Anterior tarsal tunnel syndrome

Three hundred twenty patients complaining of pain and/or numbness of their feet were evaluated in our Clinical Neurophysiology Laboratory. Nerve conduction studies of deep peroneal, superficial peroneal, sural and posterior tibial nerves were studied bilaterally. Needle electromyography (EMG) of anterior tibial, long peroneal, abductor hallucis longus, extensor hallucis longus, gastrocnemius and extensor digitorum brevis muscles were examined bilaterally. Nerve conduction studies of 25 healthy volunteer subjects (16 female, 9 male, age range 36-70, mean age 52.82 +/- 8.8) with no complaint composed the control group. Fourteen of these patients (8 female, 6 male, age range 40-70, mean age 55.73 +/- 12.04) were found to have anterior tarsal tunnel syndrome (anterior TTS) bilaterally or unilaterally. In the patients with anterior TTS, the nerve conduction studies revealed deep peroneal nerve distal latency as 6.5 +/- 1.9 msec; the amplitude as 1.8 +/- 1.3 mV at the ankle level; and the conduction velocity as 41.5 +/- 5.9 m/sec in the distal segment. When these values were compared with the control group statistically, results were found highly significant (p < 0.005). Needle EMG findings in the anterior TTS group showed only in the extensor digitorum brevis muscle. Other nerves and muscles were normal. All patients with anterior TTS were performing Namaz for years, and none of them had the predisposing factor which may cause entrapment neuropathy. So, we suggest that chronic prolonged stretching of the deep peroneal nerve on the dorsum of the foot during Namaz may cause anterior TTS.     

The innervation of the joints of the foot

The nerve supply of the ankle joint and of the joints of the foot was studied in dissections of fetal and adult feet and in serial sections of fetal feet stained with silver. The ankle joint was supplied by the tibial, sural, deep peroneal, and saphenous nerves, and by the accessory deep peroneal nerve when present. The tarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves, and on their dorsal aspects chiefly by the deep peroneal nerve. The joint between the lateral and intermediate cuneiform received branches from the intermediate dorsal cutaneous nerve also. The lateral dorsal cutaneous nerve and the accessory deep peroneal nerve when present provided additional branches to the subtalar and calcaneocuboid joints. The tarsometatarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves. Most of them were supplied on their dorsal aspects by the deep peroneal nerve, but the cuboid-metatarsal joints received their supply from the intermediate dorsal cutaneous nerve. The intermetatarsal joints had a similar but sparser supply. The joint between the fourth and fifth metatarsal received branches from the intermediate dorsal cutaneous nerve. The plantar digital nerves provided the main supply to the metatarsophalangeal joints. The dorsal aspect of the first metatarsophalangeal joint was supplied by the deep peroneal and the medial dorsal cutaneous nerves, of the second metatarsophalangeal joint by the deep peroneal nerve, and of the fourth and fifth metatarsophalangeal joints by the lateral dorsal cutaneous nerve. The interphalangeal joints did not receive articular branches from the dorsal digital nerves, except in the case of the interphalangeal joint of the big toe, which was supplied by the deep peroneal and the medial dorsal cutaneous nerves.     

Easily identifiable bony landmarks as an aid in targeted regional ankle blockade

Regional anesthesia around the ankle joint is well suited to a large number of surgical procedures of the foot. Previous studies have alluded to the variable nerve distribution of the foot, which may result in incomplete blocks. The aim of the study was to determine the position of the nerves in relation to the ankle joint to easily identifiable bony and prominent soft tissue landmarks to aid more accurate targeting of these nerves. A number of 94 ankles (47 left; 47 right) were dissected to expose the tibial, sural, deep fibular (peroneal), superficial fibular (peroneal), and saphenous nerves. The distance of the nerves relative to easy to find bony landmarks was measured. A distance (alpha) was measured from the middle of the tibial nerve to the most medial aspect of the medial malleolus. Measurement beta was considered from the inferior tip of the lateral malleolus to the anterior border of the sural nerve on a horizontal plane. Measurement delta was taken from the medial border of the deep fibular (peroneal) nerve to the most anterior aspect of the medial malleolus. epsilon was measured from the middle of the superficial fibular (peroneal) nerve to the most anterior aspect of the medial malleolus on a horizontal plane. The saphenous nerve was measured (gamma) from its medial border to the most anterior aspect of the medial malleolus on a horizontal plane. Factors such as sex, length, and ankle side were also analyzed concerning their influence on the position of the nerves. This study suggests that a greater degree of certainty may possibly be attained when palpable and easy to find bony landmarks are used to determine the position of the nerves around the ankle and ensure a simple to perform, predictable, and selectively targeted block.     

