上中下三干后股对指总伸肌及肱三头肌长头交叉支配的电生理研究

目的通过术中电生理检测,在臂丛神经中找到指总伸肌支配神经的相对集中区,为神经移位重建伸指功能新术式的设计提供理论依据。方法2008年2月-2009年10月,17例臂丛神经撕脱伤行健侧C7神经根移位术。应用Keypoint型肌电图仪,术中分别对上、中、下三干后股进行电刺激,在指总伸肌及肱三头肌长头记录复合肌肉动作电位（compound muscle action potential,CMAP）。结果指总伸肌记录到的CMAP最大波幅有76．5％（13／17）为电刺激下干后股,17．6％（3／17）为电刺激中干后股,5．9％（1／17）为电刺激上干后股。电刺激上、中、下三干后股在指总伸肌记录到的CMAP波幅平均值分别为：0．75±1．16mV,1．64±1．54mV,5．32±4．58mV。在肱三头肌长头记录到的最大CMAP波幅有53％（9／17）为电刺激中干后股,47％（8／17）为电刺激下干后股。电刺激中干及下干后股在肱三头肌长头记录到的CMAP平均波幅分别为4．57±3．84mV,5．98±8．43mV。结论支配指总伸肌的神经纤维来自下千后股比C7后股的多,而下干后股亦是肱三头肌长头的主要支配神经。     

同侧C_7神经根移位后对其支配肌影响的初步观察

目的　观察C7神经移位后对C7神经根所支配肌肉功能的影响。方法　 1996年 2月至 2 0 0 0年 2月 ,对 7例臂丛上干或C5,6神经根损伤患者 ,均采用同侧C7神经根 (全部 )移位修复 ;并观察手术前、后背阔肌、肱三头肌及指总伸肌肌力及肌电的变化。术后 1周 7例 ,术后 4个月 6例 ,术后 1年 5例进行了肌力测定及肌电检查。结果　术后 1周背阔肌、肱三头肌及指总伸肌的肌力较术前均有所下降 ,下降幅度多在 1级以内。肌力的下降均呈可逆性 ,术后 4个月三块肌肉的肌力均已恢复正常。术后 3个时间组三块肌肉CMAP(复合肌肉动作电位 )的波幅、潜伏期和术前比无明显影响。结论　臂丛上干损伤采用同侧C7移位后 ,供区背阔肌肌力下降最明显 ,肱三头肌次之 ,指总伸肌最小。     

同侧C7神经根移位后对其支配肌影响的初步观察

目的：观察C7神经移位后对C7神经根所支配肌肉功能的影响。方法：1996年2月至2000年2月,对7例臂丛上干或C5,6神经根损伤患者,均采用同侧C7神经根（全部）移位修复,并观测手术前、后背阔肌、肱三头肌及指总伸肌肌力及肌电的变化。术后1周7例,术后4个月6例,术后1年5例进行了肌力测定及肌电检查。结果：术后1周背阔肌、肱三头肌及指总伸肌的肌力较术前均有所下降,下降幅度多在1级以内。肌力的下降均呈可逆性,术后4个月三块肌肉的肌力均已恢复正常。术后3个时间组三块肌肉CMAP(复合肌肉动作电位）的波幅、潜伏期和术前比无明显影响。结论：臂丛上干损伤采用同侧C7移位后,供区背阔肌肌力下降最明显,肱三头肌次之,指总伸肌最小。     

