Our results demonstrate pedicle screw instrumentation at index-level vertebra should be considered when possbile as it may have a protective effect against cage subsidence in patients undergoing vertebral body replacement surgery.
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Affiliation(s)
- Maximilian Weber
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany.
| | - Nikolaus Kernich
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany
| | - Max J Scheyerer
- Department of Trauma and Spine Surgery, Heinrich Heine University Hospital Düsseldorf, Düsseldorf, Germany
| | - Andreas Prescher
- Institute of Molecular and Cellular Anatomy (MOCA), Wendlingweg 2, 52074 Aachen, Germany
| | - Sebastian Walter
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany
| | - Vincent J Heck
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany
| | - Peer Eysel
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany
| | - Krishnan Sircar
- University of Cologne, Faculty of Medicine and University Hospital, Center for Orthopedic and Trauma Surgery, Kerpener Str. 62, 50937 Cologne, Germany
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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.
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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.
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Ran L, Xie T, Zhao L, Huang S, Zeng J. Low Hounsfield units on computed tomography are associated with cage subsidence following oblique lumbar interbody fusion (OLIF). Spine J 2022; 22:957-964. [PMID: 35123050 DOI: 10.1016/j.spinee.2022.01.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/06/2022] [Accepted: 01/27/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND CONTEXT Cage subsidence is one of the most common complications following lumbar interbody fusion surgery. Low bone mineral density (BMD) is an important risk factor that contributes to cage subsidence. Hounsfield units (HU) obtained from clinical computed tomography (CT) scans provided a reliable method for determining regional BMD. The association between HU and cage subsidence following oblique lumbar interbody fusion (OLIF) remains unclear. PURPOSE The objective of this study is to evaluate the association between vertebral HU value and cage subsidence following OLIF. STUDY DESIGN/SETTING A retrospective study. PATIENT SAMPLE Adults with degenerative spinal conditions underwent single-level OLIF at our institution from October 2017 and August 2020 OUTCOME MEASURES: Cage subsidence, disc height, vertebral body global HU value, upper and lower instrumented vertebrae HU value, endplate HU value, fusion rate. METHODS This retrospective study was conducted on patients who underwent single-level OLIF at one institution between October 2017 and August 2020. Cage subsidence was measured using the CT scan postoperatively based on the cage protrusion through the vertebral endplates. The HU values were measured from preoperative CT according to previously reported methods. RESULTS A total of 70 patients with a mean follow-up of 15.4 months were included in the analysis. The subsidence rate was 25.7% (n=18/70). The average cage subsidence was 2.2 mm, with a range of 0-7.7 mm. No significant difference was found in age, sex, or body mass index (BMI) between the two groups. The mean global HU value of the lumbar vertebral body (L1-5) was 142.7±30.1 in nonsubsidence and 103.7±11.5 in subsidence (p=.004). The upper instrumented vertebrae (UIV) HU value was 141.4±29.7 in the nonsubsidence and 101.1±10.2 in subsidence, (p=.005). The lower instrumented vertebrae (LIV) HU value was 147.4±34.9 in nonsubsidence and 108.1±13.7 in subsidence, (p<.001). The AUC of the UIV HU value was 0.917 (95% CI: 0.853-0.981), and the most appropriate threshold of the HU value was 115 (sensitivity: 84.6%, specificity: 100%). The AUC of the LIV HU value was 0.893 (95%CI: 0.819-0.966), and the most appropriate threshold of the HU value was 125 (sensitivity: 76.9%, specificity: 100%). The mean upper endplate HU value was 235.4±50.9, and the mean lower endplate HU value was 193.4±40.3. No significant difference (upper endplate p=.314, lower endplate p=.189) was observed between the two groups. CONSLUSIONS Lower preoperative vertebral body HU values were associated with cage subsidence after single-level OLIF. However, the endplate HU values were not associated with cage subsidence. Preoperative HU measurement is useful in the prediction of the cage subsidence.
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Affiliation(s)
- Liyu Ran
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China
| | - Tianhang Xie
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China
| | - Long Zhao
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China
| | - Shishu Huang
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China.
| | - Jiancheng Zeng
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China.
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Morcellized local grafts as cost effective option for interbody fusion in thoracolumbar fracture dislocation: Seven years follow up of 53 patients. J Orthop 2022; 31:33-39. [PMID: 35368733 PMCID: PMC8967702 DOI: 10.1016/j.jor.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022] Open
Abstract
Study design Retrospective cohort study. Purpose Traumatic fracture dislocation of the spine injury is essentially a three column injury that optimally needs surgical intervention to decompress, stabilize and fuse the spinal column. This study evaluate the outcome of posterior and posterolateral decompression, instrumentation and 360° fusion achieved with help of locally harvested autologus morcellized grafts in traumatic fracture dislocation of thoracolumbar spine. Methods 53 patients were included in this retrospective study. Patients aged 16-55 years, single level fracture dislocation of thoraco-lumbar spine (D5-L5) were included. Patients with multiple level fractures, coexisting degenerative diseases of spine,pathological fractures, patients presenting more than three weeks after initial trauma, patients with concomitant severe head injury that necessitated emergency surgery for the same were excluded from the study. Patients underwent posterior and posterolateral decompression, posterior instrumentation and interbody as well as posterolateral fusion with use of morcellized bone from resected posterior elements. Follow up data at immediate post operative period, 12 months and yearly thereafter up to minimum 7 years was obtained from previous record. Results There were 46 males and 7 females. Mean age was 31.15 ± 9.64 yrs. Mean follow up period was 7.4 yrs (range 7-10 yrs). Thoracolumbar dislocation was most frequently noted at thoraco lumbar junction (T10-L2). Thirty six patients had complete neurological deficit (ASIA A) and sixteen had incomplete neurology. At one year follow up, osseous fusion was noted in 48 (90.56%) patients and 5 patients (9.44%) had fibrous union which was determined on CT scan. Immediete post operative, one year and 7 year kyphosis angle was calculated and change in kyphosis angle was not statistically significant. There was no implant failure till last follow up. Conclusion Morcellized locally harvested autologus grafts are sufficient to achieve 360° spinal fusion in fracture dislocation of thoracolumbar spine.
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Guha D, Mushlin HM, Muthiah N, Vodovotz LL, Agarwal N, Alan N, Hamilton DK, Okonkwo DO, Kanter AS. CT Hounsfield Units as a predictor of reoperation and graft subsidence following standalone and multi-level lateral lumbar interbody fusion. World Neurosurg 2022; 161:e417-e426. [PMID: 35149250 DOI: 10.1016/j.wneu.2022.02.015] [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: 11/18/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Standalone single and multi-level lateral lumbar interbody fusion (LLIF) are increasingly being applied to treat degenerative spinal conditions in a less invasive fashion. Graft subsidence following LLIF is a known complication and has been associated with poor bone mineral density (BMD). Previous research has demonstrated the utility of CT Hounsfield Units (HU) as a surrogate for BMD. This study aims to investigate the relationship between CT HU and subsidence and reoperation after standalone and multi-level LLIF. METHODS A prospectively-maintained single-institution database was retrospectively reviewed for LLIF patients from 2017-2020 including single and multi-level standalone cases with or without supplemental posterior fixation. Data on demographics, graft parameters, BMD on DEXA, preoperative mean segmental CT HU, and postoperative subsidence and reoperation, were collected. Three-foot standing radiographs were used to measure preoperative global sagittal alignment and disc height, and subsidence at last follow-up. Subsidence was classified using the Marchi grading system corresponding to disc height loss: Grade 0: 0-24%; I: 25-49%; II: 50-74%; III: 75-100%. RESULTS Eighty-nine LLIF patients met study criteria, with mean follow-up 19.9 ± 13.9 months. Among the 54 patients who underwent single-level LLIF, mean segmental HU was 152.0 ± 8.7 in 39 patients with Grade 0 subsidence, 136.7 ± 10.4 in nine with Grade I subsidence, 133.9 ± 23.1 in three with Grade II subsidence, and 119.9 ± 30.9 in three with Grade III subsidence (p=0.032). In the 96 instrumented levels in 35 patients who underwent multi-level LLIF, 85 had Grade 0 subsidence, 9 Grade I, 1 Grade II, and 1 Grade III, with no differences in HU. In multivariate logistic regression, increased CT HU was independently associated with a decreased risk of reoperation in both single-level and multi-level LLIF (OR:0.98, 95%CI:0.97-0.99, p=0.044; and OR:0.97, 95%CI: 0.94-0.99, p=0.017, respectively). Overall BMD on DEXA was not associated with graft subsidence nor reoperation. Using a receiver-operating-characteristic curve to establish separation between patients requiring reoperation and those that did not, the determined threshold HU for single-level LLIF was 131.4 (sensitivity 0.62, specificity 0.65), and for multi-level was 131.0 (sensitivity 0.67, specificity 0.63). CONCLUSIONS Lower CT HU are independently associated with an increased risk of graft subsidence following single-level LLIF. In addition, lower CT HU significantly increased the risk of reoperation in both single and multi-level LLIF with a critical threshold of 131 HU. Preoperative CT HU may provide a more robust gauge of local bone quality and the likelihood of graft subsidence requiring reoperation following LLIF, than overall BMD.
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Affiliation(s)
- Daipayan Guha
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Division of Neurosurgery, McMaster University, Hamilton, Ontario, Canada.
| | - Harry M Mushlin
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Nallammai Muthiah
- Faculty of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lena L Vodovotz
- Faculty of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nitin Agarwal
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Nima Alan
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - D Kojo Hamilton
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Faculty of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - David O Okonkwo
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Faculty of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Adam S Kanter
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Faculty of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Falowski SM, Koga SF, Northcutt T, Garamszegi L, Leasure J, Block JE. Improving the Management of Patients with Osteoporosis Undergoing Spinal Fusion: The Need for a Bone Mineral Density-Matched Interbody Cage. Orthop Res Rev 2021; 13:281-288. [PMID: 34934366 PMCID: PMC8684416 DOI: 10.2147/orr.s339222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/03/2021] [Indexed: 11/23/2022] Open
Abstract
With an increasingly aging population globally, a confluence has emerged between the rising prevalence of degenerative spinal disease and osteoporosis. Fusion of the anterior spinal column remains the mainstay surgical intervention for many spinal degenerative disorders. However, decreased vertebral bone mineral density (BMD), quantitatively measured by dual x-ray absorptiometry (DXA), complicates treatment with surgical interbody fusion as weak underlying bone stock increases the risk of post-operative implant-related adverse events, including cage subsidence. There is a necessity for developing cages with advanced structural designs that incorporate bioengineering and architectural principles to tailor the interbody fusion device directly to the patient’s BMD status. Specifically, lattice-designed cages that mimic the web-like structure of native cancellous bone have demonstrated excellent resistance to post-operative subsidence. This article provides an introductory profile of a spinal interbody implant designed intentionally to simulate the lattice structure of human cancellous bone, with a similar modulus of elasticity, and specialized to match a patient’s bone status across the BMD continuum. The implant incorporates an open pore design where the degree of pore compactness directly corresponds to the patient’s DXA-defined BMD status, including patients with osteoporosis.
