Clinical outcomes following arthroscopic pectoralis minor release

Pectoralis minor syndrome (PMS) may produce scapulothoracic abnormal motion and associated neurogenic thoracic outlet syndrome (nTOS) which are under-recognized causes of shoulder dysfunction. The 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 PMi release for diagnoses of PMS and nTOS performed between 2021 and 2024 at a single institution by 3 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 the subclavius, was recorded.

Two hundred seventy-three patients receiving arthroscopic PMi release for PMS and nTOS were included for analysis. One hundred sixty-four patients (60.1%) additionally received 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) of follow-up. Subjective Shoulder Value (P < .001), visual analog scale for pain (P ≤ .001), Patient Reported Outcomes Measurement Information System Short Form Score Physical component (P = .03), and Quick Disabilities of the Arm, Shoulder and Hand (P = .007) scores significantly improved post-operatively. Post-operative forward elevation (P = .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 PMi release 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 that in the general population, implicating muscle hyperactivity as a cause of PMS.