肱三头肌及指总伸肌电生理支配权重分析在同侧C7神经根移位术中的临床意义

目的 分析在健侧C7神经根移位术中得出的臂丛神经各干对肱三头肌/指总伸肌的电生理支配权重,推断其对于同侧C7神经根移位术的影响,为探讨其安全性和适应证提供电生理依据.方法 随机选择2007年8月-2007年10月15例全臂丛神经根性撕脱伤,行健侧C7神经根移位的患者.男13例,女2例:年龄18～49岁,平均28岁.致伤原因:坠落伤1例,压砸伤2例,余均为车祸伤.左侧8例,右侧7例.术中依次刺激健侧臂丛神经上、中、下干,于肱三头肌/指总伸肌记录复合肌肉动作电位(compound muscle action potential,CMAP),比较各干的CMAP波幅所占百分比,确定臂丛神经各干对肱三头肌,指总伸肌的电生理支配权重.术后6个月内随访肱三头肌/指总伸肌肌力,并复查肌电图了解其自发电活动和主动募集反应情况.结果 15例患者均获随访6个月.肱三头肌的电生理支配权重:上中干型3例(20%),中下干型3例(20%),全干型7例(47%),中干型2例(13%);指总伸肌:中下干型3例(20%),全干型10例(67%),下干型2例(13%).肱三头肌:术后1个月,2例出现肱三头肌肌力4级,募集反应单纯相,至术后3个月恢复正常.余患者术后1个月肌力均达5级,募集反应单纯混合相或混合相.指总伸肌:术后1个月,患者肌力及募集反应均恢复正常.结论 对于各种电生理支配权重的患者,C7神经根的切取均不会造成肱三头肌和指总伸肌的实质性损害,同侧C7神经根移位术是安全可行的;但对于中干支配权重高的患者,采用同侧C7神经根全干移位应慎重,有可能造成肱三头肌短期内的肌力下降.     

不同术式切断C7神经根后对神经支配肌影响的实验研究

目的　研究切断大鼠 C7神经根不同纤维束组后其支配肌的肌电图变化 ,为临床选择性 C7神经根移位术提供理论根据。方法　 SD大鼠 2 4只 ,按手术术式不同随机分成 3组 ,每组 8只鼠。A组 :单纯切断上干 ;B组 :切断上干及部分中干 ( C7前股前外侧部分 ) ;C组 :切断上干及全中干。左侧为实验侧 ,右侧为自身正常对照组。术后 4周 ,各组大鼠测定双侧背阔肌、肱三头肌、指总伸肌的复合肌肉动作电位 ( CMAP) ,并计算其潜伏期和波幅。所得数据进行统计学处理。结果　与对照组相比 ,C组背阔肌、肱三头肌及指总伸肌 CMAP的波幅及潜伏期均有明显的变化 ,波幅衰减、潜伏期延长 ;以背阔肌受的影响最为显著。A、B两组上述肌肉 CMAP的波幅及潜伏期均无明显改变。结论　单纯上干损伤后切取 C7神经根前股前外侧束组对 C7神经根主要支配肌 (背阔肌、肱三头肌、指总伸肌 )并无多大影响 ;而 C7全干切断后对上述肌肉影响较大     

颈7神经根切断术后的肌电电生理改变（II）

为进一步研究颈７神经根切断后对上肢神经功能的早期影响，近年来我们对１８例应用健侧颈７神经根移位桥接治疗的臂丛神经损伤患者，于同一个体相同检测条件下测定并观察切断颈７神经根术前、术后２周内，健侧上肢的肌电电生理变化。观察内容及结果１．肌电：背阔肌、肱三头肌、伸指总肌和尺侧屈腕肌，术后均无明显失神经改变。２．周围神经传导：（１）五个手指指神经的腕感觉神经动作电位（ＳＮＡＰ），术后１￣３指ＳＮＡＰ波幅均     

同侧颈7神经根移位治疗臂丛上干根性撕脱伤患肢功能变化的实验研究

目的研究臂丛上干根性撕脱伤再切取同侧颈，后不造成肢体功能进一步损害的代偿机制。方法60只SD大鼠随机等分为二组，上干根性撕脱＋同侧颈7神经根切断为实验组，单纯上干根性撕脱为对照组。术后3、6和12周每组取10只大鼠对颈7神经根代表肌（背阔肌、肱三头肌、桡侧腕短伸肌和指总伸肌）作肌肉组织学、神经电生理与运动终板组织形态学的检测。结果术后3周实验组与对照组相比，四块颈7代表肌的湿重显著减轻且肌细胞截面积缩小，复合肌肉动作电位（CMAP）的潜伏期显著延长并波幅明显下降，运动终板突触后膜面积明显减小，上述指标的二组差异均有统计学意义（P〈0．05或P〈0．01）。荧光显微镜观察显示实验组颈7代表肌的运动终板分布稀疏，电镜下可见形态不成熟的再生运动终板。伤后6周，实验组肱三头肌CMAP潜伏期及波幅的恢复率以及桡侧腕短伸肌与指总伸肌肌细胞截面积、CMAP潜伏期及波幅和突触后膜面积的恢复率与对照组相比，差异无统计学意义（P均〉0．05）。实验组颈7代表肌的运动终板数量已较3周时明显增多，超微形态亦趋于成熟。到12周，实验组各项检测指标的恢复率均已接近对照组（P均〉0．05），其颈7代表肌的运动终板分布密集且数量较多，超微结构接近成熟，形态与对照组基本一致。结论臂丛上干根性撕脱伤切取同侧颈7神经根后，下干神经纤维能通过末梢运动终板的再生对中干代表肌进行代偿性支配，故不会导致肢体功能的进一步损害。     