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Affiliation(s)
- Steven M Falowski
- Argires-Marotti Neurosurgical Associates of Lancaster, Lancaster, PA, USA
| | | | | | | | | | - Jon E Block
- Independent Clinical Consultant, San Francisco, CA, USA
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Amorim-Barbosa T, Pereira C, Catelas D, Rodrigues C, Costa P, Rodrigues-Pinto R, Neves P. Risk factors for cage subsidence and clinical outcomes after transforaminal and posterior lumbar interbody fusion. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2021; 32:1291-1299. [PMID: 34462820 DOI: 10.1007/s00590-021-03103-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 08/19/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cage subsidence is a very common complication after lumbar interbody fusion. It may compromise vertebral interbody fusion through progressive spinal deformity and consequently cause compression of neural elements. Clinical relevance remains, however, unclear, with few studies on this subject and even less information regarding its correlation with clinical findings. The aim of this study was to identify risk factors for cage subsidence and clinical evaluation after transforaminal (TLIF) and posterior (PLIF) lumbar interbody fusion. METHODS A retrospective study in patients submitted to TLIF and PLIF between 2008 and 2017 was conducted. RESULTS A total of 165 patients were included (123 TLIF and 42 PLIF). Univariate analysis showed an increased risk of cage subsidence in spondylolisthesis comparing with degenerative disk disease (p = 0.007). A higher preoperative lumbar lordosis angle (p = 0.014) and cage placement in L2-L3 (p = 0.012) were associated with higher risk of subsidence. The posterior cage positioning on vertebral endplate was associated with a higher risk of subsidence (p = 0.028) and significant subsidence (p = 0.005), defined as cage migration > 50% of cage height. PLIF presented a higher risk when comparing with TLIF (p = 0.024). Hounsfield unit (HU) values < 135 (OR6; 95% CI [1.95-34]) and posterior positioning (OR7; 95% CI [1.7-27.3]) were independent risk factors for cage subsidence and significant subsidence, respectively, in multivariate analysis. There was a tendency for significant subsidence in degrees ≥ 2 of Meyerding spondylolisthesis (OR4; 95% CI [0.85-21.5]). Significant cage subsidence was not associated with worse clinical results. Other analyzed factors, such as age (p = 0.008), low bone mineral density (BMD) (p = 0.029) and type of surgery (TLIF) (p = 0.004), were associated with worse results. CONCLUSION The present study shows that lower BMD and posterior cage positioning are relevant risk factors for lumbar cage subsidence. Low BMD is also a predictor of poor clinical results, so it must be properly evaluated and considered, through HU values measurement in CT scan, a feasible and reliable tool in perioperative planning.
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Affiliation(s)
- Tiago Amorim-Barbosa
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal.
| | - Catarina Pereira
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
| | - Diogo Catelas
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
| | - Cláudia Rodrigues
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
| | - Paulo Costa
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
| | - Ricardo Rodrigues-Pinto
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
| | - Pedro Neves
- Department of Orthopaedics, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, 4099-001, Porto, Portugal
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Costi JJ, Ledet EH, O'Connell GD. Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence. JOR Spine 2021; 4:e1138. [PMID: 33778410 PMCID: PMC7984003 DOI: 10.1002/jsp2.1138] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
Biomechanical testing methodologies for the spine have developed over the past 50 years. During that time, there have been several paradigm shifts with respect to techniques. These techniques evolved by incorporating state-of-the-art engineering principles, in vivo measurements, anatomical structure-function relationships, and the scientific method. Multiple parametric studies have focused on the effects that the experimental technique has on outcomes. As a result, testing methodologies have evolved, but there are no standard testing protocols, which makes the comparison of findings between experiments difficult and conclusions about in vivo performance challenging. In 2019, the international spine research community was surveyed to determine the consensus on spine biomechanical testing and if the consensus opinion was consistent with the scientific evidence. More than 80 responses to the survey were received. The findings of this survey confirmed that while some methods have been commonly adopted, not all are consistent with the scientific evidence. This review summarizes the scientific literature, the current consensus, and the authors' recommendations on best practices based on the compendium of available evidence.
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Affiliation(s)
- John J. Costi
- Biomechanics and Implants Research Group, Medical Device Research Institute, College of Science and EngineeringFlinders UniversityAdelaideAustralia
| | - Eric H. Ledet
- Department of Biomedical EngineeringRensselaer Polytechnic InstituteTroyNew YorkUSA
- Research and Development ServiceStratton VA Medical CenterAlbanyNew YorkUSA
| | - Grace D. O'Connell
- Department of Mechanical EngineeringUniversity of California‐BerkeleyBerkeleyCaliforniaUSA
- Department of Orthopaedic SurgeryUniversity of California‐San FranciscoSan FranciscoCaliforniaUSA
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Kreinest M, Kelka S, Grützner PA, Vetter SY, Kobbe P, Pishnamaz M. Influence of endplate size and implant positioning of vertebral body replacements on biomechanics and outcome. Clin Biomech (Bristol, Avon) 2021; 81:105251. [PMID: 33373970 DOI: 10.1016/j.clinbiomech.2020.105251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Spinal stabilization by an anterior vertebral body replacement is frequently used in patients suffering from destroyed vertebral bodies. The aim of this study was to analyse (i) the choice of endplate size and positioning of vertebral body replacements in daily patient care and (ii) if these factors have an influence on clinical and radiological outcomes. METHOD Patients' outcomes were analysed three years after vertebral body replacement implantation using the visual analogue scale spine score. Safe zones on the vertebral body endplates were defined. Overall endplate coverage and implant subsidence were evaluated by CT and X-ray. Compression tests were performed on 22 lumbar vertebral bodies to analyse endplates sizes' influence on subsidence. FINDING Mean coverage of the vertebral body's superior and inferior endplates by the vertebral body replacement was 27.8% and 30.8%, respectively. Mean overlap of the safe zone by the implant was 49.8% and 40.6%. Mean subsidence was 1.1 ± 1.2 mm, but it did not have any effect on the outcome. In the compression tests, no significant difference (p = 0.468) was found between the two endplate sizes. INTERPRETATION Coverage of vertebral body endplates and positioning of implants in the safe zone did not entirely comply with the given recommendations. The amount of endplate coverage had no influence on subsidence or long-term outcomes in daily patient care. On the other hand, correct positioning of the implant may influence its subsidence.
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Affiliation(s)
- Michael Kreinest
- BG Klinik Ludwigshafen, Zentrum für Wirbelsäulenchirurgie, Klinik für Unfallchirurgie und Orthopädie, Ludwig-Guttmann-Str. 13, 67071 Ludwigshafen, Germany.
| | - Sabine Kelka
- BG Klinik Ludwigshafen, Zentrum für Wirbelsäulenchirurgie, Klinik für Unfallchirurgie und Orthopädie, Ludwig-Guttmann-Str. 13, 67071 Ludwigshafen, Germany; Bundeswehrkrankenhaus Hamburg, Klinik für Allgemein-, Viszeral- und Gefäßchirurgie, Lesserstraße 180, 22049 Hamburg, Germany.
| | - Paul A Grützner
- BG Klinik Ludwigshafen, Zentrum für Wirbelsäulenchirurgie, Klinik für Unfallchirurgie und Orthopädie, Ludwig-Guttmann-Str. 13, 67071 Ludwigshafen, Germany.
| | - Sven Y Vetter
- BG Klinik Ludwigshafen, Zentrum für Wirbelsäulenchirurgie, Klinik für Unfallchirurgie und Orthopädie, Ludwig-Guttmann-Str. 13, 67071 Ludwigshafen, Germany.
| | - Philipp Kobbe
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Pauwelsstr. 30, 52074 Aachen, Germany.
| | - Miguel Pishnamaz
- Universitätsklinikum Aachen, Klinik für Unfall- und Wiederherstellungschirurgie, Pauwelsstr. 30, 52074 Aachen, Germany.
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Wang QD, Guo LX. Biomechanical role of osteoporosis in the vibration characteristics of human spine after lumbar interbody fusion. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3402. [PMID: 33021071 DOI: 10.1002/cnm.3402] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/30/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Lumbar vertebrae osteoporosis is the most common challenge for lumbar interbody fusion, and this challenge has been widely concerned by scholars for many years. However, under whole-body vibration, osteoporosis how to affect the vibration characteristics of the fusion lumbar spine, complications, and fusion outcomes is urgent to know. The L1-L5 finite element model of lumbar spine was modified to simulate the transforaminal lumbar interbody fusion model with the bilateral pedicle screw fixator at L4-L5 level. A 5 Hz, 40 N sinusoidal vertical load supplemented with a 400 N preload was used to simulate the vertical vibration of human body. The results showed that under whole-body vibration, osteoporosis of fused vertebrae may cause the adjacent segments more unstable and increase the risk of adjacent segment diseases, subsidence, cage failure, rod failure, and lumbar instability. Osteoporosis of the fused vertebrae may cause the vertebral cells an unstable, inhibited growth and lead to poorer fusion outcomes. The findings may assist us in understanding the effect of osteoporosis on the vibration characteristics of lumbar spine fusion and provide references to clinical treatments for lumbar interbody fusion and lumbar vertebrae osteoporosis.
