The Association of Long Thoracic Nerve Variants With Medial Scapular Winging in Thoracic Outlet Syndrome: A Clinical and Anatomical Study.

Abstract

The long thoracic nerve (LTN) arises from the cervical spinal nerve roots and traverses the middle scalene muscle. Compressive neuropathy of the LTN leads to medial scapular winging and dyskinesia. Muscle imbalance of the shoulder is associated with thoracic outlet syndrome. We aimed to investigate the prevalence of preoperative medial scapular winging and dyskinesia in patients with thoracic outlet syndrome and its correlation with anatomical variations of the LTN. A multicenter retrospective review was conducted between January 2019 and September 2024, involving 117 patients with thoracic outlet syndrome. Patients underwent anterior and middle scalenectomy, with or without first rib resection. Preoperative medial scapular winging was clinically evaluated. Intraoperatively, the LTN was carefully dissected and documented for anatomical variations. LTN variations were classified as intramuscular or extramuscular relative to the middle scalene muscle, with further subclassification based on the notable major contribution of cervical roots to the LTN. Medial scapular winging and dyskinesia were observed in 33.3 % of the patients. Two main LTN variants were identified: extramuscular (59.8%) and intramuscular (40.2%). Scapular winging and dyskinesia occurred in 66% of the intramuscular group compared to 11.4% of the extramuscular group. The intramuscular course of the LTN is associated with preoperative scapular winging and dyskinesia in patients with thoracic outlet syndrome. Diagnostic IV.