Role of the target in end-to-side neurorrhaphy: reinnervation of a single muscle vs. multiple muscles

The authors examined the effects of end-to-side neurorrhaphy for reinnervation of the musculocutaneous nerve (Group A) which innervates the biceps muscle, compared to reinnervation of the median nerve which innervates multiple muscles in a rat model. Additionally, end-to-end neurorrhaphy to the musculocutaneous nerve using one-third of the median nerve (Group B) was investigated. End-to-end coaptation of the musculocutaneous nerve served as a control (Group C). In a grooming test, the biceps muscle function in Group A animals demonstrated a slower but nearly similar good recovery to Groups B and C. Biceps muscle contraction force investigated after 24 weeks demonstrated no statistically significant differences among all groups. In Groups A and B, no significant impairment of the donor median nerve function was found in a grasping test and the muscle contraction force of the flexor carpi radialis muscle, and histologic evaluation of the musculocutaneous nerve showed multiple regenerated axons distal to the coaptation site. Retrograde double-labeling in Group A animals showed reinnervation of the musculocutaneous nerve by median nerve axons located at the coaptation site. These results validate that end-to-side neurorrhaphy to a nerve innervating a single muscle is more efficient than to a nerve innervating multiple muscles, as demonstrated in an earlier study. The reason for this phenomenon is most likely that all sprouting axons are directed toward one target rather than toward multiple targets, with the latter situation resulting in a smaller number of axons and a variable distribution of axons per target. Since donor nerve sprouting axons were observed at the coaptation site, a relevance of the selected site for end-to-side neurorrhaphy is suggested. Both end-to-side neurorrhaphy and end-to-end neurorrhaphy, using one-third of the median nerve, led to useful functional recovery in this rat model, if an agonistic donor nerve is employed.     

Quantitative characterization of regenerating axons after end-to-side and end-to-end coaptation in a rat brachial plexus model: a retrograde tracer study

The efficacy of end-to-side repair as a method of nerve reconstruction has been questioned, and most studies that characterize the mode of re-innervation are marred by inappropriate experimental design and lack quantitative analysis. This makes characterization of re-innervating neurons confusing and consequently controversy remains as to the extent and source of reinnervating axons. In an experimental brachial plexus rat model, we transected the musculocutaneous nerve, labeled its neuron pool with Fast-Blue and joined the distal stump to the side of the intact ulnar nerve, or to the proximal stump of the divided ulnar nerve, to characterize neurons that reinnervate the recipient nerve. Tetramethyl-rhodamine dextran (TMRD) or fluoro-gold was used to map the reinnervating motor and sensory neurons at 12 weeks post-transection. No neurons originally labeled from musculocutaneous nerve were subsequently labeled with TMRD or fluoro-gold, showing that this original neuron pool does not contribute to re-innervation of the distal musculocutaneous nerve, but that reinnervation occurs solely by ulnar nerve motor and sensory axons. In the end-to-side group, 16.4% of the motor and 7% of the sensory donor ulnar nerve neurons re-innervated the musculocutaneous nerve exclusively, and a further 10% motor and 11.6% sensory innervated the musculocutaneous nerve by collateral sprouting of their axons. This compared to re-innervation by 62.6% of motor and 70.4% of ulnar nerve sensory neurons in the positive control that underwent end-to-end repair. Our results confirm the concept of collateral sprouting and support the use of end-to-side repair.     

