Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. An anatomic study and case report

BACKGROUND: The current method for treatment of median nerve palsy after a brachial plexus injury is unpredictable. On the basis of an anatomic study of the median nerve in the arm, we present a new method of selective neurotization of the median nerve. METHODS: Internal topographic features of the fascicular groups of the median nerve were observed in seventeen cadavera. On the basis of the anatomical results, selective neurotization of the posterior fascicular group of the median nerve in the arm was performed in one patient with a complete brachial plexus palsy. RESULTS: In the distal half of the arm, the branches of the median nerve consistently collect into three fascicular groups, which are located at the anterior, middle, and posterior parts of the median nerve trunk. The anterior fascicular group is composed of the branches to the pronator teres and the flexor carpi radialis, the posterior fascicular group is composed mainly of the anterior interosseous nerve and the branches to the palmaris longus, and the middle fascicular group is made up mostly of the branches to the hand and the flexor digitorum superficialis. A transfer of the full length of the phrenic nerve was used to selectively reinnervate the posterior fascicular group of the median nerve in a patient with a complete brachial plexus palsy. The muscles supplied by the posterior fascicular group regained Grade-4 power, according to the system of the Medical Research Council, sixteen months after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: The typical arrangement of the fascicular groups of the median nerve in the arm favors the technique of selective neurotization, which has been used effectively in one patient to date.     

Vascularized nerve grafts for the treatment of large nerve gap after severe trauma to an upper extremity

We reviewed the clinical outcomes of vascularized nerve grafts for the repair of large nerve gaps (longer than 20 cm) after severe trauma to an upper extremity. Six patients who underwent vascularized sural nerve grafting (five to the median nerve and one to the ulnar nerve) with a monitoring skin flap were evaluated. The length of the vascularized sural nerve grafts ranged from 20 to 30 cm, with a mean length of 23.3 cm. All but one of the monitoring skin flap grafts was successful. In those patients for whom the monitoring skin flap graft was successful, the mean static-2PD at the corresponding fingertip was 14.2 mm (range 10–20 mm). Evaluation of these patients with the Semmes-Weinstein test produced the following results: filament 6, two patients; filament 10, three patients. The results of this study show that vascularized sural nerve grafting should be considered as a clinical alternative for nerve reconstruction in patients with nerve defects longer than 20 cm.     

Partial nerve injuries in the upper extremity

The level of injury of a peripheral nerve is a critical factor that has a great impact on the result of the repair. At the level of the wrist, the median and ulnar nerves have pure motor and sensory fascicular groups. Proximal to the wrist, the motor fascicular groups combine with sensory fascicles and become mixed nerves. Mapping the fascicular orientation with electrical stimulation is indicated for injuries located from the wrist to the distal third of the forearm. Successful application of this technique depends on the level of injury, anesthetic technique, and careful patient selection. Children and patients with other serious coexisting injuries are not candidates for this technique. The depth of anesthesia must provide adequate analgesia while allowing the patient to communicate and cooperate with the surgeon during the procedure. There are few reports in the literature about repair of partially injured nerves in the upper extremities and the comparison of functional outcomes with or without the use of nerve grafts is not easy. Even under ideal operative conditions and with ideal indications, the outcomes are not always satisfactory. Hurst et al reported very good results using end-to-end repair of fascicular groups in their series. Using the rating system of the British Medical Research Council, they reported motor values of 4.0 (normal 5.0), and sensory values of 3.8 (normal 4.0). Kato et al reported very good results in their series of 51 cases with group fascicular end-to-end suture using orientation with electrical stimulation. In this series, there were five patients with partial nerve laceration and end-to-end coaptation of the fascicular groups provided very satisfactory outcome. End-to-end repair of the fascicular groups seems to provide better results than repair of the nerve using nerve grafts. It is desired, however, that the nerve gap be less than 2 cm for the application of end-to-end repair of the nerve.     

猕猴组织工程化周围神经移植物的实验研究

目的 评价利用化学萃取法获得的神经支架制备猕猴组织工程化周围神经移植物修复40mm尺神经缺损的效果。方法 共使用成年猕猴9只，随机取其中的6只，培养自体雪旺细胞，应用已经制备好的去细胞神经为支架材料构建组织工程化周围神经移植体修复猕猴尺神经的40mm缺损。实验分实验组，空白组，正常对照组3组。术后5个月通过形态学，肌电检测和免疫组织化学方法观察。结果 3组均未发现猕猴双手有糜烂或溃疡形成，猕猴小鱼际肌群的饱满度和弹性于术前无明显差别。实验组与正常对照组间小鱼际肌群的运动动作电位潜伏期．最大振幅及再生神经纤维的数目差异均无统计学意义（P〉0．05）。但在实验组与空白组间的差异有统计学意义（P〈0．05）。结论 用自体源雪旺细胞微注入去细胞同种异体神经支架构建的组织工程化神经移植物修复猕猴40mm的尺神经缺损，可取得与自体神经移植相似的效果。     

