Prevalence of Concomitant Distal Suprascapular Nerve Injury in Patients with Root-level Brachial Plexus Palsy: A Clinical Anatomic Study of Injury Pattern.

Abstract

Root-level suprascapular nerve palsy is commonly reconstructed via spinal accessory nerve transfer in brachial plexus injury, yet some patients fail to recover. We hypothesize that this relates to concomitant undetected lesions distal to the nerve transfer coaptation. 67 patients with plexus injury and C5/6 root involvement were included in this prospective study between March 2021 and October 2022. During spinal accessory to suprascapular nerve transfer the entire suprascapular nerve was explored, via cresenteric clavicular osteotomy, and anatomic variations and injury patterns categorized. Proximal root involvement was C5-C6 (n=8), C5-C7 (n=13), C5-C8 (n=17), C5-T1(29). Mean time from injury to surgery was 5.6 months. The suprascapular nerve was found to be injured in 16/67 cases (24%). In 9 cases (13%) the lesion was proximal to the suprascapular fossa. In 3 cases (4%) the suprascapular nerve was injured both proximally and within the fossa, and in 4 cases (6%) in the fossa or distal to it. Therefore, in 7 cases (10%), a traditional suprascapular nerve transfer would not successfully bypass the zone of injury of the suprascapular nerve in the fossa. Of the 16 cases of concomitant suprascapular nerve injury, 1/8 in occurred in C5-C6 root injury, 4/13 of C5-C7 root injury, 5/17 of C5-C8 root injury and 6/39 in total paralysis. Concomitant distal suprascapular nerve injury in brachial plexus stretch palsy occurred in 24% of the cases. This warrants attention from the surgeon to identify distal lesions and to perform the nerve transfer beyond any secondary lesions.