生长棒撑开术中经颅刺激运动诱发电位和体感诱发电位监测的应用价值

目的:分析生长棒撑开术中经颅刺激运动诱发电位(MEP)和体感诱发电位(SEP)神经功能监测的应用价值。方法:回顾性分析2010年10月~2015年1月我院进行的65例141次生长棒撑开手术,在生长棒撑开术中,运用MEP和SEP进行神经功能监测。MEP监测采用经颅刺激C3、C4,记录外周肌源性MEP,SEP监测采用刺激双侧胫后神经,记录电极采用Cz-CPz。阳性诊断标准:与基线相比,MEP波幅下降75%,SEP波幅下降50%或潜伏期延长10%。结果:141例次撑开手术中成功获得具有监护价值且重复性较好MEP 139例次,检出率98.6%,全程失败2例次(占1.4%);SEP成功监测140例次,检出率99.3%,失败1例(占0.7%)。所有患者均能成功记录到一种以上的诱发电位。本组141例次手术中未出现MEP及SEP监测阳性。所有患儿术后神经系统检查均无异常发现,神经功能监测结果均为真阴性。结论:生长棒撑开术是简单安全的手术操作,但是,运用MEP和SEP进行术中神经功能监测可以为生长棒撑开术提供客观的安全评估指标。     

颈椎外伤前路手术中体感诱发电位监护应用

目的探讨体感诱发电位(somatosensory evoked potential,SSEP)在颈椎外伤前路手术中的作用。方法 2008-07-2015-02收治颈椎外伤前路手术患者53例,年龄16~69岁,男44例,女9例。对照组(33例)无SSEP监护,监护组20例。在麻醉诱导后摆放体位前确立SSEP基线,波幅降低50%或潜伏期延长10%为报警标准。记录SSEP报警因素、改善措施及有无医源性神经损伤。计算SSEP监护神经损伤的敏感性和特异性。结果 53例病人术后未出现新的神经损伤。SSEP监护颈椎外伤前路手术中神经损伤的敏感性和特异性为100%。结论在颈椎外伤前路手术中SSEP监护医源性神经损伤是有意义的。     

经颅刺激运动诱发电位联合体感诱发电位监测在脊柱畸形手术中的应用

 目的分析联合应用经颅刺激运动诱发电位(transcranial electric stimulation motor evoked potential, TcMEP)+体感诱发电位(somatosensory-evoked potential, SEP)的多模式术中神经功能监测对预 测脊柱畸形矫形手术中医原性神经功能损害的意义。方法 在脊柱畸形矫形手术中, 同时应用 TcMEP 和(或)SEP进行神经功能监测。 MEP监测采用经颅刺激 ₃、C₄, 记录外周肌源性 MEP, SEP监测采用刺 激双侧胫后神经, 记录置于 C_z-FP_z。阳性诊断标准为, 与基线相比, MEP波幅下降 75%, SEP波幅下降 50%。结果 153例脊柱畸形患者中, 150例成功进行了术中 MEP监测, 83例进行了术中 SEP监测。联 合 MEP、SEP监测的检出率为 100%。MEP监测阳性共 12例, 所有患者中有 1例出现永久性神经功能障 碍, 4例出现一过性神经功能障碍。 MEP监测的敏感性为 90.9%, 特异性为 98.6%; SEP监测敏感性为 54.5%, 特异性为 94.3%;联合 MEP、SEP监测的敏感性达 92.3%, 特异性为 99.3%。结论 联合 MEP+ SEP的多模式术中神经功能监测可提高监测的敏感性及特异性, 可预测术中神经功能损伤事件的发生。 MEP是多模式监测的基础, 而 SEP是重要补充。     

Motor evoked potential monitoring during upper cervical spine surgery

Motor evoked potential (MEP) produced by transcranial electrical stimulation was recorded from an epidural electrode in 20 consecutive patients during upper cervical spine surgery. In 5 patients, transient attenuation to approximately 50% followed by complete recovery was observed, and no neurologic deficit was noted. One patient had complete loss of MEP and was left a respiratory quadriplegic. In 2 cases, MEP amplitudes increased after tumor extirpation and remarkable remissions were observed. The MEP correlated with clinical outcomes and was a useful monitoring technique for upper cervical spine surgery, free of complication. In cat experiments designed to analyze conducting pathways, the maximal amplitude of the initial spike of MEP existed in the ventromedial spinal cord, which contains the extrapyramidal tracts. Motor evoked potential was proven to reflect motor function based on the spinal cord compression study.     

