Brachial Muscle Shift Repair Of Brachial Plexus Lower Trunk Injury Basic And Clinical Research

Objective To investigate the innervation of the brachialis muscle and the topographic features of the fascicular group of the median nerve, and to provide the anatomic evidence of transferring of the brachialis muscle branch of the musculocutaneous nerve (BMBMCN) for selective neurotization the finger flexion fasciculus of the median nerve in the lower trunk of brachial plexus injury.Methods The study was done on the 50 limbs in 20 fixed and 5 fresh adult human cadavers. Assisted by the operating loupe, the microanatomy and measurement were done to observe the origin, branches, types of the BMBMCN and the median nerve, as well as their adjacent structures were concerned. The length and diameters of the BMBMCN were measured. And based on the Hunter's line, the level of the origin the BMBMCN was surveyed by the measuring scale. Histochemical stain of the acetylcholinesterase (AchE), HE and Weil's myelin staining were done to the BMBMCN and the median nerve, so that the feature of the nerves can be observed and the medullated nerve fibers were counted by the Leica FW4000 analysis system. The internal topographic features of the fascicular groups of the median nerve in the level of the BMBMCN were observed by combining of the microanatomical technique and the histochemical stain of the acetylcholinesterase (AchE). Additionally, the technique of transferring of BMBMCN for selective neurotization the finger flexion fasciculus of the median nerve were designed and tested in the 6 fresh adult human cadavers.Results The brachialis muscle was innervated by the musculocutaneous nerve (MCN) totally, and doubly innervated by about 44% of the radial nerve. The length, the diameter and the branches of the BMBMCN was 4.84±1.29cm, 1.69±0.30mm, 1.16±0.55branches respectively. According to the type of the BMBMCN, there were three types in our study, which was type I , 45 limbs (90%);type II ,3 limbs (6%); typeIII,2 limbs (4%) respectively. Based on the Hunter's line and the coracoid, the level of the origin the BMBMCN were 13.18±2.77cm, 18.1 l±2.76cm respectively. The histochemical stain of AchE indicated that the BMBMCN were totally made up with the medullated nerve fibers. And the counting of the medullated nerve fibers is 1324±116. At the same time, the micro-anatomy of the median nerve indicated thatthere were 44 (88% ) limbs of superior position type;4(8%) limbs of inferior position type; 2(4%) limbs of simple-root type. In the level of the BMBMCN, the median nerve consistently collected into three fascicular groups, which were 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. And it was tested in 6 fresh cadavers with success by incision of 10~ 15cm long , except stoma split was observed in one case. Conclusion1. To transfer BMBMCN is the effective and safe technique;2. The internal topographic features of the fascicular groups of the median nerve provides the anatomic evidence for transferring the median nerve fascicles or selective neurotization of the median nerve in the arm.3. The success sham operation confirms the feasibility of this technique, and provides the anatomic evidence for its clinical applications.Part Two Transfer of brachialis branch of musculocutaneous nerve to reconstruct the finger flexion for the brachial plexus lower trunk injury of the rat: experimental studyObjective To establish the model of the brachial plexus lower trunk injury in the rat, and to explore the experimental feasibility of transferring of the brachialis muscle branch of the musculocutaneous nerve (BMBMCN) for selective neurotization the finger flexion in the brachial plexus lower trunk injury of the rat.Methods 1. 60 adult SD rats were randomly divided into 3 groups: group A was C8> Tl nerve root avulsion simply to establish the model of the brachial plexus lower trunk injury in the rat; group B wasC7^ C8 and Tl nerve root avulsion toestablish the model; group C was C8^ Tl nerve root avulsion combined with about two centimeters defect of the median nerve in the arm to establish the model. The models were evaluated by the observation and nerve electrophysiology.2. 128 adult SD rats were randomly divided into 4 groups: group A was lower trunk injury with no repairing; group B was contralateral C7 transferring to restore the finger flexion; group C was BMBMCN transferring with end-to-end technique; group D was BMBMCN transferring with end-to-side technique. The ethology of the rat was observed 1st ,2nd ,3rd ,4th month postoperatively. At the same time, the recovery rate of the grasping force, the recovery rate of the latency and the amplitude of the median nerve, the recovery rate of the wet muscle weight of the flexor pollicis longus (FPL) and the flexor disitorum profundus (FDP) and their muscle fibers sectional area, and the myelinated nerve fibers through put and the sectional area of the median nerve were performed respectively. And in the 4th month postoperatively. the recovery rate of the Fmax and Tmax of the FPL and FDP were performed. And the ultrastructure of the median nerve and the muscle fibers of the FPL and FDP were observed with the electron microscope.Results 1 .The efficiency of the model of the group C was better than group A or B, because group C can provide the entire palsy of the lower trunk, and the normality of the upper trunk .2. The elbow flexion of the experimental side of the rats were not appearing the obvious impediment.(T)The rats of group A were not grasping the finger constantly. And There were remarkable significances between group C and other groups in the 3rd month (p<0.05) , and between group C and group A/D in the 4th month (p<0.05) . ?In the 4th month postoperatively, the recovery rate of the Fmax of the FPL and FDP were remarkable significances between group C and group D (p<0.05) ,and no remarkable significances between group C and group B (p>0.05) .And the Tmax of the FPL and FDP were no remarkable significances between group C and other groups (p>0.05) . ?The recovery rate of the latency of the median nerve were remarkable significances between group B and groupC/ D in the 1st ,2nd month, and between group C and group D in the 3rd ,4th month. And the amplitude of the median nerve were remarkable significances between group C and group D (p<0.05) .and no remarkable significances between group C and group B( p>0.05 )postoperatively.@The recovery rate of the wet muscle weight of the FPL and the FDP were remarkable significances between group A and group D (p<0.05) .and no remarkable significances between group C and group B(p>0.05) in the 2nd~4lh month postoperatively. And their muscle fibers sectional area were remarkable significances between group A and other groups (p<0.05) .? The recovery rate of the myelinated nerve fibers through put a of the median nerve were remarkable significances between group C and group B in the 2nd month, and between group C and group D in the 3rd ,4lh month (p<0.05) . (6) The recovery rate of the sectional area of the median nerve were remarkable significances between group C and group B/D in the 2nd~4lh month postoperatively (p<0.05) .Conclusion 1. C8^ Tl nerve root avulsion combined with about two centimeters defect of the median nerve in the arm to establish the brachial plexus lower trunk palsy is the feasible and ideal model.2.The technique of transferring the BMBMCN to selectively restore the median nerve to reconstruct the finger flexion in the brachial plexus lower trunk palsy of the rat is better than that of the contralateral C7 transferring, because the former has shorter interval to regenerate than another one.Part Three Transfer of brachialis branch of musculocutaneous nerve to reconstruct the finger flexion for the brachial plexus lower trunk injury: The clinical studyObjective To design and apply a new technique of transferring of the brachialis muscle branch of the musculocutaneous nerve (BMBMCN) for finger flexion in the clinic and to evaluate the curative effects of the various therapy methods for the lower trunk of brachial plexus injury.Methods Retrospective study was done in 26 adult lower trunks injury from October 2001 to August 2004. Three therapy methods were applied for repairing the median nerve to restore the digital flexion: group A transferring with the BMBMCN; group B transferring with contralateral C7; group C transferring with intercostal nerve respectively. The cases were followed up in the 3rd ,6th ,9th ,12th month postoperatively. And the observation of the restoration in the limbs, grip strength, muscle power and nerve electrophysiology were mensurated at that time.