躯体感觉诱发电位在脊柱手术监护中的应用

目的 探讨躯体感觉诱发电位（SEP）在脊柱手术监护中的应用价值。方法 分析４５８例脊柱手术中SEP监护的结果,特征,适用范围,其中颈部手术275例,胸椎,腰椎部手术183例,刺激电极为手指、足趾的环状电极或腕、踝的表面电极,记录电极为头皮针电极。结果 大部分患者的肌电图改变在器质性改变的范围内。409例（89．3％）,术中SEP有波幅轻度下降,潜伏期轻度延长,术后又恢复后近手术开始时水平;32例（7．1％）,SEP波幅有一定程度的提高,潜伏期部分缩短;12例（2．6％）有术中SEP明显恢复;2例（0．4％）术中未见SEP明显改变,术后有功能障碍;3例（0．7％）,术中出现SEP的波幅明显下降,潜伏期轻度延长,术持恢复欠佳。结论 SEP在脊柱手术监护中的作用是肯定的,但有一定的局限性。     

皮层体感诱发电位及经颅电刺激运动诱发电位联合监护在脊柱畸形矫正术中的应用

目的:探讨脊柱畸形矫正术中皮层体感诱发电位(CSEP)及经颅电刺激运动诱发电位(TES-MEP)联合监护在脊柱畸形矫正手术中的应用。方法:对我院收治的脊柱畸形患者根据术中监护方法分为两组:A组37例,其中男25例,女12例,年龄13～42岁,平均26.1岁,术中进行CSEP及TES-MEP联合监护;B组29例,其中男10例,女19例,年龄13～20岁,平均15.8岁,单纯采用CSEP监护作为对照组。术中持续观察CSEP及TES-MEP波幅及潜伏期变化,出现波幅下降50%、潜伏期延长10%或刺激强度高于初始刺激强度100V仍未引出者,停止手术并对症处理,术后给予激素治疗。结果:A组术中出现CSEP异常者4例(10.8%),TES-MEP异常者19例(60%)。术中CSEP及TES-MEP均异常者4例(10.8%),无术中CSEP异常而TES-MEP正常者。2例(陈旧性结核并后凸畸形1例,陈旧性骨折并后凸畸形1例)术中合拢截骨平面时,TES-MEP波形均消失,但仅1例出现CSEP异常,经术中积极处理,至手术结束时波形仍未恢复至术前水平,术后均出现神经功能障碍。余35例患者术后无神经功能损伤(假阴性率0%)。B组9例(21%)术中出现CSEP波形异常,其中2例虽经减少矫形角度及激素冲击治疗,术后仍出现双下肢瘫,余术后未出现神经功能障碍。3例术中监护未见异常者,术后出现重度不可逆性脊髓损伤(假阴性率10%)。结论:CSEP结合TES-MEP联合监护能较可靠、准确的反映术中脊髓功能状态,可降低监护假阴性率,为手术治疗过程提供参考。     

右美托咪定对特发性脊柱侧弯矫形术中体感诱发电位和运动诱发电位的影响

目的:研究右美托咪定（dexmedetomidine, Dex）对特发性脊柱侧弯矫形术中体感诱发电位（somatosensory evoked potentials, SEPs）和经颅电刺激运动诱发电位（transcranial electric motor evoked potentials, TCeMEPs）的影响...     

体感诱发电位在脊柱手术中的监测作用

目的：探讨脊柱外科手术中体感诱发电位监护技术的准确性。方法：对78例颈、胸椎手术患者术中采用皮层体感诱发电位(cortical somatosensory evoked potential，CSEP)术中监测，记录术前、术中、术后各个重要手术步骤的CSEP变化，根据不同阶段诱发电位的变化与术后临床脊髓功能改变相结合，判断CSEP的准确性。结果：78例患者中，CSEP未达到监护界值71例，术后无脊髓损伤；5例患者术中CSEP达到预警标准，告诫手术医生，注意手术操作，术后无脊髓损伤；另外，出现假阳性和假阴性各1例，术后恢复亦良好。结论：排除各种干扰因素后体感诱发电位可较准确地对脊髓的功能状况进行监测，是较准确的脊柱外科手术监护技术。     

Improvement of intraoperative somatosensory evoked potentials by ketamine

Many anaesthetics effect the latency and amplitude of somatosensory evoked potentials (SSEP). We present a patient who underwent two anterior/posterior spine fusions (A/PSF) at age 11 and 12 years old after resection of a spinal astrocytoma. She did have residual neurologic deficits of her lower extremities. SSEPs were unobtainable during the first surgery using an opioid-based anaesthetic. A ketamine-based anaesthetic was used for the second surgery and SSEPs were easily monitored. No other factors seem to have changed between the two surgeries. The anaesthetic management during each procedure is reviewed and the contributions of other factors to SSEP monitoring discussed.     