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Affiliation(s)
- Qing-Dong Wang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Wang QD, Guo LX. Comparison of dynamic response of three TLIF techniques on the fused and adjacent segments under vibration. Comput Methods Biomech Biomed Engin 2020; 24:308-319. [PMID: 33047970 DOI: 10.1080/10255842.2020.1829604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
To explore which TLIF techniques are advantageous in reducing the risk of complications and conducive to bone fusion under the vibration. The L1-L5 finite element lumbar model was modified to simulate three different TLIF techniques (a unilateral standard cage, a crescent-shaped cage, and bilateral standard cages). The results showed that the crescent-shaped cage may reduce the risk of subsidence and provide a more stable and suitable environment for vertebral cell growth under the vibration compared to the other TLIF techniques. Unilateral cage may increase the risk of adjacent segment disease and cage failure including fatigue failure under vibration.
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Affiliation(s)
- Qing-Dong Wang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Xi Z, Mummaneni PV, Wang M, Ruan H, Burch S, Deviren V, Clark AJ, Berven SH, Chou D. The association between lower Hounsfield units on computed tomography and cage subsidence after lateral lumbar interbody fusion. Neurosurg Focus 2020; 49:E8. [DOI: 10.3171/2020.5.focus20169] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 05/13/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVEOne vexing problem after lateral lumbar interbody fusion (LLIF) surgery is cage subsidence. Low bone mineral density (BMD) may contribute to subsidence, and BMD is correlated with Hounsfield units (HUs) on CT. The authors investigated if lower HU values correlated with subsidence after LLIF.METHODSA retrospective study of patients undergoing single-level LLIF with pedicle screw fixation for degenerative conditions at the University of California, San Francisco, by 6 spine surgeons was performed. Data on demographics, cage parameters, preoperative HUs on CT, and postoperative subsidence were collected. Thirty-six–inch standing radiographs were used to measure segmental lordosis, disc space height, and subsidence; data were collected immediately postoperatively and at 1 year. Subsidence was graded using a published grade of disc height loss: grade 0, 0%–24%; grade I, 25%–49%; grade II, 50%–74%; and grade III, 75%–100%. HU values were measured on preoperative CT from L1 to L5, and each lumbar vertebral body HU was measured 4 separate times.RESULTSAfter identifying 138 patients who underwent LLIF, 68 met the study inclusion criteria. All patients had single-level LLIF with pedicle screw fixation. The mean follow-up duration was 25.3 ± 10.4 months. There were 40 patients who had grade 0 subsidence, 15 grade I, 9 grade II, and 4 grade III. There were no significant differences in age, sex, BMI, or smoking. There were no significant differences in cage sizes, cage lordosis, and preoperative disc height. The mean segmental HU (the average HU value of the two vertebrae above and below the LLIF) was 169.5 ± 45 for grade 0, 130.3 ± 56.2 for grade I, 100.7 ± 30.2 for grade II, and 119.9 ± 52.9 for grade III (p < 0.001). After using a receiver operating characteristic curve to establish separation criteria between mild and severe subsidence, the most appropriate threshold of HU value was 135.02 between mild and severe subsidence (sensitivity 60%, specificity 92.3%). After univariate and multivariate analysis, preoperative segmental HU value was an independent risk factor for severe cage subsidence (p = 0.017, OR 15.694, 95% CI 1.621–151.961).CONCLUSIONSLower HU values on preoperative CT are associated with cage subsidence after LLIF. Measurement of preoperative HU values on CT may be useful when planning LLIF surgery.
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Affiliation(s)
- Zhuo Xi
- Departments of 1Neurosurgery and
- 3Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | | | | | | | - Shane Burch
- 2Orthopedic Surgery, University of California, San Francisco, California; and
| | - Vedat Deviren
- 2Orthopedic Surgery, University of California, San Francisco, California; and
| | | | - Sigurd H. Berven
- 2Orthopedic Surgery, University of California, San Francisco, California; and
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Massel DH, Mayo BC, Long WW, Modi KD, Lopez GD, Shifflett GD, Basques BA, Louie PK, Bohl DD, Hijji FY, Narain AS, Singh K. Minimally Invasive Transforaminal Lumbar Interbody Fusion: Comparison of Grade I Versus Grade II Isthmic Spondylolisthesis. Int J Spine Surg 2020; 14:108-114. [PMID: 32355614 DOI: 10.14444/7016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is often used to treat low-grade isthmic spondylolisthesis (IS). No studies have compared surgical outcomes for grade I and II IS following MIS-TLIF. Therefore, the objective of the current study was to compare outcomes between patients with grade I and II IS following MIS-TLIF. Methods A retrospective cohort analysis was performed on a prospectively maintained database of patients who underwent a primary 1-level MIS-TLIF for treatment of IS between 2007 and 2015. Grade I patients underwent a unilateral tubular approach with a single interbody cage and bilateral pedicle screw instrumentation. Grade II patients underwent a bilateral tubular approach with bilateral interbody cage and pedicle screw placement. Baseline patient demographics and characteristics were compared using Student t test and χ2 analysis. Differences in peri- and postoperative outcomes were assessed using Poisson regression with robust error variance or linear regression adjusted for perioperative variables. Results A total of 58 patients with IS underwent MIS-TLIF; 21 (36.2%) were grade I and 37 (63.8%) were grade II. The grade I cohort was younger (42.2 versus 50.6 years, P = .029); no other differences in preoperative variables were observed. No significant differences in operative time, estimated blood loss, length of hospital stay, postoperative visual analogue scale scores, or complication and revision rates were demonstrated between cohorts. Arthrodesis rate was lower in the grade I cohort, though not statistically significant. Conclusions Despite the grade I cohort being younger with less-severe diagnoses, the grade II cohort experienced similar outcomes. This finding may be due to the grade II cohort receiving bilateral cages, potentially providing a better fusion environment. Clinical Relevance These results suggest that MIS-TLIF provides sufficient stabilization and fusion for treatment of grade II IS despite increased vertebral body displacement. In addition, MIS-TLIF with bilateral approach and interbody cage placement should be examined for treatment of high-grade IS cases.
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Affiliation(s)
- Dustin H Massel
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Benjamin C Mayo
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - William W Long
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Krishna D Modi
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Gregory D Lopez
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Grant D Shifflett
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Bryce A Basques
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Philip K Louie
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Daniel D Bohl
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Fady Y Hijji
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Ankur S Narain
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
| | - Kern Singh
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St. Suite #300, Chicago, Illinois
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Collino RR, Kiapour A, Begley MR. Subsidence of Additively-Manufactured Cages in Foam Substrates: Effect of Contact Topology. J Biomech Eng 2020; 142:1075792. [DOI: 10.1115/1.4046584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Indexed: 01/21/2023]
Abstract
Abstract
Subsidence of implants into bone is a major source of morbidity. The underlying mechanics of the phenomenon are not clear, but are likely related to interactions between contact stresses and the underlying porous trabecular bone structure. To gain insight into these interactions, we studied the penetration of three-dimensional (3D)-printed indenters with systematically varying geometries into Sawbones® foam substrates and isolated the effects of contact geometry from those of overall contact size and area. When size, contact area, and indented material stiffness and strength are controlled for, we show that resistance to penetration is in fact a function of topology only. Indenters with greater line contact lengths support higher subsidence loads in compression. These results have direct implications for the design of implants to resist subsidence into bone.
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Affiliation(s)
- Rachel R. Collino
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Ali Kiapour
- Research & Development 4WEB Medical, Inc., Frisco, TX 75034
| | - Matthew R. Begley
- Departments of Mechanical Engineering and Materials, University of California, Santa Barbara, CA 93106
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Tandon V, Franke J, Kalidindi KKV. Advancements in osteoporotic spine fixation. J Clin Orthop Trauma 2020; 11:778-785. [PMID: 32904223 PMCID: PMC7452352 DOI: 10.1016/j.jcot.2020.06.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 01/01/2023] Open
Abstract
With the global rise in the population of elderly along with other risk factors, spine surgeons have to encounter osteoporotic spine more often. Osteoporotic spine, however, causes problems in management, particularly where instrumentation is involved, resulting in screw loosening, pull out, pseudoarthroses or adjacent segment kyphosis. Osteoporosis alters the bio mechanics at the bone implant interface resulting in various degrees of fixation failure. Various advancements have been made in this field to deal with such issues in addition to modification of basic surgical techniques such as increasing the diameter and length of the screw, smaller pilot hole, under tapping, longer constructs, supplemental anterior fixation, sublaminar wires or laminar hooks, use of transverse connectors and triangulation techniques, among others. They include novel surgical techniques such as cortical bone trajectory, superior cortical trajectory, double screw technique, cross trajectory technique, bicortical screw technique or prophylactic vertebroplasty. Advances in the screw design include expandable screws, fenestrated screws, conical screws and coated screws. In addition to PMMA cement augmentation, other biodegradable cements have been introduced to mitigate the side effects of PMMA such as calcium phosphate, calcium apatite and hydroxyapatite. Pharmacotherapy with teriparatide can aid fusion and lower the rate of pedicle screw loosening. Many of these strategies have only bio mechanical evidence and require well designed clinical trials to establish their clinical efficacy. Though no single technique is fool proof, little modifications in the existing techniques or utilizing a combination of techniques without adding to the cost of the surgery may help to achieve a near-ideal result. Surgeons have to equip their armamentarium with all the recent advances, and should be open to novel thoughts and techniques.