不同端-侧缝合方式修复周围神经的比较研究

目的 比较周围神经标准端-侧缝合方式与其他变体在修复效果上的差异.方法 SD大鼠126只,随机分为7组,将右侧肌皮神经切断,以同侧尺神经作为供体神经,按照端-端缝合组(end-to-end,E-E组)、端-侧缝合组(end-to-side,E-S组)、侧-侧缝合外膜开窗组(side-to-side,S-S组)、侧-侧缝合外膜不开窗组(side-to-side,S-S'组)、螺旋缠绕外膜去除组(spiral,Sp组)、螺旋缠绕外膜保留组(spiral,Sp'组)、阳性对照组(controlling group,CG组)制作模型,各组分别于术后1、2、3个月取材,进行神经电生理、病理组织学检测.结果 术后3个月,各端-侧缝合组均有明显神经再生现象,但效果均不及端-端缝合组,各种端-侧缝合术式的变体与标准端-侧缝合方式相比差异不明显(P＞O.05),保留神经外膜的两组为各组中效果最差.结论 神经外膜对端-侧缝合效果有影响,各种缝合方式差异无统计学意义,单纯通过手术方式提高神经端-侧缝合后神经再生能力的效果非常有限.     

Selection of donor nerves--an important factor in end-to-side neurorrhaphy.

We have examined the effects of end-to-side neurorrhaphy on peripheral nerve regeneration using the median nerve as recipient nerve and either the antagonistic radial nerve or the agonistic ulnar nerve as donor nerves in rat upper limbs. A perineural window was created in all cases. Motor recovery up to 16 weeks postoperation was tested with the grasping test. No recovery of motor function was evident after end-to-side neurorrhaphy of the median nerve to the antagonistic radial nerve, whereas six of eight rats with end-to-side neurorrhaphy to the agonistic ulnar nerve achieved 367 g +/- 47 g grasping power as compared to 526 g +/- 6 g in end-to-end coapted control animals. No significant difference in flexor digitorum sublimus-motor nerve conduction velocity was found among all three groups. Radial nerve stimulation produced simultaneous contraction of both extensor and flexor muscles of the lower arm that disabled any coordinated movement of the paw. Histology (toluidine blue, acetylcholinesterase-stain) showed multiple regenerated (motor)-axons distal to the coaptation site in the median nerve. Reinnervation of the median nerve solely by the respective donor nerve was demonstrated by a retrograde double labelling technique. These results show that averaged 70% muscle power as compared to end-to-end neurorrhaphy with well coordinated muscle function can be achieved by axonal sprouting through end-to-side neurorrhaphy if an agonistic nerve is used as donor nerve. However, satisfying results are unpredictable. Antagonistic nerves show the ability to induce axonal regeneration, but no useful function can be expected.     

荧光逆行示踪法定位神经端侧缝合后再生来源的实验研究

目的 应用荧光逆行示踪法研究神经端.侧缝合修复臂丛神经损伤的有效性及再生神经的脊髓定位.方法 雌性SD大鼠24只,随机分为4组,造成臂丛神经上干损伤模型,分别以膈神经、同侧颈,神经根为供体神经,按照端.侧和端.端两种缝合方式修复肌皮神经.术后3个月,对大鼠肌皮神经和供体神经分别采用真蓝和双脒基黄进行逆行示踪.3、7、14 d后进行灌注固定,取颈段脊髓连续切片,荧光显微镜观察.结果 各观察点背根节及脊髓前角均出现荧光标记细胞,并逐渐增多.以同侧颈,为供体神经组,标记细胞仅出现在该节段,而以膈神经为供体神经组,标记细胞出现在颈_(3-5)节段.端一侧缝合组在相应脊髓前角或背根神经节出现,同时具有两种荧光剂的双标细胞或在同一脊髓节段同时出现分别以两种荧光剂标记的单标细胞.结论 采用不同供体神经进行端.侧缝合联合神经移植修复臂丛神经可使神经再生,荧光逆行示踪可以准确定位端.侧缝合后再生神经的来源.     