皮层体感诱发电位在脊柱脊髓疾患诊治中的应用

目的：评价皮层体感诱发电位（CSEP）在脊柱脊髓疾患诊治中的临床应用价值。方法：120例患者用Frankel分级判断脊髓功能，行CSEP术前检查，术中监护以及术后疗效评估，并分析应用不同标准的监测结果。结果：（1）CSEPⅠ型表现者全部为FrankelA级；Ⅱ型主要为B，C级，Ⅲ型主要为,C,D，Ⅳ型主要为D，E级。（2）Ⅰ-Ⅳ型CSEP表现者疗效分别为0,54.2%,82.8%,84.2%;(3)行椎体肿瘤切除，椎管内肿瘤切除，脊柱侧凸凹侧撑开及颈椎后路“单开门”时最易引发CSEP变化。（4）应用不同标准行术中监测灵敏度均为100％，特异度分别为85．6％，93．3％，误诊率分别为14．4％，6．7％，漏诊率均为0。结论：CSEP与Franke分级，临床疗效有良好的相关性；CSEP灵敏度高，可及时反映出脊髓功能的变化，提高脊髓手术的安全性；CSEP术中监测标准具有一定弹性，常因病情，体位及操作不同而变化。     

Motor versus somatosensory evoked potential changes after acute experimental spinal cord injury in rats

Summary In this study, averaged cortical somatosensory evoked potentials (SEP) after sciatic nerve stimulation, and lower extremity muscle responses after motor cortex stimulation (MEP) were compared in rats. 10 animals served as light (25g-cm) and 10 animals as severe (80g-cm) acute spinal cord injury group after weight dropping trauma. After the initial loss of components, both SEP and MEP recovered in most cases in the light injury group. In the severe injury group, however, no recovery was observed in cortical SEPs, while the muscle MEP recovered in some animals. Light spinal cord injury had little effect on muscle MEPs and caused a paradoxical amplitude increase in some MEP recordings. Latency values of muscle MEPs did not show great changes after either kind of injury, while cortical SEP latency was considerably delayed.In this model cortical SEPs were more sensitive to light spinal cord injury than muscle MEPs after single electrical cortical stimuli. Severe spinal cord injury caused amplitude changes or loss of waves from both SEP and MEP.This work was partly presented in the poster sections at 39. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie, Köln (F. R. G., May 8-1, 1988 and Congress of the International Medical Society of Motor Disturbances, Rome, Italy, June 2–4, 1988.     

Effects of dexmedetomidine on propofol and remifentanil infusion rates during total intravenous anesthesia for spine surgery in adolescents

Introduction: Total intravenous anesthesia with propofol and a synthetic opioid is a frequently chosen anesthetic technique for posterior spinal fusion. Despite its utility, adverse effects may occur with high or prolonged propofol dosing regimens including delayed awakening. The current study investigated the propofol‐sparing effects of the concomitant administration of the α₂‐adrenergic agonist, dexmedetomidine, during spinal fusion surgery in adolescents. Methods: The surgical database of the department of orthopedic surgery was searched and patients (12–21 years of age) were identified who had undergone spinal fusion for either idiopathic or neuromuscular scoliosis during the past 24 months. Patients were assigned to two groups. Group 1 included patients anesthetized with propofol and remifentanil and group 2 included patients anesthetized with dexmedetomidine, propofol, and remifentanil. In the latter group, dexmedetomidine was administered as a continuous infusion of 0.5 μg·kg^?1·h^?1 started after the induction of anesthesia without a loading dose. Propofol was adjusted to maintain the bispectral index (BIS) number at 40–50 and remifentanil was adjusted to maintain the mean arterial pressure (MAP) at 50–65 mmHg. Labetolol or hydralazine was used if the MAP could not be maintained at 50–65 mmHg with remifentanil up to a maximum dose of 0.6 μg/kg/min. Statistical analysis included a nonpaired t‐test for parametric data (age, weight, remifentanil/propofol infusion requirements, and heart rate/blood pressure values). A nonparametric statistical analysis (Dunn) was used to compare BIS numbers. Parametric data are presented as the mean ± sd while nonparametric data are presented as the median and the 95th percentile confidence intervals. Results: Twelve patients received propofol–remifentanil–dexmedetomidine and 24 received propofol–remifentanil. There were no differences in the demographic data, BIS numbers or hemodynamic parameters between the two groups. There was a reduction in the propofol infusion requirements in patients who also received dexmedetomidine (71 ± 11 μg·kg^?1·min^?1) compared with those receiving only propofol–remifentanil (101 ± 33 μg·kg^?1·min^?1, P = 0.0045). No difference was noted in the remifentanil infusion requirements or the use of supplemental agents (hydralazine and labetolol) to maintain controlled hypotension. Conclusion: The concomitant use of dexmedetomidine in patients undergoing spinal fusion reduces propofol infusion requirements when compared with those patients receiving only propofol and remifentanil.     