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Affiliation(s)
- Vikas Tandon
- Department of Spine Service, Indian Spinal Injuries Center, Sector-C, Vasant Kunj, New Delhi, 110070, India,Corresponding author. Sr. Consultant and Unit Head, Department of Spine Service, Indian Spinal Injuries Center, Vasant Kunj, New Delhi, 110070, India.
| | - Jorg Franke
- Department of Orthopedics, Klinikum Magdeburg, Magdeburg, Germany
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Jung JM, Chung CK, Kim CH, Yang SH. Clinical and radiologic outcomes of single-level direct lateral lumbar interbody fusion in patients with osteopenia. J Clin Neurosci 2019; 64:180-186. [DOI: 10.1016/j.jocn.2019.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/07/2019] [Indexed: 11/27/2022]
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Soriano-Baron H, Newcomb AGUS, Malhotra D, Martinez Del Campo E, Palma AE, Theodore N, Crawford NR, Kelly BP, Kaibara T. Biomechanical Effects of an Oblique Lumbar PEEK Cage and Posterior Augmentation. World Neurosurg 2019; 126:e975-e981. [PMID: 30876999 DOI: 10.1016/j.wneu.2019.02.200] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Lumbar interbody spacers are widely used in lumbar spinal fusion. The goal of this study is to analyze the biomechanics of a lumbar interbody spacer (Clydesdale Spinal System, Medtronic Sofamor Danek, Memphis, Tennessee, USA) inserted via oblique lumbar interbody fusion (OLIF) or direct lateral interbody fusion (DLIF) approaches, with and without posterior cortical screw and rod (CSR) or pedicle screw and rod (PSR) instrumentation. METHODS Lumbar human cadaveric specimens (L2-L5) underwent nondestructive flexibility testing in intact and instrumented conditions at L3-L4, including OLIF or DLIF, with and without CSR or PSR. RESULTS OLIF alone significantly reduced range of motion (ROM) in flexion-extension (P = 0.005) but not during lateral bending or axial rotation (P ≥ 0.63). OLIF alone reduced laxity in the lax zone (LZ) during flexion-extension (P < 0.001) but did not affect the LZ during lateral bending or axial rotation (P ≥ 0.14). The stiff zone (SZ) was unaffected in all directions (P ≥ 0.88). OLIF plus posterior instrumentation (cortical, pedicle, or hybrid) reduced the mean ROM in all directions of loading but only significantly so with PSR during lateral bending (P = 0.004), without affecting the compressive stiffness (P > 0.20). The compressive stiffness with the OLIF device without any posterior instrumentation did not differ from that of the intact condition (P = 0.97). In terms of ROM, LZ, or SZ, there were no differences between OLIF and DLIF as standalone devices or OLIF and DLIF with posterior instrumentation (CSR or PSR) (P > 0.5). CONCLUSIONS OLIF alone significantly reduced mobility during flexion-extension while maintaining axial compressive stiffness compared with the intact condition. Adding posterior instrumentation to the interbody spacer increased the construct stability significantly, regardless of cage insertion trajectory or screw type.
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Affiliation(s)
- Hector Soriano-Baron
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Anna G U S Newcomb
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Devika Malhotra
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Eduardo Martinez Del Campo
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Atilio E Palma
- Department of Neurosurgery, Wake Forest Baptist Hospital, Winston Salem, North Carolina, USA
| | - Nicholas Theodore
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | | | - Brian P Kelly
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Taro Kaibara
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
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Park MK, Kim KT, Bang WS, Cho DC, Sung JK, Lee YS, Lee CK, Kim CH, Kwon BK, Lee WK, Han I. Risk factors for cage migration and cage retropulsion following transforaminal lumbar interbody fusion. Spine J 2019; 19:437-447. [PMID: 30142459 DOI: 10.1016/j.spinee.2018.08.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 08/09/2018] [Accepted: 08/09/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure, but cage migration (CM) and cage retropulsion (CR) are associated with poor outcomes. PURPOSE This study seeks to identify risk factors associated with these serious events. STUDY DESIGN A prospective observational longitudinal study. PATIENT SAMPLE Over a 5-year period, 881 lumbar levels in 784 patients were treated using TLIF at three spinal surgery centers. OUTCOME MEASURES We evaluated the odds ratio of the risk factors for CM with and without subsidence and CR in multivariate analysis. METHODS Our study classified CM into two subgroups: CM without subsidence and CM with subsidence. Cases of spinal canal and/or foramen intrusion of the cage was defined separately as CR. Patient records, operative notes, and radiographs were analyzed for factors potentially related to CM with subsidence, CM without subsidence, and CR. RESULTS Of 881 lumbar levels treated with TLIFs, CM without subsidence was observed in 20 (2.3%) and CM with subsidence was observed in 36 (4.1%) patients. Among the CM cases, CR was observed in 17 (17/56, 30.4%). The risk factors of CM without subsidence were osteoporosis (OR 8.73, p < .001) and use of a unilateral single cage (OR 3.57, p < .001). Osteoporosis (OR 5.77, p < .001) and endplate injury (OR 26.87, p < .001) were found to be significant risk factors for CM with subsidence. Risk factors of CR were osteoporosis (OR 7.86, p < .001), pear-shaped disc (OR 8.28, p = .001), endplate injury (OR 18.70, p < .001), unilateral single cage use (OR 4.40, p = .03), and posterior cage position (OR 6.45, p = .04). A difference in overall fusion rates was identified, with a rate of 97.1% (801 of 825) for no CM, 55.0% (11 of 20) for CM without subsidence, 41.7% (15 of 36) for CM with subsidence, and 17.6% (3 of 17) for CR at 1.5 years postoperatively. CONCLUSIONS Our results suggest that osteoporosis is a significant risk factor for both CM and CR. In addition, a pear-shaped disc, posterior positioning of the cage, the presence of endplate injury and the use of a single cage were correlated with the CM with and without subsidence and CR.
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Affiliation(s)
- Man-Kyu Park
- Department of Neurosurgery, Parkweonwook Hospital, 130, 4, Gwangan-ro, Suyeong-gu, Busan 48298, Republic of Korea
| | - Kyoung-Tae Kim
- Department of Neurosurgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, 130, Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea.
| | - Woo-Seok Bang
- Department of Neurosurgery, Daegu Chamtntn hospital, 1807, Dalgubeol-daero, Seo-gu, Daegu, Republic of Korea
| | - Dae-Chul Cho
- Department of Neurosurgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, 130, Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea
| | - Joo-Kyung Sung
- Department of Neurosurgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, 130, Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea
| | - Young-Seok Lee
- Department of Neurosurgery, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - Chang Kyu Lee
- Department of Neurosurgery, Keimyung University Dongsan Medical Center, Jung-gu, Daegu, Republic of Korea
| | - Chi Heon Kim
- Department of Neurosurgery, Seoul National University Hospital and Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Brian K Kwon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, British Columbia V5Z 1M9, Canada; Vancouver Spine Surgery Institute, Department of Orthopaedics, University of British Columbia, Blusson Spinal Cord Centre, 818 West 10th Avenue, Vancouver, British Columbia V5Z 1M9, Canada
| | - Won-Kee Lee
- Medical Research Collaborating Center in Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Inbo Han
- Department of Neurosurgery, CHA University, School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggido, Republic of Korea
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Wang Y, Lu T, He X, Wen Z, Gao Z, Gao Z, Liang H. Effect of Dome-Shaped Titanium Mesh Cages on Cervical Endplate Under Cyclic Loading: An In Vitro Biomechanics Study. Med Sci Monit 2019; 25:142-149. [PMID: 30612133 PMCID: PMC6330843 DOI: 10.12659/msm.911888] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background This study aimed to verify the anti-subsidence ability of dome-shaped titanium mesh cage (TMC) used in anterior cervical corpectomy and fusion (ACCF). Material/Methods Thirty fresh human cervical vertebrae specimens were collected and randomly harvested into 2 groups: the traditional TMC group and the dome-shaped TMC group. The bone mineral density (BMD) of the specimens was recorded. Each group was biomechanically tested in axial compression with a cyclically loading range from 60 to 300 N at 0.5Hz for 10 000 cycles. The displacement data of the 2 groups were recorded every 10 cycles. Results There was no significant difference in bone mineral density between the 2 groups of cervical specimens. The traditional TMC group stabilized at 535±35 cycles while the dome-shaped TMC group stabilized at 1203±57 cycles, which showed that the rate of subsidence of the dome-shaped TMC group was significantly slower than that of the traditional TMC group (p<0.05). After reaching stability, both groups had a more gradual and sustained growth. The peak displacement during fatigue testing was −2.064±0.150mm in the traditional TMC group and −0.934±0.086mm in the dome-shaped TMC group, which showed a significant difference (p<0.05). Conclusions The dome-shaped TMC showed a smaller subsidence displacement and a gentler subsidence tendency following the same cyclic loading (compared to the traditional TMC). From a biomechanical point of view, the dome-shaped TMC has stronger anti-subsidence ability due to its unique structural design that closely matches the vertebral endplate.
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Affiliation(s)
- Yibin Wang
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Teng Lu
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Xijing He
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Zhijing Wen
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Zhengchao Gao
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Zhongyang Gao
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
| | - Hui Liang
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China (mainland)
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Alkalay RN, Adamson R, Groff MW. The effect of interbody fusion cage design on the stability of the instrumented spine in response to cyclic loading: an experimental study. Spine J 2018. [PMID: 29526639 DOI: 10.1016/j.spinee.2018.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT In the lumbar spine, end plate preparation for the interbody fusion cages may critically affect the cage's long-term performance. This study investigated the effect of the interbody cage design on the compliance and cage subsidence of instrumented spines under cyclic compression. PURPOSE We aimed to quantify the role of cage geometry and bone density on the stability of the spinal construct in response to cyclic compressive loads. STUDY DESIGN Changes in the cage-bone interface and the effect of bone density on these changes were evaluated in a human cadaveric model for three intervertebral cage designs. METHODS The intervertebral space of 27 functional cadaveric spinal units was instrumented with bilateral linear cages, single anterior conformal cages, or single unilateral oblique cages. Once augmented with a pedicle screw fixation system, the instrumented spine unit was tested under cyclic compression loads (400-1,200 N) to 20,000 cycles at a rate of 2 Hz. Compliance of the cage-bone interface and cage subsidence was computed. Two-way repeated multivariate analysis of variance was used to test the effects of cage design and bone density on the compliance and subsidence of the cages. RESULTS The anterior conformal shaped cage showed reduced interface stiffness (p<.01) and higher hysteresis (p<.01) and subsidence rate (10%-30%) than the bilateral linear and unilateral oblique-shaped cages. Bone density was not associated with the initial compliance of the cage-bone interface or the rate of cage subsidence. Higher bone density did decrease the rate of reduction in cage-bone interface stiffness under higher cyclic loads for the anterior conformal shaped and unilateral oblique cages. CONCLUSIONS Cage design and position significantly affected the degradation of the cage-bone interface under cyclic loading. Comparisons of subsidence rate between the different cage designs suggest the peripheral location of the cages, using the stronger peripheral subchondral bone of the apophyseal ring, to be advantageous in preventing the subsidence and failure of the cage-bone interface.
