Woodall Michael Neil, Shakir Basheer, Smitherman Adam, Choudhri Haroon
Department of Neurological Surgery, Georgia Regents University, Augusta, GA.
Int J Spine Surg. 2013 Dec 1;7:e39-41. doi: 10.1016/j.ijsp.2013.02.002. eCollection 2013.
The lateral transpsoas interbody fusion (LTIF) is an increasingly popular minimally invasive technique for lumbar interbody fusion. Although a posterior approach to the lumbar spine has traditionally been favored for the treatment of canal stenosis and neural foraminal stenosis, a growing body of evidence suggests that indirect decompression of the spinal canal and neural foramen can be achieved using a lateral transpsoas approach to the lumbar spine. We present 2 cases that may suggest a role for spontaneous electromyography (s-EMG) monitoring in assessing the adequacy of decompression during LTIF.
The 2 cases presented in this technical note illustrate resolution of s-EMG firing during LTIF, following distraction across the disk space. Removal of the distracting device produced the return of s-EMG firing. Both of these cases were operated at the L2-3 level.
In the first case, s-EMG firing was noted in the bilateral tibialis anterior leads. Resolution of EMG firing may suggest indirect decompression of the canal via ligamentotaxis as the L5 root traverses the L2-3 disk space. In the second case, s-EMG firing was noted in the left abductor hallucis and resolved with distraction of the L2-3 disk space. Again, this may be explained by canal decompression via ligamentotaxis as the S1 root traverses the L2-3 disk space.
In both cases, distraction across the disk space resulted in resolution of s-EMG discharges-this correlated with an improvement in symptoms. These findings may suggest a role for s-EMG as a marker for adequacy of decompression in a select subset of patients undergoing LTIF. Further study is needed to determine if resolution of s-EMG is a useful measure of indirect decompression during LTIF.
腰大肌外侧椎间融合术（LTIF）是一种越来越受欢迎的用于腰椎椎间融合的微创技术。尽管传统上治疗椎管狭窄和神经孔狭窄时更倾向于采用腰椎后路，但越来越多的证据表明，通过腰椎腰大肌外侧入路可实现椎管和神经孔的间接减压。我们报告2例病例，提示自发肌电图（s-EMG）监测在评估LTIF减压充分性方面可能具有作用。
本技术说明中介绍的2例病例显示，在LTIF过程中，椎间盘间隙撑开后s-EMG放电消失。移除撑开装置后s-EMG放电恢复。这2例均在L2-3节段进行手术。
在第一例中，双侧胫前肌导联记录到s-EMG放电。肌电图放电消失可能提示当L5神经根穿过L2-3椎间盘间隙时通过韧带整复实现了椎管的间接减压。在第二例中，左侧拇展肌记录到s-EMG放电，L2-3椎间盘间隙撑开后放电消失。同样，这可能是由于当S1神经根穿过L2-3椎间盘间隙时通过韧带整复实现了椎管减压。
在这2例病例中，椎间盘间隙撑开均导致s-EMG放电消失，这与症状改善相关。这些发现可能提示s-EMG在部分接受LTIF的患者中作为减压充分性的标志物具有作用。需要进一步研究以确定s-EMG消失是否是LTIF期间间接减压的有用指标。
