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Hung SF, Tsai TT, Wang SF, Hsieh MK, Kao FC. Additional cement augmentation reduces cage subsidence and improves clinical outcomes in oblique lumbar interbody fusion combined with anterolateral screw fixation: A retrospective cohort study. Curr Probl Surg 2024; 61:101441. [PMID: 38360009 DOI: 10.1016/j.cpsurg.2024.101441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 02/17/2024]
Affiliation(s)
- Shih-Feng Hung
- Department of Orthopedic Surgery, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan
| | - Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Sheng-Fen Wang
- Department of Anesthesiology, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ming-Kai Hsieh
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Fu-Cheng Kao
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan; Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
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Kaya O, Ozkunt O, Sungur M, Semih Cakir M, Baydogan M, Sariyilmaz K. Intraoperative lateral wall breach simulation in the cadaveric spine and the impact of thread designs of screws on pullout strength in the osteoporotic thoracic vertebrae: A biomechanical study in human cadavers. ACTA ORTHOPAEDICA ET TRAUMATOLOGICA TURCICA 2024; 58:57-61. [PMID: 38525511 PMCID: PMC11059965 DOI: 10.5152/j.aott.2024.22067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 11/06/2023] [Indexed: 03/26/2024]
Abstract
OBJECTIVE This study aimed (1) to simulate pedicle screw pullout after intraoperative external wall perforation and (2) to assess restoration strength with different thread designs in the pedicle screw instrumentation for osteoporotic thoracic vertebrae. METHODS Twenty fresh-frozen human cadaveric thoracic vertebra bodies were prepared and divided into 4 groups: group 1, 5.5 mm × 45 mm polyaxial single thread pedicle screws (PASTS); group 2, after wall injury 5.5 mm × 45 mm PASTS; group 3, 6.5 mm × 45 mm PASTS after wall injury; and group 4: 6.5 mm × 45 mm polyaxial mixed-threaded screws after wall injury. While group 1 was the control group, groups 2, 3, and 4 were used as study groups after the lateral wall breach. All prepared screw units were placed on a universal pullout measurement testing device. RESULTS The mean bone mineral density for 20 thoracic vertebrae was 0.57 ± 0.12 g/cm2 (range 0.53-0.6 g/cm2 ). The mean pullout strength was 474.90 Newtons (N) for group 1, 412.85 N for group 2, 475.4 N for group 3, and 630.74N for group 4. The lateral wall breach caused a 14.1 % decrease in average pullout strength compared with the initial screw pullout. Mixed (double)-threaded screws increased pullout strength compared to 6.5 mm screws (P=.036) Conclusion: Using a 1 mm thicker polyaxial pedicle screw or mixed (double)-threaded pedicle screw seems to increase pullout strength; however, this was statistically significant only for group 4. In the thoracic spine, the redirection possibility of the pedicle screw is limited, and augmentation with cement will not be appropriate due to the risk of wall injury-related leakage. Therefore, care should be taken to avoid violating the lateral cortex by using appropriate pedicle entry points and trajectories.
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Affiliation(s)
- Ozcan Kaya
- Department of Orthopedics and Traumatology, Istanbul Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Okan Ozkunt
- Department of Orthopedics and Traumatology, Medicana Istanbul Bahçelievler Hospital, Istanbul, Turkey
| | - Mustafa Sungur
- Department of Orthopedics and Traumatology, Acıbadem MAA University, School of Medicine, Istanbul, Turkey
| | - Mehmet Semih Cakir
- Department of Interventional Radiology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| | | | - Kerim Sariyilmaz
- Department of Orthopedics and Traumatology, Acıbadem MAA University, School of Medicine, Istanbul, Turkey
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Lee SJ, Lee JH, Lee HJ, Oh JW, Park IH. Pullout strength of pedicle screws using cadaveric vertebrae with or without artificial demineralization. Spine J 2021; 21:1580-1586. [PMID: 33872804 DOI: 10.1016/j.spinee.2021.04.010] [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: 09/21/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To evaluate the differences in the pullout strength and displacement of pedicle screws in cadaveric thoracolumbar vertebrae with or without artificial demineralization. METHODS Five human lumbar and five thoracic vertebrae from one cadaver were divided into two hemivertebrae. The left-side specimens were included in the simulated osteopenic model group and the right-side bones in a control group. In the model group, we immersed each specimen in HCl (1 N) solution for 40 minutes. We measured bone mineral density (BMD) using dual-energy X-ray absorptiometry and quantitative computerized tomography. We inserted polyaxial pedicle screws into the 20 pedicles of the cadaveric lumbar and thoracic spine after measuring the BMD of the 2 hemivertebrae of each specimen. We measured the pullout strength and displacement of the screws before failure in each specimen using an Instron system. RESULTS The average pullout strength of the simulated osteopenic model group was 76% that of the control group. In the control and model groups, the pullout strength was 1678.87±358.96 N and 1283.83±341.97 N, respectively, and the displacement was 2.07±0.34 mm and 2.65±0.50 mm, respectively (p<.05). We detected positive correlations between pullout strength and BMD in the control group and observed a negative correlation between displacement and BMD in the model group. CONCLUSIONS By providing an anatomically symmetric counterpart, the human cadaveric model with or without demineralization can be used as a test bed for pullout tests of the spine. In the simulated osteopenic model group, pullout strength was significantly decreased compared with the untreated control group. CLINICAL SIGNIFICANCE Decreased bone mineral density may significantly reduce the pullout strength of a pedicle screw, even though the range is osteopenic rather than osoteoporotic.