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Affiliation(s)
- Ron N Alkalay
- Center for Advanced Orthopaedic Studies, Department of Orthopaedics, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA.
| | - Robert Adamson
- Center for Advanced Orthopaedic Studies, Department of Orthopaedics, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA
| | - Michael W Groff
- Center for Advanced Orthopaedic Studies, Department of Orthopaedics, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA; Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Liu WB, Zhao WT, Shen P, Zhang FJ. The effects of bisphosphonates on osteoporotic patients after lumbar fusion: a meta-analysis. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:2233-2240. [PMID: 30046237 PMCID: PMC6054279 DOI: 10.2147/dddt.s164548] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Purpose We conducted a meta-analysis of controlled clinical trials to evaluate the efficacy of bisphosphonates in lumbar fusion. Introduction Bisphosphonates reduce bone resorption and remodeling by osteoclast activity inhibition, inactivation, and apoptosis. However, it remains controversial whether bisphosphonate therapy affects spinal fusion. Methods We searched MEDLINE, Cochrane CENTRAL, ScienceDirect, EMBASE, and Google Scholar to identify studies reporting the effects of bisphosphonates on osteoporotic patients after lumbar fusion. Secondary sources were identified from the references of the included literature. Pooled data were analyzed using RevMan 5.1. Results Seven studies met the inclusion criteria. There were significant differences in solid intervertebral fusion (RD=0.07, 95% CI: −0.00 to 0.15, P=0.05), subsequent VCFs (RD=−0.21, 95% CI: −0.30 to −0.12, P<0.00001), pedicle screw loosening (RD=−0.17, 95% CI: −0.28 to −0.05, P=0.006), and cage subsidence (RD=−0.25, 95% CI: −0.42 to −0.07, P=0.005) between two groups. No significant differences between two groups were found regarding implant fixation failure (RD=−0.06, 95% CI: −0.22 to 0.10, P=0.48). Conclusion This meta-analysis showed that bisphosphonates may increase solid intervertebral fusion and decrease subsequent VCFs, pedicle screw loosening, and cage subsidence.
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Affiliation(s)
- Wen-Bin Liu
- Department of Joint Surgery, Tianjin Hospital, Tianjin 300211, People's Republic of China,
| | - Wen-Tao Zhao
- Department of Orthopedics, The First Affiliated Hospital of Yunnan Traditional Chinese Medical University, Yunnan 650021, People's Republic of China
| | - Peng Shen
- Department of Rheumatology and Immunology, Tianjin First Center Hospital, Tianjin 300192, People's Republic of China
| | - Fu-Jiang Zhang
- Department of Joint Surgery, Tianjin Hospital, Tianjin 300211, People's Republic of China,
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Length of Lumbar Interbody Cage Using Radiological Measurements of Chinese Endplates and the Apophyseal Ring. World Neurosurg 2018; 116:e1204-e1213. [PMID: 29886299 DOI: 10.1016/j.wneu.2018.05.234] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To radiologically measure the parameters of endplates and the apophyseal ring and to suggest an applicable length for a lumbar interbody cage for Chinese patients. METHODS Twenty-four volunteers were enrolled to undergo lumbar computed tomography (CT). On the endplate plane, the diameters of the endplates (L1-S1) were measured along the axis of the cage with different lumbar interbody fusion procedures. Whereas the mid-oblique diameter (mid-OD) and maximum oblique diameter (max-OD) were defined as the minimal and maximal diameters of the endplates in transforaminal lumbar interbody fusion (TLIF), side-sagittal diameter (side-SD), mid-sagittal diameter (mid-SD), and transverse diameter (TD) represented the diameters of endplates in posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion (ALIF); and oblique lateral interbody fusion (OLIF)/extreme lateral interbody fusion (XLIF), /direct lateral interbody fusion (DLIF), respectively. R1-R10 were the widths of the apophyseal ring covered by diameters at both ends. We used the proposed formula to calculate the cage length: 1) minimal length of TLIF cage = mid-OD - ½ (R1 + R2), 2) maximal length of TLIF cage = max-OD - ½ (R3 + R4), 3) length of PLIF cage = side-SD - ½ (R5 + R6), 4) length of OLIF/XLIF/DLIF cage = TD - ½ (R7 + R8), and 5) length of ALIF cage = mid-SD - ½ (R9 + R10). RESULTS The lengths of the TLIF cage were more than 30 mm for men and 26 mm for women in L1/2-L4/5, with a large range in L5-S1. For PLIF, the lengths were 28 to 30 mm for men and 24 to 26 mm for women in L1/2-L4/5, with 26 mm and 22 mm, respectively, in L5-S1. For the OLIF/XLIF/DLIF cage, the lengths were 38 mm in L1/2 and 41 to 43 mm in L2/3-L4/5 for men and 35 mm in L1/2-L2/3 and 38 mm in L3/4-L4/5 for women. The ALIF cage lengths were 27 mm in L1/2 and L5-S1 and 29 mm in L2/3-L4/5 for men and 23 mm in L1/2 and L5-S1 and 25 mm in L2/3-L4/5 for women. CONCLUSIONS The choice of an appropriate length for a lumbar interbody cage should be based on the procedure and fusion level, which can match the endplates anatomically. The size of the lumbar interbody cage is affected by many factors, and a simple calculation may not be clinically relevant.
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Soriano-Baron H, Newcomb AG, Malhotra D, Palma AE, Martinez-del-Campo E, Crawford NR, Theodore N, Kelly BP, Kaibara T. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer. World Neurosurg 2018; 114:e616-e623. [DOI: 10.1016/j.wneu.2018.03.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/06/2018] [Indexed: 10/17/2022]
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Oberkircher L, Krüger A, Hörth D, Hack J, Ruchholtz S, Fleege C, Rauschmann M, Arabmotlagh M. Anterior cement augmentation of adjacent levels after vertebral body replacement leads to superior stability of the corpectomy cage under cyclic loading-a biomechanical investigation. Spine J 2018; 18:525-531. [PMID: 29174458 DOI: 10.1016/j.spinee.2017.10.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/08/2017] [Accepted: 10/26/2017] [Indexed: 02/03/2023]
Abstract
BACKGROUND In the operative treatment of osteoporotic vertebral body fractures, a dorsal stabilization in combination with a corpectomy of the fractured vertebral body might be necessary with respect to the fracture morphology, whereby the osteoporotic bone quality may possibly increase the risk of implant failure. To achieve better stability, it is recommended to use cement-augmented screws for dorsal instrumentation. Besides careful end plate preparation, cement augmentation of the adjacent end plates has also been reported to lead to less reduction loss. PURPOSE The aim of the study was to evaluate biomechanically under cyclic loading whether an additional cement augmentation of the adjacent end plates leads to improved stability of the inserted cage. STUDY DESIGN/SETTING Methodical cadaver study. MATERIALS AND METHODS Fourteen fresh frozen human thoracic spines with proven osteoporosis were used (T2-T7). After removal of the soft tissues, the spine was embedded in Technovit (Kulzer, Germany). Subsequently, a corpectomy of T5 was performed, leaving the dorsal ligamentary structures intact. After randomization with respect to bone quality, two groups were generated: Dorsal instrumentation (cemented pedicle screws, Medtronic, Minneapolis, MN, USA)+cage implantation (CAPRI Corpectomy Cage, K2M, Leesburg, VA, USA) without additional cementation of the adjacent endplates (Group A) and dorsal instrumentation+cage implantation with additional cement augmentation of the adjacent end plates (Group B). The subsequent axial and cyclic loading was performed at a frequency of 1 Hz, starting at 400 N and increasing the load within 200 N after every 500 cycles up to a maximum of 2,200 N. Load failure was determined when the cages sintered macroscopically into the end plates (implant failure) or when the maximum load was reached. RESULTS One specimen in Group B could not be clamped appropriately into the test bench for axial loading because of a pronounced scoliotic misalignment and had to be excluded. The mean strength for implant failure was 1,000 N±258.2 N in Group A (no cement augmentation of the adjacent end plates, n=7); on average, 1,622.1±637.6 cycles were achieved. In Group B (cement augmentation of the adjacent end plates, n=6), the mean force at the end of loading was 1,766.7 N±320.4 N; an average of 3,572±920.6 cycles was achieved. Three specimens reached a load of 2,000 N. The differences between the two groups were significant (p=.006 and p=.0047) regarding load failure and number of cycles. CONCLUSIONS Additional cement augmentation of the adjacent end plates during implantation of a vertebral body replacement in osteoporotic bone resulted in a significant increased stability of the cage in the axial cyclic loading test.
