选择性腰骶神经后根切断术中肌电监测的应用研究

目的 研究在痉挛型脑瘫患者选择性脊神经后根切断术(SPR)中的肌电监测技术与标准.方法 在89例痉挛型脑瘫患者SPR中,采用50 Hz方波电脉冲,分别刺激L3-S1神经后根小束,分别于双侧三角肌、长收肌、股直肌、股二头肌、胫骨前肌和腓肠肌内、外侧头记录自由肌电反应及触发肌电反应,同时观察下肢肌肉痉挛性收缩活动.对肌电反应向对侧、乃至远隔神经支配节段明显扩散的3+级和4+级神经后根小束,及引起下肢或足趾肌肉收缩活动的相对低阈值的神经后根小束进行选择性切断.术后观察下肢肌张力的改善程度,并对下肢感觉、运动及排便功能进行评估.结果 触发肌电反应的出现明显滞后于自由肌电反应,观察自由肌电反应更能及时的判断"异常的"神经小束.89例患儿的372根神经后根被选择性切断,其中324根(83.5%)腰神经后根的出现3+～4+级肌电反应的神经小束被选择性切断;48根(12.9%)神经后根的神经小束根据"相对低阈值"被选择性切断.所有患儿术后下肢肌张力明显降低,未出现明显的下肢感觉、运动及排便功能障碍.结论 SPR中,肌电监测所出现的向对侧和(或)远隔节段扩散的持续的肌肉动作电位反应,是判定"异常"神经后根小束并进行选择性切断的有效并可重复的客观标准.

Application of intraoperative electrophysiological monitoring in lumbosacral selective posterior rhizotomy for spastic cerebral palsy

Objective To evaluate the clinical application of intraoperative electrophysiological monitoring in lumbosacral selective posterior rhizotomy for spastic cerebral palsy. Methods Total 372 dorsal roots of 89 patients underwent selective posterior rhizotomy at a single medical center. The dorsal roots from L3 to S1 were divided into rootlets and stimulated with a 1-second 50 Hz train. Motor responses were recorded by electomyography. Rootlets were assigned according to the extent of abnormal electrophysiological propagation, and grades of 3 + to 4 + were cut. If no electrical response was observed, the second criterion is the behavioral response (that is, muscle contraction in the legs or toes) assessed by the physical therapist, when rootlets were stimulated at the lowest threshold with a 1-second 50 Hz train. Results The rootlets of 340 dorsal roots were assigned according to the extent of abnormal electrophysiological propagation ,324 (83. 5% ) roots were assigned the maximally abnormal response of grade 3 + (76, 22. 4% ) or 4 + (248, 72. 9% ) in EMG monitoring and were cut. For no electrical response was observed, according to the second criterion, 48 roots were partially cut. It was also be found that free running EMG occurred earlier than stimulus triggered EMG, and identified "abnormal" rootlets on free running EMG monitoring was more easily and quickly than on stimulus triggered EMG. During the postoperative 2 weeks in hospital , there was a significant decrease in lower-limb spasticity and an increase in range of movement in all patients, and no one case occurred obvious loss of muscle strength, abnormity of sensory,or deterioration of bladder/bowel control. Conclusions The spread of electromyography response to the contra lateral limb and/or upper extremity remains a valid criterion to define a "abnormal" posterior nerve rootlet that feeds into a disinhibited spinal circuit involved in uncontrolled spasticity. Intraoperative electrophysiological monitoring is reproducible and reliable for selection of "abnormal" rootlets.