A Modified Posterior Approach to the Nerve Transfer of the Spinal Accessory Nerve to the Suprascapular Nerve

Restoration of shoulder abduction and external rotation is critical in patients with upper brachial plexus injuries (BPIs). The transfer of the spinal accessory nerve to the suprascapular nerve is a well-established surgical technique; however, the optimal approach remains debated. The traditional posterior approach may compromise muscle integrity because of trapezius detachment and splitting of the supraspinatus. This study introduces a muscle-sparing modification to the posterior approach and evaluates functional outcomes in pediatric and adult patients with obstetric or traumatic BPIs.

A retrospective review was conducted on patients who underwent spinal accessory nerve to suprascapular nerve transfer using a muscle-sparing posterior approach from September 2018 to November 2022. Inclusion criteria comprised pediatric patients (aged ≤18 months) with obstetric BPIs and adult patients with traumatic BPIs with a minimum postoperative follow-up of 24 months. Pediatric patients were evaluated using the Toronto Muscle Grading System, Modified Mallet Grading System, and Birch Triple System. Adults were assessed using range of motion and Disabilities of the Arm, Shoulder, and Hand questionnaire scores.

Fourteen patients met the inclusion criteria (six pediatric and eight adult). Pediatric outcomes demonstrated Modified Mallet Grading System scores of grade IV and Birch Triple System stages IV-V, indicating good shoulder function. Toronto Muscle Grading System scores of 3 reflected active movement against gravity. Among adults, mean forward flexion improved from 35° to 53°, abduction improved from 28° to 47°, and external rotation improved from 12° to 23°. The mean Disabilities of the Arm, Shoulder, and Hand questionnaire score improved from 91 to 48, exceeding the minimal clinically notable difference. No complications were observed.

The muscle-sparing posterior approach for spinal accessory nerve to suprascapular nerve transfer is a safe and effective technique that yields favorable functional outcomes in both pediatric and adult BPI populations. Further comparative studies are warranted.

Therapeutic IV.