经颅刺激运动诱发电位联合体感诱发电位监测在特发性脊柱侧凸矫形手术中应用的研究

背景：特发性脊柱侧凸手术治疗中神经功能障碍是最应受到关注的并发症,术中神经功能监测可帮助早期发现可能的神经功能损伤。目的：分析联合应用经颅刺激运动诱发电位（TcMEP）和体感诱发电位（SEP）的多模式术中神经功能监测在特发性脊柱侧凸矫形手术中对预测医源性神经功能损害的作用。方法：在特发性脊柱侧凸矫形手术中,运用TcMEP和（或）SEP进行神经功能监测。MEP监测采用经颅刺激C3、C4,记录外周肌源性MEP,SEP监测采用刺激双侧胫后神经,记录电极采用Cz—CPz。阳性诊断标准：与基线相比,MEP波幅下降75％,SEP波幅下降50％。结果：112例特发性脊柱侧凸患者中,联合MEP、SEP监测的检出率为100％。MEP监测阳性6例,假阳性1例。1例出现一过性神经功能障碍。MEP的监测敏感性为100％,特异性为99％;SEP监测敏感性50％,特异性为100％;联合MEP、SEP监测的敏感性、特异性均为100％。结论：特发性脊柱侧凸矫形手术中MEP＋SEP的术中神经功能监测可提高监测敏感性及特异性,可预测术中神经功能损伤事件的发生。MEP是多模式监测的基础,SEP是重要补充。单独应用MEP监测在特发性脊柱侧凸患者手术中有应用前景。     

经颅磁刺激运动诱发电位在脊柱脊髓术中监测的应用研究

目的 探索应用经颅磁刺激运动诱发电位(TMS-MEP)在脊柱脊髓手术中进行神经监测的可行性和有效性.方法 2001年2月至2004年6月间在我科接受脊柱脊髓手术共37例患者,术中分别使用常规方法和依托咪酯+芬太尼技术进行麻醉,应用双频指数(BIS)和四个成串刺激(TOF)监测麻醉深度与肌松状态,使用TMS-MEP进行术中监测.比较不同麻醉方法和麻醉深度对TMS-MEP的影响,并分析TMS-MEP监测操作的可行性及其对手术操作的影响.结果 以安氟醚或异氟醚维持麻醉的11例患者无法记录到TMS-MEP;使用依托咪酯+芬太尼技术麻醉的26例患者,MEP均记录良好.与麻醉前相比,术中的MEP波形一般都能够保持,但其波幅显著下降、潜伏期亦明显延长(P<0.05).随着麻醉和肌松的加深,MEP的波幅会进一步降低,而潜伏期的变化相对较小.在麻醉相对平稳的情况下,MEP波幅能保持相当的平稳.MEP操作对手术没有明显的不良影响.成功记录MEP的患者中有6例(23%)因为术中MEP波幅下降超过50%而向术者发出报警,其中仅1例患者术后肌力较术前下降.结论 应用TMS-MEP进行脊柱脊髓手术的术中监测是一项有效而切实可行的技术,依托咪酯+芬太尼麻醉技术适用于使用TMS-MEP进行术中监测的手术,BIS、TOF等麻醉、肌松监测指标的应用有助于维持术中麻醉的平稳和对TMS-MEP监测结果的判断.     