Normal values of F wave in lower extremities of 73 healthy individuals in Iran

F wave latency has been shown to be a simple and valuable method in evaluation of proximal part of peripheral nerves. According to our previous study of F wave of upper extremity nerves (1), maximum normal F wave latency for the median nerve was 28 ms with stimulation at wrist and 25 ms with stimulation at elbow. These values for the ulnar nerve were 29 ms and 25 ms respectively. Maximum normal difference between right and left F wave latency with wrist stimulation was 2 ms for median nerve and 2.5 ms for ulnar nerve. Maximum normal difference between median and ulnar nerve F latency was 3.5 ms with stimulation at wrist. In this study we measured F wave of lower extremity nerves in 73 healthy individuals in Shiraz. Maximum normal F wave latency for tibial nerve was 55 ms with stimulation at ankle and 46 ms with stimulation at popliteal area. Maximum normal F wave latency for the peroneal nerve was 54 ms with stimulation at ankle and 47 ms with stimulation at fibular head. Mean F ratio for both nerves was 1.29 with stimulation at knee. Maximum normal difference in F wave latency between right and left lower extremities was 3.5 ms with stimulation at ankle and 3 ms with stimulation at knee for the peroneal nerve. These values were 3 ms and 2.5 ms for the tibial nerve respectively. Maximum normal difference in F wave latency between tibial and peroneal nerve was 4 ms with stimulation at ankle and 3 ms with stimulation at knee.     

Restoration of motor function of the deep fibular (peroneal) nerve by direct nerve transfer of branches from the tibial nerve: an anatomical study

Traction injuries of the common fibular (peroneal) nerve frequently result in significant morbidity due to tibialis anterior muscle paralysis and the associated loss of ankle dorsiflexion. Because current treatment options are often unsuccessful or unsatisfactory, other treatment approaches need to be explored. In this investigation, the anatomical feasibility of an alternative option, consisting of nerve transfer of motor branches from the tibial nerve to the deep fibular nerve, was studied. In ten cadaveric limbs, the branching pattern, length, and diameter of motor branches of the tibial nerve in the proximal leg were characterized; nerve transfer of each of these motor branches was then simulated to the proximal deep fibular nerve. A consistent, reproducible pattern of tibial nerve innervation was seen with minor variability. Branches to the flexor hallucis longus and flexor digitorum longus muscles were determined to be adequate, based on their branch point, branch pattern, and length, for direct nerve transfer in all specimens. Other branches, including those to the tibialis posterior, popliteus, gastrocnemius, and soleus muscles were not consistently adequate for direct nerve transfer for injuries extending to the bifurcation of the common fibular nerve or distal to it. For neuromas of the common fibular nerve that do not extend as far distally, branches to the soleus and lateral head of the gastrocnemius may be adequate for direct transfer if the intramuscular portions of these nerves are dissected. This study confirms the anatomical feasibility of direct nerve transfer using nerves to toe-flexor muscles as a treatment option to restore ankle dorsiflexion in cases of common fibular nerve injury.     

