失神经纤颤电位及正尖波波幅与神经修复后肌肉功能恢复关系的实验研究

目的 研究大鼠腓肠肌失神经支配后纤颤电位与正尖波波幅的变化,并探讨其与在损伤后不同时期修复断伤胫神经后腓肠肌功能恢复间的相关性。方法 雄性SD大鼠54只,按手术先后顺序随机分为8组。第1组12只大鼠,于切断其右侧胫神经后即刻、48h、72h、1周、2周、4周、8周、12周、16周,测定右侧腓肠肌的纤颤电位及正尖波。第2－7组（每组6只大鼠）,分别在胫神经切断后1、2、4、8、12、16周时修复神经,各组于修复后12周取腓肠肌,测定肌湿重及肌纤维直径及截面积。第8组（6只大鼠）作为正常对照组。结果 第1组的正尖波先于纤颤电位出现,纤颤电位的波幅在术后1周最高,在神经切断后4周内维持在较高水平;术后8周起春波幅呈进行性,16周时全部消失。正尖波于神经切断后478h开始出现,术后8周其波幅最大,术后16周时半数大鼠的正尖波消失。于神经断伤后8周内修复后胫神经,恢复的肌肉功能与正常对照组相比,差异无显著性意义（t＝1．952,P＞0．05）;神经断伤后12周以后修复组恢复的肌肉功能明显变差,与正常对照组相比差异有显著性意义（t＝3．127,P＜0．05）。结论 失神经支配腓肠肌纤颤电位下正尖波的波幅。与神经修复后功能恢复程度间有密切的相关性,可作为大鼠失神经骨骼肌萎缩是可逆的一个量化指标。     

Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats

BACKGROUND AND OBJECTIVE: The purpose of the present study was to examine the recovery of the crushed sciatic nerve of rats after low-power laser irradiation applied to the corresponding segments of the spinal cord. STUDY DESIGN/MATERIALS AND METHODS: After a crush injury to the sciatic nerve in rats, low-power laser irradiation was applied transcutaneously to corresponding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He-Ne laser. The laser treatment was repeated 30 minutes daily for 21 consecutive days. RESULTS: The electrophysiologic activity of the injured nerves (compound muscle action potentials--CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow-up period (P < 0.001). CONCLUSION: This study suggests that low-power laser irradiation applied directly to the spinal cord can improve recovery of the corresponding insured peripheral nerve.     

不同刺激间隔对全麻患者经颅磁刺激运动诱发电位监测的影响

目的 评价不同刺激间隔对全麻患者经颅磁刺激运动诱发电位（TMS-MEP）监测的影响。方法 择期脊髓手术患者20例，ASAⅠ或Ⅱ级，静脉注射异丙酚2mg／kg、芬太尼2μg，kg、氯化琥珀胆碱2mg／kg麻醉诱导，气管插管后机械通气，持续输注异丙酚5mg·kg^-1·h^-1、芬太尼1μg·kg^-1·h^-1维持麻醉至试验结束。在麻醉前、后分别记录2、5、10ms（分别为500、200、100Hz）刺激间隔下4次刺激引出的复合肌肉动作电位（CMAP）的波幅和潜伏期。结果 麻醉前：与2ms相比，5ms刺激间隔下CMAP波幅差异无统计学意义（P〉0．05），与2In8和5In8相比，10ms刺激间隔下CMAP波幅减小（P〈0．05）；麻醉后：与2ms相比，5、10ms刺激间隔下CMAP波幅减小（P〈0．05），与5ms相比，10ms刺激间隔下CMAP波幅减小（P〈0．05）。麻醉前、后各刺激间隔下CMAP潜伏期差异无统计学意义（P〉0．05）。麻醉后5ms刺激间隔下2例患者未记录到CMAP，10ms刺激间隔下4例患者未记录到CMAP。结论 采用2ms刺激间隔下对全麻患者4次经颅磁刺激可在靶肌肉上记录到最大的CMAP波幅，更适用于全麻患者术中施行经颅磁刺激运动诱发电位监测，可有效对抗异丙酚静脉麻醉对运动诱发电位的抑制作用，增加运动诱发电位监测的准确性。     

