Accessory Nerve Disruption Following Core-Needle Biopsy: A Review of Iatrogenic Accessory Nerve Injuries and an Illustrative Case

Iatrogenic spinal accessory neve (SAN) injury is a rare complication. It most commonly occurs after open lymph node biopsies. Needle biopsy is thought to present lower risk to the SAN. However, we describe a case of a 66-year-old man who underwent core needle biopsy for lymphadenopathy and subsequently experienced ipsilateral shoulder weakness and pain. Physical examination revealed shoulder depression, lateral scapular winging, and decreased range of motion. Subsequent studies and magnetic resonance imaging demonstrated complete paralysis and denervation of SAN muscles. The nonfunctional SAN was repaired by sural nerve grafting 3 months after the injury. The patient demonstrated improved shoulder strength, range of motion, and decreased pain at 6-month follow-up. SAN injuries can be challenging to diagnose and require prompt surgical intervention. This case represents an unusual case of complete SAN disruption and palsy after core needle biopsy treated with sural nerve grafting. We review the literature on iatrogenic SAN injuries, diagnostic strategies, options for SAN surgical repair, and outcomes. SAN injuries can be challenging to diagnose but are amenable to prompt surgical options based on the mechanism and type of SAN injury.