In vitro biomechanical study of pedicle screw pull-out strength based on different screw path preparation techniques
| Autor: | Brandon Bucklen, Kanaan Salloum, Jwalant S Mehta, Saif Khalil, Mark Moldavsky |
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| Rok vydání: | 2016 |
| Předmět: |
mesh:Bone screws
musculoskeletal diseases Insertion torque medicine.medical_specialty Strengths based pull-out strength tapping technique spinal fractures biomechanics Calf vertebral bodies 03 medical and health sciences 0302 clinical medicine lcsh:Orthopedic surgery Fracture fixation Medicine Orthopedics and Sports Medicine mesh:pedicle Pedicle screw mesh:spinal fractures Fixation (histology) 030222 orthopedics business.industry stress relaxation Significant difference Biomechanics pedicle Surgery tapping technique MeSH terms: Bone screws mesh:fracture fixation lcsh:RD701-811 fracture fixation Original Article business insertion torque Maximum torque mesh:biomechanics 030217 neurology & neurosurgery Biomedical engineering |
| Zdroj: | Indian Journal of Orthopaedics Indian Journal of Orthopaedics, Vol 50, Iss 2, Pp 177-182 (2016) |
| ISSN: | 1998-3727 0019-5413 |
| DOI: | 10.4103/0019-5413.177572 |
| Popis: | Background: Poor screw-to-bone fixation is a clinical problem that can lead to screw loosening. Under-tapping (UT) the pedicle screw has been evaluated biomechanically in the past. The objective of the study was to determine if pedicle preparation with a sequential tapping technique will alter the screw-to-bone fixation strength using a stress relaxation testing loading protocol. Materials and Methods: Three thoracolumbar calf spines were instrumented with pedicle screws that were either probed, UT, standard-tapped (ST), or sequential tapped to prepare the pedicle screw track and a stress relaxation protocol was used to determine pull-out strength. The maximum torque required for pedicle screw insertion and pull-out strength was reported. A one-way ANOVA and Tukeys post-hoc test were used to determine statistical significance. Results: The pedicle screw insertion torques for the probed, UT, ST and sequentially tapped (SQT) techniques were 5.09 (±1.08) Nm, 5.39 (±1.61) Nm, 2.93 (±0.43) Nm, and 3.54 (±0.67) Nm, respectively. There is a significant difference between probed compared to ST (P ≤ 0.05), as well as UT compared to both ST and SQT (P ≤ 0.05). The pull-out strength for pedicle screws for the probed, UT, ST and SQT techniques was 2443 (±782) N, 2353(±918) N, 2474 (±521) N, and 2146 (±582) N, respectively, with no significant difference (P ≥ 0.05) between techniques. Conclusions: The ST technique resulted in the highest pull-out strength while the SQT technique resulted in the lowest. However, there was no significant difference in the pull-out strength for the various preparation techniques and there was no correlation between insertion torque and pull-out strength. This suggests that other factors such as bone density may have a greater influence on pull-out strength. |
| Databáze: | OpenAIRE |
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