Midlatency auditory evoked potentials in children: effect of age and general anaesthesia

BACKGROUND: Midlatency auditory evoked potentials (MLAEP) are a promising tool for monitoring suppression of sensory processing during anaesthesia and might help to avoid awareness. MLAEP in children are different to those in adults and the exact changes during general anaesthesia are unknown. METHODS: In 49 children of age between 2 and 12 yr, MLAEP were recorded before anaesthesia, during tracheal intubation, at steady-state balanced anaesthesia, and after extubation. RESULTS: MLAEP were recordable in all children in the awake (premedicated) state with latencies but not amplitudes dependent on children's age. MLAEP latencies significantly increased during tracheal intubation and steady-state anaesthesia. Changes in amplitudes were inconsistent. All MLAEP variables returned to near baseline values after extubation. CONCLUSIONS: The results of this study imply that MLAEP can successfully be recorded during anaesthesia in children above the age of 2 yr. Further studies are necessary before MLAEP might be applicable for monitoring purposes in paediatric anaesthesia.     

Predicting intraoperative feasibility of combined TES-mMEP and cSSEP monitoring during scoliosis surgery based on preoperative neurophysiological assessment

Background contextCombined monitoring of muscle motor evoked potentials elicited by transcranial electric stimulation (TES-mMEP) and cortical somatosensory evoked potentials (cSSEPs) is safe and effective for spinal cord monitoring during scoliosis surgery. However, TES-mMEP/cSSEP is not always feasible. Predictors of feasibility would help to plan the monitoring strategy.PurposeTo identify predictors of the feasibility of TES-mMEP/cSSEP during scoliosis surgery.Study design/settingProspective cohort study in a clinical neurophysiology unit and pediatric orthopedic department of a French university hospital.Patient sampleA total of 103 children aged 2 to 19 years scheduled for scoliosis surgery.Outcome measuresFeasibility rate of intraoperative TES-mMEP/cSSEP monitoring.MethodsAll patients underwent a preoperative neurological evaluation and preoperative mMEP and cSSEP recordings at both legs. For each factor associated with feasibility, we computed sensitivity, specificity, positive predictive value (PPV), and negative predictive value. A decision tree was designed.ResultsPresence of any of the following factors was associated with 100% feasibility, 100% specificity, and 100% PPV: idiopathic scoliosis, normal preoperative neurological findings, and normal preoperative mMEP and cSSEP recordings. Feasibility was 0% in the eight patients with no recordable mMEPs or cSSEPs during preoperative testing. A decision tree involving three screening steps can be used to identify patients in whom intraoperative TES-mMEP/cSSEP is feasible.ConclusionsPreoperative neurological and neurophysiological assessments are helpful for identifying patients who can be successfully monitored by TES-mMEP/cSSEP during scoliosis surgery.     

Transcranial Magnetic Stimulation: Use of Motor Evoked Potentials in the Evaluation of Surgically Induced Spinal Cord Ischemia

Abstract

We evaluated transcranial magnetic stimulation producing motor evoked potentials (TMS MEP) as a method to detect spinal cord ischemia during surgery for thoracoabdominal aneurysms. Four groups of swine were subjected to different types of surgically-induced ischemia. TMS MEP and neurological function were assessed at baseline, immediately after the ischemic insult and after four hours of reperfusion/post-ligation. Cross-clamping of the aorta in groups A & B resulted in the disappearance and subsequent reappearance of TMS MEP with significantly prolonged latencies in most animals and variable neurological function. Ligation of intercostal arteries produced no changes in TMS MEP or neurological function (group C). However, after ligation of intercostal and lumbar arteries, group D demonstrated no reappearance of TMS MEP and severe neurological deficits. TMS MEP can provide rapid detection of global spinal cord ischemia and can also predict local devascularization injury. (J Spinal Cord Med 1997; 20:395-401)     

The electrovesicogram in the overactive bladder: role in determining pathogenesis and diagnostic significance