脊柱手术中经颅电刺激运动诱发电位监护的应用探讨

目的探讨脊柱手术中经颅电刺激运动诱发电位（transcranial electrical stimulation motor evoked potential,TES-MEP）监护的可行性和应用价值。方法2006年7月至2008年10月,在241例胸椎手术中对双侧胫前肌、足踇短屈肌、大鱼际肌或小鱼际肌（颈椎病变时）实施TES-MEP监护。术中全静脉麻醉58例,静脉麻醉＋七氟烷吸入麻醉（浓度〈1％）67例,静脉麻醉＋小剂量肌松剂116例。结果TES-MEP的检出率为89．2％,虽然3种麻醉方式的检出率无显著性差异,但各年龄组、不同靶肌肌力的检出率有显著性差异。术中TES-MEP阳性26例,其中不明原因的假阳性6例,真阳性20例,且均与手术操作有直接相关性。TES-MEP对脊髓运动功能监护的灵敏度为100％,特异度为97．9％,约登指数为0．979;对脊髓感觉功能监护的灵敏度为74．1％,特异度为97．9％,约登指数为0．72。结论异丙芬静脉麻醉＋七氟烷吸入麻醉（浓度〈1％）为首选方案,异丙芬静脉麻醉＋小剂量肌松剂为次选方案。TES-MEP不但能瞬间、直接、准确地监护脊髓的运动传导功能,而且能间接反映脊髓的感觉传导功能,是安全监护脊柱手术的新方法。     

颈椎病前路手术中体感诱发电位监护临床研究

目的探讨体感诱发电位监护(SSEP)在颈椎病前路手术中的应用价值。方法收治颈椎病前路手术患者142例,年龄37~75岁,男96例,女46例。神经根型颈椎病35例,脊髓型颈椎病107例。对照组83例无SSEP监护,监护组59例。在麻醉诱导后和摆放体位前确立SSEP基线,波幅降低50%或潜伏期延长10%为报警标准。记录SSEP报警因素及改善措施,术后明确有无医源性神经损伤。结果对照组无医源性神经损伤。监护组:真阳性2例出现报警,采取措施后解除报警;假阳性0例;真阴性56例SSEP无报警,无医源性神经损伤;假阴性1例SSEP无报警,术后右侧三角肌麻痹;SSEP监护医源性神经损伤的敏感性和特异性分别为66.7%和100%。结论 SSEP在颈椎病前路手术中监护脊髓损伤方面较敏感,对神经根损伤不敏感。     

Variability of somatosensory evoked potential monitoring during scoliosis surgery

OBJECTIVE: Somatosensory evoked potentials (SEPs) of 65 patients undergoing scoliosis surgery were monitored by stimulation of posterior tibial nerve to observe variations in latencies and amplitudes. METHODS: Monitoring was divided into five stages: pre incision, spine exposure, instrumentation loading, deformity correction, and wound closure (stages 1-5, respectively). RESULTS: We found the latency showed significant increase and the amplitude significant reduction from stages 1 to 2. There was no significant variability from stages 2, 3, and 4, but both latency and amplitude recovered significantly from stage 4 to 5. This variability correlated with the changes in mean arterial pressure and end-tidal concentrations of isoflurane and was not dependent on the type of surgical procedure. If either 50% amplitude reduction or 10% latency prolongation of SEP compared with baseline recordings at stage 1 (pre incision) was used as warning criterion, the overall false-positive rate was 23.1%. It was significantly reduced to 7.7% if stage 2 (spine exposure) recordings were used as the baseline (P < 0.05). The false-positive rate decreased to 0% if a combined 50% amplitude reduction and 10% latency prolongation of SEP compared with the stage 2 baseline were used (P < 0.001). CONCLUSION: Based on these findings, we concluded that the time to obtain SEP baseline data should be adjusted to be post incision instead of pre incision.     

