Rare Presentation of Thoracic Outlet Syndrome with First Rib Fracture - Case Report

Thoracic outlet syndrome (TOS) results from compression of the neurovascular structures within the thoracic outlet. Neurogenic TOS (NTOS) is the most common subtype and often presents with non-specific upper-limb neurological symptoms, making diagnosis challenging. First rib pathology as a cause of NTOS is rare and may delay recognition and treatment.

A 21-year-old male presented with progressive pain, paresthesia, and weakness of the left upper limb for 2 months, aggravated by overhead activities. Clinical examination revealed reduced motor power in the C7, C8, and T1 myotomes with decreased grip strength. Provocative tests for thoracic outlet compression were positive. Computed tomography demonstrated a fractured first rib with mixed lytic-sclerotic changes causing narrowing of the costoclavicular space and compression of the brachial plexus. Magnetic resonance imaging showed edema of the brachial plexus, and nerve conduction studies supported brachial plexopathy. Due to progressive neurological deficits, surgical decompression was performed through a supraclavicular approach, including first rib excision, anterior scalenectomy, and pectoralis minor tendon tenotomy. Postoperatively, the patient showed significant improvement in pain, sensory symptoms, and motor strength.

NTOS should be considered in patients presenting with unexplained upper-limb neurological symptoms, particularly when conventional investigations are inconclusive. Identification of rare etiologies, such as first rib pathology and timely surgical decompression, can lead to excellent functional outcomes.