Results of reinnervation of the biceps and brachialis muscles with a double fascicular transfer for elbow flexion

PURPOSE: To report the results of a surgical technique of nerve transfer to reinnervate the brachialis muscle and the biceps muscle to restore elbow flexion after brachial plexus injury. METHODS: Retrospective review was performed on 6 patients who had direct nerve transfer of a single expendable motor fascicle from both the ulnar and median nerves directly to the biceps and brachialis branches of the musculocutaneous nerve. Assessment included degree of recovery of elbow flexion and ulnar and median nerve function including pinch and grip strengths. RESULTS: Clinical evidence of reinnervation was noted at a mean of 5.5 months (SD, 1 mo; range, 3.5-7 mo) after surgery and the mean follow-up period was 20.5 months (SD, 11.2 mo, range, 13-43 mo). Mean recovery of elbow flexion was Medical Research Council grade 4+. Postoperative pinch and grip strengths were unchanged or better in all patients. No motor or sensory deficits related to the ulnar or median nerves were noted and all patients maintained good hand function. No patients required additional procedures to further improve elbow flexion strength. CONCLUSIONS: Transfer of expendable motor fascicles from the ulnar and median nerves successfully can reinnervate the biceps and brachialis muscles for strong elbow flexion. The reinnervation of the brachialis muscle, the primary elbow flexor, as well as the biceps muscle provides an additional biomechanical advantage that accounts for the excellent elbow flexion strength obtained using this technique. Direct coaptation of the nerve fascicles was performed without the need for nerve grafts and there was no functional or sensory donor morbidity.     

Anatomical and functional connectivity of the transected ulnar nerve after intercostal neurotization in cats.

OBJECT: Acute transfer of three intercostal nerves to the ulnar nerve was performed in cats for histological and clinical evaluation of a distal muscle reinnervation. METHODS: Infraclavicular intercostal-ulnar communications were created after dividing the motor branches of the upper intercostal nerves in 14 adult cats. Reinnervation of distal forelimb muscles in the ulnar territory was assessed by electromyographic (EMG) studies and motor function rating each month until 18 months postsurgery. In five of these treated animals, and in tour controls, horseradish peroxidase (HRP) was applied to the ulnar or intercostal nerves to study the amount and distribution of retrograde motor neuron labeling in the spinal cord. Also, samples of reinnervated muscles and neurotized ulnar nerves were processed to assess regeneration. Simple ulnar transection without reconstruction led to permanent atrophy of ulnar muscles, lack of recovery according to EMG or clinical studies, and disappearance of the ulnar motor neuron pool. In contrast, ulnar neurotization with the intercostal nerves led to a high rate of functional recovery, which began 5 months postsurgery, and progressed from muscle activity synchronized with ventilatory movements to spontaneous movements that were independent of respiration. This recovery was accompanied by substantial retrograde labeling of intercostal motor neurons after HRP application in the ulnar nerve. Cell counts showed that practically the whole motor neuron pool of the involved intercostal nerves contributed to reinnervation of the transected ulnar nerve. CONCLUSIONS: These findings demonstrate that the use of intercostal nerves to neurotize long brachial plexus nerves can achieve long-lasting and successful reinnervation of distal forelimb muscles.     

Restoration of elbow flexion by performing contralateral lateral thoracic and thoracodorsal nerve transfers after experimental musculocutaneous nerve transection

OBJECT: The immediate transfer of the right lateral thoracic nerve (LTN) and the thoracodorsal nerve (TDN) to the transected left musculocutaneous nerve (MCN), leading to nerve cross-neurotization, was performed in cats to evaluate reinnervation of the biceps brachii muscle (BBM). METHODS: Surgery to produce cross-neurotization of the MCN was performed in 12 cats (treatment group). Transection of the MCN was performed without attempts at neurotization in three cats (control group). Reinnervation of the BBM was assessed by performing electromyography (EMG) 6 months (14 cats) and 26 months (one cat) postsurgery. True Blue retrograde axonal tracing studies, tensile force measurements (muscle extensometry), and histopathological analyses were performed. All cats in the treatment group recovered voluntary contraction of the BBM and regained elbow flexion. Electromyography revealed no abnormal spontaneous activity in the BBM. Muscle evoked potentials were recorded in that muscle after right C-8 ventral branch stimulation. The muscle contraction strength in the left BBM varied from 108 to 557 g. The BBMs regained their normal appearances. The region of the MCN distal to the anastomosis displayed a normal histological appearance. Fluorescence was detected in the ventral horn of the spinal cord in the right C-8 and T-1 segments. In contrast, in all cats in the control group there was atrophy of the BBM, no EMG signal, and no clinical sign of recovery. There was no contraction of the BBM, no labeled neuron in the spinal cord, and the MCN displayed major degenerative changes. CONCLUSIONS: These findings demonstrate that the LTN and TDN can be used to neurotize injured contralateral brachial plexus nerves and obtain successful reinnervation in cats.     

