RESUMEN
INTRODUCTION: In this study we aimed to determine whether needle electromyographic assessment of voluntary motor unit recruitment in traumatic brachial plexus injuries could predict spontaneous motor recovery. METHODS: A retrospective study was performed on patients with brachial plexus injury affecting deltoid, supraspinatus/infraspinatus, and biceps brachii. The outcome measure was strength on manual muscle testing at least 1 year after injury. Good outcome was considered strength >3/5 on the Medical Research Council (MRC) scale. RESULTS: No muscles with no recruitment (n = 27) at 1-9 months improved to MRC 4/5 strength at a mean of 2.0 years postinjury. Twenty-five percent of muscles with discrete or severely reduced recruitment (n = 8) regained strength to >3/5 at a mean of 1.4 years postinjury (P = .047). DISCUSSION: Absent voluntary motor unit potential recruitment at 1-9 months predicted poor prognosis for spontaneous recovery. A high percentage of patients with discrete recruitment did not improve to >3/5 strength. These patients should be considered for early nerve transfer surgery.