Modified end-to-side neurorrhaphy enhances axonal sprouting: a motor functional and morphological study

This study evaluated the effect of modified end-to-side neurorrhaphy on functional recovery by modulating the epineurial window and contact areas, with a donor nerve, using a rat median nerve and finger flexors. Grasping testing, muscle contractility testing, and a histological study were performed 20 weeks after surgery. The modified end-to-side repair can enhance axonal sprouting from an intact nerve, and improve the functional recovery. Either the epineurial window surface area, or the contact configuration with the donor nerve is an important factors in an end-to-side coaptation model.     

端侧吻合修复臂丛损伤实验模型的建立

目的建立端侧吻合修复臂丛神经损伤的实验模型.方法选用体重为180g～200g的Wister大白鼠36只,随机分为三组,每组12只,每只右侧神经外膜开窗(0.2cm×0.2cm),左侧外膜未开窗.将臂丛后束损伤后的桡神经远断端端侧吻合于外膜开窗的内侧束远端0.5cm部位,分别于术后1月、2月、3月在麻醉下行电生理、肌纤维截面积、肌肉湿重的检测.术后3月同时行内侧束吻合口远、近端神经纤维数目及神经束截面积测定.结果桡神经端侧吻合后,随时间的延长,运动神经诱发电位潜伏期缩短,波幅增高,传导速度加快,肱三头肌肌湿重及肌纤维截面积值逐渐加大,但开窗组优于未开窗组(P＜0.05).端侧吻合对主干神经无影响.结论后束损伤的桡神经端侧吻合于外膜开窗的内侧束的模型简便易行、可靠,有较好的实用价值.该模型的建立为研究端侧吻合技术在臂丛神经损伤的临床运用提供了一条直接途径.     

神经端侧缝合后趋化性的神经元逆行示踪研究

目的 应用神经元荧光逆行示踪技术探讨外周神经端侧缝合后神经再生的趋化性问题. 方法 选用雌性SD大鼠40只,随机分为4组,端侧缝合肌皮神经主干标记组、正常肌皮神经主干标记组、端侧缝合肌皮神经肌支标记组和正常肌皮神经肌支标记组,每组10只.端侧缝合的两组切断肌皮神经,尺神经后内侧方外膜开窗,将肌皮神经和开窗的尺神经外膜做端侧缝合,正常对照两组仅显露肌皮神经和尺神经.5个月后采用Fhuoro-Gold荧光逆行示踪技术,标记第一、二组肌皮神经主干和第三、四组肌皮神经肌支,精确计数各组大鼠脊髓C4-T1前角和背根神经节神经元. 结果 在肌皮神经主干标记两组中,端侧组脊髓前角神经元数目占正常组的30.0%(P＜0.01);背根神经节感觉神经元数目占正常组的28.1%(P＜0.01),运动神经元比例为0.36±0.09,与正常组差异无统计学意义(P＞0.05).在肌皮神经肌支标记两组中,端侧组脊髓前角神经元数目占正常组的38.1%(P＜0.01),背根神经节感觉神经元数目占正常组的70.2%(P＞0.05),运动神经元比例为o.40±0.14.与正常组差异有统计学意义(P＜0.01). 结论 外周神经端侧缝合后神经侧方出芽对特定靶器官的趋化性不明显.     

Current concepts in end-to-side neurorrhaphy

In peripheral nerve injury, end-to-side neurorrhaphy involves coaptation of the distal stump of a transected nerve to the trunk of an adjacent donor nerve. It has been proposed as an alternative technique when the proximal stump of an injured nerve is unavailable or the nerve gap is too long to be bridged by a nerve graft. Experimental and clinical data suggests that end-to-side neurorrhaphy can provide satisfactory functional recovery for the recipient nerve, without any deterioration of the donor nerve function. The most accepted mechanism of nerve regeneration following end-to-side neurorrhaphy is collateral sprouting. The source of the regenerating axons traveling in the epineurium of the donor nerve is thought to be the proximal Ranvier's nodes at the site of end-to-side neurorrhaphy, however, histologic evidence is still lacking. Partial neurotomy of the donor nerve may enhance regeneration of motor neurons through end-to-side neurorrhaphy and reinnervation of motor targets.     

