A Fourteen-Year Experience with Vascular Anomalies Encountered during Transaxillary Rib Resection for Thoracic Outlet Syndrome

Abstract

Transaxillary approach to first rib resection and scalenectomy (TAFRRS) is a well-established technique for treatment of thoracic outlet syndrome (TOS). Although anatomic features encountered during TAFRRS are in general constant, vascular anomalies may be encountered but have not been described to date. Herein we describe vascular abnormalities encountered during TAFRRS. We performed a retrospective review of a prospective practice database of 224 operations for TOS performed in 172 patients from March 2000 to March 2014. We excluded 10 patients with missing operative reports, 3 reoperations on the same patient, and 8 non-transaxillary resections. We recorded vascular anomalies identified in operative reports and reviewed computed tomography imaging to delineate the nature of these abnormalities. The overall incidence of vascular anomalies was 11% (22 of 203 TAFRRS). Most patients with anomalies had venous TOS (vTOS) (9 patients, 41%), followed by 7 (32%) with neurogenic TOS (nTOS). The remainder of the patients had arterial TOS (aTOS) (6 patients, 27%). Seven patients (32%) had an abnormal subclavian artery (SCA) with 5 (23%) having an abnormal arterial course in the anterior scalene muscle (ASM); 6 patients (27%) had an abnormal internal mammary artery (IMA) originating from distal SCA; 4 (18%) had abnormalities in the supreme thoracic artery (bifurcation or duplication); 2 (9%) had an abnormal branch from the SCA with anomalous location in the operative field; and 3 (14%) had an abnormal large venous branch penetrating the ASM. In the 19 patients with arterial anomalies, 8 (42%) were recognized as arterial branches penetrating the ASM, and 11 (58%) were noticed as they had anomalous arterial locations within the operative field. Most arterial anomalies were seen in vTOS (9, 45%), followed by nTOS (7, 35%). No intraoperative vascular complications occurred. Perioperative complications included 1 occurrence of postoperative transfusion for bleeding following axillary drain discontinuation and 2 Horner's syndromes. One aberrant IMA was electively ligated to allow complete thoracic outlet decompression. Arterial anomalies during TAFRRS are encountered in 11% of operations, and may present with vessel locations in unusual areas within the operative field, or as abnormal vessels penetrating the ASM, thus making scalenectomy precarious. Careful attention must be paid to possible abnormal locations of vessels in the thoracic outlet to avoid bleeding complications.