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Affiliation(s)
- Ludwig Oberkircher
- Center for Orthopaedics and Trauma Surgery, Philipps University Marburg, Germany.
| | - Antonio Krüger
- Center for Orthopaedics and Trauma Surgery, Philipps University Marburg, Germany
| | - Dominik Hörth
- Center for Orthopaedics and Trauma Surgery, Philipps University Marburg, Germany
| | - Juliana Hack
- Center for Orthopaedics and Trauma Surgery, Philipps University Marburg, Germany
| | - Steffen Ruchholtz
- Center for Orthopaedics and Trauma Surgery, Philipps University Marburg, Germany
| | - Christoph Fleege
- Department of Spine Surgery, Johann Wolfgang Goethe University Frankfurt, Germany
| | - Michael Rauschmann
- Department of Spine Surgery, Johann Wolfgang Goethe University Frankfurt, Germany
| | - Mohammad Arabmotlagh
- Department of Spine Surgery, Johann Wolfgang Goethe University Frankfurt, Germany
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Vertebral Body Hounsfield Units are Associated With Cage Subsidence After Transforaminal Lumbar Interbody Fusion With Unilateral Pedicle Screw Fixation. Clin Spine Surg 2017; 30:E1130-E1136. [PMID: 27906743 DOI: 10.1097/bsd.0000000000000490] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To assess the association between Hounsfield units (HU) measurement and cage subsidence after lumbar interbody fusion. BACKGROUND Transforaminal lumbar interbody fusion (TLIF) with unilateral fixation becomes a popular treatment modality for lumbar degenerative disease. Cage subsidence is a potentially devastating complication after lumbar interbody fusion with unilateral fixation. Recently, a new technique for assessing bone mineral density using HU values from computed tomography has been proposed. Bone quality is believed to be one of the important factors that cause cage subsidence after TLIF. MATERIALS AND METHODS Cage subsidence after single-level (L4/5) TLIF with unilateral fixation was prospectively documented at a single institution between 2013 and 2014. Patients with cage subsidence were matched 1:1 to a control cohort without cage subsidence on the basis of age and sex. HU values were measured from the preoperative computed tomography. All patients received computed tomographic scans at a minimum of 6 months postoperatively. Sagittal images were evaluated for evidence of cage subsidence. RESULTS Eighteen patients with cage subsidence were well matched 1:1 to a cohort without cage subsidence and had complete imaging data. The global lumbar HU values were significantly lower in patients with cage subsidence than in the controls (112.4±10.08 vs. 140.2±10.17; P=0.0015). Similarly, a regional assessment of HU across the fusion levels was significantly lower in patients with cage subsidence (113.4±10.47 vs. 127.9±8.13; P=0.0075). The areas under the receiver operating characteristic cure were 0.715 and 0.636 for global and regional assessment, respectively. The best cut-offs for global and regional assessment were 132 (sensitivity: 83.3%; specificity: 61.1%) and 122 (sensitivity: 72.2%; specificity: 55.6%), respectively. CONCLUSIONS Lower preoperative HU values is associated with cage subsidence after TLIF with unilateral fixation. HU measurement may be used as a predictor of cage subsidence after unilateral fixation, which also should be incorporated in preoperative planning.
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Tomé-Bermejo F, Piñera AR, Alvarez-Galovich L. Osteoporosis and the Management of Spinal Degenerative Disease (I). THE ARCHIVES OF BONE AND JOINT SURGERY 2017; 5:272-282. [PMID: 29226197 PMCID: PMC5712392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 11/16/2016] [Indexed: 06/07/2023]
Abstract
Osteoporosis has become a major medical problem as the aged population of the world rapidly grows. Osteoporosis predisposes patients to fracture, progressive spinal deformities, and stenosis, and is subject to be a major concern before performing spine surgery, especially with bone fusions and instrumentation. Osteoporosis has often been considered a contraindication for spinal surgery, while in some instances patients have undergone limited and inadequate procedures in order to avoid concomitant instrumentation. As the population ages and the expectations of older patients increase, the demand for surgical treatment in older patients with osteoporosis and spinal degenerative diseases becomes progressively more important. Nowadays, advances in surgical and anesthetic technology make it possible to operate successfully on elderly patients who no longer accept disabling physical conditions. This article discusses the biomechanics of the osteoporotic spine, the diagnosis and management of osteoporotic patients with spinal conditions, as well as the novel treatments, recommendations, surgical indications, strategies and instrumentation in patients with osteoporosis who need spine operations.
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Affiliation(s)
- Félix Tomé-Bermejo
- Spine Department, Fundación Jiménez Díaz University Hospital, Madrid, Spain
| | - Angel R Piñera
- Spine Department, Fundación Jiménez Díaz University Hospital, Madrid, Spain
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Elimination of Subsidence with 26-mm-Wide Cages in Extreme Lateral Interbody Fusion. World Neurosurg 2017; 104:644-652. [DOI: 10.1016/j.wneu.2017.05.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/05/2017] [Accepted: 05/06/2017] [Indexed: 11/22/2022]
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Oh KW, Lee JH, Lee JH, Lee DY, Shim HJ. The Correlation Between Cage Subsidence, Bone Mineral Density, and Clinical Results in Posterior Lumbar Interbody Fusion. Clin Spine Surg 2017. [PMID: 28632554 DOI: 10.1097/bsd.0000000000000315] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
STUDY DESIGN A retrospective review of prospectively collected radiographic and clinical data. OBJECTIVE This study aims to investigate the relationship between cage subsidence and bone mineral density (BMD), and to reveal the clinical implications of cage subsidence. SUMMARY OF BACKGROUND DATA Posterior lumbar interbody fusion (PLIF) has become one of the standard treatment modality for lumbar degenerative disease. However, cage subsidence might result in recurrent foraminal stenosis and deteriorate the clinical results. Furthermore, numbers of osteoporosis patients who underwent PLIF are increasing. Therefore, the information on the correlations between cage subsidence, BMD, and clinical results will be of great significance. MATERIALS AND METHODS A total 139 segments was included in this retrospective study. We examined functional rating index (Visual Analogue Scale for pain, Oswestry Disability Index, Short Form-36 score) preoperatively, and investigated their changes after postoperative 1 year. Correlation between cage subsidence and clinical scores was investigated. Plain anteroposterior and lateral radiograph were taken preoperatively and postoperatively and during follow-up. Preoperative BMD and subsidence measured by postoperative 1 year 3-dimensional computed tomography were achieved and their correlation was assessed. RESULTS All postoperative clinical scores improved significantly compared with preoperative ones (pain Visual Analogue Scale: 7.34-2.89, Oswestry Disability Index: 25.34-15.86, Short Form-36: 26.45-16.46, all P<0.001). BMD showed significant weak correlation with subsidence (r=-0.285, P<0.001). Severe osteoporotic segments (T score <-3.0) had more risk to develop severe subsidence (>3 mm) compared with the segments in which T score were higher than -3.0 (P=0.012), and its odds ratio was 8.44. Subsidence had no significant correlation with all clinical scores. CONCLUSIONS This study revealed that cage subsidence is relevant to BMD. However, it was demonstrated that subsidence is not related to the clinical deterioration. Therefore, PLIF procedure which is conducted carefully can be a good surgical option to treat lumbar degenerative disease for osteoporotic patients.
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Affiliation(s)
- Kyu Won Oh
- *Department of Orthopedic Surgery, SMG-SNU Boramae Medical Center, College of Medicine and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University †Department of Orthopedic Surgery, College of Medicine Seoul National University, Seoul, Korea
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Du Plessis PNB, Lau BPH, Hey HWD. Traumatic dislocation of the S1 polyaxial pedicle screw head: a case report. JOURNAL OF SPINE SURGERY 2017; 3:95-101. [PMID: 28435927 DOI: 10.21037/jss.2017.03.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Polyaxial screw head dislocation in the absence of a manufacture defect is extremely rare and represents a biomechanical overload of the screw, leading to early failure. A 58-year-old gentleman underwent instrumented fusion using polyaxial pedicle screws-titanium rod construct with interbody cage for spondylolytic spondylolisthesis at the L5/S1 level. He attempted to bend forward ten days after the surgery which resulted in a dislocation of the right S1 polyaxial screw head from the screw shank with recurrence of symptoms. He underwent revision surgery uneventfully. This case highlights the need to pay particular attention to the strength of fixation and the amount of release to avoid such a complication.
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Affiliation(s)
- Pieter N B Du Plessis
- University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National University Hospital, Singapore
| | - Bernard P H Lau
- University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National University Hospital, Singapore
| | - Hwee Weng Dennis Hey
- University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National University Hospital, Singapore
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Kerolus M, Turel MK, Tan L, Deutsch H. Stand-alone anterior lumbar interbody fusion: indications, techniques, surgical outcomes and complications. Expert Rev Med Devices 2016; 13:1127-1136. [PMID: 27792409 DOI: 10.1080/17434440.2016.1254039] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Anterior lumbar interbody fusion (ALIF) is a well-established technique to achieve lumbar spine fusion with various indications including degenerative disk disease, spondylolisthesis, recurrent disk herniation, adjacent level disease, pseudoarthrosis, as well as being used as part of the overall strategy to restore sagittal balance. ALIF can be an extremely useful tool in any spine surgeon's armamentarium. However, like any surgical procedure, proper patient selection is key to success. A solid understanding of the biomechanics, careful surgical planning, along with clear knowledge of the advantages and disadvantages of stand-alone ALIF will ensure optimal clinical outcome. Stand-alone ALIF may be a suitable surgical option in carefully selected patients that can provide good clinical results and adequate fusion rates without the need for posterior instrumentation. Areas covered: A brief overview of the indications, techniques, biomechanics, surgical outcome and complications of stand-alone ALIF is provided in this article with a review of the pertinent literature. Expert commentary: In this review we discuss the clinical evidence of using a stand-alone ALIF compared to other fusion techniques of the lumbar spine. The development of interbody cages with integrated screws has increased the arthrodesis rate and improved clinical outcomes while decreasing morbidity and operative time.
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Affiliation(s)
- Mena Kerolus
- a Department of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Mazda K Turel
- a Department of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Lee Tan
- a Department of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
| | - Harel Deutsch
- a Department of Neurosurgery , Rush University Medical Center , Chicago , IL , USA
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Caffrey JP, Cory E, Wong VW, Masuda K, Chen AC, Hunt JP, Ganey TM, Sah RL. Ex vivo loading of trussed implants for spine fusion induces heterogeneous strains consistent with homeostatic bone mechanobiology. J Biomech 2016; 49:4090-4097. [PMID: 27836500 DOI: 10.1016/j.jbiomech.2016.10.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 10/30/2016] [Indexed: 10/20/2022]
Abstract
A truss structure was recently introduced as an interbody fusion cage. As a truss system, some of the connected elements may be in a state of compression and others in tension. This study aimed to quantify both the mean and variance of strut strains in such an implant when loaded in a simulated fusion condition with vertebral body or contoured plastic loading platens ex vivo. Cages were each instrumented with 78 fiducial spheres, loaded between platens (vertebral body or contoured plastic), imaged using high resolution micro-CT, and analyzed for deformation and strain of each of the 221 struts. With repeated loading of a cage by vertebral platens, the distribution (variance, indicated by SD) of strut strains widened from 50N control (4±114με, mean±SD) to 1000N (-23±273με) and 2000N (-48±414με), and between 1000N and 2000N. With similar loading of multiple cages, the strain distribution at 2000N (23±389με) increased from 50N control. With repeated loading by contoured plastic platens, induced strains at 2000N had a distribution similar to that induced by vertebral platens (84±426με). In all studies, cages exhibited increases in strut strain amplitude when loaded from 50N to 1000N or 2000N. Correspondingly, at 2000N, 59-64% of struts exhibited strain amplitudes consistent with mechanobiologically-regulated bone homeostasis. At 2000N, vertically-oriented struts exhibited deformation of -2.87±2.04μm and strain of -199±133με, indicating overall cage compression. Thus, using an ex vivo 3-D experimental biomechanical analysis method, a truss implant can have strains induced by physiological loading that are heterogeneous and of amplitudes consistent with mechanobiological bone homeostasis.