Long-term evaluation of rat peripheral nerve repair with end-to-side neurorrhaphy

This study was designed to assess long-term reinnervation of end-to-side neurorrhaphy in the rat. The cut right peroneal nerve was repaired and sutured to the side of the intact tibial nerve. Both the extent of reinnervation and the integrity of the intact donor nerve were evaluated in 48 Sprague-Dawley rats randomly treated with fresh or delayed nerve repair with or without perineurotomy. Evaluations included nerve conduction velocity (NCV) of both the peroneal and tibial nerves, dry muscle weight, and histologic examination (neurofilament stain and morphometric assessment) at 8 and 12 months postoperatively. Although animals treated with perineurotomy tended to have better NCV and dry muscle weight recovery than those without, the difference was not statistically significant. No difference was observed between fresh and predegenerated nerve repair. The mean total (all four subgroups) NCV recovery rates were 87 percent and 94 percent for the peroneal nerve, and 93 percent and 95 percent for the tibial nerve, compared to the contralateral intact nerves, at 8 and 12 months, respectively. Tibialis anterior muscle mass measurements revealed a recovery in dry muscle weight of about 85 percent and 89 percent at 8 and 12 months, respectively, compared to the intact contralateral tibialis anterior muscles. Histologic studies with neurofilament staining revealed numerous axons at the distal end of the peroneal nerve in all groups, indicative of myelinated axonal regeneration. Morphometric analysis demonstrated that the presence of a window in the perioneurium improved the histologic picture. The mean number of myelinated fibers at 12 months postoperatively was significantly higher in animals with a perineurotomy window (compared to without) in both fresh and predegenerated nerve repair subgroups, respectively (p <0.05). These results indicated that 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.     

周围神经端侧缝合后神经再生及其趋化性的实验研究

目的进一步验证周围神经端侧缝合的有效性,初步探讨端侧缝合后神经再生的趋化性问题。方法雌性清洁级SD大鼠10只20侧,实验分3组,分别为神经端侧缝合组、正常对照组、切断对照组。神经缝合后5个月采用电生理、组织学、电镜等方法,观测再生神经纤维及其靶器官结构功能的改变;乙酰胆碱酯酶染色观测再生运动神经纤维及比例。结果端侧组肱二头肌复合肌肉动作电位的(CMAP)潜伏期较正常组减慢64％,最大波幅为正常组的27％。肱二头肌肌湿重为正常组的72％,肌纤维横截面积与正常组元明显差异。端侧组肌皮神经有髓神经纤维计数占正常组的44．5％,有髓神经纤维髓鞘厚度、最大直径、最小直径分别占正常组的85．9％、77．3％和65．5％。乙酰胆碱酯酶染色示端侧组肌皮神经主干运动神经纤维比例为[(0．39±0．07)％,x±s,下同],与正常组的差异无统计学意义;肱二头肌肌支运动神经纤维比例为(0．38±0．07)％,与正常组比较差异有统计学意义(P>0．01)。结论周围神经端侧缝合后有相当数目的再生神经纤维,但以髓鞘薄,直径小的纤维为主,同时能有效防止肌肉萎缩。周围神经端侧缝合后神经侧方出芽对特定靶器官的趋化性不明显。     

