Quadrangular Space Decompression

The quadrangular (or quadrilateral) space is defined by its anatomical borders and is the passageway for the axillary nerve and posterior circumflex humeral artery (PCHA). Quadrangular space syndrome (QSS) can present due to various compressive pathologies but is commonly seen in overhead athletes. Quadrangular space syndrome can present with neurogenic symptoms including pain and paresthesias, as well as vascular complications from compression of the PCHA including thrombosis, aneurysm formation, and distal emboli.

Surgical decompression of the quadrangular space is indicated for severe neurogenic or vascular compromise in the case of QSS refractory to nonoperative treatment.

After appropriate preoperative physical examination findings and trial of nonoperative treatment, including physical therapy and injections, surgical decompression was indicated. The posterior border of the deltoid was marked, and an incision centered over the posterior border of the deltoid lateral to the axillary fold was made. Posterior border of deltoid was identified and retracted, revealing the interval of the teres minor and major. The nerve to the teres minor was identified, protected, and fibrous bands compressing the nerve were released. The nerve to the teres minor was tracked deep to find the axillary nerve. This was identified and fibrous bands around the nerve were decompressed. The circumflex vessels were protected throughout. Following decompression of the nerves, there was free movement of the nerves indicating adequate surgical decompression.

Adequate surgical decompression of the axillary nerve and PCHA achieved with resolution of neurogenic symptoms of pain and paresthesias at first postoperative visit.

Quadrangular space syndrome is a rare disorder, can be difficult to diagnose, and is the cause of significant morbidity, particularly in overhead athletes. If symptoms persist after nonoperative treatment, operative decompression of the quadrangular space may be indicated. Adequate surgical decompression results in relief of neurogenic and vascular symptoms.