直线前进变换为侧向跨步切入动作时的下肢生物力学变化

背景:侧向跨步切入动作是运动领域最常见的进攻技术,这显著增加了运动员膝关节受伤的风险,但目前相关侧向跨步动作的生物力学表现策略及下肢关节负荷特征并不十分清楚。目的:选择大学女子甲组篮球、足球运动员进行侧向跨步切入下肢动作策略,进行生物力学测试,并分析下肢关节的运动学及动力学参数,从而为运动员及教练员预防下肢伤害,尤其是膝关节十字韧带损伤提供重要参考。方法:选择某高校女子甲组足球及篮球各12名运动员作为研究对象,利用三维测力台及运动图像拍摄系统同步获取其侧向跨步切入动作的相关运动学及动力学参数,并运用SPSS 21.0分析软件对相关数据进行处理分析。该试验方案经天津体育学院伦理委员会批准。结果与结论:①足球运动员有较大的着地瞬间踝关节跖屈角度及髋关节外展角度、最大踝关节外翻角度、膝关节屈曲及内旋角度、膝关节屈曲及内旋角度变化量;②足球运动员有较大的踝关节外旋与髋关节内收力矩峰值,篮球运动员则有较大的踝关节跖屈力矩峰值;③篮球运动员有较小的前后分力制动第一及第二峰值、垂直分力第一峰值及较大的前后分力推蹬力峰值;④结果表明,跨步切入动作过程中,足球运动员习惯于前足着地方式进行急停,进而产生较高的地面反作用力,并增加膝关节屈曲角度进行缓冲,同时有较大的踝关节外翻角度及膝关节内旋角度,而篮球运动员在切入过程中膝关节屈曲角度较少,不利于下肢关节对地面反作用力的缓冲,并进而增加前十字韧带损伤风险。     

日韩健康人运动神经传导的比较

目的：检测健康的日本人和韩国人的末梢神经传导以研究不同国家的国民之间的传导差异,进而探讨各国民族生活习惯对末梢神经传导指标的影响。方法：以40名日本志愿者和30名韩国志愿者为对象,检测正中、尺、胫及腓神经的复合肌肉动作电位（CMAP）和F波,比较日本人和韩国人的神经传导检测结果。结果：经比较,正中、尺、胫及腓神经CMAP的远端波幅（DAmp）平均值,日本组高于韩国组（P〈0．05）;尺神经运动传导速度（MCV）日本组快于韩国组;F波最短潜伏期（F-Lat）日韩两组均有延长现象。腓神经D—Lat和F-Lat,日本组较韩国组延长;日本组中,腓神经DLat大于（x±s）的神经组的DAmp和F-Lat低下或延长。结论：正中、尺、胫及腓神经CMAP的DAmp,日本组高于韩国组;提示日韩两组均有腕肘部潜在性尺神经损伤;日本组中,可观察到踝前部的潜在性腓神经损伤。推测日常生活中的频繁而反复的轻微外伤以及日本人的正坐习惯是导致腕肘部及踝前部的潜在性神经损伤的根源。     

MEP、NCV、FW在突眼性甲状腺肿中的应用

目的:了解突眼性甲状腺肿患者感觉传入神经以及运动传出通路(包括运动中枢、脊髓、神经根和远、近端周围神经)的功能状态。方法:对44例突眼性甲状腺肿患者采用表面电极法常规顺向检测正中神经和胫后神经共88条神经感觉传导速度(SCV)、运动末端潜伏期(DL)及波幅,F波(FW)潜伏期及出现率。并在88条尺神经和腓总神经从中枢至外周传出通路不同部位予以磁刺激,分别在小指展肌和胫前肌记录复合肌肉动作电位,分别测定各段潜伏期和中枢运动传导时间(CMCT)。结果:88条正中神经和胫后神经中有16条(18%)SCV减慢或波幅降低,12条(14%)ML延长或波幅降低。4条FW潜伏期延长,4条FW出现率降低。88条尺神经和腓总神经运动诱发电位(MEP)检查中有34条(39%)波幅降低,各节段潜伏期和CMCT均未见异常。结论:NCV、FW、MEP联合检测对判断突眼性甲状腺肿是否合并神经病变具有较重要作用。     

Mechanical Properties of the Human Tibial and Peroneal Nerves Following Stretch With Histological Correlations

