Arthroscopic Transcapsular Axillary Nerve Decompression

Quadrilateral space syndrome remains a relatively uncommon shoulder diagnosis. Despite this, it can result in debilitating pain, weakness, and atrophy if a timely diagnosis is not made. Fibrous bands are reported to be the most frequent compressive etiology, however malunited fractures, malignancies, humeral osteophytes, and hypertrophied musculature are also occasionally implicated.

Quadrilateral space syndrome typically afflicts active patients between the ages of 20 and 40 years. Patients typically present with vague posterolateral shoulder pain and occasionally report declining athletic performance. In more subtle cases, fatigue in overhead positions may be the patients’ primary complaint. Physical examination often reveals tenderness with palpation of the quadrilateral space and parasthesias may be noted along the lateral arm. Muscular atrophy in more chronic cases can result in clinically appreciable weakness of the deltoid or teres minor. Electromyographic studies are capable of revealing objective evidence of axillary nerve compression however, similar to carpal tunnel syndrome, are often normal in patients with quadrilateral space syndrome. Magnetic resonance imaging is frequently obtained to characterize concomitant shoulder injuries and determine if a soft tissue cause of compression can be identified. If of a chronic nature, these studies may also reveal neurogenic edema or fatty atrophy of the deltoid or teres minor muscles.