Comparison of transcranial motor evoked potentials and somatosensory evoked potentials during thoracoabdominal aortic aneurysm repair

OBJECTIVE: To compare transcranial motor evoked potentials (tc-MEPs) and somatosensory evoked potentials (SSEPs) as indicators of spinal cord function during thoracoabdominal aortic aneurysm repair. SUMMARY BACKGROUND DATA: Somatosensory evoked potentials reflect conduction in dorsal columns. tc-MEPs represent anterior horn motor neuron function. This is the first study to compare the techniques directly during thoracoabdominal aortic aneurysm repair. METHODS: In 38 patients, thoracoabdominal aortic aneurysm repair (type I, n = 10, type II, n = 14, type III, n = 6, type IV, n = 8) was performed using left heart bypass and segmental artery reimplantation. tc-MEP amplitudes <25% and SSEP amplitudes <50% and/or latencies >110% were considered indicators of cord ischemia. The authors compared the response of both methods to interventions and correlated the responses at the end of surgery to neurologic outcomes. RESULTS: Ischemic tc-MEP changes occurred in 18/38 patients and could be restored by segmental artery reperfusion (n = 12) or by increasing blood pressure (n = 6). Significant SSEP changes accompanied these tc-MEP events in only 5/18 patients, with a delay of 2 to 34 minutes. SSEPs recovered in only two patients. In another 11 patients, SSEP amplitudes fell progressively to <50% of control without parallel tc-MEP changes or association with cross-clamp events or pressure decreases. At the end of the procedure, tc-MEP amplitudes were 84 +/- 46% of control. In contrast, SSEP amplitudes were <50% of control in 15 patients (39%). No paraplegia occurred. CONCLUSION: In all patients, tc-MEP events could be corrected by applying protective strategies. No patient awoke paraplegic. SSEPs showed delayed ischemia detection and a high rate of false-positive results.     

Variability of somatosensory cortical evoked potential monitoring during spinal surgery

The intraoperative variability of somatosensory cortical evoked potentials (SCEPs) has been measured for 320 consecutive spinal surgeries and found to be a function of patient diagnosis, neuromuscular status, age, and procedural factors. In many cases, it is likely that this variability severely limits the reliability and usefulness of spinal cord monitoring in detecting early cord compromise. Patients with idiopathic scoliosis, spondylolisthesis, and pseudarthrosis have the smallest spontaneous variability and strongest amplitudes, while those with congenital, paralytic scoliosis, stenosis, or tumor have very variable, weak SCEPs. Patients with neurologic disorders, particularly cerebral palsy, myelomeningocele, Friedreich's ataxia, and peripheral deficits, also have high variability and weak amplitudes. A monitoring quality scoring system is proposed that may be useful during surgery in judging how well the SCEPs can discern surgically related changes in cord function from background variations.     

Effects of dexmedetomidine on intraoperative motor and somatosensory evoked potential monitoring during spinal surgery in adolescents

Background: Dexmedetomidine may be a useful agent as an adjunct to an opioid–propofol total intravenous anesthesia (TIVA) technique during posterior spinal fusion (PSF) surgery. There are limited data regarding its effects on somatosensory (SSEPs) and motor evoked potentials (MEPs). Methods: The data presented represent a retrospective review of prospectively collected quality assurance data. When the decision was made to incorporate dexmedetomidine into the anesthetic regimen for intraoperative care of patients undergoing PSF, a prospective evaluation of its effects on SSEPs and MEPs was undertaken. SSEPs and MEPs were measured before and after the administration of dexmedetomidine in a cohort of pediatric patients undergoing PSF. Dexmedetomidine (1 μg·kg^?1 over 20 min followed by an infusion of 0.5 μg·kg^?1·h^?1) was administered at the completion of the surgical procedure, but prior to wound closure as an adjunct to TIVA which included propofol and remifentanil, adjusted to maintain a constant depth of anesthesia as measured by a BIS of 45–60. Results: The cohort for the study included nine patients, ranging in age from 12 to 17 years, anesthetized with remifentanil and propofol. In the first patient, dexmedetomidine was administered in conjunction with propofol at 110 μg·kg^?1·min^?1 which resulted in a decrease in the bispectral index from 58 to 31. Although no significant effect was noted on the SSEPs (amplitude or latency) or the MEP duration, there was a decrease in the MEP amplitude. The protocol was modified so that the propofol infusion was incrementally decreased during the dexmedetomidine infusion to achieve the same depth of anesthesia. In the remaining eight patients, the bispectral index was 52 ± 6 at the start of the dexmedetomidine loading dose and 49 ± 4 at its completion (P = NS). There was no statistically significant difference in the MEPs and SSEPs obtained before and at completion of the dexmedetomidine loading dose. Conclusion: Using the above‐mentioned protocol, dexmedetomidine can be used as a component of TIVA during PSF without affecting neurophysiological monitoring.     

