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

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 cadave...

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Main Authors: Ozcan Kaya, Okan Ozkunt, Mustafa Sungur, Mehmet Semih Cakir, Murat Baydogan, Kerim Sariyilmaz
Format: Article
Language:English
Published: AVES 2024-01-01
Series:Acta Orthopaedica et Traumatologica Turcica
Online Access:https://www.aott.org.tr/en/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-137377
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author Ozcan Kaya
Okan Ozkunt
Mustafa Sungur
Mehmet Semih Cakir
Murat Baydogan
Kerim Sariyilmaz
author_facet Ozcan Kaya
Okan Ozkunt
Mustafa Sungur
Mehmet Semih Cakir
Murat Baydogan
Kerim Sariyilmaz
author_sort Ozcan Kaya
collection DOAJ
description 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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series Acta Orthopaedica et Traumatologica Turcica
spelling doaj-art-ff2c87da154847b282f7b687c5523c7f2024-11-20T08:50:59ZengAVESActa Orthopaedica et Traumatologica Turcica1017-995X2024-01-01581576110.5152/j.aott.2024.22067Intraoperative 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 cadaversOzcan Kaya0Okan Ozkunt1Mustafa Sungur2Mehmet Semih Cakir3Murat Baydogan4Kerim Sariyilmaz5Department of Orthopedics and Traumatology, Istanbul Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, TurkeyDepartment of Orthopedics and Traumatology, Medicana Istanbul Bahçelievler Hospital, Istanbul, TurkeyDepartment of Orthopedics and Traumatology, Acıbadem MAA University, School of Medicine, Istanbul, TurkeyDepartment of Interventional Radiology, Istanbul University, Istanbul Faculty of Medicine, Istanbul, TurkeyIstanbul Technical University, Istanbul, TurkeyDepartment of Orthopedics and Traumatology, Acıbadem MAA University, School of Medicine, Istanbul, TurkeyObjective: 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.https://www.aott.org.tr/en/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-137377
spellingShingle Ozcan Kaya
Okan Ozkunt
Mustafa Sungur
Mehmet Semih Cakir
Murat Baydogan
Kerim Sariyilmaz
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
title 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
title_full 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
title_fullStr 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
title_full_unstemmed 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
title_short 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
title_sort 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
url https://www.aott.org.tr/en/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-137377
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