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Affiliation(s)
- Suk-Joong Lee
- Department of Orthopaedic Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Changwon Hospital, Changwon, Republic of Korea
| | - Jin-Han Lee
- Department of Orthopaedic Surgery, Kyungpook National University Hospital, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea
| | - Hyun-Joo Lee
- Department of Orthopaedic Surgery, School of Medicine, Kyungpook National University, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea; Department of Orthopaedic Surgery, Kyungpook National University Hospital, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea
| | - Ji Won Oh
- Department of Anatomy, School of Medicine, Kyungpook National University, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea; Biomedical Research Institute, Kyungpook National University Hospital, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea
| | - Il-Hyung Park
- Department of Orthopaedic Surgery, School of Medicine, Kyungpook National University, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea; Department of Orthopaedic Surgery, Kyungpook National University Hospital, 130 Dongduk-ro, Jung-gu, Daegu, Republic of Korea.
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Loenen ACY, Noriega DC, Ruiz Wills C, Noailly J, Nunley PD, Kirchner R, Ito K, van Rietbergen B. Misaligned spinal rods can induce high internal forces consistent with those observed to cause screw pullout and disc degeneration. Spine J 2021; 21:528-537. [PMID: 33007470 DOI: 10.1016/j.spinee.2020.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/31/2020] [Accepted: 09/24/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Manual contouring of spinal rods is often required intraoperatively for proper alignment of the rods within the pedicle screw heads. Residual misalignments are frequently reduced by using dedicated reduction devices. The forces exerted by these devices, however, are uncontrolled and may lead to excessive reaction forces. As a consequence, screw pullout might be provoked and surrounding tissue may experience unfavorable biomechanical loads. The corresponding loads and induced tissue deformations are however not well identified. Additionally, whether the forced reduction alters the biomechanical behavior of the lumbar spine during physiological movements postoperatively, remains unexplored. PURPOSE To predict whether the reduction of misaligned posterior instrumentation might result in clinical complications directly after reduction and during a subsequent physiological flexion movement. STUDY DESIGN Finite element analysis. METHODS A patient-specific, total lumbar (L1-S1) spine finite element model was available from previous research. The model consists of poro-elastic intervertebral discs with Pfirrmann grade-dependent material parameters, with linear elastic bone tissue with stiffness values related to the local bone density, and with the seven major ligaments per spinal motion segment described as nonlinear materials. Titanium instrumentation was implemented in this model to simulate a L4, L5, and S1 posterolateral fusion. Next, coronal and sagittal misalignments of 6 mm each were introduced between the rod and the screw head at L4. These misalignments were computationally reduced and a physiological flexion movement of 15° was prescribed. Non-instrumented and well-aligned instrumented models were used as control groups. RESULTS Pulling forces up to 1.0 kN were required to correct the induced misalignments of 6 mm. These forces affected the posture of the total lumbar spine, as motion segments were predicted to rotate up to 3 degrees and rotations propagated proximally to and even affect the L1-2 level. The facet contact pressures in the corrected misaligned models were asymmetrical suggesting non-physiological joint loading in the misaligned models. In addition, the discs and vertebrae experienced abnormally high forces as a result of the correction procedure. These effects were more pronounced after a 15° flexion movement following forced reduction. CONCLUSIONS The results of this study indicate that the correction of misaligned posterior instrumentation can result in high forces at the screws consistent with those reported to cause screw pullout, and may cause high-tissue strains in adjacent and downstream spinal segments. CLINICAL SIGNIFICANCE Proper alignment of spinal posterior instrumentation may reduce clinical complications secondary to unfavorable biomechanics.
