Open AccessComparison of Biomechanical Properties of Single‐ and Two‐segment Fusion for Denis Type B Spinal Fractures
Author(s) -
Su Yunshan,
Ren Dong,
Wang Pengcheng
Publication year - 2013
Publication title -
orthopaedic surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 23
eISSN - 1757-7861
pISSN - 1757-7853
DOI - 10.1111/os.12068
Subject(s) - medicine , spinal fusion , displacement (psychology) , fusion , intervertebral disc , biomechanics , orthodontics , surgery , anatomy , psychology , linguistics , philosophy , psychotherapist
Objective To compare the biomechanical properties of single‐ and two‐segment fusion for D enis type B spinal fracture. Methods Two female patients with D enis type B L 1 vertebral fractures were studied. Both patients had achieved intervertebral fusion by 1 year postoperatively, at which time CT data were collected, including data of one patient before and after removal of pedicle screws and of another whose pedicle screws were not removed. The data were imported into M imics software and T 11 ‐ L 2 three dimensional models established. After construction of the models, they were imported into ANSYS software. An axial load (260 N ) and 10 Nm torque were loaded to simulate the flexion, extension, lateral bending and rotation of the spine, respectively.Results There was no significant difference in the average displacement of the spine motion between the two‐segment and single‐segment fusion patients without removal of pedicle screws. However, for all motion forms, the average displacement of the single‐segment fusion patient' spine after removal of pedicle screws was significantly greater than that before removal of pedicle screws and that of the two‐segment fusion patient. The average V on M ises stress of T 11–12 intervertebral disc of two‐segment fusion patient was significantly greater than that of the one‐segment fusion patient. Moreover, the average V on M ises stress of T 11–12 intervertebral disc of single‐segment fusion patient was greater before than after removal of pedicle screws. Conclusion Provided there is satisfactory interbody fusion, removal of pedicle screws after one‐segment fusion can increase spinal motion, reduce the stress on adjacent intervertebral discs and delay disc degeneration.