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Affiliation(s)
- Jason P Caffrey
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive MC 0412, La Jolla, CA 92093-0412, USA
| | - Esther Cory
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive MC 0412, La Jolla, CA 92093-0412, USA
| | - Van W Wong
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive MC 0412, La Jolla, CA 92093-0412, USA
| | - Koichi Masuda
- Department of Orthopedic Surgery, University of California-San Diego, 9500 Gilman Drive MC 0863, La Jolla, CA 92093-0863, USA
| | - Albert C Chen
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive MC 0412, La Jolla, CA 92093-0412, USA
| | - Jessee P Hunt
- 4WEB Medical, 6170 Research Road, Suite 219, Frisco, TX 75033, USA
| | - Timothy M Ganey
- Atlanta Medical Center, 303 Parkway Drive NE, Box 227, Atlanta, GA 30312, USA
| | - Robert L Sah
- Department of Bioengineering, University of California-San Diego, 9500 Gilman Drive MC 0412, La Jolla, CA 92093-0412, USA; Department of Orthopedic Surgery, University of California-San Diego, 9500 Gilman Drive MC 0863, La Jolla, CA 92093-0863, USA; Center for Musculoskeletal Research, Institute of Engineering in Medicine, University of California-San Diego, 9500 Gilman Dr. MC 0412, La Jolla, CA 92093-0412, USA.
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Yun DJ, Hwang BW, Oh HS, Kim JS, Jeon SH, Lee SH. Salvage Percutaneous Vertebral Augmentation Using Polymethyl Methacrylate in Patients with Failed Interbody Fusion. World Neurosurg 2016; 95:618.e13-618.e20. [PMID: 27546339 DOI: 10.1016/j.wneu.2016.08.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Percutaneous vertebral augmentation with cement is used as a salvage procedure for failed instrumentation. Few studies have reported the use of this procedure for failed anterior lumbar fusion in elderly patients with osteoporosis and other complicated diseases who have undergone a previous major operation. METHODS Between January 2007 and December 2015, the clinical and radiographic results of 8 patients with osteoporosis who showed subsidence and migration of the implant after an initial operation were examined. After the development of implant failure, the patients underwent vertebral augmentation with polymethyl methacrylate. RESULTS Mean patient age was 73.4 years (range, 67-78 years), and mean bone mineral density was -2.96 (range, -2.1 to -3.8). The mean radiologic follow-up period between augmentation and the last follow-up examination was 16 months (range, 3-38 months). Although the subjective clinical outcome was not satisfying to the patients, no loss of correction, fractures, or screw loosening occurred during the follow-up period. CONCLUSIONS The injection of cement around the instrument might help to stabilize it by providing strength to the axis and preventing further loosening. This salvage procedure could be an alternative in the management of cases with failed interbody fusion.
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Affiliation(s)
- Dong-Ju Yun
- Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea
| | - Byeong-Wook Hwang
- Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea.
| | - Hyeong-Seok Oh
- Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea
| | - Jin-Sung Kim
- Department of Neurosurgery, Seoul St. Mary's Hospital, Seoul, Korea
| | - Sang-Hyeop Jeon
- Department of Cardiothoracic Surgery, Spine Health Wooridul Hospital, Busan, Korea
| | - Sang-Ho Lee
- Department of Neurosurgery, Spine Health Wooridul Hospital Gangnam, Seoul, Korea
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Muñiz Luna L, Vilchis Sámano H, Marban Heredia M, Salcedo Oviedo E, Ordaz J, María Morales A, De La Cruz Álvarez JS, Canales Nájera JA, Bahena Salgado Y, Negrete-Mundo E. FUNCTIONAL DISABILITY, SAGITTAL ALIGNMENT AND PELVIC BALANCE IN LUMBAR SPONDYLOLISTHESIS. COLUNA/COLUMNA 2016. [DOI: 10.1590/s1808-185120161501152836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ABSTRACT Objectives: To demonstrate the recovery of lumbar sagittal pelvic alignment and sagittal pelvic balance after surgical reduction of lumbar spondylolisthesis and establish the benefits of the surgery for reduction and fixation of the lumbar spondylolisthesis with 360o circumferential arthrodesis for 2 surgical approaches by clinical and functional evaluation. Method: Eight patients with lumbar spondylolisthesis treated with surgical reduction and fixation of listhesis and segmental circumferential fusion with two surgical approaches were reviewed. They were evaluated before and after treatment with Oswestry, Visual Analogue for pain and Odom scales, performing radiographic measurement of lumbar sagittal alignment and pelvic sagittal balance with the technique of pelvic radius. Results: Oswestry scales and EVA reported improvement of symptoms after treatment in 8 cases; the Odom scale had six outstanding cases reported. The lumbar sagittal alignment presented a lumbosacral lordosis angle and a lumbopelvic lordosis angle reduced in 4 cases and increased in 4 other cases; pelvic sagittal balance increased the pelvic angle in 4 cases and decreased in 3 cases and the sacral translation of the hip axis to the promontory increased in 6 cases. Conclusion: The surgical procedure evaluated proved to be useful by modifying the lumbar sagittal alignment and the pelvic balance, besides reducing the symptoms, enabling the patient to have mobility and movement and the consequent satisfaction with the surgery.
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Affiliation(s)
- Luis Muñiz Luna
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Hugo Vilchis Sámano
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Marcos Marban Heredia
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Enrique Salcedo Oviedo
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Juvenal Ordaz
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Ana María Morales
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | | | - José Antonio Canales Nájera
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Yadira Bahena Salgado
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
| | - Edgar Negrete-Mundo
- Hospital de Traumatología y Ortopedia "Lomas Verdes" of the IMSS (Instituto Mexicano del Seguro Social), Mexico
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Liu J, Hao L, Suyou L, Shan Z, Maiwulanjiang M, Li S, Wang C, Fan S, Zhao F. Biomechanical properties of lumbar endplates and their correlation with MRI findings of lumbar degeneration. J Biomech 2016; 49:586-93. [DOI: 10.1016/j.jbiomech.2016.01.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 01/22/2016] [Accepted: 01/28/2016] [Indexed: 12/15/2022]
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Park CK, Park CK, Lee DC, Lee DG. A new technique of bone cement augmentation via the disc space for percutaneous pedicle screw fixation. J Neurosurg Spine 2015; 24:16-9. [PMID: 26360145 DOI: 10.3171/2015.4.spine141115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In elderly patients with severe osteoporosis, instrumented lumbar interbody fusion may result in fixation failure or nonunion because of decreased pedicle screw pullout strength or increased interbody graft subsidence risk. Thus, given its many advantages, percutaneous pedicle screw fixation with cement augmentation can be an effective method to use in elderly patients. The authors report on an easy, safe, and economical technique for bone cement augmentation using a bone biopsy needle inserted into the disc space in 2 osteoporotic patients who were treated with posterior interbody fusion and percutaneous pedicle screw fixation. METHODS Two elderly patients who complained of back pain and intermittent neurological claudication underwent posterior interbody fusion with percutaneous pedicle screw fixation. After routinely assembling rods on the screws, a bone biopsy needle was inserted into the disc space via the operative field; the needle was then placed around the tips of the screws using fluoroscopic radiography for guidance. Bone cement was injected through the bone biopsy needle, also under fluoroscopic radiography guidance. RESULTS Both patients' symptoms improved after the operation, and there was no evidence of cage subsidence or screw loosening at the 4-month follow-up. CONCLUSIONS The indirect technique of bone cement augmentation via the disc space for percutaneous screw fixation could be an easy, safe, and economical method.
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Affiliation(s)
- Chang Kyu Park
- Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea
| | - Choon Keun Park
- Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea
| | - Dong Chan Lee
- Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea
| | - Dong Geun Lee
- Department of Neurosurgery, The Leon Wiltse Memorial Hospital, Suwon, Republic of Korea
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Soriano-Baron H, Newcomb AGUS, Malhotra D, de Tranaltes K, Martinez-Del-Campo E, Reyes PM, Crawford NR, Theodore N, Tumialán LM. Biomechanics of Nested Transforaminal Lumbar Interbody Cages. Neurosurgery 2015; 78:297-304. [PMID: 26348015 DOI: 10.1227/neu.0000000000001005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Arthrodesis is optimized when the structural graft occupies most of the surface area within a disc space. The transforaminal corridor inherently limits interbody size. OBJECTIVE To evaluate the biomechanical implications of nested interbody spacers (ie, a second curved cage placed behind a first) to increase disc space coverage in transforaminal approaches. METHODS Seven lumbar human cadaveric specimens (L3-S1) underwent nondestructive flexibility and axial compression testing intact and after transforaminal instrumentation at L4-L5. Specimens were tested in 5 conditions: (1) intact, (2) interbody, (3) interbody plus bilateral pedicle screws and rods (PSR), (4) 2 nested interbodies, and (5) 2 nested interbodies plus PSR. RESULTS Mean range of motion (ROM) with 1 interbody vs 2 nested interbodies, respectively, was: flexion, 101% vs 85%; extension, 97% vs 92%; lateral bending, 127% vs 132%; and axial rotation, 145% vs 154%. One interbody and 2 nested interbodies did not differ significantly by loading mode (P > .10). With PSR, ROM decreased significantly compared with intact, but not between interbody and interbody plus PSR or 2 interbodies plus PSR (P > .80). Mean vertical height during compressive loading (ie, axial compressive stiffness) was significantly different with 2 nested interbodies vs 1 interbody alone (P < .001) (compressive stiffness, 89% of intact vs 67% of intact, respectively). CONCLUSION Inserting a second interbody using a transforaminal approach is anatomically feasible and nearly doubles the disc space covered without affecting ROM. Compressive stiffness significantly increased with 2 nested interbodies, and foraminal height increased. Evaluation of the clinical safety and efficacy of nested interbodies is underway.