Despite the extensive literature regarding peripheral nerve stretch injuries, there are few studies that compare the nerve histology with the mechanical properties in humans. There is clinical evidence suggesting that the peroneal nerve is at greater risk for injury compared to the tibial nerve following total hip arthroplasty and hip trauma. We examined the two nerves from fresh human cadavers with or without controlled stretch. The mechanical properties, stiffness, and strain were compared with light microscopic preparations in longitudinal sections stained by the trichrome method for collagen and showing the effects of structural deformation. The tibial nerve had an average failure load 1.7× that for the peroneal nerve (P = 0.0001). Although the corresponding average stiffness showed a trend toward being larger (4.39 vs. 3.81 N/mm), the difference was not significant (P = 0.126). Histologically, the perineurium along with the underlying nerve fascicle was undulated in the control specimens and straightened out in the stretched specimens. Peroneal nerves went on to failure at lower loads and exhibited a wavy pattern on pathologic slides after failure, which shows that peroneal nerves fail mechanically before they can unfold. The tibial nerve has a biomechanical and histological advantage compared to the peroneal nerve during tensile testing, which could be the reason why it is less commonly damaged. We conclude that the perineurium is especially protective against deformation changes in human nerves relative to the respective nerve size and number of fascicles. Anat Rec, 302:2030–2039, 2019. © 2019 American Association for Anatomy     

Ankle sprain injuries: a 2-year prospective cohort study in female Greek professional basketball players

CONTEXT: Ankle sprains are a common basketball injury. Therefore, examination of risk factors for injury in female professional basketball players is worthwhile. OBJECTIVE: To examine rates of ankle sprains, associated time missed from participation, and risk factors for injury during 2 consecutive seasons. DESIGN: Prospective cohort study. SETTING: Eighteen professional basketball facilities. PATIENTS OR OTHER PARTICIPANTS: We observed 204 players from 18 female professional basketball teams for 2 consecutive seasons during a 2-year period. MAIN OUTCOME MEASURE(S): Using questionnaires, we recorded the incidence of ankle sprains, participation time missed, and mechanisms of injury in games and practice sessions. Potential risk factors, such as age, body mass, height, training experience, and history of ankle sprain, were examined using multivariate logistic regression. RESULTS: Fifty of the 204 participants sustained ankle injuries; injuries included 32 ankle sprains, which translated to an ankle sprain rate of 1.12 per 1000 hours of exposure to injury. The 32 players missed 224.4 training and game sessions and an average of 7.01 sessions per injury. Most injuries occurred in the key area of the basketball court and were the result of contact. Injury rates during games were higher than injury rates during practice sessions. Centers, followed by guards and forwards, had the highest rate of injury. Players who did not wear an external ankle support had an odds ratio of 2.481 for sustaining an ankle sprain. CONCLUSIONS: Female professional basketball athletes who did not wear an external ankle support, who played in the key area, or who functioned as centers had a higher risk for ankle sprain than did other players.     

自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变

背景：有研究表明移植骨髓单个核细胞治疗糖尿病下肢神经病变动物模型,通过在组织内能促进血管再生和增加血管生成因子及神经营养因子能改善临床症状。                             目的：观察自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变的临床效果。 方法：30例糖尿病下肢闭塞症患者60条下肢,按治疗方式的不同分为2组：自体骨髓单个核细胞移植的治疗组和对侧下肢非自体骨髓单个核细胞移植的对照组,各30条下肢。 结果与结论：移植4周后,治疗组总有效率高于对照组(P < 0.05)。两组治疗后神经病变自主症状问卷神经病变主觉症状问卷评分均较治疗前明显降低,治疗组评分降低更明显(P < 0.01),治疗组胫神经和腓总神经感觉和运动神经传导速度均较对照组快(P < 0.01),患者未出现并发症和不良反应。说明自体骨髓单个核细胞移植治疗糖尿病下肢周围神经病变的临床效果较好。     

健康青年人四肢远端神经F波特征

目的:观察健康青年志愿者的正中、尺、腓、胫神经F波最短潜伏期以及出现率与年龄、性别的关系.方法:选择延边大学医学院健康志愿者996名为研究对象,采用美国NICOLET公司出产的Portabook肌电图诱发电位仪,检测正中神经、尺神经、腓神经和胫神经F波,比较分析男18～21岁组、女18～21岁组与男22～25岁组、女2...     

