Free Gracilis muscle transfer to restore elbow flexion in brachial plexus injuries

Abstract

Restoration of elbow flexion is an important step in managing brachial plexus injuries. After more than one year of functional denervation, the muscle atrophy is significant enough that transferring a free muscle to act as a new effector becomes a treatment option. The goal of this study was to evaluate the effectiveness of transferring a gracilis free muscle, innervated by three intercostal nerves, to restore elbow flexion. This was a retrospective study of a series of gracilis transfer procedures in 12 men having an average age of 25.6 years (23-37) and average follow-up of 112 months (28-260). The patients were operated on average at 42 months (14-153) following their motor vehicle accident; five had a partial paralysis (C5C6C7) and seven had a complete paralysis (C5-T1). The surgical technique and rehabilitation protocol were the same for all the patients. There were two cases of acute arterial thrombosis (17%) that led to functional failure. When these two cases were excluded from the analysis, all the remaining patients had a useful result (British Medical Research Council score ≥ M4) and 2.5 kg of elbow flexion strength measured on a dynamometer. The strength was 3.8 kg (2.7 to 55) for partial plexus injuries and 1.6 kg (0.3 to 1.5) for complete plexus injuries. For partial injuries, active elbow flexion was 128° and extension -38°, versus 103° and -23° for complete injuries. The average DASH score was 42 for partial injuries and 32 for complete injuries. Free Gracilis muscle transfer is a challenging technique that leads to reproducible and encouraging results, but has vascular failure rate that cannot be ignored. When compared to published results, our series provides similar results to primary suturing performed within 6 months for cases of complete paralysis and within 12 months for cases of C5C6C7 partial paralysis; our series was better for cases beyond 12 months.