Concepts of nerve regeneration and repair applied to brachial plexus reconstruction

Brachial plexus injury is a serious condition that usually affects young adults. Progress in brachial plexus repair is intimately related to peripheral nerve surgery, and depends on clinical and experimental studies. We review the rat brachial plexus as an experimental model, together with its behavioral evaluation. Techniques to repair nerves, such as neurolysis, nerve coaptation, nerve grafting, nerve transfer, fascicular transfer, direct muscle neurotization, and end-to-side neurorraphy, are discussed in light of the authors' experimental studies. Intradural repair of the brachial plexus by graft implants into the spinal cord and motor rootlet transfer offer new possibilities in brachial plexus reconstruction. The clinical experience of intradural repair is presented. Surgical planning in root rupture or avulsion is proposed. In total avulsion, the authors are in favor of the reconstruction of thoraco-brachial and abdomino-antebrachial grasping, and on the transfer of the brachialis muscle to the wrist extensors if it is reinnervated. Surgical treatment of painful conditions and new drugs are also discussed.     

Intraneural topography of the ulnar nerve in the cubital tunnel facilitates anterior transposition

The surgical management of cubital tunnel syndrome includes anterior transposition of the ulnar nerve. The success of all transposition procedures is dependent on placement of the nerve anterior to the medial epicondyle without tension. Fifteen cadaveric upper extremities underwent anterior transposition followed by anterior transposition with separation of the most proximal motor branches from the main ulnar nerve for a distance of 1, 2, and 3 cm. Proximal dissection of these motor branches achieved an average gain in distance from the epicondyle of 71%, with an average distance from the epicondyle of 3.6 cm. The intraneural topography of the ulnar nerve was studied in five additional cases. Cross-section analysis of the fascicular anatomy at 333 μm intervals along the length of the nerve with longitudinal reconstructions confirmed a safe dissection plane without interfascicular plexus formation. The most proximal motor branch in the forearm could be traced proximally an average of 6.7. cm within the nerve before interfascicular mingling occurred (range 6.0 to 7.5 cm). Thus, 6.0 cm represented the upper limit of safe proximal dissection in these nerves. Proximal separation may be performed without disruption of interfascicular plexus connections and will facilitate anterior transposition.     

幼年大鼠神经根断裂后移植修复对神经元凋亡基因表达影响的研究

目的 观察幼年大鼠神经根损伤后即行神经移植修复对近端神经元C-Jun和Bcl-2表达水平的影响.方法 将出生18 d SD大鼠24只等分为2组:神经根切断组,将右侧颈5神经根切除0.3cm;神经根修复组,颈5 神经根切除后取腓肠神经移植修复.于术后4周取颈5脊髓和背根神经节.通过RT-PCR检测大鼠近端神经元C-Jun和Bcl-2 mRNA的表达水平,并比较两组间的差异.结果 与神经根切断组相比,神经根修复组神经元C-Jun mRNA的表达水平明显下降,Bcl-2 mRNA 的表达水平显著升高.结论 幼年大鼠凋亡基因表达水平变化是产瘫早期臂丛神经修复手术保护近端神经元的分子机制.     

幼年大鼠神经根断裂后移植修复对神经元凋亡基因表达影响的研究

目的 观察幼年大鼠神经根损伤后即行神经移植修复对近端神经元C-Jun和Bcl-2表达水平的影响.方法 将出生18 d SD大鼠24只等分为2组:神经根切断组,将右侧颈5神经根切除0.3cm;神经根修复组,颈5 神经根切除后取腓肠神经移植修复.于术后4周取颈5脊髓和背根神经节.通过RT-PCR检测大鼠近端神经元C-Jun和Bcl-2 mRNA的表达水平,并比较两组间的差异.结果 与神经根切断组相比,神经根修复组神经元C-Jun mRNA的表达水平明显下降,Bcl-2 mRNA 的表达水平显著升高.结论 幼年大鼠凋亡基因表达水平变化是产瘫早期臂丛神经修复手术保护近端神经元的分子机制.     