Ultrastructure of early axonal regeneration in an end-to-side neurorrhaphy model

The ultrastructure of the early regenerative response in an end-to-side neurorrhaphy rat model was studied using transmission electron microscopy. The ipsilateral saphenous nerve was grafted to the sciatic nerve under the following conditions: Group 1, the epineurium and perineurium of the sciatic nerve remained intact; Group 2, an epineurial and perineurial window was created at the site of the lateral neurorrhaphy; Group 3, the same as in Group 2 and, in addition, the sciatic nerve sustained a partial neurectomy. Rats were perfused through the heart with fixative containing 2 percent paraformaldehyde and 2.5 percent glutaraldehyde in 0.1 M cacodylate buffer (pH 7.4) at 4, 8, 12, 24 and 48 hr after surgery. In Group 1, no regenerating axons were observed and the myelin sheath in the donor nerve did not demonstrate any degenerative changes through 48 hr. In Group 2, an increased diameter of the unmyelinated axons and growth cones was observed in the donor nerve proximal to the coaptation site after 12 hr. Degenerative changes in the myelin sheath were observed after 12 hr within the several layers under the coaptation site. In Group 3, many growth cone-like structures were observed in the area proximal to the coaptation site after 12 hr. After 24 hr, proximal regenerating axons elongated to the coaptation site and, at 48 hr, many regenerating nerves grew inside the Schwann cell basement membrane of the graft nerve. These results indicate that the perineurial window and nerve graft are the critical conditions for inciting nerve regeneration in the donor nerve.     

Origin and history of end-to-side neurorrhaphy

This historical note offers a perspective concerning the origin of the employment of end-to-side (termino-lateral) anastomosis for nerve repair and summarizes the works that have been published on this surgical technique through the first part of the 20th Century. While the origin of end-to-side neurorrhaphy is usually dated to the beginning of the 20th Century, some works referring to this technique were published earlier, the first of which dates as far back as 1873. A number of interesting clinical and experimental studies have been carried out on end-to-side nerve anastomosis during the first years of the twentieth century. However, this literature is not easily detectable through current online scientific databases. In this paper we will give an overview of these early works. This history contributes interesting information to the debate surrounding this surgical concept and adds perspective to the use of a technique that has attracted a great deal of attention over the last 15 years.     

Neurohistochemical analysis of regeneration in rat peripheral nerve after end-to-side neurorrhaphy

We investigated the regenerative capacity of motor nerves repaired by end-to-side or end-to-end neurorrhaphy, using choline-acetyltransferase (ChAT) activity measurement or histological analysis. The right medial gastrocnemius nerves (MGNs) of 62 male Fisher strain rats were transected and divided into three groups. In group 1, the distal ends of the MGN were coapted to the side of the lateral gastrocnemius nerve, using a Y-shaped silicone tube in end-to-side neurorrhaphy. In group 2, the nerve ends were reconnected by the traditional end-to-end technique. In group 3, the nerve ends were separated and remained unrepaired. The MGNs were sampled 1, 2, and 3 months postoperatively for histological examinations and ChAT activity measurement. The medial gastrocnemius muscle (MGM) was also sampled for histological evaluations. Axonal regeneration of MGN and the recovery of MGM to nearly normal histology and weight were observed in groups 1 and 2 3 months postoperatively. Although there were no significant differences in ChAT values between groups 1 and 2, the values were significantly larger than that of group 3 3 months postoperatively. These findings suggested that end-to-side neurorrhaphy would be an alternative treatment for peripheral nerve injury in certain clinical situations. Received: June 5, 2000 / Accepted: August 25, 2000     

Axonal supercharging technique using reverse end-to-side neurorrhaphy in peripheral nerve repair: an experimental study in the rat model

OBJECT: In an attempt to improve peripheral nerve repair, the influence of the addition of reverse end-to-side neurorrhaphy for an injured peripheral nerve was investigated in the rat sciatic nerve transection model. METHODS: Twelve Sprague-Dawley rats were divided into two groups (six rats in each group). In Group I, the right sciatic nerve was cut at a point distal to the gluteal notch and repaired using end-to-end neurorrhaphy with four 10-0 nylon epineurial sutures. In Group II, after performing the same procedure as in Group I, the left sciatic nerve was cut distally and passed through a subcutaneous tunnel to the right side. The proximal stump of the left sciatic nerve was coapted to the epineurial window of the right sciatic nerve distal to the injured point in an end-to-side fashion using 10-0 nylon epineurial sutures. The effects were evaluated using analgesimeter recordings for the hind paw, electrophysiological tests, measurement of the muscle contraction force, a double-labeling technique, weight measurement and histological examination of the gastrocnemius muscle, histological examination of the bilateral sciatic nerves, and immunofluorescent staining. RESULTS: Results from the many tests used to evaluate the reverse end-to-side neurorrhaphy technique indicated that functional recovery of the denervated target organs was promoted by axonal augmentation. CONCLUSIONS: The reverse end-to-side neurorrhaphy technique could be useful in peripheral nerve repair.     