Pure motor hemiparesis with stable somatosensory evoked potential monitoring during aneurysm surgery: case report.

We report a patient who sought treatment for an acute subarachnoid hemorrhage as a result of an intracranial aneurysm. Management included early surgical repair and intraoperative monitoring of evoked potentials. Pan-angiography revealed berry aneurysms of the communicating anterior artery and right middle cerebral artery. Surgery was uneventful, and the somatosensory evoked potential monitoring did not show any abnormalities. Nevertheless, the patient showed a neurological deficit due to a clip-related infarct in the right middle cerebral artery territory characterized by a right hemiparesis with no sensory deficit. This case report supports the possibility of false-negative results in single-mode intraoperative monitoring during aneurysm surgery.     

Evaluation of combined use of transcranial and direct cortical motor evoked potential monitoring during unruptured aneurysm surgery

The feasibility and reliability of combined use of transcranial and direct cortical motor evoked potential (MEP) monitoring during unruptured aneurysm surgery were evaluated. Forty-eight patients with unruptured cerebral aneurysms underwent craniotomy and neck clipping accompanied by muscle MEP monitoring. MEPs were elicited successfully by transcranial electrical stimulation in all patients. Direct cortical stimulation elicited MEPs in 44 patients. Reduction in MEP amplitude to less than 50% of baseline was considered significant. No postoperative motor paresis occurred in 39 patients in whom transcranial and direct MEPs remained unchanged. Four patients in whom direct MEPs could not be recorded had no intraoperative abnormality in transcranial MEPs and no postoperative motor dysfunction. Four of the other 5 patients manifested significant transient direct MEP changes without transcranial MEP changes. The transient MEP changes were observed in 3 patients during temporary clipping of the parent artery and in one patient with inadequate clipping of an middle cerebral artery aneurysm, and were considered due to insufficiency of blood flow. Decrease or disappearance of direct MEP waves recovered immediately after re-application of the clip and release of the temporary clip. Direct MEP waves disappeared and did not recover until the end of microsurgical procedures in one patient, although transcranial MEP amplitude remained at less than 50% of baseline. She developed hemiparesis postoperatively, which recovered within 6 hours. The duration of temporary occlusion in patients with direct MEP changes was significantly longer than that in patients without (p < 0.05). Direct MEP was sensitive in detecting ischemic stress to descending motor pathways during aneurysm surgery. Transcranial MEPs could be elicited in patients in whom direct MEPs could not be obtained, and during periods such as craniotomy or after dural closure, in which direct MEPs could not be recorded. These findings suggest that combined transcranial and direct cortical MEP recording may improve the feasibility and reliability of MEP monitoring during unruptured aneurysm surgery.     

Differential rates of false-positive findings in transcranial electric motor evoked potential monitoring when using inhalational anesthesia versus total intravenous anesthesia during spine surgeries