Direct spinal versus peripheral nerve stimulation as monitoring techniques in epidurally recorded spinal cord potentials

Summary We recorded spinal cord evoked potentials (SCEPs) and spinal somatosensory evoked potentials (spinal SEPs) in 30 operations following stimulation of the epidural spinal cord and the peripheral nerve, respectively, to compare their feasibility as an intraoperative technique for spinal cord monitoring. SCEPs produced quicker responses and had larger amplitudes with simpler waveforms. SCEPs could reflect residual function of the pathological spinal cord and predict the postoperative clinical outcome, findings which are not observed with spinal SEPs. Moreover, SCEPs had a much higher sensitivity to spinal cord insult. Therefore, we conclude that the SCEPs were more appropriate indicator than the spinal SEPs as an intra-operative monitoring method for spinal cord function.     

体感诱发电位在椎体后凸成形术中的脊髓监测

目的探讨体感诱发电位（SEP）在椎体后凸成形术（PKP）中的脊髓监测作用。方法33例46个椎体行PKP,术中均予SEP监护。结果46个椎体疼痛均好转,椎体复位良好,2例出现波幅降低,1例出现潜伏期延长,无重大并发症。结论SEP在PKP中对脊髓有良好的监测作用。     

体感诱发电位监测在脊柱畸形Ponte截骨矫形手术中的应用

[目的]探讨体感诱发电位(SEP)监测在脊柱畸形Ponte截骨矫形手术中的应用价值.[方法]对36例因脊柱畸形行Ponte截骨矫形手术的患者进行术中SEP监测,其中男10例,女26例;年龄6.5～45.2岁,平均18.8岁.成人脊柱侧凸8例,青少年特发性脊柱侧凸14例,先天性脊柱侧凸4例.手术均采用后路Ponte截骨矫形.SEPP40波幅下降＞50％和(或)潜伏期延长超过10％或波形消失为异常标准.[结果]截骨、减压和矫形过程中8例患者出现SEPP40波异常,立即停止手术操作,寻找原因,并作相应处理.其中2例因术中出血导致血压下降,1例为胸腰段截骨,1例为中胸段截骨:另4例考虑与手术操作因素有关.2例为中胸段,2例为胸腰段.2例同时有波幅下降＞50％和潜伏期延长超过10％患者.1例成人脊柱侧凸患者术后出现短期的神经功能障碍,1例成人脊柱侧凸患者术后神经功能正常.[结论]术中体感诱发电位监测可作为指示Ponte截骨矫形术中脊髓功能的重要手段,敏感性较高,对其变化应积极应对并正确处理,以避免脊髓损伤.     

Effects of subarachnoid lidocaine, meperidine and fentanyl on somatosensory and motor evoked responses in awake humans

Although the effects of local anaesthetics (LA) on motor and sensory transmission in the spinal cord have been described, the effects of opioids are controversial. Our aim was to evaluate the action of clinically relevant doses of subarachnoid (SA) meperidine (MP) and fentanyl (FN), on somatosensory (SSEP) and cortical motor evoked responses (CMER) in awake subjects. Thirty ASA I-II patients scheduled for infra umbilical surgery received SA (N = 10/group): 1 mg/kg lidocaine (LD), 1 mg/kg MP or 25 μg FN. SSEP elicited by stimulation of the posterior tibial nerve at the ankle, and cortical motor evoked response at rest (r-CMER) and during facilitation (f-CMER) were obtained prior and 30 min after treatment. Conduction at the proximal segment of the motor nerve (F-wave) was evaluated by stimulation ot the posterior tibial nerve at the popliteal fossa. Motor/sensory block and side effects were clinically assessed.
LD completely abolished SSEP and CMER. At the same dose, MP abolished SSEP in 40% of the patients, while r-CMER and f-CMER were absent in 70% and 30%, respectively; in addition, the F-wave was absent in 50% of the patients. Fentanyl induced small changes in the latencies of SSEP and F-wave; however, a 28% decrease in the amplitude of the f-CMER (P<0.05) was observed. Pruritus was present in 60% of patients in the FN group (P<0.006).
Our results show that while LD and MP block sensory and motor conduction at the spinal roots, FN seems to decrease the excitability of the spinal interneurons in the corticospinal tract.     

