Impact of Scalene Muscle Botulinum Toxin Injection With and Without Surgery in Neurogenic Thoracic Outlet Syndrome.

[OBJECTIVE] Scalene blocks are part of both the diagnostic and treatment algorithm for patients presenting with symptoms of neurogenic thoracic outlet syndrome (nTOS). However, there is a paucity of data on the utility of scalene botulinum toxin injection (BTI) before surgical decompression. We sought to determine the impact of BTI with and without surgery at a multidisciplinary referral center.

[DESIGN] Retrospective cohort study.

[SETTING] Single institution tertiary academic center, 2011 to 2020.

[PATIENTS] Seventy-seven consecutive patients.

[INTERVENTIONS] Scalene muscle BTI for nTOS with or without surgical decompression.

[MAIN OUTCOME MEASURES] Pain relief and Quick Disability of the Arm, Shoulder and Hand (QDASH) score.

[RESULTS] Seventy-seven patients, with a mean age of 31.4 years, had BTI for symptoms of nTOS. All patients underwent pretreatment physical therapy through the Edgelow protocol for a mean duration of 3.4 months. However, 72.7% had dynamic vascular compression on duplex ultrasound with provocative maneuvers and 85.7% had a positive physical examination finding. After BTI, 77.9% reported subjective relief, confirmed by an improved QDASH disability score. Thirty-one patients (40.3%) then went on to have further persistent symptoms and proceeded with first rib resection. After BTI + Surgery, 96.8% reported symptomatic relief and had a median QDASH score improvement of 21 (range: 10-40), with all reaching minimal clinically important differences in the QDASH score after combination therapy.

[CONCLUSIONS] In this reported series of chemodenervation in patients with nTOS, BTI is helpful in alleviating symptoms before definitive surgical decompression. BTI followed by first rib resection provides additional symptom improvement over BTI alone.