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.     

周围神经损伤端侧吻合法进展

本世纪初Ｂａｌａｎｃｅ首先报道了周围神经端侧吻合方法 ,将离断的面神经与副神经作端侧吻合治疗面神经瘫 ,虽因术后出现面部和肩部同时产生运动而放弃了该术式 ,但却肯定了端侧吻合方法的有效性。几十年来 ,周围神经损伤缺损的外科治疗出现了许多新的方式和方法 ,但与临床应用均有相当的距离 ,特别是在神经缺损太多、无法端端吻合的情况下 ,仍以自体、异体神经移植为主。由于自体神经来源有限 ,而异体神经存在排异反应等问题 ,效果不尽如人意 ,而组织工程才刚刚起步 ,所以探索神经缺损的治疗方法和机制仍是目前急待解决的问题。进入 90年…     

Selection of the donor nerve for end-to-side neurorrhaphy

OBJECT: The authors of other studies have reported that the selection of an agonistic donor nerve is required for recovering voluntary motor control after end-to-side nerve repair. In this experimental investigation, the authors' goal was to verify this assumption by performing end-to-side neurorrhaphy of the rat median nerve on its antagonistic radial nerve. METHODS: The left median nerve in 10 adult female rats was repaired by end-to-side neurorrhaphy after epineuriotomy on the radial nerve at the middle of the brachium. The time course of median nerve functional recovery was then assessed using the grasping test until postoperative Week 30. Before removing the nerve, the surgical site was carefully explored to exclude contamination by the proximal nerve stump, and the functional anatomy of median and radial nerves was assessed by electrical stimulation. Repaired nerves were then processed for resin embedding, and semithin sections were obtained for nerve fiber histomorphometry by using the dissector method. RESULTS: Repaired median nerves were repopulated by nerve fibers regenerating from the radial donor nerve as previously shown. Moreover, voluntary motor control of the flexor muscles innervated by the median nerve was progressively recovered beginning in postoperative Week 10 and reaching 42% of normal by Week 30. CONCLUSIONS: Contrary to previously reported data, recovery of voluntary motor function after end-to-side nerve repair can also be expected when an antagonistic nerve is used as a donor nerve.     

Influence of aging on regeneration in end-to-side neurorrhaphy

Aging profoundly affects the structural and functional characteristics of the peripheral nervous system. Although several experiments have investigated the effect of aging on nerve regeneration after crush and transection nerve injuries, little is known about the influence of age on end-to-side nerve repairs. It was hypothesized that decreased terminal and collateral sprouting in older animals would be associated with less robust regeneration through end-to-side nerve repairs. In this study, 27 Lewis rats underwent end-to-side repair at ages 2 weeks, 3 months, or 1 year. Histomorphometric assessments at 12 weeks demonstrated increased fiber width, percent neural tissue, and neural density in animals undergoing nerve reconstruction at the age of 2 weeks (P < 0.05). A trend toward further decline in regeneration was noted at ages 1 year versus 3 months. After end-to-side nerve repair, younger animals exhibit a more robust regenerative response, consistent with prior experience in other nerve injury models.     

周围神经端侧缝合的研究进展

神经损伤的修复通常采用两神经断端的端端缝合法 ,直至今日仍然如此。神经端侧缝合是将损伤神经的远断端缝合到相邻健康的神经干上 ,或者取一段神经段以端侧缝合的方式桥接于正常神经和损伤神经之间 ,使损伤的神经功能得到一定的恢复。神经端侧缝合术在 2 0世纪初就已开展。 190 3年Ｂａｌａｎｃｅ应用神经端侧缝合术治疗面瘫 ,与此同时 ,Ｈａｍ和Ｌｏｗ将臂丛神经上干植入颈7神经根治疗臂丛上干损伤。在此后的90年 ,再没有学者进行过神经端侧缝合术的研究。1992年巴西学者Ｖｉｔｅｒｂｏ进行了一系列神经端侧缝合的实验研究及临床应用研究…     