F-wave latencies of the deep peroneal nerve in diabetic polyneuropathy

The F-wave latency of the deep peroneal nerve in function of leg length was determined in 66 normal persons and 25 diabetic patients with known polyneuropathy. The latencies were measured by stimulating the nerve at the ankle and recording the F-wave at the musculus extensor digitorum brevis using a needle electrode. The leg length was represented by the distance between the spina iliaca anterior superior and the lateral malleolus. The F-wave latencies obtained in diabetic patients were significantly higher than in controls (p less than 0.01). The method is suitable to detect polyneuropathy, especially in early cases where the conventional techniques (determination of the motor and/or sensory latencies and/or conduction velocities at the lower limbs) may still yield normal or borderline values. The upper limits of the normal values of the F-wave latencies in function of leg length is given by a non-linear curve, which can be represented by the equation: F-wave latency (msec) = 14.7 + 47.5 x (leg length in m)2. For practical purposes, the upper limit of the normal value for a given leg length can be readily determined from a latency-length curve.     

Estimation of nerve conduction velocity using surface multielectrode.

The nerve conduction velocity (NCV) was measured by using the multichannel surface EMG technique. The subjects were 7 healthy volunteers (20-49 years). The evoked responses were recorded from the tibialis anterior muscle when electrically stimulating the common peroneal nerve. The distribution and propagation pattern of the nerve action potentials (NAPs) preceding M-waves could be obtained by the multichannel surface EMG. The NCV of the fastest nerve fibers could be estimated from the time delays of the latencies of the NAPs. The average NCV (ANCV) of active nerve fibers could be also estimated from the time delays of the peak latencies of the NAPs. In 4 of 7 normal subjects, the shortest latencies and the fastest NCVs were obtained with threshold stimulation. The mean values of the NCV and the ANCV with supramaximal stimulation in 7 normal deep peroneal nerves calculated by this method were 55.9 +/- 6.5 m/s and 43.3 +/- 3.2 m/s respectively.     

正常儿童的神经电图检测报告

目的:利用神经电图检测技术,获取不同年龄期正常儿童的有关神经电生理数据,以便在儿科临床应用中提供其详细、有效的判断依据。方法:采用肌电图／诱发电位仪检测405名儿童的正中神经、尺神经、腓神经、胫神经的运动传导速度(MCV)和感觉传导速度(SCV)、F波及股神经运动潜伏期(FML)。此405名正常儿童按年龄分15组,每组25-40人,分别检测双侧肢体,取单肢结果统计制表。结果:各年龄期各检查项目波形引出率100％。MCV、SCV随年龄增加而增快,潜伏期随年龄增加而延长。除胫后神经感觉神经动作电位(SNAP)随年龄增加而降低外,其余神经复合肌肉动作电位(CMAP)、SNAP波幅均随年龄增加而增高。F波潜伏期随年龄增加而延长,F波响应率无明显年龄规律,但各神经中以胫神经响应率最高,腓总神经响应率最低。结论:不同年龄儿童MCV、SCV、F波、FML的测值与年龄的增长相关,在临床应用中,应参照相应年龄期正常值作出判断。     

Similarities and dissimilarities of the blood supplies of the human sciatic,tibial, and common peroneal nerves

The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty‐six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. Fetal age ranged from 12 to 28 weeks of gestation. Microdissection of the fetal lower extremities was done under ×5 magnifying lenses. The sciatic nerves of 10 lower extremities were dissected and excised and radiographs taken. The extraneural arterial chain of the sciatic nerve was composed of 2–6 arterial branches of the inferior gluteal artery, the medial circumflex femoral artery, the perforating arteries, and the popliteal artery. The extraneural arterial chain of tibial nerve was composed of 2–5 arteries, which were branches of the popliteal, the peroneal, and the posterior tibial arteries. Radiographs showed the presence of complete intraneural arterial chains in the sciatic and tibial nerves, formed from anastomosing vessels. Dissection showed that, in 97.2% of the specimens, the common peroneal nerve was supplied only by one popliteal artery branch, the presence of which was confirmed radiologically. The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression. Clin. Anat. 26:875–882, 2013. © 2012 Wiley Periodicals, Inc.     

