Benefit of Pectoralis Minor Release in Conjunction with Thoracic Outlet Decompression for the Treatment of nTOS
Luigi Pascarella, Lexi Betancourt Betancourt, Sidney Browder, Mark Farber, William A Marston, Katharine McGinigle
University of North Carolina, Chapel Hill, NC
INTRODUCTION: Thoracic outlet syndrome (TOS) results from the compression of the neurovascular structures at the thoracic outlet. Patients with neurogenic TOS present with pain in the neck, shoulder, and/or arm and often have accompanying numbness, paresthesia, and weakness of the limb on the affected side. Surgical intervention typically focuses on a combination of first rib and/or cervical rib removal, anterior and middle scalenectomies, and brachial plexus neurolysis. For some patients, the neurogenic symptoms are actually due to pectoralis minor syndrome with compression on the other side of the thoracic outlet and undergoing a pectoralis minor release (PMR) alone or in combination rib resection will improve symptoms. We aim to explore the potential benefits of preoperative blocks in guiding our treatment of nTOS. METHODS: All nTOS patients were identified in our institutional TOS Registry from January 2018 to May 2020. Demographics, comorbidities, presenting symptoms, Disability of the Arm, Shoulder, and Hand (DASH) survey results work-up, treatment, and follow-up data were collected for each patient prospectively. Descriptive statistics were used to summarize the findings.
RESULTS: Over 28 months, 103 nTOS patients (116 limbs) were enrolled into the registry. The cohort was 83% female, 80% white, and with a mean age 38 ± 13. 13% had cervical ribs, 27% had a prior history of shoulder/upper extremity surgery, and 33% of patients were obese. A total of 78 TOS operations were performed: 14 combined first rib resection and PMR (18%), 47 first rib resection without PMR (60%), and 17 PMR only (22%). Of the patients who received a first rib resection without a PMR, 25% of those patients returned for a PMR. On average, 3-month post-op DASH scores for patients who underwent combined first rib removal and PMR improved by 19.6 points. For the patients who underwent first rib resection and returned for a PMR, their scores improved by 1.7, then 20.4 points, respectively, for a total improvement of 22.1 points. Of the patients who underwent combined surgery, 86% received both scalene and pectoralis minor blocks prior to surgery. Of the patients who underwent first rib removal and later returned for a PMR, none had both a scalene and pectoralis minor block prior to surgery; however, 82% of these patients received a pectoralis minor block prior to their PMR. CONCLUSIONS:One in four patients who underwent thoracic outlet decompression for nTOS without a pec minor release at our institution later returned for a pec minor release. The overall DASH score improvement was similar for both the combined first rib removal and PMR group and the first rib removal followed by PMR group. This, combined with our findings on pre-surgical blocks, suggests that patients diagnosed with nTOS may benefit from receiving both a scalene and pec minor block prior to their initial surgery and decrease the need for additional operations.
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