大鼠臂丛上中干损伤后肱三头肌背阔肌功能状态变化的实验研究

目的:研究大鼠臂丛神经下干对上肢三头肌、背阔肌的支配权重,为临床臂丛上干损伤后,同侧C_7移位的可行性提供依据。方法:成年SD大鼠,将一侧臂丛中、上干切除,术后2周、2个月后,分别做同侧三头肌、背阔肌电生理检测,健侧对照。结果:术后2周,三头肌、背阔肌动作电位波幅明显下降,动作电位潜伏期明显延长。术后2个月,该两项指标均可以恢复到正常水平。结论:臂丛下干单独存在时,在短期内肱三头肌、背阔肌功能明显下降,但随着时间延长,该两肌肉可以恢复正常电活动。     

背阔肌电生理支配权重分析在同侧C7神经根移位术中的临床意义

目的 通过比较健侧G移位术中背阔肌上、中、下份复合肌肉动作电位（compound muscle action potential，CMAP）波幅的差异，了解臂丛神经根对背阔肌的支配权重，从而为同侧G移位术的应用提供电生理依据。方法于健侧G移位术中依次刺激臂丛神经上、中、下干，分别于背阔肌上、中、下份记录CMAP，比较CMAP波幅差异，确定各臂丛神经对背阔肌的支配权重。术后4周随访背阔肌肌力。结果CMAP波幅提示背阔肌上份主要受臂丛中干和上中干支配占60％，受上干支配仅10％；中份受中干支配占70％，受上干支配占15％；下份受中、下干和中干支配占70％，无单独上干支配。综合背阔肌上中下份分析显示由上干主要支配仅占8％、由中干主要支配占33％、由下干主要支配占10％、中下干支配占23％、上中下干支配占8％。术后4周随访背阔肌功能无明显影响。结论通过术中对背阔肌所受臂丛神经支配的电生理权重的研究，证实了同侧G神经根移位术的安全性。     

应用电生理检测肌皮神经肱肌肌支在神经根的定位

目的 探讨应用电生理检测肌皮神经肱肌肌支在神经根的定位,为肱肌肌支移位术的临床应用寻求理论依据.方法 选择30例臂丛神经损伤行健侧C7移位的患者,年龄16～50岁,平均[(28.9±7.7)岁,-x±s,下同],术中暴露健侧正常的臂丛神经,运用意大利ESAOTE的Reposer四道程肌电诱发电位仪,分别刺激C5～T1神经根,在肱肌记录诱发电位的潜伏期及波幅.结果 30例健侧C7移位者术中电生理检测,刺激臂丛神经根时,其中C529例、C630例、C728例记录到肱肌运动电位,而刺激C8、T1仅有6例记录到较小的肱肌运动电位.C5、6、7运动电位的潜伏期和波幅分别为(6.32±1.50)ms、(6.51±1.36)ms、(6.99±1.33)ms和(4.87±4.43)mV、(5.65±4.76)mV、(0.90±2.29)mV,其中以C6的波幅最大,C5次之,C7波幅较小,提示C5、6支配肱肌的神经纤维数可能最多.结论 肱肌主要接受来自C5、6神经纤维的支配,该肌支移位至正中神经(骨间前神经)是可行及有效的,同时该方法为今后临床研究周围神经的定位提供了检测手段.     