Intraoperative somatosensory evoked potential monitoring in achondroplasia

Surgical airway intervention in children with achondroplastic dwarfism poses potential neurological risk secondary to the neck manipulation required for tracheal intubation and operative head positioning. This is particularly true of achondroplastic dwarfs with radiographically documented foramen magnum and spinal canal stenosis. In these children, upper extremity somatosensory evoked potential monitoring establishes the integrity of sensory conduction from peripheral nerve to cortex, providing intraoperative notification of neurologically significant cervicomedullary compression during laryngoscopy and surgical positioning.     

颈胸椎手术中体感诱发电位监护的影响因素分析及准确性观察

目的探讨体感诱发电位监护在颈、胸椎手术中的应用价值,对其准确性及影响因素进行分析。方法颈、胸椎疾病患者采用皮层体感诱发电位（CSEP）及皮层下体感诱发电位（Sub-CSEP）术中监测,根据麻醉前、后及不同手术阶段体感诱发电位的变化与术后功能相结合,判断体感诱发电位（SEP）的准确性。结果麻醉因素引起的SEP波幅降低主要影响CSEP,双侧刺激均改变,但基本未达到手术预警标准值,而Sub-SEP变化不明显。手术高危操作侵及脊髓,SEP波幅降低主要影响高危操作的同侧,表现为同侧CSEP及Sub—CSEP波幅同时降低,并且降低幅度较大,达到预警标准值,而对侧CSEP及Sub-CSEP波幅变化不甚明显。其他非手术原因如低体温、局部冷盐水冲洗脊髓,引起SEP潜伏期延长,波幅变化不明显。失血过多致平均动脉压降低可引起SEP波幅降低,潜伏期变化不明显。局部低温及低血压引起的SEP改变,均未达到预警标准值。结论颈、胸椎手术中采用体感诱发电位监测排除各种干扰,可较准确地反映脊髓的生理或病理状况。     

慢性脊髓压迫及减压后运动诱发电位及病理学改变

目的探讨脊髓慢性压迫及减压后神经病理学及运动诱发电位(MEP)的变化.方法选用 54只SD大鼠,随机分为对照组,轻、中、重压迫组和减压组.应用磁刺激MEP各组行30 min、6 h和1、2、4周动态观察.用HE染色观察脊髓的组织学变化.结果轻度压迫组MEP潜伏期在损伤后30 min及6 h比术前分别延长0.29倍和0.32倍,至4周恢复,与术前相比,伤后30 min和6 h中度压迫组MEP潜伏期延长0.83倍和0.88倍,重度组延长1.14倍和1.22倍,减压后MEP潜伏期分别缩短了0.21倍和0.23倍.结论轻和中度压迫组的病变是可逆的,而重度压迫导致神经细胞和运动功能的不可逆改变.MEP能反映脊髓受损程度,可作为评价减压效果的客观指标.     

Combined motor and somatosensory evoked potentials for intraoperative monitoring: intra- and postoperative data in a series of 69 operations

The primary objective of neurophysiologic monitoring during surgery is to avoid permanent neurological injury resulting from surgical manipulation. To prevent motor deficits, either somatosensory (SSEP) or transcranial motor evoked potentials (MEP) are applied. This prospective study was conducted to evaluate if the combined use of SSEP and MEP might be beneficial. Combined SSEP/MEP monitoring was attempted in 100 consecutive procedures, including intracranial and spinal operations. Repetitive transcranial electric motor cortex stimulation was used to elicit MEP from muscles of the upper and lower limb. Stimulation of the tibial and median nerves was performed to record SSEP. Critical SSEP/MEP changes were defined as decreases in amplitude of more than 50% or increases in latency of more than 10% of baseline values. The operation was paused or the surgical strategy was modified in every case of SSEP/MEP changes. Combined SSEP/MEP monitoring was possible in 69 out of 100 operations. In 49 of the 69 operations (71%), SSEP/ MEP were stable, and the patients remained neurologically intact. Critical SSEP/ MEP changes were seen in six operations. Critical MEP changes with stable SSEP occurred in 12 operations. Overall, critical MEP changes were recorded in 18 operations (26%). In 12 of the 18 operations, MEP recovered to some extent after modification of the surgical strategy, and the patients either showed no (n = 10) or only a transient motor deficit (n = 2). In the remaining six operations, MEP did not recover and the patients either had a transient (n = 3) or a permanent (n = 3) motor deficit. Critical SSEP changes with stable MEP were observed in two operations; both patients did not show a new motor deficit. Our data again confirm that MEP monitoring is superior to SSEP monitoring in detecting impending impairment of the functional integrity of cerebral and spinal cord motor pathways during surgery. Detection of MEP changes and adjustment of the surgical strategy might allow to prevent irreversible pyramidal tract damage. Stable SSEP/MEP recordings reassure the surgeon that motor function is still intact and surgery can be continued safely. The combined SSEP/ MEP monitoring becomes advantageous, if one modality is not recordable.     

