Costoclavicular ligament as a novel cause of venous thoracic outlet syndrome: from anatomic study to clinical application.

ABSTRACT

PURPOSE: Venous thoracic outlet syndrome (VTOS) is a compressive disorder of subclavian vein (SCV); we aimed to investigate the role of costoclavicular ligament (CCL) in the pathogenesis of VTOS. METHODS: A cadaver study was carried out to investigate the presence and morphology of CCL in thoracic outlet regions, as well as its relationship with the SCV. Six formalin-fixed adult cadavers were included, generating 12 dissections of costoclavicular regions (two sides per cadaver). Once CCL was identified, observation and measurement were made of its morphology and dimensions, and its relationship with SCV was studied. To take a step further, a clinical VTOS case was reported to prove the anatomical findings. RESULTS: Two out of twelve costoclavicular regions (2/12, 16.7%) were found to possess CCLs. Both ligaments were located in the left side of two male cadavers and were closely attached to the lateral aspect of sternoclavicular joint capsules. The lateral fibers of the ligament proceed in a superolateral-to-inferomedial manner, while the medial fibers proceed more vertically. Both ligaments were tightly adherent to the SCV, causing significant compression on the vein. In the clinical case, multiple bunches of CCLs were found to compress the SCV tightly intraoperatively. After removing the ligaments, the patient's symptom kept relief during a follow-up period of 2 years. CONCLUSION: Our study demonstrated that CCL could be a novel cause of VTOS by severe compression of SCV. Patients diagnosed with this etiology could get less invasive surgical treatment by simply removing the ligament.