Electrophysiological study of the dominant motor innervation to the extensor digitorum communis muscle and long head of triceps brachii at posterior divisions of brachial plexus

Background: Restoration of elbow and finger extension function is still challenging in management of complete brachial plexus avulsion injury, mainly because of fewer available donor nerves for transfer to the radial nerve. Selective neurotization could be a potentially alternative for overcoming this dilemma. This study was designed to identify the innervation dominance of the extensor digitorum communis muscle (EDCM) and long head of the triceps brachii (LTB) at the level of division of brachial plexus. Methods: From February 2008 to October 2009, 17 patients with complete brachial plexus avulsion injury underwent the procedure of contralateral C7 nerve root transfer. The posterior divisions of brachial plexus on the healthy donor side were intraoperatively stimulated and the compound muscle action potentials (CMAPs) from the extensor digitorum communis muscle and long head of triceps brachii were recorded by an electrophysiological device. Results: In 13 out of 17 patients (76.5%), the maximal amplitude of CMAP from EDCM was induced by stimulation of the posterior division of lower trunk (PDLT). The mean amplitudes of CMAP from EDCM with stimulation of the posterior division of upper trunk (PDUT), middle trunk (PDMT), and PDLT were 0.64 ± 0.95, 1.64 ± 1.56, and 5.32 ± 4.67 mV (P < 0.05), respectively. The maximal amplitude of CMAP from LTB was induced mainly by stimulation of the PDMT) and PDLT (6 out of 11 and 5 out of 11 patients). The mean amplitudes of CMAP from LTB with stimulation of the PDUT, PDMT, and PDLT were 0.15 ± 0.24, 5.20 ± 4.27, and 7.48 ± 9.90 mV, respectively. The differences of CMAPs between stimulation of PDUT and other two divisions were significant (P < 0.05). Conclusions: From the electrophysiological point of view, this study showed that the PDLT was the major motor division innervating EDCM, and the PDMT and PDLT shared the similar proportion of LTB innervation. © 2011 Wiley‐Liss, Inc. Microsurgery, 2011.     

Functional compensative mechanism of upper limb with root avulsion of C5-C6 of brachial plexus after ipsilateral C7 transfer

Objective： To investigate the compensative mechanism of no further impairment of the upper limb after ipsilateral C7 transfer for treatment of root avulsion of C5-C6 of the brachial plexus.
Methods： Sixty Sprague Dawley （SD） rats were randomly divided into a CT-transection group and a control group, 30 rats each. In the CT-transection group, the left forelimbs of the animals underwent transection of ipsilateral C7 nerve root while C5 and C6 nerve roots were avulsed. In the control group, the left forelimbs only underwent C5 and C6 root avulsion. The representative muscles of C7 （innervated mainly by C7） including latissimus dorsi, triceps, extensor carpi radialis brevis and extensor digitorum communis were evaluated with neurophysiological investigation, muscular histology and motor end plate histomorphometry 3, 6 and 12 weeks after operation. The right forelimbs of all rats were taken as the control sides.
Results： Three weeks after operation, the recovery rates of amplitudes of compound muscle action potential （CMAP） and CMAP latency, muscular wet weight and cross-sec- tional area of muscle fibers, and area of postsynaptic membranes of those four representative muscles in the C7- transection group were significantly lower than those of the control group （P 〈0.05 or P 〈0.01）. Six weeks postoperatively, the recovery rates of CMAP amplitude and latency of the triceps showed no significant difference between the C7- transection group and the control group （P〉0.05）. For theextensor carpi radialis brevis and the extensor digitorum communis, the recovery rates of the cross-sectional area of muscle fibers, the amplitude and latency of CMAP and the area of postsynaptic membranes showed no significant dif- ference between the two groups （P 〉0.05）, while the rest parameters were still significantly different between the two group （P 〈0.05 or P 〈0.01）. As far as the ultramicrostructure was concerned in the CT-transection group, more motor end plates of four representative m     

Continuous EMG recordings and intraoperative electrical stimulation for identification and protection of cervical nerve roots during foraminal tumor surgery

