脊柱侧凸矫形术中脊髓监护基准的选择

Determination of baseline for intraoperative spinal cord monitoring during scoliosis surgery

目的 对脊柱侧凸矫形手术中体感诱发电位（ SEP)的监护基准进行选择，以降低监护过程中脊髓损伤预报之假阳性率，从而提高脊柱外科手术中对脊髓监护的可靠性。方法 回顾分析 160例特发性脊柱侧凸患者在不同手术阶段中的 SEP潜伏期和波幅值及其百分比变化率，比较脊柱暴露前后 SEP波变化对术中脊髓损伤预报的准确性与可靠性，由此而选择脊髓监护基准。结果 各监护阶段 SEP潜伏期的变化差异无显著性意义 (P >0.05)；第二阶段的 SEP波幅值与第一阶段相比明显降低，差异有显著性意义 (P0.05)。观察结果显示，在术中，当以脊柱暴露前 (第一阶段 )的 SEP值作为监护基准时， 160例中有 5例假阳性 (3.2％ )预报，而改以脊柱暴露后 (第二阶段 )的 SEP值作为监护基准时则无一例假阳性结果。结论 SEP波幅值在不同手术阶段具有正常变异性，以脊柱暴露后的 SEP值作为监护基准稳定性较好，可以提高对脊髓监护的可靠性。

Objective To determine the baseline for intraoperative somatosensory evoked potential (SEP)monitoring to diminish the false-positive rates and improve the reliability of monitoring.Methods One hundred and sixty patients of idiopathic scoliosis undergoing intraoperative spinal cord monitoring were collected to this retrospective study. The amplitudes, latencies and their percentage variabilities of SEP were observed in different stages of surgery. The monitoring outcomes were assessed between the pre-incision baseline and spine-exposure baseline. Results The change of SEP latencies had no statistic significant difference (P >0.05) during spinal cord monitoring. The values of SEP amplitudes at the 2nd stage was higher in comparison with that of the 1st stage(P0.05). There were 5 patients false-positive(3.2％ ) when the values of SEP at pre-incision was used as baseline, while no false-positive case was found in spine exposure baseline. Conclusion Some variability of latencies and amplitudes during different stages of scoliosis surgery is normal. The study results suggest that to determine the SEP after spine exposure as the reference baseline is more reliable for intraoperative spinal cord monitoring.