Department of Neurological Surgery, Cleveland Clinic.
Spine Research Lab, Lutheran Hospital, Cleveland Clinic Center for Spine Health; and.
J Neurosurg. 2017 Oct;127(4):829-836. doi: 10.3171/2016.7.JNS16293. Epub 2016 Oct 14.
OBJECTIVE The far lateral transcondylar approach to the ventral foramen magnum requires partial resection of the occipital condyle. Early biomechanical studies suggest that occipitocervical (OC) fusion should be considered if 50% of the condyle is resected. In clinical practice, however, a joint-sparing condylectomy has often been employed without the need for OC fusion. The biomechanics of the joint-sparing technique have not been reported. Authors of the present study hypothesized that the clinically relevant joint-sparing condylectomy would result in added stability of the craniovertebral junction as compared with earlier reports. METHODS Multidirectional in vitro flexibility tests were performed using a robotic spine-testing system on 7 fresh cadaveric spines to assess the effect of sequential unilateral joint-sparing condylectomy (25%, 50%, 75%, 100%) in comparison with the intact state by using cardinal direction and coupled moments combined with a simulated head weight "follower load." RESULTS The percent change in range of motion following sequential condylectomy as compared with the intact state was 5.2%, 8.1%, 12.0%, and 27.5% in flexion-extension (FE); 8.4%, 14.7%, 39.1%, and 80.2% in lateral bending (LB); and 24.4%, 31.5%, 49.9%, and 141.1% in axial rotation (AR). Only values at 100% condylectomy were statistically significant (p < 0.05). With coupled motions, however, -3.9%, 6.6%, 35.8%, and 142.4% increases in AR+F and 27.3%, 32.7%, 77.5%, and 175.5% increases in AR+E were found. Values for 75% and 100% condyle resection were statistically significant in AR+E. CONCLUSIONS When tested in the traditional cardinal directions, a 50% joint-sparing condylectomy did not significantly increase motion. However, removing 75% of the condyle may necessitate fusion, as a statistically significant increase in motion was found when E was coupled with AR. Clinical correlation is ultimately needed to determine the need for OC fusion.
经远外侧寰枢后外侧入路到达腹侧颅颈交界区需要部分切除枕髁。早期生物力学研究表明，如果切除 50%的髁突，应考虑行枕颈（OC）融合。然而，在临床实践中，常采用关节保存性髁突切除术，而无需行 OC 融合。关节保存性技术的生物力学尚未报道。本研究作者假设，与之前的报道相比，临床上相关的关节保存性髁突切除术将增加颅颈交界区的稳定性。方法：使用机器人脊柱测试系统对 7 具新鲜尸体脊柱进行多方向体外灵活性测试，通过使用基本方向和耦合矩以及模拟头部重量“跟随负载”，评估连续单侧关节保存性髁突切除术（25%、50%、75%、100%）与完整状态相比对颅颈交界区稳定性的影响。结果：与完整状态相比，连续髁突切除术后运动范围的百分比变化为屈伸（FE）5.2%、8.1%、12.0%和 27.5%；侧屈（LB）8.4%、14.7%、39.1%和 80.2%；轴向旋转（AR）24.4%、31.5%、49.9%和 141.1%。只有在 100%髁突切除时才有统计学意义（p<0.05）。然而，在耦合运动中，AR+F 增加了 3.9%、6.6%、35.8%和 142.4%，AR+E 增加了 27.3%、32.7%、77.5%和 175.5%。在 AR+E 中，75%和 100%髁突切除值有统计学意义。结论：在传统的基本方向上进行测试时，50%的关节保存性髁突切除术并未显著增加运动。然而，当 E 与 AR 耦合时，切除 75%的髁突可能需要融合，因为运动明显增加。最终需要临床相关性来确定是否需要 OC 融合。