幼年大鼠神经根断裂后移植修复对神经元凋亡基因表达影响的研究

目的 观察幼年大鼠神经根损伤后即行神经移植修复对近端神经元C-Jun和Bcl-2表达水平的影响.方法 将出生18 d SD大鼠24只等分为2组:神经根切断组,将右侧颈5神经根切除0.3cm;神经根修复组,颈5 神经根切除后取腓肠神经移植修复.于术后4周取颈5脊髓和背根神经节.通过RT-PCR检测大鼠近端神经元C-Jun和Bcl-2 mRNA的表达水平,并比较两组间的差异.结果 与神经根切断组相比,神经根修复组神经元C-Jun mRNA的表达水平明显下降,Bcl-2 mRNA 的表达水平显著升高.结论 幼年大鼠凋亡基因表达水平变化是产瘫早期臂丛神经修复手术保护近端神经元的分子机制.     

尺神经功能束组走行模式的三维重建

目的 在组织学切片基础上，应用计算机三维成像技术，重建尺神经功能束组走行的三维图象，以期指导临床臂丛与尺神经损伤后的显微修复，为臂丛神经根性撕脱伤后手内肌功能的恢复提供必要的形态学基础。方法 制作尺神经连续断面组织切片，AchE组织化学染色，将切片转化为数字图象，人工判断功能束组性质，图形处理软件配准后，采用体数据场轮廓线表面重建方法，应用VC语言编制三维图象存储构建程序，在程序中重建尺神经功能束组走行的三维图象。结果 在程序中实现了尺神经功能束组走行的三维重建。对重建的各神经功能束的外表面进行三维显示，实现人机交互的任意三维旋转、任意断面切割。通过对感兴趣的显示对象(神经干和各束组)的选择，可以在同一三维空间同时显示任意神经功能束组的立体结构，结果反映出它们的在空问位置上的结构、毗邻关系和走行。通过与显微解剖结果对照，发现其显示图象与解剖结果基本吻合。结论 构建的尺神经功能束组的三维图象，能较真实的反映束组的走行分布情况，对临床医生理解神经内部结构，设计手术方案和在术中对照束组的分布方位调整手术方法有积极的作用。     

Rat sciatic nerve repair with a poly-lactic-co-glycolic acid scaffold and nerve growth factor releasing microspheres

The effect of microsphere delivered Nerve Growth Factor (NGF) in a poly-lactic-co-glycolic-acid (PLGA) 85/15 nerve conduit bridging a 10mm rat sciatic nerve gap was assessed, comparing nine groups (n = 6): PLGA conduits filled with saline, saline and NGF, saline with blank microspheres; four different NGF microspheres (5, 20, 50, and 100 mg/ml); an autologous graft and sciatic nerve gap. Histomorphometry, retrograde tracing, electrophysiology, and functional outcomes were evaluated up to 16 weeks. The autologous graft showed the largest fascicular area (0.65 mm(2) ) and had a significantly greater number of myelinated fibers (P < 0.0001). Electrophysiology showed Compound Muscle Action Potential (CMAP) recordings for the autologous graft returning at 6 weeks after nerve transection, reaching their highest amplitude of 3.6 mV at endpoint. No significant differences were found in functional evaluation between groups or between conduits with microspheres and the saline filled conduit. A PLGA 85/15 nerve conduit is capable of sustaining nerve regeneration. The microsphere delivery system does not interfere with regeneration.     

臂部正中神经内神经束组分布的解剖学研究及其临床意义

目的 为在修复臂段正中神经中的重要束组及利用臂段部分神经作束组移位提供解剖学依据。方法 对34侧成人上肢标本的臂部正中神经内神经束组的分布作了显微外科观察。结果 在臂中、下段,正中神经的分支恒定地组成3个神经束组：旋前圆肌肌支和桡侧腕屈肌肌支束组在神经干的前方,骨间前神经和掌长肌肌支束组在神经干的后方,中间束组是由指浅屈肌肌支和手部分支组成的正中神经前臂主干的近段。结论 骨间前神经和掌长肌肌支、旋前圆肌肌支和桡侧腕屈肌肌支可在臂中、下段从正中神经干分离出来进行修复和移位。在臂部采用正中神经部分移位时,要了解神经干内束组的分布特点。     

Nerve graft prefabrication: preliminary study

This study aimed to produce prefabricated nerve graft as effective as autologous nerve graft without donor site morbidity for repairing segmental nerve defects. Thirty rats were used and were separated into three groups. In the first group, vein graft excised from jugular vein was sutured to make a bridge between epineural gaps of tibial and peroneal nerve. In the second group, one-quarter of the nerve diameter was incised after excision of the epineurial sheath, and the vein graft was sutured between epineurial gaps. In the third group, the vein graft was sutured between epineurial gaps, and plasmid including vascular endothelial growth factor (VEGF) gene were injected into muscle next to the nerve. Functional and morphological assessments were performed at the end of the 8 weeks. We prefabricated nerve graft by using autologous vein as a conduit material between two intact nerves and by gene therapy, which increases the VEGF level in the medium.     

