Wire-guided resection of a muscular axillary arch causing neurovascular compression

The axillary arch is a variant muscle found in approximately 7% of individuals. Most reports describe its incidental finding in cadaveric limbs. Several reports describe its potential clinical relevance, typically axillary neurovascular compression due to an axillary arch detected at surgical exploration. This report presents a case in which preoperative identification of this muscle led to a limited surgical approach using computed tomography (CT) guided, percutaneously placed, localizing wires. A 32-year-old man presented with intermittent, vague left arm pain and forearm and hand paresthesias that were aggravated with overhead activity. Routine neurologic examination, electrophysiologic testing, as well as CT and magnetic resonance imaging of the shoulder were interpreted as normal. Focused diagnostic ultrasonography of the axillary region did not reveal a definite abnormality. However, retrospective review of the CT with arms overhead during the ultrasound appointment confirmed the presence of an axillary arch compressing the neurovascular bundle. Percutaneous CT-guided needle localization wires were placed preoperatively to mark the axillary arch, limit the operative exposure, and simplify the resection. Postoperatively, the patient had complete resolution of his arm symptoms and returned to his premorbid activity as a telephone lineman within 6 weeks. At 3-month follow-up, CT with arms overhead confirmed decompression of the neurovascular bundle.