End-to-side nerve repair: attachment of a distal, compared with a proximal and distal, nerve segment.

Regeneration occurs if a distal nerve segment is attached end-to-side to an intact donor nerve after the nerve has been injured. We investigated if attachment of a proximal nerve segment as well, as an extra source of axons, had any advantage over the single attachment of a distal nerve segment to the same donor nerve. In rats, a single distal radial nerve, or both the proximal and distal radial nerve segments, were attached end-to-side to the musculocutaneous nerve, and effects were examined up to eight months after the repair. Cell profiles were double-labelled, indicating recruitment of axons by collateral sprouting, but there were few such cells. There was a shift in the distribution of retrograde labelled neuronal cell profiles in spinal cord and in DRGs between the two types of repair. Both procedures resulted in axonal outgrowth and some functional recovery, but there was no improvement if a proximal nerve segment was also used as a source for axons.     

Helicoid end-to-side and oblique attachment technique in repair of the musculocutaneous nerve injury with the phrenic nerve as a donor: an experimental study in rats

The purpose of this study was to identify if a modified end-to-side repair can achieve equal results of nerve regeneration compared to an end-to-end repair using donor phrenic nerves in repair of the musculocutaneous nerve and also pulmonary protection. Eighteen rats were divided into three groups of six each comparing two nerve graft techniques: helicoid end-to-side plus distal oblique repair vs. traditional end-to-end repair, using a donor phrenic nerve. The saphenous nerve was used as a graft between the phrenic nerve and the musculocutaneous nerve. The third group was used as control; the musculocutaneous nerve was transected without any repair. Three months postoperatively, electrophysiology, tetanic force, moist muscle weight, histology, nerve fiber counting, and chest X-ray were evaluated. All results have shown that this modified end-to-side repair was superior to the end-to-end repair. The former did not compromise the diaphragm function, but the latter showed an elevation of the diaphragm. Little recovery was seen in the third group. The conclusion is that this modified end-to-side repair can replace the traditional end-to-end repair using donor phrenic nerves with better results of nerve regeneration without diaphragm compromise.     

膈神经端侧吻合移位治疗肌皮神经损伤的实验研究

目的 研究膈神经端侧吻合移位至肌皮神经治疗臂丛神经撕脱伤的可行性.方法 取雄性SD大鼠51只,随机分成4组:A组,单侧全臂丛神经撕脱组;B组,膈神经端端吻合组;C组,膈神经端侧吻合组;D组,膈神经螺旋状端侧吻合组(B、C、D组膈神经均移植2.0 cm腓肠神经至肌皮神经).并于术后进行肢体功能、组织学和神经电生理检测.另取绿色荧光蛋白(green fluorescent protein,GFP)转基因F344大鼠9只,通过荧光显微镜观察膈神经轴突再生情况.方果 各实验组术后手术侧肢体功能逐渐恢复,术后神经电生理和组织学检测表明,术后3个月,C、D组左侧肱二头肌肌张力恢复率和肌湿重恢复率,分别为B组的76.4%和86.3%、85.6%和87.7%,即端侧吻合组肱二头肌功能达到端端吻合组的80%以上,同时保留了膈肌的功能.荧光显微镜观察发现膈神经轴突通过端侧吻合口长入移植神经.方论 膈神经端侧吻合治疗臂丛神经损伤的手术方法是有效、可行的.     

