Transfer of the musculocutaneous nerve branch to the brachialis muscle to the triceps for elbow extension: anatomical study and report of five cases.

We report the study of the anatomical feasibility of transferring the nerve to the brachialis muscle to the upper medial head motor branch that innervate the triceps, and outcomes of such transfers in restoring elbow extension in five patients with posterior cord lesion of the brachial plexus. The length of the branches to the brachialis muscle measured 7.6 cm and the triceps upper medial head motor branch was 5 cm in 10 adult cadavers. Five male patients were treated with this transfer 5 months after the injury (range 4 to 6 months) after posterior cord injury of the brachial plexus with a mean follow-up of 31 months (range 28 to 36 months). Elbow extension scored M4 in all cases. No complications occurred. These preliminary results suggest that transferring the nerve to the brachialis muscle is an effective technique for the reconstruction of elbow extension after posterior cord brachial plexus injuries. LEVEL OF EVIDENCE: IV.

Stretch-induced nerve injury: a proposed technique for the study of nerve regeneration and evaluation of the influence of gabapentin on this model.

The rat models currently employed for studies of nerve regeneration present distinct disadvantages. We propose a new technique of stretch-induced nerve injury, used here to evaluate the influence of gabapentin (GBP) on nerve regeneration. Male Wistar rats (300 g; n=36) underwent surgery and exposure of the median nerve in the right forelimbs, either with or without nerve injury. The technique was performed using distal and proximal clamps separated by a distance of 2 cm and a sliding distance of 3 mm. The nerve was compressed and stretched for 5 s until the bands of Fontana disappeared. The animals were evaluated in relation to functional, biochemical and histological parameters. Stretching of the median nerve led to complete loss of motor function up to 12 days after the lesion (P<0.001), compared to non-injured nerves, as assessed in the grasping test. Grasping force in the nerve-injured animals did not return to control values up to 30 days after surgery (P<0.05). Nerve injury also caused an increase in the time of sensory recovery, as well as in the electrical and mechanical stimulation tests. Treatment of the animals with GBP promoted an improvement in the morphometric analysis of median nerve cross-sections compared with the operated vehicle group, as observed in the area of myelinated fibers or connective tissue (P<0.001), in the density of myelinated fibers/mm2 (P<0.05) and in the degeneration fragments (P<0.01). Stretch-induced nerve injury seems to be a simple and relevant model for evaluating nerve regeneration.

Stretch-induced nerve injury: a proposed technique for the study of nerve regeneration and evaluation of the influence of gabapentin on this model

The rat models currently employed for studies of nerve regeneration present distinct disadvantages. We propose a new technique of stretch-induced nerve injury, used here to evaluate the influence of gabapentin (GBP) on nerve regeneration. Male Wistar rats (300 g; n=36) underwent surgery and exposure of the median nerve in the right forelimbs, either with or without nerve injury. The technique was performed using distal and proximal clamps separated by a distance of 2 cm and a sliding distance of 3 mm. The nerve was compressed and stretched for 5 s until the bands of Fontana disappeared. The animals were evaluated in relation to functional, biochemical and histological parameters. Stretching of the median nerve led to complete loss of motor function up to 12 days after the lesion (P<0.001), compared to non-injured nerves, as assessed in the grasping test. Grasping force in the nerve-injured animals did not return to control values up to 30 days after surgery (P<0.05). Nerve injury also caused an increase in the time of sensory recovery, as well as in the electrical and mechanical stimulation tests. Treatment of the animals with GBP promoted an improvement in the morphometric analysis of median nerve cross-sections compared with the operated vehicle group, as observed in the area of myelinated fibers or connective tissue (P<0.001), in the density of myelinated fibers/mm2 (P<0.05) and in the degeneration fragments (P<0.01). Stretch-induced nerve injury seems to be a simple and relevant model for evaluating nerve regeneration.

Clinical findings in C5-C6 and C5-C7 root palsies with brachial plexus traction lesions.

Stretch injuries of the C5-C7 roots of the brachial plexus traditionally have been associated with palsies of shoulder abduction/external rotation, elbow flexion/extension, and wrist, thumb, and finger extension. Based on current myotome maps we hypothesized that, as far as motion is concerned, palsies involving C5-C6 and C5-C7 root injuries should be similar. In 38 patients with upper-type palsies of the brachial plexus, we examined for correlations between clinical findings and root injury level, as documented by CT tomomyeloscan. Contrary to commonly held beliefs, C5-C7 root injuries were not associated with loss of extension of the elbow, wrist, thumb, or fingers, but residual hand strength was much lower with C5-C7 vs C5-C6 lesions.

Transfer of the supinator muscle to the extensor pollicis brevis for thumb extension reconstruction in C7-T1 brachial plexus palsy.

With C7-T1 brachial plexus injuries, finger motion is absent while shoulder, elbow and wrist function are largely preserved. Previously, we have reconstructed finger flexion by transferring the brachialis muscle to the flexor digitorum profundus and flexor pollicis longus; and we have restored extension of thumb and finger by transferring the motor nerve to the supinator to the posterior interosseous nerve, which is only feasible in fresh injuries. We describe the transfer of the supinator muscle to the extensor pollicis brevis to reanimate thumb extension in patients with long standing C7-T1 brachial plexus palsy.

Variation in nerve autograft length increases fibre misdirection and decreases pruning effectiveness: an experimental study in the rat median nerve.

