皮节体感诱发电位在术中评价腰骶神经根减压效果的价值

The value of dermatomal somatosensory evoked potentials on the evaluation of lumbosacral nerve root decompression during operation

中文关键词:  皮节体感诱发电位  腰骶神经根  减压  手术  评价

英文关键词:Dermatomal somatosensory evoked potentials  Lumbosacral nerve root  Decompression  Operation  Evaluate

中文摘要:

  【摘要】 目的：探讨皮节体感诱发电位（dermatomal somatosensory evoked potentials，DSEP）术中评价腰骶神经根减压效果的适用指标及其临床价值。方法：2011年5月～2011年12月对46例以感觉障碍为主诉，经查体、腰椎MRI及术前DSEP检查证实存在单侧腰骶神经根（L5或S1神经根）受压而接受神经根减压手术的患者进行术中DSEP监测，男34例，女12例；年龄20～63岁，平均41.2岁。其中L5神经根受累36例，S1神经根受累10例，MRI显示为旁侧型椎间盘突出或神经根管狭窄。记录并比较麻醉后至减压前及减压后受累神经根的P40潜伏期和波幅，术中结合自发肌电（EMG）监测相应节段神经支配肌肉，作为可能出现即时神经根医源性损伤的预警。术前、术后采用VAS评分和ODI评估患者的临床疗效，比较术前、术后的VAS及ODI评分。结果：术中自发EMG均未提示神经根医源性损伤。减压后32例患者潜伏期延长<0.1，14例潜伏期缩短，其中8例改善率≥0.1。根据潜伏期改善率分为三组：无改善组（改善率≤0）、改善组（0<改善率<0.1）以及明显改善组（改善率≥0.1），无改善组的VAS改善率显著低于其他两组（P<0.05），明显改善组与改善组的VAS改善率无显著性差异（P>0.05），术后6个月随访时三组之间的ODI改善率无显著性差异（P>0.05）。减压后所有患者P40波幅均无降低，其中明显改善（改善率≥0.5）37例，改善（0.3≤改善率<0.5）4例，无明显改善（改善率<0.3）5例，明显改善组术后VAS改善率显著性大于其他两组（P<0.05）；术后6个月随访时明显改善组和改善组的ODI改善率均显著性大于无明显改善组（P<0.05），而前两组之间的ODI改善率无显著性差异（P>0.05）。P40波幅改善率与VAS改善率和病程之间存在相关关系（P<0.05）。结论：对于病史较短且有典型相应皮区感觉症状的单侧腰骶神经根压迫患者，减压术中受累神经根DSEP P40波幅改善率可预示患者术后临床症状的改善情况，可作为评估减压效果的指标。

英文摘要:

  【Abstract】 Objectives: To explore the available index and the value of dermatomal somatosensory evoked potentials(DSEP) on the operation of lumbosacral nerve root decompression. Methods: Forty-six cases complained of sensory numbness and diagnosed as unilateral lumbosacral nerve root(L5 or S1) by clinical, magnetic resonance imaging(MRI) and DSEP examination were monitored by DSEP during operation under general anaesthesia form May 2011 to December 2011. There were 34 males and 12 females with a mean age of 41.2 years(range, 20-63 years). 36 cases had L5 nerve root involved, and 10 cases had S1 nerve root . MRI showed intervertebral disc herniation or nerve root canal narrow in all cases. The P40 latency and amplitude of involving nerve root were recorded and compared at pre- and post-decompression after anaesthesia. The free EMG of corresponding segment was monitored as the precaution of nerve root injury during operation(anterior tibial muscle for L5, and gastrocnemius for S1). VAS and ODI scores were used to evaluate the patients′ clinic symptom and neulogical function before and after operation, then the scores were compared. Results: The free EMG showed no iatrogenic injure of nerve root. After decompression, P40 lantency showed extension <0.1 in 32 cases, shortening in 14 cases and shortening >0.1 in 8 cases. The improvement rates of P40 lantency were noted delay in 3 groups: unimproved group(improvement rate ≤0), improved group(00.05). The improvement rate of ODI showed no significant difference among the groups(P>0.05). All the P40 amplitudes of the patients had no loss after decompression. The improvement rate of P40 amplitude was delayed in unimproved group(improvement rate <0.3), improved group(0.3≤improvement rate <0.5) and significant improved group(improvement rate ≥0.5). The improvement rate of VAS in significant improved group was significantly higher than the other groups(P<0.05); and at the follow-up of 6 months, the improvement rate of ODI in the unimproved group was not significant than other groups(P<0.05); and there was no difference between groups with respect to ODI(P>0.05). There were relationships between the improvement rates of P40 amplitude and VAS, as well as course(P<0.05). Conclusions: For cases with short-term typical sensory numbness and diagnosed as unilateral lumbosacral nerve root deficit, the improvement rate of P40 amplitude can be used as index for evaluating the effect of decompression.