Effects of repeated transection and coaptation of peripheral nerves on axonal regeneration and motoneuron survival

Background and purposeSalvage procedures for facial reanimation can involve a second neurorrhaphy operation. It remains unclear whether reuse of the original donor nerve in the salvage procedure remains likely to produce successful outcome. This study aimed to investigate the effect of repeated transection and coaptation of a nerve on axonal regrowth and motoneuron survival.Materials and methodsThe sciatic nerves of Sprague Dawley rats were transected and microsutured once (the one-time group) or repeatedly at eight-week intervals (the repeated group), and the animals remained alive for eight weeks before sacrifice. The gastrocnemius muscle was weighed, and muscle fiber diameter was measured with hematoxylin-eosin staining. Axonal count of the distal nerve stump was calculated by toluidine blue staining. Myelin thickness and axonal diameter were analyzed by transmission electronic microscopy. Finally, motoneurons were retrogradely traced to the spinal cord using Fluoro-Gold.ResultsRepeated coaptation of nerves resulted in significant decreases of the wet weight ratio of gastrocnemius and muscle fiber diameter. The axonal counts and myelin thicknesses of the distal stumps were comparable between the groups, whereas axonal diameter was significantly smaller after repeated injury. Additionally, retrograde tracing demonstrated significantly less motoneurons in the L4–L6 spinal segments of the repeatedly injured animals than that of the one-time group.ConclusionsCompared with one-time nerve injury, repetitive transection and coaptation of nerves resulted in compromised axonal regeneration, motoneuron survival, and target muscle recovery. It is possible that the final functional outcome could also be compromised, and the patients should be counseled accordingly.     

Repair of the main nerve trunk of the upper limb with end-to-side neurorrhaphy: an experimental study in rabbits

The aim of this study was to assess the effectiveness of reinnervation using end-to-side neurorrhaphy in the upper extremity of the rabbit. The cut right ulnar nerve was repaired and sutured to the side of the median nerve about 3 cm above the elbow joint. The extent of reinnervation was quantitatively evaluated, as well as the integrity of the intact donor nerve in 36 rabbits randomly treated with fresh or delayed nerve repair with or without perineurotomy. Evaluations included nerve conduction velocity (NCV) of both the ulnar and medial nerves, dry muscle weight, and histologic examination (neurofilament stain and morphometric assessment) at 3 and 6 months postoperatively. NCV recovery rates were 79% and 87% for the ulnar nerve, and 89% and 94% for the median nerve compared to contralateral intact nerves, at 3 and 6 months, respectively. Flexor carpi ulnaris muscle mass measurements revealed a recovery in dry muscle weight of about 81% and 88% at 3 and 6 months, respectively, compared to the intact contralateral flexor carpi ulnaris. Histologic studies with neurofilament staining reveal numerous axonal sprouts at the distal end of the median nerve, indicative of myelinated axonal regeneration. Morphometric analysis demonstrated no difference between fresh and delayed repairs. These results indicate that in the upper extremity of rabbits, end-to-side neurorrhaphy permits axonal regeneration from the intact donor nerve, and is associated with satisfactory recovery. The effect of the procedure on the donor nerve was negligible.     