Low-power laser biostimulation enhances nerve repair after end-to-side neurorrhaphy: a double-blind randomized study in the rat median nerve model

Previous studies have shown that low-power laser biostimulation (lasertherapy) promotes posttraumatic nerve regeneration. The objective of the present study was to investigate the effects of postoperative lasertherapy on nerve regeneration after end-to-side neurorrhaphy, an innovative technique for peripheral nerve repair. After complete transection, the left median nerve was repaired by end-to-side neurorrhaphy on the ulnar donor nerve. The animals were then divided into four groups: one placebo group, and three laser-treated groups that received lasertherapy three times a week for 3 weeks starting from postoperative day 1. Three different types of laser emission were used: continuous (808 nm), pulsed (905 nm), and a combination of the two. Functional testing was carried out every 2 weeks after surgery by means of the grasping test. At the time of withdrawal 16 weeks postoperatively, muscle mass recovery was assessed by weighing the muscles innervated by the median nerve. Finally, the repaired nerves were withdrawn, embedded in resin and analyzed by light and electron microscopy. Results showed that laser biostimulation induces: (1) a statistically significant faster recovery of the lesioned function; (2) a statistically significant faster recovery of muscle mass; (3) a statistically significant faster myelination of the regenerated nerve fibers. From comparison of the three different types of laser emissions, it turned out that the best functional outcome was obtained by means of pulsed-continuous-combined laser biostimulation. Taken together, the results of the present study confirm previous experimental data on the effectiveness of lasertherapy for the promotion of peripheral nerve regeneration and suggest that early postoperative lasertherapy should be considered as a very promising physiotherapeutic tool for rehabilitation after end-to-side neurorrhaphy.     

鼠周围神经端侧缝合与侧侧缝合修复方式的比较研究

目的　进一步探讨神经缝合修复方式对神经再生的影响。　方法　将SD鼠分为两组。端-侧缝合组将腓神经远侧断端与去外膜胫神经（开窗）行端侧缝合,开窗大小相当于腓神经的直径。侧-侧缝合组将腓神经远侧断段侧壁去除外膜,同样胫神经侧壁去外膜,两者去除外膜的面积相当于腓神经直径的3倍。将去外膜的两神经干进行侧-侧缝合。通过足印分析法,组织学方法,电生理,神经纤维密度等测量。比较两种修复法神经再生质量。　结果　术后16周时端-侧组和侧-侧组腓神经功能指数分别为(－39.92±11.67)和（-64.49±31.31）（P=0.033）,有显著差异。电生理术后16周侧-侧组腓神经潜伏期（Lat）(1.17±0.26)、波幅（Amp）(24.9±3.59)优于端-侧组Lat(1.42±0.06)、Amp(16.5±7.04)。组织学检查显示侧-侧组神经纤维密度(4330±672)较端-侧组(3186±199)高。　结论　鼠类腓-胫神经侧-侧缝合对神经再生有益。     

神经高位端端与低位端侧或侧侧缝合相结合提高神经修复能力的实验研究

目的对无缺损的周围神经高位损伤，提出高位端端与低位端侧或侧侧缝合相结合的新方法，观察神经再生和靶器官的恢复情况。方法SD大鼠80只，高位切断左侧胫神经。随机分为5组：A组：胫神经两断端行端端缝合，远端于膝关节水平与腓神经干行侧侧缝合。B组：断端处理同A组，远端移植正中神经作胫腓神经干之间的端侧桥接缝合。C组：单纯作断端的端端吻合。D组：胫神经干近端结扎并固定，远端与腓神经干行侧侧缝合。E组：近端处理同D组，远端切除部分神经段后，与腓神经干行端侧缝合。术后行肌电图检查及组织学观察并作统计学分析。结果术后早期（4周）D、E组有神经再生，术后12周A、B组的神经再生、传导功能及靶肌肉和运动终板的恢复情况均优于C、D、E组。结论高位端端与低位端侧或侧侧缝合相结合的方法，可尽早恢复对靶组织的营养和神经再支配，为高位缝合处高质量神经的长入赢得时间，提高了有效功能的恢复。