Modern Treatment of Neurogenic Thoracic Outlet Syndrome: Pathoanatomy, Diagnosis, and Arthroscopic Surgical Technique

Ultrasound-guided minimally invasive release of the pectoralis minor: Initial experience in cadaveric specimens

INTRODUCTION

Pectoralis minor syndrome results from excessive contraction or shortening of the pectoralis minor muscle, causing scapular dyskinesis, shoulder dysfunction, and potential neurovascular compression. Existing surgical treatments, including open and arthroscopic pectoralis minor releases, lack minimally invasive options.

OBJECTIVE

To evaluate the feasibility, safety and efficiency of ultrasound-guided release of the pectoralis minor coracoid insertion in a cadaveric model.

METHODS

A single-operator study was conducted on eight shoulders from four fresh cadavers. Under ultrasound guidance, the coracoid insertion of the pectoralis minor was visualized, and a minimally invasive release was performed using a specialized KEMIS© knife. The completeness of the tendon release was validated by open dissection. Operative times and potential injury to adjacent structures were recorded.

RESULTS

Complete tendon sectioning was achieved in all specimens without injury to the brachial plexus, subclavian artery, or vein. Minor damage to anterior deltoid fibres (<10%) was noted in some shoulders. Localization times improved significantly (from 75 to 35 s), and tendon cutting times were consistently less than 20 s after the second procedure.

CONCLUSION

Ultrasound-guided pectoralis minor muscle release is a safe, efficient, minimally invasive technique with a short learning curve. These findings warrant further studies to investigate its clinical applicability and long-term outcomes.

Identifying and treating pectoralis minor syndrome in women with breast hypertrophy, poor posture and diffuse shoulder symptoms

Pectoralis minor syndrome (PMS) has been identified as a cause of chronic shoulder pain, involving compression of the brachial plexus at the thoracic outlet associated with scapulothoracic abnormal motion (STAM). This condition is poorly recognised and frequently overlooked in clinical practice.We present three patients with breast hypertrophy who experienced shoulder girdle pain and intermittent paraesthesia. Ultrasound-guided pectoralis minor (PM) muscle blocks provided effective but transient relief. Definitive treatment with arthroscopic PM release (APMR) resulted in durable symptom resolution.PMS is often overlooked due to its diffuse symptoms. Although women have been reported to suffer from PMS more frequently, this is the first report to describe the association between female gender, breast hypertrophy, postural overload and PMS, as well as the outcomes in these patients after APMR. Based on the current literature and our clinical experience, we propose an assessment and treatment algorithm for this challenging syndrome.

Arthroscopic Pectoralis Minor Release and Infraclavicular Brachial Plexus Decompression for Neurogenic Thoracic Outlet Syndrome: A Novel Treatment for an Old Problem

Background

Neurogenic thoracic outlet syndrome (nTOS) of infraclavicular etiology is a complex condition involving the compression of the brachial plexus through the interscalene triangle and costoclavicular, infraclavicular, and pectoralis minor space. New insight into nTOS of infraclavicular etiology and its association with scapular dyskinesia has enabled minimally invasive treatments: endoscopic pectoralis minor release (PMR) and infraclavicular brachial plexus neurolysis. The purpose of this study was to analyze clinical outcomes of this technique compared with historically published outcomes for open first rib resection (FRR) and/or scalenectomy.

Methods

All patients who underwent endoscopic surgical decompression for nTOS of infraclavicular etiology were retrospectively reviewed at a single institution. Surgical treatment included endoscopic PMR, subclavius release, and neurolysis of the infraclavicular brachial plexus. Patient-reported outcomes were collected prospectively and compared with prior research on FRR and scalenectomy. A subgroup analysis was performed on patients with prior open FRR or anterior cervical discectomy and fusion (ACDF).

Results

Fifty-eight shoulders among 55 patients were included, with an average follow-up of 25.8 months (range: 12-52). Patients showed significant improvement in visual analog scale pain (7.0-2.1) and single alpha-numeric evaluation scores (37% to 84%). Overall, 90% of patients experienced good or excellent outcomes according to the Derkash classification. There were no major complications and only 2 minor ones (one wound infection and one case of adhesive capsulitis). Satisfaction and Derkash scores among patients undergoing endoscopic surgery were comparable with previously published studies on open FRR and scalenectomy, with lower rates of major complications and equivalent or improved clinical outcomes. Patients with prior ACDF or open FRR had worse postoperative American Shoulder and Elbow Surgeons; Quick Disabilities of the Arm, Shoulder, and Hand; and Derkash scores than the subgroup with no prior intervention.

Conclusions

Endoscopic PMR and infraclavicular brachial plexus decompression is a viable and effective treatment option for nTOS of infraclavicular etiology driven by the pectoralis minor and associated scapular girdle dyskinesia. This cohort demonstrates improvements in clinical outcomes comparable with open scalenectomy and FRR with high patient satisfaction and no major neurologic, vascular, or thoracic complications.

Level of Evidence

Therapeutic Level IV-Case Series. See Instructions for Authors for a complete description of levels of evidence.

Diagnostic and Therapeutic Approach to Thoracic Outlet Syndrome

Thoracic outlet syndrome (TOS) is a group of symptoms caused by the compression of neurovascular structures of the superior thoracic outlet. The knowledge of its clinical presentation with specific symptoms, as well as proper imaging examinations, ranging from plain radiographs to ultrasound, computed tomography and magnetic resonance imaging, may help achieve a precise diagnosis. Once TOS is recognized, proper treatment may comprise a conservative or a surgical approach.

Current concepts in clinical features and diagnosis of thoracic outlet syndrome

The diagnosis and clinical features of thoracic outlet syndrome have long confounded clinicians, owing to heterogeneity in symptom presentation and many overlapping competing diagnoses that are "more common." Despite the advent and prevalence of high-resolution imaging, along with the increasing awareness of the syndrome itself, misdiagnoses and untimely diagnoses can result in significant patient morbidity. The authors aimed to summarize the current concepts in the clinical features and diagnosis of thoracic outlet syndrome.