恒河猴周围神经再生纤维放大及代偿效应的电生理与功能学分析

目的 建立灵长类动物恒河猴周围神经再生纤维放大、代偿效应模型,并作电生理分析.方法 8只恒河猴右侧尺神经和肌皮神经在胸大肌下缘下4 cm水平处切断,采用可降解生物套管小间隙套接法修复,近端为损伤的尺神经近端,远端为损伤的尺神经和肌皮神经远端.生物套管内径4 mm,长度10 mm,套接后神经断端的间距为2 mm.左侧为对照组.术前采集尺神经和肌皮神经的正常传导速度作为正常对照,对修复模型于修复术后3个月和6个月分别进行电生理学检查并进行电生理与组织学分析.结果 3个月时电生理测试显示:刺激电极在尺神经近端、远端的肱二头肌和小鱼际肌内分别记录到动作电位,由尺神经近端到肌皮神经的神经传导速度为(14.62±0.53)mm/s,远远低于肌皮神经对照组的(34.17±0.93)mm/s;由尺神经近端到尺神经远端的运动神经传导速度为(20.99±1.71)mm/s,低于尺神经对照组的(48.84±1.89)mm/s.3个月时功能学检查未见肘关节的屈曲活动,未见手指的分开、合拢动作.6个月时电生理测试显示:刺激电极在尺神经近端、远端的肱二头肌和小鱼际肌内分别记录到动作电位,由尺神经近端到肌皮神经的神经传导速度为(18.47±0.86)mm/s,远远低于肌皮神经对照组的(34.17±0.93)mm/s;由尺神经近端到尺神经远端的运动神经传导速度为(27.03±1.19)mm/s,低于尺神经对照组的(48.84±1.89)mm/s.6个月时功能学检查可见肘关节的轻微屈曲活动,手指的轻微分开、合拢动作.结论 恒河猴周围神经损伤后存在神经纤维的放大、代偿效应.损伤的尺神经近端在特定的动物模型内再生的神经纤维可以长入远端的尺神经和肌皮神经,构成完整的神经传导通路并恢复尺神经和肌皮神经的部分功能.

Abstract：

Objective To establish a model of peripheral nerve fiber enlargement and compensation in rhesus monkey and conduct electrophysiological analysis. Methods Right ulnar nerve and musculocutaneous nerve of 8 rhesus monkeys were cut at 4 cm below the pectoralis major muscle and repaired with small gap bridging by using a degradable and biocompatible conduit (inner diameter 4 mm,length 10 mm) that left 2 mm distance between nerve ends. At the proximal end of the conduit was the proximal ulnar nerve end,and at the distal end of the conduit both ulnar nerve and musculocutaneous nerve were sutured in. Before the surgery,baseline conduction velocities of both nerves were collected. The electrophysiological evaluation and histological analyze were performed after 3 and 6 months respectively. Results The electrophysiological results at 3 months showed that there was action potential recorded at biceps and hypothenar muscles when the proximal ulnar nerve was stimulated. However,motor nerve conduction velocity between proximal ulnar nerve and distal musculocutaneous nerve was (14.62±0.53)mm/s,which was much lower compared to the baseline (34.17±0.93)mm/s. And the conduction velocity between proximal and distal ulnar nerve was (20.99±1.71)mm/s,which was less than 1/2 of the baseline (48.84±1.89)mm/s value. During the functional evaluation,there were no elbow flexion and finger separation and closing movement.Electrophysiologic evaluations at 6 monthsshowed conductive velocity of (18.47±0.86) mm/s and (27.03±1.19) mm/s for ulnar to musculocutaneous nerve and ulnar to ulnar nerve,respectively. Slight movement of the elbow and figures were observed. Conclusion The injured peripheral nerve fibers of rhesus monkey are enlargeable and have compensatory effects. It is possible that the regenerated nerve fibers from injured proximal ulnar nerve could integrate with distal ulnar nerve and musculocutaneous nerve and complete the pathway that could lead to partial functional restoration.     

Motor functional and morphological findings following end-to-side neurorrhaphy in the rat model.