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Affiliation(s)
- Hector Soriano-Baron
- *Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; ‡Division of Neurological Surgery, Spine Group Arizona, HonorHealth Research Institute, Scottsdale, Arizona
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Mabe I, Weiss C, Goswami T. Locations of initial failure in the lower cervical spine: a finite element investigation. Biomed Phys Eng Express 2015. [DOI: 10.1088/2057-1976/1/2/025004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ambati DV, Wright EK, Lehman RA, Kang DG, Wagner SC, Dmitriev AE. Bilateral pedicle screw fixation provides superior biomechanical stability in transforaminal lumbar interbody fusion: a finite element study. Spine J 2015; 15:1812-22. [PMID: 24983669 DOI: 10.1016/j.spinee.2014.06.015] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/27/2014] [Accepted: 06/17/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Transforaminal lumbar interbody fusion (TLIF) is increasingly popular for the surgical treatment of degenerative lumbar disease. The optimal construct for segmental stability remains unknown. PURPOSE To compare the stability of fusion constructs using standard (C) and crescent-shaped (CC) polyetheretherketone TLIF cages with unilateral (UPS) or bilateral (BPS) posterior instrumentation. STUDY DESIGN Five TLIF fusion constructs were compared using finite element (FE) analysis. METHODS A previously validated L3-L5 FE model was modified to simulate decompression and fusion at L4-L5. This model was used to analyze the biomechanics of various unilateral and bilateral TLIF constructs. The inferior surface of the L5 vertebra remained immobilized throughout the load simulation, and a bending moment of 10 Nm was applied on the L3 vertebra to recreate flexion, extension, lateral bending, and axial rotation. Various biomechanical parameters were evaluated for intact and implanted models in all loading planes. RESULTS All reconstructive conditions displayed decreased motion at L4-L5. Bilateral posterior fixation conferred greater stability when compared with unilateral fixation in left lateral bending. More than 50% of intact motion remained in the left lateral bending with unilateral posterior fixation compared with less than 10% when bilateral pedicle screw fixation was used. Posterior implant stresses for unilateral fixation were six times greater in flexion and up to four times greater in left lateral bending compared with bilateral fixation. No effects on segmental stability or posterior implant stresses were found. An obliquely-placed, single standard cage generated the lowest cage-end plate stress. CONCLUSIONS Transforaminal lumbar interbody fusion augmentation with bilateral posterior fixation increases fusion construct stability and decreases posterior instrumentation stress. The shape or number of interbody implants does not appear to impact the segmental stability when bilateral pedicle screws are used. Increased posterior instrumentation stresses were observed in all loading modes with unilateral pedicle screw/rod fixation, which may theoretically accelerate implant loosening or increase the risk of construct failure.
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Affiliation(s)
- Divya V Ambati
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720-A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA; Uniformed Services University of the Health Sciences, Division of Surgery, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Edward K Wright
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720-A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA; Uniformed Services University of the Health Sciences, Division of Surgery, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA; Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Building 19, Room #2101, 8901 Wisconsin Ave., Bethesda, MD 20889, USA
| | - Ronald A Lehman
- Uniformed Services University of the Health Sciences, Division of Surgery, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA; Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Building 19, Room #2101, 8901 Wisconsin Ave., Bethesda, MD 20889, USA.
| | - Daniel G Kang
- Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Building 19, Room #2101, 8901 Wisconsin Ave., Bethesda, MD 20889, USA
| | - Scott C Wagner
- Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Building 19, Room #2101, 8901 Wisconsin Ave., Bethesda, MD 20889, USA
| | - Anton E Dmitriev
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720-A Rockledge Dr., Suite 100, Bethesda, MD 20817, USA; Uniformed Services University of the Health Sciences, Division of Surgery, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA; Department of Orthopaedic Surgery, Walter Reed National Military Medical Center, Building 19, Room #2101, 8901 Wisconsin Ave., Bethesda, MD 20889, USA
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Biomechanical Evaluation of the Pedicle Screw Insertion Depth Effect on Screw Stability Under Cyclic Loading and Subsequent Pullout. ACTA ACUST UNITED AC 2015; 28:E133-9. [DOI: 10.1097/bsd.0000000000000178] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Biomechanical effects of cage positions and facet fixation on initial stability of the anterior lumbar interbody fusion motion segment. Spine (Phila Pa 1976) 2014; 39:E770-6. [PMID: 24732834 DOI: 10.1097/brs.0000000000000336] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro biomechanical study using porcine lumbar segments as specimens. OBJECTIVE To evaluate the effects of interbody cage support and endplate strength on the stability of instrumented segments. SUMMARY OF BACKGROUND DATA The anterior lumbar interbody fusion (ALIF) cage is widely used to restore disc height and support the anterior column. Transpedicle or posterior spinal fusion or facet screw fixation (FSF) can improve the stability of the vertebra-instrumented segments. The cage position can affect the anterior support and initial stability of the ALIF region, but there is no consistent data on its biomechanical effects on ALIF and ALIF/FSF segments. METHODS Nine variations of 3 instrumentation modes (intact, ALIF, ALIF/FSF) and 3 cage positions (type I, anterolateral; type II, mediolateral; and type III, posteromedial) are tested under 5 lumbar motions. The range of motion and axial displacement are used as comparison indices for the different variations. RESULTS The cage placement serves as support for the intervertebral loads while the posterior fixation behaves as lever to further enhance the anterior support. At the endplate-cage interfaces, the endplate strength directly affects the cage subsidence. Type III exhibits higher stability for standing due to the greater strength of the endplate in the posterior region. Otherwise, type I consistently has higher stability for all other types of motion. CONCLUSION The initial stability of the ALIF region is affected by the moment arm and the mechanical strength of the engaged endplates. Type I has greater moment arm and provides more efficient support to the instrumented segments. Endplate strength provides an ability to withstand lumbar loads and suppress the cage subsidence. Bone quality at the endplate-cage interfaces must therefore be cautiously evaluated preoperatively. LEVEL OF EVIDENCE N/A.
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Influences of endplate removal and bone mineral density on the biomechanical properties of lumbar spine. PLoS One 2013; 8:e76843. [PMID: 24244269 PMCID: PMC3820638 DOI: 10.1371/journal.pone.0076843] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 09/03/2013] [Indexed: 11/19/2022] Open
Abstract
Purpose To investigate (1) effects of endplate removal and bone mineral density (BMD) on biomechanical properties of lumbar vertebrae (2) whether the distributions of mechanical strength and stiffness of endplate are affected by BMD. Methods A total of thirty-one lumbar spines (L1-L5) collected from fresh cadavers were used in this study. Bone density was measured using lateral DEXA scans and parts of samples were performed with partial or entire endplate removal. All the specimens were divided into three BMD groups. According to endplate integrity of the lumbar vertebrae, each BMD group was then divided into three subgroups: subgroup A: intact endplate; subgroup B: central region of endplate removal; subgroup C: entire endplate removal. The axial compression test was conducted with material testing system at a speed of 2mm/min. The experimental results were statistically analyzed using SPSS 17.0. Results (1) Significant differences of biomechanical properties occurred among normal BMD, osteoporotic and serious osteoporotic group (P<0.05). (2) Spearman analysis showed that BMD was positively correlated with the failure load and stiffness of lumbar vertebrae. (3) For each BMD group, significant differences of biomechanical properties were found between subgroup A and C, and between subgroup B and C (P<0.05). (4) For each BMD group, there was no statistical difference of biomechanical properties between subgroup A and B (P>0.05). Conclusions Entire endplate removal can significantly decrease the structural properties of lumbar vertebrae with little change in biomechanical properties by preservation of peripheral region of the endplate. BMD is positively correlated to the structural properties of the lumbar vertebrae.
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Chen SH, Chiang MC, Lin JF, Lin SC, Hung CH. Biomechanical comparison of three stand-alone lumbar cages--a three-dimensional finite element analysis. BMC Musculoskelet Disord 2013; 14:281. [PMID: 24088294 PMCID: PMC3852219 DOI: 10.1186/1471-2474-14-281] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 09/24/2013] [Indexed: 11/16/2022] Open
Abstract
Background For anterior lumbar interbody fusion (ALIF), stand-alone cages can be supplemented with vertebral plate, locking screws, or threaded cylinder to avoid the use of posterior fixation. Intuitively, the plate, screw, and cylinder aim to be embedded into the vertebral bodies to effectively immobilize the cage itself. The kinematic and mechanical effects of these integrated components on the lumbar construct have not been extensively studied. A nonlinearly lumbar finite-element model was developed and validated to investigate the biomechanical differences between three stand-alone (Latero, SynFix, and Stabilis) and SynCage-Open plus transpedicular fixation. All four cages were instrumented at the L3-4 level. Methods The lumbar models were subjected to the follower load along the lumbar column and the moment at the lumbar top to produce flexion (FL), extension (EX), left/right lateral bending (LLB, RLB), and left/right axial rotation (LAR, RAR). A 10 Nm moment was applied to obtain the six physiological motions in all models. The comparison indices included disc range of motion (ROM), facet contact force, and stresses of the annulus and implants. Results At the surgical level, the SynCage-open model supplemented with transpedicular fixation decreased ROM (>76%) greatly; while the SynFix model decreased ROM 56-72%, the Latero model decreased ROM 36-91%, in all motions as compared with the INT model. However, the Stabilis model decreased ROM slightly in extension (11%), lateral bending (21%), and axial rotation (34%). At the adjacent levels, there were no obvious differences in ROM and annulus stress among all instrumented models. Conclusions ALIF instrumentation with the Latero or SynFix cage provides an acceptable stability for clinical use without the requirement of additional posterior fixation. However, the Stabilis cage is not favored in extension and lateral bending because of insufficient stabilization.
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Affiliation(s)
- Shih-Hao Chen
- Department of Mechanical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan.
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Yoshihara H. Surgical options for lumbosacral fusion: biomechanical stability, advantage, disadvantage and affecting factors in selecting options. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2013; 24 Suppl 1:S73-82. [DOI: 10.1007/s00590-013-1282-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 07/06/2013] [Indexed: 10/26/2022]
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