Nerve Transfers and Adjunct Procedures for Restoration of Shoulder External Rotation in Obstetrical Brachial Plexus Palsy: Long-Term Outcomes and Review of the Literature

<b>Background</b>: Obstetrical brachial plexus palsy (OBPP) often results in medial shoulder contracture, with limited abduction and external rotation due to muscle imbalance and joint deformities. Late nerve transfers, such as spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer, combined with soft tissue release, represent a therapeutic option for shoulder reanimation in children presenting after infancy. <b>Methods</b>: 56 children treated between 2007 and 2019 have been evaluated. Inclusion criteria were as follows: age at time of surgery > 9 months, no primary reconstruction of the brachial plexus, late presentation, two years of follow-up. Patients were divided into groups based on age (<18 months vs. >18 months) and procedures: SAN to SSN transfer associated with subscapularis release (58.9%), SAN to SSN transfer associated with coracohumeral ligament release (17.9%), isolated SAN to SSN (12.5%), multiple nerve transfer (10.7%). Universal Mallet Grading Score was applied. A review of literature on the topic published on Pub Med up to December 2024 was associated with the retrospective analysis of clinical data. <b>Results</b>: At 2 years 84% of patients achieved Mallet Scores > 3, with progressive improvement up to 5 years. No significant differences were observed between age groups or type of palsy. Coracohumeral ligament release demonstrated comparable effectiveness to subscapularis release with fewer complications. Secondary surgical interventions were required in 30% of cases, mainly in those undergoing multiple nerve transfers. <b>Conclusions</b>: SAN to SSN transfer is a reliable and effective procedure for restoring shoulder external rotation. Coracohumeral ligament release provides a minimally invasive means to improve passive range of motion while preserving internal rotation muscle integrity. These combined interventions may reduce the need for more invasive secondary surgeries.