Nerve repair cannot always be achieved by the conventional end-to-end technique. This study evaluated the functional recovery of nerves repaired with end-to-side neurorrhaphy in a rat model. The right peroneal nerves of 80 female rats were transected and divided into four groups. In group A, the nerve ends were separated and remained unrepaired; in group B, the distal peroneal ends were directly sutured to the epineurium of the tibial nerves in end-to-side fashion; in group C, the distal ends were sutured through an epineurial window at the repair site in end-to-side fashion; and in group D, the nerve ends were reconnected by the traditional end-to-end technique. Evaluation included gait analysis by calculation of a peroneal functional index, measurement of contractile function of the extensor digitorum longus muscle, wet weight of the extensor digitorum longus, and histological examination. The findings of this study suggested the following: (a) end-to-side neurorrhaphy allows effective motor functional recovery, demonstrated by earlier improvement of the peroneal functional index, stronger muscle contractile function, greater muscle weight, and higher density of regenerated axons compared with unrepaired nerves; (b) removal of the epineurium of the donor nerve at the nerve coaptation site increases the effectiveness of end-to-side neurorrhaphy, but the epineurium appears to be a partial barrier to axonal regeneration; (c) removal of the epineurium does not affect the structure and function of the donor nerve; and (d) end-to-end repair achieved the best functional recovery among the four groups; therefore, end-to-side repair should be considered as a potential alternative only when no proximal nerve is available.     

End-to-side neurorrhaphy of sensory nerves

One century passed before end-to-side neurorrhaphy was rediscovered, and now it finds more frequent use in clinical practice. Experimental studies have improved our understanding of the underlying mechanism and its potential. However, still discussed is whether reinnervation by end-to-side neurorrhaphy works as well in sensory nerves as in motor nerves. The digital nerves are sensory nerves and therefore an ideal model to investigate this question. Two cases of successful sensory reinnervation by end-to-side nerve suture are reported. We began to use end-to-side nerve repair clinically in 1995 and have used it for motor or sensory reinnervation in a total of 13 cases. In two patients primary nerve repair using end-to-side neurorrhaphy was performed in digital avulsion injuries. In one patient the avulsed ulnar nerve of the thumb was sutured end-to-side to the median nerve; in the other the ulnar digital nerve of the ring finger had been destroyed over a distance of 20 mm, and the distal stump was joined end-to-side to the radial nerve of the same finger. Sensory recovery was obtained in both patients. The static two-point discrimination was 3.0 mm, and dynamic two-point discrimination was 2-3 mm for the reinnervated finger compared to 2 mm for static and dynamic two-point discrimination in the adjacent "donor" finger. The sensation of the finger supplied by the "donor nerve" was not altered in relation to the corresponding contralateral finger site. Excellent sensory reinnervation is possible through an end-to-side nerve suture. Proximal avulsion, missing proximal nerve stumps, partial recovery, and prevention of nerve grafts are good indications for resensitization using end-to-side neurorrhaphy. No harm to the donor nerve is expected. Preference should be given to donor nerves that supply skin areas near to the anesthetic area.     

Functional Recovery Following an End to Side Neurorrhaphy of the Accessory Nerve to the Suprascapular Nerve: Case Report

The use of end-to-side neurrorhaphy remains a controversial topic in peripheral nerve surgery. The authors report the long-term functional outcome following a modified end-to-side motor reinnervation using the spinal accessory to innervate the suprascapular nerve following a C5 to C6 avulsion injury. Additionally, functional outcomes of an end-to-end neurotization of the triceps branch to the axillary nerve and double fascicular transfer of the ulnar and medial nerve to the biceps and brachialis are presented. Excellent functional recoveries are found in respect to shoulder abduction and flexion and elbow flexion.     