The consistent presence of the human accessory deep peroneal nerve

Twenty-four human legs were dissected macroscopically to study the morphological details of the accessory deep peroneal nerve. This nerve arose from the superficial peroneal nerve and descended in the lateral compartment of the leg, deep to peroneus longus along the posterior border of peroneus brevis. Approaching the ankle joint, this nerve passed through the peroneal tunnels to wind around the lateral malleolus; it then crossed beneath the peroneus brevis tendon anteriorly to reach the dorsum of the foot. The accessory deep peroneal nerve was found in every case examined and constantly gave off muscular branches to peroneus brevis and sensory branches to the ankle region. In addition, this nerve occasionally had muscular branches to peroneus longus and extensor digitorum brevis, and sensory branches to the fibula and the foot. The anomalous muscles around the lateral malleolus were also innervated by this nerve. Neither cutaneous branches nor communicating branches with other nerves were found. The present study reveals that the accessory deep peroneal nerve is consistently present and possesses a proper motor and sensory distribution in the lateral region of the leg and ankle. It is not an anomalous nerve as has previously been suggested.     

Electrophysiologic response recorded in the first dorsal interosseous muscle with stimulation of the tibial and deep fibular nerves

Foot intrinsic muscle innervation may demonstrate some variability. The first dorsal interosseous muscle (FDI) is innervated by the deep branch of the lateral plantar nerve (LPN) from the main trunk of the tibial nerve. Contribution from the deep fibular nerve (DFN) may also play a role in the supply of the FDI. Thirty healthy adult volunteers were studied to determine the presence and type of response in the FDI with stimulation of the tibial nerve/deep branch of the LPN and DFN. Both nerves were stimulated at the ankle and knee with a surface and needle recording from the FDI. Latency, amplitude, and conduction values were recorded for each nerve. The incidence of DFN supply to the FDI was 16.6% with a mean ankle amplitude of 152 microV. The incidence of tibial nerve/deep branch of the LPN supply to the FDI was 100%, with a mean ankle amplitude of 5.11 mV. The superficial branch of the LPN is most often studied when evaluating for tarsal tunnel syndrome because the standard recording site is the abductor digiti minimi (ADM). Recording from the ADM, however, frequently produces a less than desirable waveform, and the technical challenges encountered with this site make tarsal tunnel syndrome assessment difficult. It is also possible that selective involvement of the deep branch of the LPN may occur, and if so, recording from the FDI may prove valuable.     

小腿神经肌支自身比例定位及其临床意义

目的：为小腿创伤修复及肌瓣移植提供形态学依据。方法：采用解剖剥离测量方法，对３６具（共７２侧）成人下肢标本的胫神经及腓总神经肌支进行自身比例定位研究。结果：①腓总神经和胫神经发出的各肌支主要以２支型出现率最多；②腓总神经和胫神经发出的各肌支主要集中于小腿的１段和２段；③腓总神经和胫神经发出的各肌支进入各肌的区位，均有倾向于以神经干为轴心近距离分布的规律。结论：确定了腓总神经和胫神经肌支的危险区段和危险区位。讨论了有利于开展带神经血管蒂肌瓣移植的肌支类型。     

Conduction block--the diagnostic value in the early stage of Guillain-Barre syndrome

Immune-mediated segmental demyelination is the basic pathomorphological substrate of the Guillain-Barre syndrome (GBS). The aim of the study is to determine the diagnostic value of the conduction block in the early stage of GBS, as well as its changes during of the development of the disease. Sixteen patients with GBS were examined. Electroneurography (motor nerve conduction studies) was performed at interval from the third day of the onset till the first year. Partial CB in the early stage of the disease (range 0-15 days) was registered in 81,2% of the patients. In demyelinating forms of GBS partial CB was determined in 61% of the investigated nerves. It is the most often observed in peroneal nerves, followed by tibial, ulnar and median nerves in the same order. The maximal reduction of the amplitude of the CMAP (maximal CB) was registered before the 30th day from the onset of the disease with following recovery on the sixth month and first year. Partial CB is more often observed in the early phase of GBS, when it could be the only sign of demyelination. When patients reached a clinical plateau, progressive slowing of motor nerve conduction and increasing CB were registered. Proximal CB was revealed more often than distal CB, because of the typical initial localization of the process. In the early phase of GBS, proximal CB is most often found in lower limbs (in peroneal nerve, followed by tibial nerve). In patients with axonal damage, CB was more severe than in demyelinating group. Partial CB is an important diagnostic criterion for segmental demyelination, which helps for confirming the diagnosis of early GBS, when conduction velocity and other electrodiagnostic criteria for demyelination are normal.