Mesh epineurial splinting for late median nerve repair in older patients: a preliminary report

Eleven patients over 40 years old, with median nerve lesions at the wrist, were operated on an average of 5 months after their injury. In six patients, the median nerve was repaired using a polypropylene mesh applied to secure the nerve stumps in contact, thereby allowing for direct repair with microsutures. Six patients had their median nerve repaired with sural grafts. The average gap length was 2.8 cm for the mesh repair, whereas it was 3.7 cm for the graft repair group. Eighteen months after surgery, pressure thresholds were perceived in the index and thumb pulp by all six patients with a mesh repair but in only two of five patients with a graft repair. Five in the mesh repair group recovered function in the abductor pollicis brevis muscle, versus none in the graft group. These preliminary results suggest that, in older patients, the use of a mesh to splint the coaptation site followed by direct nerve repair yields better recovery than conventional sural grafts.     

Effect of bilateral median nerve excision on sciatic functional index in rat: an applicable animal model for autologous nerve grafting

Autologous nerve graft is still the treatment of choice in peripheral nerve injury when end-to-end nerve repair is not possible. The sciatic nerve is the most widely used nerve in rat experimental studies. To assess the possibility of using the rat median nerve as a delayed animal autologous nerve graft model in nerve regeneration studies, the effect of median nerve excision on the sciatic functional index (SFI) was evaluated. Thirty rats were distributed into three equal groups: in the sciatic and median nerve excision (SMNE) group, 10 mm of the right sciatic nerve was excised and 5 mm of both median nerves were excised a week later; in the median nerve excision (MNE) group, 5 mm of both median nerves were excised (both sciatic nerves remained intact); in the control group, no intervention was performed. SFI was calculated before and after each intervention. There was no significant difference between mean SFI values calculated before and after median nerve excision in SMNE (-86.8 versus -88.4, P = 0.61) and MNE groups (-3.9 versus -3.3, P = 0.93). Therefore, it may be suggested that median nerve excision does not affect SFI measurements in intact and/or completely injured sciatic nerve, which may propose the median nerve as an autologous donor nerve graft model in rats.     

Fascicular topography of the median nerve: a computer based study to identify branching patterns

This study was undertaken to definitively describe the internal anatomy of the median nerve. Thirty median nerves were dissected in the distal forearm and hand. Sixteen nerves were sectioned every 250 to 1000 microns along their length. Computer programs were developed in our laboratory to digitize and store the data. Analysis of our data has shown the following consistent findings: (1) the number of fascicles remains relatively constant over the centimeter lengths of the nerve; (2) over 75% of the sections contain zero to one fascicular branching; (3) fascicular groups destined for the same endpoint remain localized within the nerve for long distances; and (4) calculation of Wilks' lambda demonstrates a high degree of group fascicular regionality.     

Vascularised nerve grafts

Since Taylor (1976) successfully performed the first vascularised free nerve graft, experimental and clinical data have not provided conclusive support for the superiority of this method of repairing loss of nerve substance.Experimental work yields conflicting results. Histologic results are in favour of vascularised grafts but non-vascularised fascicular grafts placed in a healthy bed recover sufficient neovascularisation within a short period of time (four to six days).In the field of brachial plexus repair, vascularised grafts give consistent results. However, if thrombosis of the anastomoses occurs, the grafts fail completely.In our experience, vascularised nerve grafts used for repairing digital nerves and arteries, have a high rate of thrombosis.There are few potential donor sites. A nerve graft cannot be considered to be physiologically vacularised if it relies only on an artery or on an arterialised vein. Given the present state of immunosuppressant treatments, vascularised allografts are not yet appropriate.Therefore, vascularised nerve grafts have limited applications. In general it is preferable to repair the tissue bed so as to promote revascularisation of conventional nerve grafts.     