We investigated the hypothesis that the abnormal contractility of the smooth musculature of the overactive bladder (OAB) may be due to derangement of its electrical activity. Percutaneous electrovesicography was performed in 22 patients (mean age 46.3 years, 12 men, ten women) with OAB and 14 healthy volunteers (mean age 45.6 years, eight men, six women). Recording was performed with the bladder full and empty. Three electrodes were applied suprapubically and one reference electrode was applied to a lower limb. Reproducible regular triphasic slow waves (SWs) were recorded in the volunteers. The pattern of the full and empty bladder were similar except for the higher amplitude of the waves in the former (P<0.05). The OAB patients showed a dysrhythmic pattern with irregular frequency, amplitude and conduction velocity in both the empty and full bladders. We obtained tachyrhythmic, bradyrhythmic and arrhythmic areas in the same recording. The OAB exhibited a dysrhythmic electrical pattern with areas of different electrical activity in the same recording. The tachyrhythmic, bradyrhythmic and arrhythmic areas are suggested to explain the abnormal vesical contractions and clinical manifestations of OAB. Further studies are required to investigate the cause of the dysrhythmic pattern and the electrovesicogram is suggested as an investigative tool in OAB diagnosis.     

急性HICH患者行FVEP ICP监测的临床应用价值

目的 探讨对急性高血压性脑出血(HICH)患者用闪光视觉诱发电位(FVEP)进行无创颅内压(ICP)监测的临床价值。方法 选取本院神经内科收治的110例急性HICH患者作为研究对象,根据患者治疗28 d的结局分为存活组87例和死亡组23例,分别对比2组患者入院后第12、24、48、72 h的ICP值,同时分析ICP值与患者的格拉斯哥昏迷评分(GCS)、急性生理与慢性健康评分(APACHEⅡ)、FVEP各波潜伏期的关系。结果 存活组患者的出血量、血弹值、WBC、中线移位发生率均显著低于死亡组(P<0.05); 在入院第12、24、48及72 h存活组患者的ICP值均显著低于死亡组患者(P<0.05); 在入院第12 h存活组患者的GCS评分显著高于死亡组患者(P<0.05),APACHEⅡ评分、FVEP各波潜伏期(P2、N2、P3、N3)均显著低于死亡组患者(P<0.05); 在入院第12 h HICH患者的ICP值与GCS评分呈显著负相关(r=-0.572,P<0.05),与APACHEⅡ评分、FVEP各波潜伏期(P2、N2、P3、N3)呈显著正相关(r=0.496,P<0.05)。结论 通过监测HICH患者的ICP值能够密切反映患者的病情程度、预后情况,对于指导临床治疗具有一定的价值。     

事件关联电位与不同目标-背景色匹配的关系

旨在探讨不同目标－背景色匹配与事件关联电位的关系。实验以“Sternberg记忆扫描任务”为刺激模式，选取不同记忆量（目标－背景色匹配相同）和不同目标－背景色匹配（记忆量相同），采用完全随机单位组实验设计，对11名健康男性青年进行实验。结果表明：①P300更确切地说是L（P300－N200），主要表征短时记忆任务负荷的大小，即与记忆字表的长度有关；②目标－背景色匹配的变化主要由N200所表征。     

MANAGEMENT OF EXTRA-SELLAR PITUITARY TUMOURS WITH BROMOCRIPTINE: COMPARISON OF PROLACTIN SECRETING AND NON-FUNCTIONING TUMOURS USING HALF-FIELD VISUAL EVOKED POTENTIALS AND COMPUTERISED TOMOGRAPHY

To determine whether prolactin secreting and non-functioning pituitary tumours respond differently in terms of shrinkage to bromocriptine, we prospectively studied ten consecutive patients (five with prolactinomas and five with non-functioning tumours) complicated by extra-sellar extensions. No patient had received prior radiotherapy or bromocriptine and the mean dose and duration of bromocriptine treatment were identical in the two groups of patients. Objective evidence of tumour shrinkage was provided by serial half-field visual evoked potentials (VEPs) and computerised tomography (CT). All five prolactinomas were shown to shrink as assessed by improvement in VEP and four of the five as assessed by CT. In contrast, only one of the five patients with nonfunctioning tumours showed any improvement in VEP or CT. Macroprolactinomas frequently shrink rapidly when treated with bromocriptine, whereas non-functioning tumours seldom show such a dramatic response.