Elbow Flexion Reconstruction by End-to-Side Neurorrhaphy in Phrenic Nerve Transfer

Abstract

Purpose: Phrenic nerve transfer (PNT) has proven to be an effective approach for the treatment of brachial plexus avulsion injuries (BPAI). But there have been major concerns about the possibility of deterioration of the pulmonary and diaphragm functions after PNT. In the current study, we performed end-to-side neurorrhaphy in PNT for BPAI patients while minimizing the potential damage to the diaphragm function. We prospectively assessed the efficacy of end-to-side neurorrhaphy for PNT in reconstructing the elbow flexion by regenerating the anterior division of the upper trunk (ADUT) or the musculocutaneous nerve (McN) in a series of 5 patients. Methods: From January to June 2008, 5 patients with BPAI underwent PNT with an end-to-side fashion, to regenerate the ADUT (3 patients) or the McN (2 patients). The operative delay after injury was from 1 to 6 months (mean, 2.5 months). The follow-up duration was 24 months. The regeneration outcomes of ADUT or McN were evaluated with an electromyography (EMG) test. The recovery of elbow flexion power was recorded according to the British Medical Research Council (MRC) grading system. Pulmonary function tests (PFTs) were used to assess the respiratory function. Chest fluoroscopy and phrenic nerve conduction studies were performed in the evaluation of phrenic nerve and diaphragm functions. Results: At the final visits after 2 years, all patients regained various degrees of biceps strength (M4 in 2 patients, M3 in 1 patient, M2 in 1 patient, and M1 in 1 patient). At 24 months after surgery, the average prolongation of latency of PN was 2.88 seconds, and the average decrease in amplitude from before the operation was 32.4%. The diaphragm function and PFTs were normal in all patients. Conclusions: PNT with end-to-side neurorrhaphy could provide functional biceps recovery in a majority of patients, with preservation of donor nerve function.