Background contextFalse-positive loss of transcranial electrical motor evoked potentials (TCe-MEPs) limits the efficacy of motor tract monitoring during spine surgery. Although total intravenous anesthesia (TIVA) is widely regarded as the optimal regimen for TCe-MEPs, inhalational anesthesia is an alternative regimen.PurposeTo compare the rates of false-positive TCe-MEPs during spine surgery for patients anesthetized with TIVA and inhalation anesthesia.Study designA retrospective analysis of data collected from consecutive patients undergoing TCe-MEP monitoring during spinal surgery.Patient sampleConsecutive adult patients from multiple surgical centers undergoing spine surgery inclusive of cervical or thoracic spinal levels during 2008–2009 who received TIVA or inhalation anesthesia.Outcome measuresThe primary outcome measure was the rate of false-positive alerts using TCe-MEPS, defined as a persistent loss of 90% or greater of the amplitude of TCe-MEP in one or more muscles not attributed to technical or transient systemic factors (hypotension or hypoxia) and not associated with any postoperative neurologic deficit.MethodsPatients were divided into two groups according to anesthetic regimen: those anesthetized with one or more inhalational agents (n=1,303) and patients anesthetized with TIVA (n=511). The Fisher exact test and unpaired t test were used to compare group characteristics and false-positive rates. Each group was further subdivided by spinal region (cervical, thoracic, and thoracolumbar) and by presence of preoperative motor deficit. A Pearson chi-squared test was used to identify differences according to spinal region. This study was not supported by any financial sources nor do the authors have any financial relationships to disclose.ResultsPatient with inhaled anesthesia showed significantly higher rates of false-positive TCe-MEP changes (15.0% vs. 3.2%) compared with the TIVA group. These differences were significant across all surgical subgroups. The inhaled group had a larger number of patients with preoperative motor deficits compared with TIVA (45.0% vs. 37.4%), a potential confounder for false-positive results. However, a significantly higher rate of false-positive TCe-MEP changes was still observed in the inhaled group (11.4% vs. 0.6% for TIVA) when analyzing only those patients without preoperative motor deficits.ConclusionsUse of inhalation anesthesia during adult spinal surgery is associated with significantly higher rates of false-positive changes compared with TIVA during TCe-MEP monitoring. This relationship appears independent of preoperative motor status. Further study and multivariate analysis of anesthetic agents, diagnosis, and symptoms is necessary to elucidate the impact of these variables. The potential confounding effects of inhalational anesthesia on TCe-MEP monitoring should be considered when determining anesthetic regimen.     

Intraoperative transcranial electrical motor evoked potential monitoring during spinal surgery under intravenous ketamine or etomidate anaesthesia

Summary Motor evoked potentials (MEPs), monitoring the motor function directly, are superior to somatosensory evoked potentials (SSEPs) in monitoring the motor system during spinal surgery. Reliable MEPs are difficult to elicit under normal anaesthesia. Using intravenous anaesthesia with either ketamine or etomidate infusion, we performed intraoperative MEP monitoring in 12 spinal operations for 11 cases from February 1992 to May 1992. For anaesthesia, ketamine was used in 5, etomidate in 7, fentanyl was supplemented in all, muscle relaxation at 30% to 50% of pre-anaesthetic muscle power was maintained with atracurium or vencuronium infusion. Transcranial bipolar electrical stimulation was used to induce MEPs. Concomitant SSEP monitoring was performed in 3. No significant anaesthesia related side effects were noted except one episode of unpleasant dream occurred in the ketamine anaesthesia group.Successful monitoring was achieved in 10 sessions. In 5 of which warning to the surgeons was made due to sudden MEP deterioration, which recovered followed by definite management in four and persisted in one. In the other 5 sessions, no warning was made due to stationary or gradual change in MEPs. Bilateral two-channel recordings were used in 3 sessions. In 2 of which unilateral transient change was noted. Loss of SSEPs was noted in one despite unchanged MEPs, in whom only new sensory deficits occurred postoperatively. Compared to the baseline MEPs in terms of latency and amplitude, the final MEPs improved in 5 sessions, did not change significantly in 4 sessions, deteriorated in one session, and were correlated well with the immediate postoperative motor status.In our small series, the intraoperative MEP monitoring showed neither false negative nor false positive result. It is concluded that the intraoperative MEP monitoring is feasible under intravenous ketamine or etomidate anaesthesia and valuable in spinal surgery.