End-to-side nerve graft repair based on synergistic peripheral terminal motor branches: investigation in a nonhuman primate model

Summary BACKGROUND: Spinal nerve avulsion frequently occurs in brachial plexus injury, becoming irreparable lesions. Nerve transfer at the very proximal site within a limited time interval after injury leads to satisfactory functional results. Oberlin reported a neurotization technique at a more peripheral location. Hypothetically, there might be useful functional results performing very peripheral end-to-side nerve graft repair using synergistic tiny terminal motor branches. We created one possible application of such a peripheral synergistic terminal end-to-side nerve transfer in a median nerve defect model in nonhuman primates. An end-to-side nerve graft repair bridging from the terminal motor branch of deep branch of the ulnar nerve to the thenar motor branch of median nerve was performed. The purpose of this study was to investigate the efficacy of this hypothesis. METHODS: Seven adult baboons were used in this study. At baseline, we electrophysiologically demonstrated no variation in innervation of median- and ulnar-nerve-innervated thenar muscles. Transection of the median nerve was performed. Subsequently, the abductor pollicis brevis muscle could neither be stimulated by the median nerve nor by the ulnar nerve. Baboons underwent end-to-side coaptation of a nerve graft to the deep branch of the ulnar nerve and end-to-end coaptation to the thenar motor branch of the median nerve. Assessment of functional recovery was performed by electrophysiological evaluation, thenar muscle weight, and video slow-motion analysis. RESULTS: All animals recovered opposition of the thumb 3 months after surgery. The abductor pollicis brevis muscle, preoperatively innervated by the median nerve, did not respond to electrophysiological stimulation of the transected median nerve but to stimulation of the ulnar nerve via the nerve graft. Length of nerve graft (in average 2.3 cm) showed no correlation to muscle weight or electrophysiological parameters. CONCLUSIONS: The results in this series demonstrate the efficacy of end-to-side nerve graft repair at the level of tiny very peripheral terminal motor branches in a nonhuman primate median nerve defect model. Applications of this technique may enhance functional results by avoidance of time-dependent end organ failure.      

臂丛神经显微结构的计算机三维重建

目的：重建臂丛神经的外轮廓及其内部神经束的精细三维行径，同时探索一种臂丛神经显微结构计算机三维重建的实用方法。方法：取健康成年尸体的臂丛神经标本2例(从神经根管出口至正中神经交叉处，平均长20cm)，作好标记，以女性头发作为定位线，采用连续组织切片后胆碱脂酶组织化学染色，高分辨率数码摄像系统获取二维数码信息后对臂丛神经显微结构进行三维重建。结果：三维重建真实地再现臂丛神经的三维立体结构及其内部各神经束的三维立体行径，并可显示臂丛神经中神经束的任意断面及其全长的解剖结构与相互关系，形象地展示臂丛神经内部神经束的复杂重组过程。重建结构均能单独或搭配显示，还能任意角度显示：在臂丛的五个根中，C6-C8内部神经束数目较C5、T1多。在C6-C8中，又以C7神经根内部神经束数目最多。结论：臂丛神经内部神经束结构相当复杂，相互间不断交叉重组，形成独特的神经束网络结构。臂丛神经显微结构三维重建由于采用了较为精确的定位材料和方法，三维图像显示效果较好，是一种较为实用的方法。     

闭孔神经移位修复腰骶丛神经根撕脱伤的解剖学观察及临床应用

目的 观察闭孔神经移位修复腰骶丛神经根撕脱伤的可行性及临床疗效.方法 取15具成人尸体标本,显露双侧闭孔神经及腰骶丛神经根.测量闭孔神经从主干起始部至闭孔入口处的长度及其在闭孔入口处的横径和纵径,计算横截面积,并在高倍显微镜下计数有髓神经纤维数目.以相同方法测量并计算股神经相应指标.2002年1月至2007年9月,共为5例腰骶丛损伤患者进行闭孔神经移位术.行健侧闭孔神经经椎体前腹膜后通路移位与患侧股神经直接吻合4例,闭孔神经移位与同侧S1神经根直接吻合1例.结果 闭孔神经的平均长度为(10.51±0.9)cm,横径(2.03±0.37)mm,纵径(2.78±0.29)mm,有髓神经纤维数目(5974±1996)根;股神经横径(3.79±0.58)mm,纵径(6.53±0.61)mm,有髓神经纤维数目(15 860±4350)根.术后3～7 d,所有患者供肢内收肌肌力均减弱至2～3级;术后3个月,4级2例,3级2例,2级1例(至术后1年时,内收肌肌力恢复3级).4例修复患侧股神经的患者,术后分别随访8个月～5年,股四头肌肌力4级2例,2级1例,1级1例;1例行闭孔神经移位与同侧S1神经根直接吻合的患者,术后11个月时小腿三头肌及屈趾肌肌力恢复至3级.结论 闭孔神经可作为一个安全有效的动力神经源,用其修复腰骶丛神经根撕脱伤可获得满意疗效.