척추수술 환자의 수술 중 신경생리감시에서 운동유발전위 기본파형의 성공적인 생성에 대한 예측인자 연구

Abstract

Background: Muscle motor evoked potentials (mMEPs), a part of intraoperative neurophysiological monitoring, have high clinical implications for predicting postoperative neurologic deficits, and the successful generation of a baseline mMEP waveform is essential for appropriate monitoring during surgery. The purpose of this study was to search for clinical factors predicting the successful generation of baseline mMEPs in patients undergoing spine surgery and to determine the relationship with postoperative functional outcome. Method: From July 2014 to June 2015, a total of 345 patients underwent spine surgery with intraoperative mMEP monitoring and were consecutively included in this study. Their demographic features, clinical parameters and mMEP recording results were reviewed retrospectively. Results: Two hundred and fifty-three (73%) patients showed successful generation of baseline mMEPs at all recording muscles, and 92 (27%) patients failed to record baseline mMEPs at one or more limb muscles. When we compared the preoperative clinical parameters of the two groups, the latter group (Failure group) significantly had a higher male ratio, lower MRC grades, higher Nurick grades, more often cervical/cervico-thoracic segment involvement, higher proportion of the presence of spine surgery history, motor deficits, sensory symptoms, bladder/bowel dysfunction, upper motor neuron (UMN) signs compared to the former group (Success group) and were older. Among these factors, male sex (Odds ratio [OR], 2.728

95% Confidence interval [CI], 1.472-5.055

p=0.001), cervical/cervico-thoracic lesion location(OR, 2.600

95% CI, 1.237-5.462

p=0.012) the presence of UMN signs(OR, 2.698

95% CI, 1.405-5.183

p=0.003), preoperative Nurick grade(OR, 1.688

95% CI, 1.209-2.356

p=0.002) and MRC grade(OR, 0.364

95% CI, 0.195-0.677

p=0.001) showed a significant contribution for predicting the successful generation of mMEPs using multivariate logistic regression analysis. When analyzing predictors for post-operative poor functional outcomes, the success rate of mMEPs recording, the presence of UMN signs and lesion etiology were significant related factors for the aggravation of the Nurick grades before and after surgery. Conclusion: Various clinical parameters including lesion location, abnormal neurologic signs, preoperative motor power and functional status were revealed to have a significant relationship with the successful generation of baseline mMEPs. Additionally, the successful generation of mMEPs was one of the indicators for predicting long-term functional outcome. Further prospective studies in multiple cohorts are required to precisely define and validate clinical factors related to the mMEP successful recording.