Effects of temperature on somatosensory evoked potentials during open heart surgery

Somatosensory evoked potentials (SEPs) have been found to be useful for early detection of brain ischemia during hypothermic cardiopulmonary bypass in cardiac surgery. However, the relationship between temperature and latency period remains unclear. We prospectively analyzed SEPs obtained during hypothermic cardiopulmonary bypass in 20 patients who had valvular replacement.
We concluded that i) a linear correlation was found between temperature and latency period during cooling and rewarming, ii) no hysteresis effect existed in cooling and rewarming, iii) there was a greater hypothermic effect on the synaptic transmission than on the conduction velocity, and, iv) age had also more profound effect on relationship between temperature and latency of SEPs.     

皮层下体感诱发电位监测脊柱侧凸手术的临床研究

目的：研究皮层下体感诱发电位对脊柱侧凸矫正手术监测的准确性,提高术中预防神经损伤的有效性。方法：对４１例脊柱侧凸患者于矫正术中采用皮层下体感诱发电位和皮层体感诱发电位监测脊髓功能。结果：皮层下体感诱发电位波形稳定可靠,很少受麻醉的影响;皮层体感诱发电位受麻醉影响较大,波幅几乎可消失。全组５例皮层下体感诱发电位出现异常,其中２例与临床相符,３例为假阳性;无假阴性发生。准确率为９２７％。结论：应用体感诱发电位术中监测脊髓功能,皮层下体感诱发电位是目前较理想的方法。     

Effect of renewed SS-cream on spinal somatosensory evoked potential in rabbits

Aim: The effect of a renewed SS-cream (RSSC) on the treatment of premature ejaculation (PE) was evaluated and compared with the original SS-cream (OSSC). Methods: Sixty male white New Zealand rabbits, weighing 2.5kg-3.0 kg, were divided at random into 3 groups: the RSSC, OSSC and placebo groups. The spinal somatosensory evoked potential (SSEP) elicited by electric stimulation of the glans penis with disk electrode was investigated with an electrophysiograph (Poseidomn, Shanghai, China) before and 10, 30 and 60 min after drug or placebo application on the glans. The Onset and the N1 latencies and the amplitude of SSEP were recorded and analyzed. Results: There was no significant difference (P>0.05) in the mean Onset and Nl latency of SSEP among the 3 groups before drug application. Compared with the pre-application value, the mean Onset and Nl latencies in the RSSC and OSSC groups were significantly prolonged at 10, 30 and 60 min after treatment (P<0.05), while they were not significantly changed (P>0.05)     

Continuous monitoring of short-latency somatosensory evoked potentials during cardiac and aortic surgery

The effectiveness of monitoring somatosensory evoked potentials (SEPs) intraoperatively to detect brain damage early remains controversial. To assess the diagnostic accuracy of this modality, a study was conducted between 1991 and 1994, recording SEPs in 287 consecutive patients undergoing cardiac and aortic surgery using cardiopulmonary bypass (CPB) with moderate hypothermia or deep hypothermic circulatory arrest. From P1 to N2 of the SEPs occurring within 50 ms latency in response to electrical stimulation of the median nerve were recorded over the contralateral postcentral cortex at 5-min intervals using a Neuropack-2 (Nihon Koden, Tokyo, Japan). Normal SEPs were recovered in 247 patients postoperatively; however, 2 of these patients had suffered a cerebral infarction and 1, a transient stroke intraoperatively, demonstrating a false-negative incidence of 1.2%. On the other hand, three different types of abnormal SEPs were recorded postoperatively. P1 and N1 absence, probably caused by a subcortical lesion, was observed in 4 patients; P2 and N2 absence, probably caused by a cortical lesion, was observed in 8 patients; and a flat SEP, representing diffuse damage, was observed in 2 patients. Among these 14 patients with abnormal SEPs, 7 showed no neurologic disturbance at all, demonstrating a false-positive incidence of 50%. Thus, we concluded that when normal SEPs are recovered during weaning from CPB, the incidence of brain damage could be predicted at below 5%. Conversely, when abnormal SEPs are demonstrated, the incidence of brain dysfunction impeding a return to active life is estimated to be about 70%.