Ultrasound-Guided Diagnostic Injections for Neurogenic Thoracic Outlet Syndrome: An Outcomes-Based Cohort Study.

Objective

Neurogenic thoracic outlet syndrome (NTOS) is an underrecognized problem causing chronic upper extremity symptoms from brachial plexus compression, often affecting overhead athletes. This study evaluated the utility of ultrasound-guided (USG) diagnostic injections for NTOS.

Design

This was a retrospective chart review.

Setting

This study was conducted at a single institution. PATIENTS In total, 203 patients (121 female, 81 male, and 1 nonbinary) with suspected NTOS underwent USG diagnostic blocks. Forty-five were athletes, including 42 overhead athletes.

Intervention

A single sports medicine physician performed USG diagnostic injections targeting the pectoralis minor (PM), anterior and middle scalenes, suprascapular nerve (SSN), or quadrilateral space. MAIN OUTCOME MEASURES Patients reported symptomatic relief >50%.

Results

PM blocks were positive in 125/186 (67%) cases and scalene blocks in 85/130 (65%). SSN and quadrilateral space blocks were positive in 34/76 (44%) and 4/11 (36%), respectively. Among 95 nonathletes receiving both PM and scalene blocks, greatest relief was reported with scalene in 40 (42%) and PM in 31 (32.6%), 8 (8.4%) improved with both, 10 (10.5%) with neither, and 6 unreported (6.3%). Among athletes, 36/42 (85.7%) had positive PM blocks and 13/20 (65%) had positive scalene blocks. SSN and quadrilateral space blocks were positive in 9/14 (64%) and 1/3 (33%), respectively. Of 22 athletes receiving both PM and scalene blocks, 16 (73%) reported greatest relief with PM, 4 (18%) with scalene, and 2 (9%) with neither.

Conclusions

PM blocks produced symptom relief comparable with scalene blocks in the general population and were the most effective diagnostic injection in athletes. These results suggest the PM is a more prominent symptom generator in NTOS than previously recognized, particularly in athletes.