Lower subscapular nerve transfer for axillary nerve repair in upper brachial plexus palsy

The potential to utilize the lower subscapular nerve for brachial plexus surgery has been suggested in many anatomical studies. However, we know of no studies in the literature describing the use of the lower subscapular nerve for axillary nerve reconstruction to date. This study aimed to examine the effectiveness of this nerve transfer in patients with upper brachial plexus palsy. Of 1340 nerve reconstructions in 568 patients with brachial plexus injury performed by the senior author (P.H.), a subset of 18 patients underwent axillary nerve reconstruction using the lower subscapular nerve and constitutes the patient group for this study. The median age was 48 years, and the median time between trauma and surgery was 6 months. A concomitant radial nerve injury was found in 8 patients. Thirteen patients completed a minimum follow-up period of 24 months. Successful deltoid recovery was defined as (1) muscle strength MRC grade ≥ 3, (2) electromyographic signs of reinnervation, and (3) increase in deltoid muscle mass. Axillary nerve reconstruction was successful in 9 of 13 patients, which represents a success rate of 69.2%. No significant postoperative weakness of shoulder internal rotation or adduction was observed after transecting the lower subscapular nerve. The lower subscapular nerve can be used as a safe and effective neurotization tool for upper brachial plexus injury, having a success rate of 69.2% for axillary nerve repair. Our technique presents a suitable alternative for patients with concomitant radial nerve injury.