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Affiliation(s)
- Arjan C Y Loenen
- Department of Orthopaedic Surgery, Laboratory for Experimental Orthopaedics, CAPHRI, Maastricht University Medical Centre, Maastricht, the Netherlands; Department of Biomedical Engineering, Orthopaedic Biomechanics, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - David C Noriega
- Spine-Unit, University Hospital of Valladolid, Valladolid, Spain
| | - Carlos Ruiz Wills
- Department of Information and Communication Technologies, Barcelona Centre for New Medical Technologies (BCN MedTech), Universitat Pompeu Fabra, Barcelona, Spain
| | - Jérôme Noailly
- Department of Information and Communication Technologies, Barcelona Centre for New Medical Technologies (BCN MedTech), Universitat Pompeu Fabra, Barcelona, Spain
| | | | - Rainer Kirchner
- Department of Orthopaedic Surgery and Trauma Surgery, Clinics Husum and Niebüll, Husum, Germany
| | - Keita Ito
- Department of Biomedical Engineering, Orthopaedic Biomechanics, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Bert van Rietbergen
- Department of Orthopaedic Surgery, Laboratory for Experimental Orthopaedics, CAPHRI, Maastricht University Medical Centre, Maastricht, the Netherlands; Department of Biomedical Engineering, Orthopaedic Biomechanics, Eindhoven University of Technology, Eindhoven, the Netherlands.
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Qian L, Chen W, Li P, Qu D, Liang W, Zheng M, Ouyang J. Comparison of the Pull-Out Strength between a Novel Micro-Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine. Orthop Surg 2020; 12:1285-1292. [PMID: 32776487 PMCID: PMC7454205 DOI: 10.1111/os.12742] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/16/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the strength of a novel micro-dynamic pedicle screw by comparing it to the traditional pedicle screw. METHODS Forty-five lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows (traditional group vs micro-dynamic group): 15 vertebrae underwent instant pull-out testing; 15 vertebrae underwent 5000-cyclic fatigue loading testing; and 15 vertebrae underwent 10,000-cyclic fatigue loading testing and micro-computed tomography (micro-CT) scanning. The peek pull-out force and normalized peek pull-out force after instant pull-out testing, 5000-cyclic and 10,000-cyclic fatigue loading testing were recorded to estimate the resistance of two types of screws. Bone mineral density was recorded to investigate the strength of the different screws in osteoporotic patients. And the semidiameter of the screw insertion area on micro-CT images after fatigue were compared to describe the performance between screw and bone surface. RESULTS The bone mineral density showed a weak correlation with peek pull-out force (r = 0.252, P = 0.024). The peek pull-out force of traditional pedicle screw after 10,000-cyclic fatigue loading were smaller than that of instant pull-out test in both osteoporotic (P = 0.017) and healthy group (P = 0.029), the peek pull-out force of micro-dynamic pedicle screw after 10,000-cyclic fatigue loading was smaller than that in instant pull-out test in osteoporotic group (P = 0.033), but no significant difference in healthy group (P = 0.853). The peek pull-out force in traditional group and micro-dynamic group underwent instant pull-out testing (P = 0.485), and pull-out testing after 5000-cyclic fatigue loading testing (P = 0.184) did not show significant difference. However, the peek pull-out force in micro-dynamic group underwent pull-test after 10,000-cyclic fatigue loading testing was significantly greater than that measured in traditional group (P = 0.005). The normalized peek pull-out force of traditional groups underwent instant pull-out testing, pull-out test after 5000-cyclic and 10,000-cyclic fatigue loading testing significantly decreased as the number of cycles increased (P < 0.001); meanwhile, the normalized peek pull-out force of micro-dynamic groups remained consistent regardless of the number of cycles (P = 0.133). The semidiameter after the fatigue loading test of the traditional screw insertion area was significantly larger than that of the micro-dynamic screw insertion area (P = 0.013). CONCLUSION The novel micro-dynamic pedicle screw provides stronger fixation stability in high-cyclic fatigue loading and non-osteoporotic patients versus the traditional pedicle screw, but similar resistance in low-cycle fatigue testing and osteoporotic group vs the traditional pedicle screw.
