术中P40-N50峰波幅变化对腰椎管狭窄症后路减压术预后判断的初步研究

Validation of P40-N50 peak amplitude variations as a predicting factor for clinical outcomes of posterior decompression for lumbar stenosis

目的探讨术中P40-N50峰波幅变化与腰椎管狭窄症后路减压内固定术后疗效之间的关系。方法选取41例于本院明确诊断为腰椎管狭窄症的患者为研究对象,于腰椎后路减压内固定术前、术后即刻与术后3个月分别进行体感诱发电位检查。术前与术后3个月进行JOA评分并计算JOA评分改善率,比较手术前后P40-N50峰波幅变化情况,研究其与术后3个月患者JOA改善率之间的关系。结果41例患者患侧P40-N50峰波幅术前与术后即刻比较差异具有显著性[术前:(1.06±0.47)UV,术后即刻:(1.99±0.58)UV;t=-20.17,P<0.01],健侧P40-N50峰波幅无明显变化;术后即刻两侧P40-N50峰波幅比较差异具有显著性[患侧:(1.99±0.58)UV,健侧:(2.14±0.51)UV;t=-2.50,P<0.05]。术后即刻两侧P40-N50峰波幅升高值比较差异具有显著性[患侧:(0.93±0.29)UV,健侧:(0.05±0.36)UV;t=13.20,P<0.01]。术前与术后3个月JOA评分比较差异具有显著性[术前:(11.00±4.24)分,术后3个月:(22.02±2.79)分;t=-17.01,P<0.01]。术后3个月,JOA评分改善率为(74.23±18.68)%。P40-N50峰波幅术后即刻提高值与JOA改善率相关性比较:患侧具有相关性(R2=0.681),健侧无明显相关性。患侧与健侧P40-N50峰波幅术后即刻与术后3个月比较差异均无显著性。结论腰椎管狭窄症患者减压手术前后P40-N50峰波幅增加可以作为症状改善的预判指标。

Objective To investigate the relationship between the changes of the intraoperative P40-N50 peak amplitude and the effect of posterior lumbar decompression and internal fixation on lumbar stenosis. Method For 41 diagnosed lumbar spinal stenosis patients, somatosensory evoked potential（SEP） tests were performed before and after and 3 months after the surgery of lumbar posterior decompression and internal fixation. JOA score was evaluated before and 3 months after operation to calculate the improvement rate of JOA score. The changes of P40-N50 peak amplitude were compared before and after decompression to investigate the relationship between the partial index and the improvement rate of JOA score in patients 3 months after operation. Result There were significant differences in P40-N50 peak amplitude before and immediately after operation in the affected side of 41 patients [before decompression（1.06±0.47） UV, immediately after operation（1.99±0.58） UV; t =-20.17, P 0.01] and no obvious variations in the unaffected side（P 0.05）. The P40-N50 peak amplitudes had statistical variations right after operation between the two sides [affected side（1.99±0.58） UV, unaffected side（2.14±0.51） UV; t =-2.50, P 0.05]. There were statistical variations in the amplitude differences between the two groups immediately after operation [affected side 0.93±0.29） UV, unaffected side（0.05±0.36） UV; t = 13.20, P 0.01]. There were statistical variations of JOA score before and 3 months after operation [before operation（11.00±4.24） points, 3 months after operation（22.02±2.79） points; t =-17.01, P 0.01）. 3 months after operation, the improvement rate of JOA score was（74.23±18.68）%. There were significant correlations between the increase value of P40-N50 peak amplitude right after operation and the improvement rate of JOA score 3 months after operation in the affected side（R2= 0.681）. While no significant correlations in the unaffected side. No statistical variations were observed immediately and 3 months after operation in both sides. Conclusion The increase of P40-N50 peak amplitude before and after operation can be used as a pre-judgment index to predict symptom improvement of lumbar spinal stenosis patients.