Mid-Term Follow-Up and Critical Analysis of the Traditional Spinal Accessory Nerve to Suprascapular Nerve Transfer

Introduction: The aim of this retrospective study was to evaluate the restoration of shoulder flexion and external rotation by neurotization of the Suprascapular Nerve with the Spinal Accessory Nerve (SAN-SSN) in patients with severe traction injuries of the brachial plexus involving C-5 and C-6 cervical roots. Methods: Eleven SAN-SSN neurotizations by direct suture were performed. Inclusion criteria were: root avulsion/rupture of C-5 and C-6; suprascapular nerve and upper trunk not stimulable intraoperatively; Minimum follow-up: 12 months. Patient average age at surgery was 28 years (13-43). The mean interval between trauma and operation was 7 months (4-13). The mean follow-up was 31 months (13-60). Shoulder function was evaluated by determining the muscular strength of abduction and external rotation according to the British Medical Research Council. Results: 73 % of the patients (8/11) did not regain useful shoulder function after SAN-SSN. Only 3 patients reached muscle strength grade 3 or greater, and in only one child the neurotization had been the isolated procedure for shoulder reconstruction. The other two patients that recovered shoulder flexion and external rotation had an upper trunk reconstruction with sural nerve grafts concurrently with SAN-SSN neurotization. Discussion: Postoperative clinical evaluation of the SAN-SSN neurotization showed poor reestablishment of shoulder function and these results led to a critical analysis of this procedure - classic and widely popular among hand surgeons - especially when performed in isolation for restoration of shoulder flexion and external rotation. The authors recommend the transfer of accessory nerve to the Suprascapular nerve only when direct coaptation is possible and when other procedures for reinnervation of the shoulder, such as grafting to the upper trunk or radial nerve transfer to axillary nerve may be performed concurrently.