Mid-Term Outcome after Selective Neurotization of the Infraspinatus Muscle in Patients with Brachial Plexus Birth Injury

BACKGROUND: Active shoulder external rotation in adduction can be restored by selective neurotization of the infraspinatus muscle with the spinal accessory nerve in select patients with brachial plexus birth injury. Does the improved shoulder external rotation stand the test of time? METHODS: Fourteen consecutive brachial plexus birth injury patients with active shoulder external rotation in adduction of ≤ 0 degrees and active shoulder elevation ≥ 90 degrees underwent selective neurotization of the infraspinatus muscle at mean 2 years of age between 2012 and 2016. All 14 patients had congruent shoulders joints with passive external rotation in adduction of 30 degrees. Pre-and postoperative electromyography was done to seven patients. Shoulder function and the subjective outcome was assessed after a mean follow-up of 3.8 years. RESULTS: Shoulder external rotation in adduction improved by a mean 57 degrees in the 12 children who did not develop shoulder internal rotation contracture. Shoulder external rotation in abduction and shoulder abduction increased in all 14 patients. Reinnervation of the supraspinatus muscle was evident in all seven children who underwent postoperative EMG. Thirteen patients’ parents were satisfied with the outcome. CONCLUSIONS: Functionally significant shoulder external rotation can be restored and maintained by reinnervation of the infraspinatus muscle in brachial plexus birth injury patients with congruent shoulder joints, if internal rotation contracture does not develop.