Clinical Outcomes Following Arthroscopic Pectoralis Minor Release.

Abstract

Pectoralis minor syndrome (PMS) may produce scapulothoracic abnormal motion (STAM) and associated neurogenic thoracic outlet syndrome (nTOS) which are underrecognized causes of shoulder dysfunction. Etiologies of these conditions have been attributed to congenital shortening or abnormal anatomy, acquired shortening and fibrosis, or muscular hyperactivity of the pectoralis minor (PMi). Our hypothesis is that arthroscopic PMi release for PMS and nTOS is safe and effective. Our secondary hypothesis is that anomalous PMi insertional anatomy is higher in this patient cohort. A retrospective chart review was performed of patients receiving arthroscopic pectoralis minor release for diagnoses of PMS and nTOS performed between 2021 and 2024 at a single institution by three surgeons. Patient demographics and pre-and post-surgical patient reported outcome measures (PROMs) were collected. Intra-operative arthroscopic evaluation of the PMi anatomy and surrounding structures including subclavius was recorded. Two hundred and seventy-three patients receiving arthroscopic pectoralis minor release for PMS and nTOS were included for analysis. One hundred sixty-four patients (60.1%) additionally received an arthroscopic brachial plexus neurolysis for a diagnosis of nTOS associated with PMS. The average patient age was 40.9 (±15.1) years with 9.4 months (±10.5) follow up. Subjective shoulder value (SSV) (p<0.001), visual analog scale (VAS) pain (p=<0.001), PROMIS Short Form Score Physical component (p=0.03), and quick disabilities arm, shoulder, and hand (qDASH) (p=0.007) significantly improved postoperatively. Postoperative forward elevation (p=0.002) significantly improved. There were 12 complications reported (4.4%). The incidence of anomalous PMi insertion was 15.4%, similar to prior anatomic studies. Additional variable anatomy included PMi insertion to the conjoint tendon (14.6%) and fascial extensions of the subclavius (17.6%). Arthroscopic pectoralis minor and associated brachial plexus neurolysis is an effective treatment for PMS and nTOS, providing improved PROMs with a limited complication profile. The incidence of anomalous PMi insertional anatomy is similar in these patients to the general population, implicating muscle hyperactivity as a cause of PMS. Level IV; Case Series; Treatment Study.