OBJECTIVES: In the clinical set, autologus nerve grafts are the current option for reconstruction of nerve tissue losses. The length of the nerve graft has been suggested to affect outcomes. Experiments were performed in the rat in order to test this assumption and to detect a possible mechanism to explain differences in recovery. METHODS: The rat median nerve was repaired by ulnar nerve grafts of different lengths. Rats were evaluated for 12 months by behavioural assessment and histological studies, including ATPase myofibrillary histochemistry and retrograde neuronal labelling. RESULTS: It was demonstrated that graft length interferes in behavioural functional recovery that here correlates to muscle weight recovery. Short nerve grafts recovered faster and better. Reinnervation was not specific either at the trunk level or in the muscle itself. The normal mosaic pattern of Type I muscle fibres was never restored and their number remained largely augmented. An increment in the number of motor fibres was observed after the nerve grafting in a predominantly sensory branch in all groups. This increment was more pronounced in the long graft group. In the postoperative period, about a 20% reduction in the number of misdirected motor fibres occurred in the short nerve graft group only. CONCLUSION: Variation in the length of nerve grafts interferes in behavioural recovery and increases motor fibres misdirection. Early recovery onset was related to a better outcome, which occurs in the short graft group.

The towel test: a useful technique for the clinical and electromyographic evaluation of obstetric brachial plexus palsy.

The towel test consists of covering an infant's face with a towel and seeing if he/she can remove it with either arm. In this study it has been used to aid the clinical and electromyographic assessment of 21 infants with obstetric brachial plexus palsy. At 2 to 3 months, none of the 21 infants succeeded in removing the towel, either with their normal or affected arm. At 6 months, all the infants succeeded in removing the towel with their normal arm, but 11 could not with their affected arm, and the same was observed at a further assessment at 9 months. The towel test is a reliable technique for evaluating children with obstetric brachial plexus injuries.

Brachial plexus dorsal rhizotomy in the treatment of upper-limb spasticity.

OBJECT: This study was conducted to evaluate the effects of dorsal rhizotomy on upper-limb spasticity, functional improvement, coordination, and hand sensibility. METHODS: Fifteen spastic upper limbs in 13 patients were selected and prospectively studied. Brachial plexus dorsal rhizotomy was performed in which two, three, or four dorsal roots were completely sectioned. Patients were followed up for at least 12 months after surgery; the mean follow-up period was 15.6 months and the maximum period was 30 months. A remarkable relief of spasticity was observed in all cases. Recurrence was observed in only one patient and was caused by insufficient dorsal root section. Functional improvement was observed in all cases, and functional improvement in the hand was found to be related to the presence of active finger extension in the preoperative period. Even when extended dorsal root section was performed, no hand anesthesia, either total or partial, was observed. No patient lost movement ability in the postoperative period, and no ataxic limbs were observed. CONCLUSIONS: Brachial plexus dorsal rhizotomy is very effective as a treatment for upper-limb spasticity and results in functional improvement without loss of sensation in the hand.

Selective motor hyperreinnervation by using contralateral C-7 motor rootlets in the reconstruction of an avulsion injury of the brachial plexus. Case report.

Brachial plexus avulsion injuries are a clinical challenge. In recent experimental studies the authors have demonstrated the high degree of muscle reinnervation attained when a C-4 motor rootlet was directly connected to the musculocutaneous nerve. This degree of reinnervation was attributed to the good chance that a muscle fiber can be reinnervated by a motor fiber when the number of regenerating motor neurons is increased and when competitive sensory fibers are excluded from the process. The authors present the first clinical case in which this phenomenon has been observed. This 26-year-old man, who was involved in an automobile accident, presented with an upper brachial plexus avulsion, for which he underwent operation 4 months later. The axillary and suprascapular nerves were directly surgically connected to the motor rootlets of the C-7 contralateral root by using two cables of sural nerve graft. Two years postsurgery, the patient was able to perform shoulder abduction of 120 degrees and hold an 800-g weight at 90 degrees. These results are encouraging, and in selected patients motor rootlet transfer might prove to be a useful surgical strategy.

A surgical approach for concomitant spinal cord and brachial plexus surgery: an anatomical study.

Spinal cord surgery is not the current treatment for brachial plexus avulsion injuries. However, several experimental and a few clinical cases have been reported with promising results. This surgical strategy in the near future, might prove to be useful. Different simultaneous anatomical approaches to the brachial plexus and spinal cord were studied in attempt to discover the best route to be used in the surgical reconstruction of avulsion lesions of the brachial plexus by spinal cord surgery. Eleven fresh subjects were used to compare: a) simultaneous dorsal approaches to the brachial plexus and spinal cord, b) the dorsal approach to the spinal cord and the anterior approach to the brachial plexus, c) a dorsal approach to the spinal cord combined with a dorsal approach through the triceps muscle to the terminal branches of the brachial plexus and d) a purely anterior approach to the spinal cord and brachial plexus. During the study, special attention was paid to the length of the grafts needed for repair, the possibility of entire exposure of the brachial plexus and the possibility of performing concomitant nerve transfers. As a result of the anatomical findings, we would suggest a dorsal approach to the spinal cord, suprascapular nerve and sometimes to the axillary nerve, combined with an anterior exposure to the brachial plexus in order to have the whole plexus explored and routine simultaneous nerve transfers performed. In selected cases, with limited root injuries, the dorsal approach to the brachial plexus and spinal cord and the anterior approach to the brachial plexus and spinal cord might be of interest.