Department of Orthopaedics, Medical University of Gdansk, Gdansk, Poland.
LfC/IBeMT-LfC Medical/IBeMT Institute of Bioengineering and Medical Technologies, Zielona Gora, Poland.
PLoS One. 2019 Aug 26;14(8):e0221494. doi: 10.1371/journal.pone.0221494. eCollection 2019.
It remains unclear what is the real safe limit of torque magnitude during Bilateral Apical Vertebral Derotation (BAVD) in thoracic curve correction. Up to author's knowledge there is no study except this one, to reproduce in-vivo real measurements and intraoperative conditions during BAVD maneuver. The objective of this study was to evaluate the torsional strength of the instrumented thoracic spine under axial rotation moment as well as to define safety limits under BAVD corrective maneuver in scoliosis surgery. 10 fresh, full-length, young and intact human cadavers were tested. After proper assembly of the apparatus, the torque was applied through its apical part, simulating thoracic curve derotation. During each experiment the torque magnitude and angular range of derotation were evaluated. For more accurate analysis after every experiment the examined section of the spine was resected from the cadaver and evaluated morphologically and with a CT scan. The average torque to failure during BAVD simulation was 73,3 ± 5,49Nm. The average angle of BAVD to failure was 44,5 ± 8,16°. The majority of failures were in apical area. There was no significant difference between the fracture occurrence of left or right side of lateral wall of the pedicle. There was no spinal canal breach and/or medial wall failure in any specimen. The safety limits of thoracic spine and efficacy of BAVD for axial plane correction in the treatment of Adolescent Idiopathic Scoliosis (AIS) were established. It provided qualitative and quantitative information essential for the spinal derotation under safe loading limits.
目前尚不清楚在胸椎曲线矫正中双侧顶点椎体旋转（BAVD）过程中扭矩大小的真正安全限制是多少。据作者所知，除了这项研究之外，没有其他研究能够复制 BAVD 操作过程中的体内真实测量和术中条件。本研究的目的是评估在轴向旋转力矩下仪器化胸椎的扭转强度，并确定在脊柱侧凸手术中 BAVD 矫正操作下的安全限制。10 个新鲜、全长、年轻和完整的人体尸体进行了测试。在适当组装仪器后，通过其顶点部分施加扭矩，模拟胸椎旋转。在每次实验中，都评估了扭矩大小和旋转角度范围。为了更准确地分析，在每次实验后，将从尸体上切除检查的脊柱节段，并进行形态学和 CT 扫描评估。在 BAVD 模拟过程中，平均失效扭矩为 73.3 ± 5.49Nm。平均失效 BAVD 角度为 44.5 ± 8.16°。大多数失效发生在顶点区域。左右侧椎弓根侧壁的骨折发生无显著差异。在任何标本中均未发生椎管破裂和/或内侧壁失效。确定了胸椎的安全限制和 BAVD 在治疗青少年特发性脊柱侧凸（AIS）中的轴向平面矫正的疗效。它提供了在安全负荷限制下脊柱旋转所需的定性和定量信息。