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Affiliation(s)
- Lei Qian
- Department of Anatomy, Southern Medical University Guangdong Provincial Key laboratory of Medical Biomechanics, Shenzhen Digital Orthopedic Engineering Laboratory, Guangzhou, China
| | - Weidong Chen
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Peng Li
- Department of Orthopedics, The Third Affiliated Hospital, Southern Medical University, Guangdong Provincial Key Laboratory of Bone and Joint Degeneration Diseases, Guangzhou, China
| | - Dongbin Qu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Wenjie Liang
- Department of Anatomy, Southern Medical University Guangdong Provincial Key laboratory of Medical Biomechanics, Shenzhen Digital Orthopedic Engineering Laboratory, Guangzhou, China
| | - Minghui Zheng
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Ouyang
- Department of Anatomy, Southern Medical University Guangdong Provincial Key laboratory of Medical Biomechanics, Shenzhen Digital Orthopedic Engineering Laboratory, Guangzhou, China
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Akgül T, Korkmaz M, Pehlivanoglu T, Bayram S, Özdemir MA, Karalar Ş. Biomechanical Comparison of Pull-out Strength of Different Cementation and Pedicle Screw Placement Techniques in a Calf Spine Model. Indian J Orthop 2020; 54:134-140. [PMID: 32952921 PMCID: PMC7474045 DOI: 10.1007/s43465-020-00199-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/11/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND We hypothesized that an entire pedicle screw tract cement augmentation has greater strength than traditional techniques. METHOD Twenty-four fresh frozen calf lumbar spines were randomized into three study groups, each having eight vertebrae: (1) screw cemented after vertebroplasty; (2) fenestrated cemented screw; and (3) cementation of the entire pedicle screw tract. For the right side screws, two pedicle screws were inserted in each vertebra with the standard position in the sagittal plane, whereas the left side screws were placed at a 30° angle craniocaudal plane. From the recorded force-displacement curves, the maximum peak load (failure load) of each screw was determined. The mode of failure was screw stripping at all levels tested. RESULTS The pull-out strength for standard screw replacement at the sagittal plane was 1843.3 N, 1707.45 N, and 5365.1 N consecutively. The failure load value in the standard position in the sagittal plane in the cementation of the entire pedicle screw tract group was significantly higher than that in the fenestrated cemented screw group and screw cemented after vertebroplasty (p < 0.001 and p < 0.001, respectively). The standard pedicle screw position in the sagittal plane showed a significant pull-out strength than the others (p < 0.001). CONCLUSION The pull-out strength of the cementation of the entire pedicle screw tract was 2.5 times higher than the others. The pull-out strength of the pedicle screws in malposition obtained the same strength to the standard positions after the augmentation procedure in our study.
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Affiliation(s)
- Turgut Akgül
- Department of Orthopedics and Traumatology, Faculty of Medicine, Istanbul University, Çapa Fatih, Istanbul, 34093 Turkey
| | - Murat Korkmaz
- Department of Orthopedics and Traumatology, Faculty of Medicine, KOÇ University, Istanbul, Turkey
| | - Tuna Pehlivanoglu
- Department of Orthopedics and Traumatology, Emsey Hospital, Istanbul, Turkey
| | - Serkan Bayram
- Department of Orthopedics and Traumatology, Faculty of Medicine, Istanbul University, Çapa Fatih, Istanbul, 34093 Turkey
| | - Mustafa Abdullah Özdemir
- Department of Orthopedics and Traumatology, Faculty of Medicine, Istanbul University, Çapa Fatih, Istanbul, 34093 Turkey
| | - Şahin Karalar
- Department of Orthopedics and Traumatology, Faculty of Medicine, Istanbul University, Çapa Fatih, Istanbul, 34093 Turkey
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Starlinger J, Lorenz G, Fochtmann-Frana A, Sarahrudi K. Bisegmental posterior stabilisation of thoracolumbar fractures with polyaxial pedicle screws: Does additional balloon kyphoplasty retain vertebral height? PLoS One 2020; 15:e0233240. [PMID: 32421734 PMCID: PMC7233542 DOI: 10.1371/journal.pone.0233240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 04/30/2020] [Indexed: 11/18/2022] Open
Abstract
We retrospectively evaluated single-level compression fractures (T12-L3) scheduled for a short-segment POS (posterior-only stabilization) using polyaxial screws. Patients averaged 55.7 years (range, 19–65). Patients received either POS or, concomitantly, BK (balloon kyphoplasty) of the fractured vertebrae as well. Primary endpoint was the radiological outcome at the last radiographic follow-up prior to implant removal. POS together with BK of the fractured vertebrae resulted in a significant improvement of the local kyphosis angle and vertebral body compression rates immediately post-OP. During the further course of FU, a considerable loss of correction was observed post-OP in both groups. (Local KA: pre-OP/ post-OP/ FU: 12.6±4.8/ 3.35±4.8/ 11.6±6.0; anterior vertebral body compression%: pre-OP/post-OP/ FU: 71.94±12.3/ 94.78±19.95/ 78.17±14.74). VAS was significantly improved from 7.2±1.3 pre-OP to 2.7±1.3 (P<0.001) at FU. We found a significant restoration of the vertebral body height by BK. Nevertheless, follow-up revealed a noticeable loss of reduction. Given the fact that BK used together with polyaxial screws did not maintain intra-operative reduction, our data do not support this additional maneuver when used together with bi-segmental polyaxial pedicle screw fixation.
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Affiliation(s)
- Julia Starlinger
- Department for Orthopedics, Mayo Clinic, Rochester, MN, United States of America
- Department for Orthopedics and Trauma Surgery, Medical University Vienna, Vienna, Austria
- * E-mail:
| | | | | | - Kambiz Sarahrudi
- Department for Trauma Surgery, Landesklinikum Wiener Neustadt, Wiener Neustadt, Austria
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