Soni Pranay, Loss Jeremy G, Gillespie Callan M, Colbrunn Robb W, Schlenk Richard, Steinmetz Michael P, Recinos Pablo F, Benzel Edward C, Kshettry Varun R
1Department of Neurological Surgery, Neurological Institute, Cleveland Clinic.
2Rose Ella Burkhardt Brain Tumor & Neuro-Oncology Center, Cleveland Clinic; and.
J Neurosurg Spine. 2021 Oct 1;36(2):269-275. doi: 10.3171/2021.4.SPINE21226. Print 2022 Feb 1.
The direct lateral approach is an alternative to the transoral or endonasal approaches to ventral epidural lesions at the lower craniocervical junction. In this study, the authors performed, to their knowledge, the first in vitro biomechanical evaluation of the craniovertebral junction after sequential unilateral C1 lateral mass resection. The authors hypothesized that partial resection of the lateral mass would not result in a significant increase in range of motion (ROM) and may not require internal stabilization.
The authors performed multidirectional in vitro ROM testing using a robotic spine testing system on 8 fresh cadaveric specimens. We evaluated ROM in 3 primary movements (axial rotation [AR], flexion/extension [FE], and lateral bending [LB]) and 4 coupled movements (AR+E, AR+F, LB + left AR, and LB + right AR). Testing was performed in the intact state, after C1 hemilaminectomy, and after sequential 25%, 50%, 75%, and 100% C1 lateral mass resection.
There were no significant increases in occipital bone (Oc)-C1, C1-2, or Oc-C2 ROM after C1 hemilaminectomy and 25% lateral mass resection. After 50% resection, Oc-C1 AR ROM increased by 54.4% (p = 0.002), Oc LB ROM increased by 47.8% (p = 0.010), and Oc-C1 AR+E ROM increased by 65.8% (p < 0.001). Oc-C2 FE ROM increased by 7.2% (p = 0.016) after 50% resection; 75% and 100% lateral mass resection resulted in further increases in ROM.
In this cadaveric biomechanical study, the authors found that unilateral C1 hemilaminectomy and 25% resection of the C1 lateral mass did not result in significant biomechanical instability at the occipitocervical junction, and 50% resection led to significant increases in Oc-C2 ROM. This is the first biomechanical study of lateral mass resection, and future studies can serve to validate these findings.
对于下颅颈交界区腹侧硬膜外病变，直接外侧入路是经口或经鼻入路的一种替代方法。在本研究中，据作者所知，他们首次对连续单侧C1侧块切除术后的颅颈交界区进行了体外生物力学评估。作者假设侧块部分切除不会导致活动范围（ROM）显著增加，可能不需要内固定。
作者使用机器人脊柱测试系统对8个新鲜尸体标本进行了多方向体外ROM测试。我们评估了3种主要运动（轴向旋转[AR]、屈伸[FE]和侧弯[LB]）以及4种耦合运动（AR+E、AR+F、LB+左AR和LB+右AR）中的ROM。测试在完整状态下、C1半椎板切除术后以及连续进行25%、50%、75%和100%C1侧块切除后进行。
C1半椎板切除术和25%侧块切除术后，枕骨（Oc）-C1、C1-2或Oc-C2的ROM没有显著增加。50%切除术后，Oc-C1的AR ROM增加了54.4%（p = 0.002），Oc的LB ROM增加了47.8%（p = 0.010），Oc-C1的AR+E ROM增加了65.8%（p < 0.001）。50%切除术后，Oc-C2的FE ROM增加了7.2%（p = 0.016）；75%和100%侧块切除导致ROM进一步增加。
在这项尸体生物力学研究中，作者发现单侧C1半椎板切除术和25%C1侧块切除不会导致枕颈交界区出现显著的生物力学不稳定，50%切除会导致Oc-C2的ROM显著增加。这是第一项关于侧块切除的生物力学研究，未来的研究可以用来验证这些发现。