多组神经束支部移位治疗臂丛神经上干损伤的近期疗效

目的 通过在各受区神经近入肌点处同时进行多组神经束支部移位,恢复臂丛神经上干损伤后丧失的肩肘功能.方法 2007年2月-9月,收治4例单纯臂丛神经上干损伤男性患者.年龄21～39岁.均为车祸伤.左侧1例,右侧3例.患侧肩关节外展、外旋、上举及屈肘不能;耸肩、伸肘、屈伸腕指肌力≥4级.肌电图检查:副神经、尺神经及肱三头肌长头肌支功能好;正中神经功能轻度受损.患者于伤后3～11个月入院.于全麻下行后路副神经到肩胛上神经、肱三头肌肌支到腋神经、尺神经部分束支到肱二头肌肌支和/或正中神经部分束支到肱肌肌支移位术.结果 术后切口均Ⅰ期愈合,其中1例术后出现手部尺侧麻木症状,经对症处理后症状消失.余患者未出现与供区神经相关的运动、感觉功能受损症状.4例均获随访,随访时间7～12个月.术后3～4个月患侧均出现肩外展、屈肘动作.肌电图显示3组受区肌肉均可记录到新生电位.术后6～7个月,患者肩外展30～65°,屈肘90～120°,肌力3～4级.1例随访12个月患者肩外展、上举、外旋及届肘主动活动度基本正常,三角肌、肱二头肌外形轮廓接近正常.结论 应用功能相近的供体神经进行多组神经束支部移位具有供区损失小、恢复时间快、功能恢复佳等优点.尤其适合因伤后时间长延误治疗及锁骨上探查有风险的臂丛神经上干损伤患者.     

End-to-side nerve coaptation: a qualitative and quantitative assessment in the primate.

There are several reasons why end-to-side nerve coaptation has not been widely adopted clinically. Among these are the putative damage inflicted on the donor nerve and the variable quality of the regeneration in the recipient nerve. So far experiments on end-to-side nerve repair have been short term and mostly carried out on rats. This long-term study of end-to-side nerve repair of ulnar to median and median to ulnar nerve was performed using adult nonhuman primates. Eleven nerve repairs were studied at different time points. Eighteen, 22, 33 and 57 months after surgery a qualitative and quantitative analysis of the donor nerve and regenerating nerve revealed variable levels of percentage axonal regeneration compared with matched controls (1.4%-136%). Morphological evidence of donor nerve damage was identified distal to the coaptation site in four of the 11 cases, and in these cases the best axonal regeneration in the corresponding recipient nerves was observed. This donor nerve damage could neither be demonstrated in terms of a decrease in axon counts distal to the coaptation nor as donor target organ denervation. Recipient target organ regeneration like the axonal regeneration varied, with evidence of motor regeneration in eight out of 11 cases and sensory regeneration, as measured by percentage innervation density compared with matched controls, varied from 12.5% to 49%. Results from the present study demonstrate that the end-to-side coaptation technique in the nonhuman primate does not give predictable results. In general the motor recovery appeared better than the sensory and in those cases where donor nerve damage was observed there was better motor and sensory regeneration overall than in the remaining cases.     

IGF-I and end-to-side nerve repair: a dose-response study

End-to-side nerve repair allows for target-muscle reinnervation, with simultaneous preservation of donor-nerve function. Local administration of insulin-like growth factor-I (IGF-I) has been shown to increase the rate of axon regeneration in crush-injured and freeze-injured rat sciatic nerve. The purpose of the current project was to determine the effects of IGF-I in a rat model of end-to-side nerve repair. The left musculocutaneous nerve of 18 adult male Sprague-Dawley rats was fully transected to induce biceps-muscle paralysis. The distal stump of the musculocutaneous nerve was then coapted by end-to-side neurorrhaphy through a perineurial window to the ipsilateral median nerve. All animals were randomly assigned to three groups: Group A received 100 microg/ml IGF-I; Group B received 50 microg/ml IGF-I; and control Group C received 10 mM acetic acid vehicle solution. Infusions were regulated by the Alzet model 2004 mini-osmotic pump, with an attached catheter directed at the coaptation site. Weekly postoperative behavioral evaluations revealed significantly increased functional return over control in both experimental groups as early as 3 weeks. After 28 days, histology evaluations revealed statistically significantly higher musculocutaneous nerve axon counts and myelin thickness/axon diameter ratios in both experimental groups vs. controls. The three groups were not significantly different in motor endplate counts of the biceps muscle. Groups A and B were not significantly different in all parameters tested. This study suggests that local infusion of IGF-I may expedite the functional recovery of a paralyzed muscle, by increasing the rate of axon regeneration through an end-to-side nerve graft.