Preoperative Electrodiagnosis of Brachial Plexopathy is Associated with Diminished Functional Outcomes after Surgery for Neurogenic Thoracic Outlet Syndrome

Objective: To assess long-term surgical outcomes for patients with neurogenic thoracic outlet syndrome (NTOS) and preoperative electrodiagnosis of brachial plexopathy (BPx). Background: BPx can accompany a diagnosis of NTOS and is a clear indication for surgery, but its impact on treatment outcomes is undefined. Methods: A retrospective cohort analysis was conducted for patients undergoing supraclavicular decompression for NTOS from January 2020 to July 2023. Percent improvement in the short-form Disability of the Arm, Shoulder, and Hand survey (QuickDASH) was the primary endpoint. A case-control analysis was conducted between patients with BPx and paired controls matched for age, gender, and preoperative QuickDASH. Multivariate analysis was used to identify independent variables associated with percent improvement in QuickDASH. Results: There were 297 operations in 276 patients (staged bilateral in 21) with a median (IQR) age of 36 (26-44) years. Nineteen operations (6%) were associated with preoperative BPx. During median follow-up of 27 (16-38) months, QuickDASH scores reached similar levels in each group but the extent of improvement was 2.4-fold greater for patients without BPx (P=0.008). In case-control comparison, percent improvement in QuickDASH remained >2-fold greater for patients without BPx (P=0.023). Multivariate linear regression showed variables associated with diminished improvement in QuickDASH were patient age (P=0.0005), previous injury (P=0.0016), previous other surgery (P=0.042), duration of the elevated arm stress test (P=0.043), and preoperative BPx (P=0.035). Conclusions: Functional improvement following surgery for NTOS is substantially diminished in patients with preoperative BPx. This finding helps clarify expectations for surgical treatment outcomes that may influence clinical decision-making.