OBJECTIVE: Spinal cord function is now routinely monitored with somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) during surgery for intraspinal cervical dumbbell and foraminal tumors. However, upper extremity nerve roots are also at risk during these procedures. Anatomic relations are frequently difficult to interpret because the nerve roots may be displaced by the tumor. We used electrical stimulation with compound muscle action potential (CMAP) recordings at multiple sites to identify the location and course of the involved nerve root and to provide real-time information regarding the functional status of the roots to predict postoperative outcome. METHODS: Ten patients were monitored during surgery for cervical dumbbell or foraminal tumors. SEPs and MEPs were monitored as a routine procedure. CMAPs were recorded from needle electrodes placed in the deltoid, biceps, triceps, and flexor carpi ulnaris muscles. Spontaneous electromyography (EMG) muscle activity was also continuously monitored. A handheld monopolar stimulation electrode was used to elicit evoked EMG responses to identify and trace the course of nerves in relation to the tumor. In four patients, the stimulation threshold was tested before and after tumor resection to predict postoperative nerve root function. RESULTS: Electrical stimulation with CMAP recording was successful in localizing nerve roots during tumor resection in all 10 patients. Monitoring predicted postoperative nerve root preservation after tumor removal in each case. It was possible to identify either by using low-level stimulation (<2.0 V) or by observing changes in spontaneous EMG amplitude if activation was present during surgical dissection. The monitoring of spontaneous muscle activity in response to direct or indirect surgical manipulation during tumor resection also provided continuous assessment of nerve root function and identified any physiologic disturbance induced by surgical manipulation. CONCLUSIONS: Electrical stimulation in the operating field and recording of CMAPs facilitated nerve root identification and predicted postoperative function during dissection and separation from ligamentous or neoplastic tissue in 10 patients. Electrical stimulation might also be useful to predict postoperative preservation of function when nerve root sacrifice is necessary and no motor response is detected intraoperatively.     

Electrophysiologic evaluation of lumbosacral single nerve roots using compound muscle action potentials

Transcutaneous electrical stimulation applied to the vertebral column produces compound muscle action potentials (CMAPs) from the leg muscles. Using this method, we evaluated the efferent pathways of the lumbosacral nerve roots. The subjects were 26 healthy volunteers and 31 patients with lumbar disc herniation (LDH). CMAP recordings were obtained from the bilateral vastus medialis, tibialis anterior, extensor digitorum brevis, and abductor hallucis muscles using low-output-impedance stimulation. In normal subjects, the CMAP latency increased linearly with the distance between the stimulating electrode and the recording electrode, with little difference in latency between the left and the right sides in each subject. The CMAP amplitude was significantly lower in the patients with LDH, and the latency was also prolonged when the stimulating electrode was placed above the lesion. This technique may thus be a useful noninvasive method for assessing lumbosacral nerve root function in patients with LDH.     

Unilateral drop finger due to cervical spondylosis at the C6/7 intervertebral level

A 64-year-old man who presented right drop fingers without pyramidal signs due to cervical spondylosis is reported. Magnetic resonance imaging showed a high signal intensity change on T2-weighted scans of the spinal cord at the C6/7 intervertebral level. Evoked spinal cord potentials following ulnar nerve stimulation were attenuated at the C6/7 intervertebral level. Compound muscle action potentials (CMAPs) following right cervical nerve root stimulation were recorded from the extensor digitorum communis. CMAPs following right C8 nerve root stimulation were evoked with small amplitudes. Small polyphasic CMAPs with prolonged onset latency were recorded following right C7 nerve root stimulation. Simultaneous C7 radiculopathy and C8 segmental spinal cord lesion due to cervical spondylosis at the C6/7 intervertebral level were the causes of drop fingers in the present case. Unilateral drop finger is a clinical symptom commonly associated with posterior interosseus nerve palsy, but mention should be made about cervical lesions causing drop finger. Electromyographic abnormalities of the triceps and first dorsal interosseus muscle were the key findings for differentiating the cause from paralysis of the posterior interosseous nerve.     

Measuring of the compensation of a nerve root in a cervical schwannoma: a case report

A 64-year-old woman experienced numbness and hypesthesia of the right C6 dermatome a year ago. Enhanced magnetic resonance imaging of the cervical spine revealed an enhanced tumor continuing into the foramen from the spinal cord at the C5/6 intervertebral level. It was thought to be an Eden type 2 schwannoma. Right unilateral laminectomy was performed on C5. The tumor was present in the intradural area and arose from the right C6 anterior root. Compound muscle action potentials (CMAPs) from the deltoid, biceps, and extensor carpi radial (ECR) muscles were recorded following electric cervical nerve root stimulation (0.2ms duration, and 7mA intensity). CMAPs of large amplitude were obtained from the deltoid, biceps, and ECR muscles following C5 root stimulation, but those following C6 root stimulation were small. As a result it was determined that the right C6 root was not associated with the nerve distribution for these muscles, so it was resected en bloc with the tumor. No apparent loss of motor function was observed. Standard needle electromyography showed no denervation potentials or decrease in motor unit potentials in either the deltoid or biceps muscles. Intraoperative investigation for compensation of nerve root is clinically useful for determining whether resection of a nerve root results in muscle weakness after surgery for a cervical schwannoma.