Combined and Secondary Forms of TOS

Thoracic outlet syndrome (TOS) classically presents in neurologic, venous, or arterial forms. Although these are three separate entities, overlap can occur. In addition, treatment for one form of TOS can result in later, secondary TOS of another type. According to strict criteria, arterial TOS rarely coexists with either of the other two forms, but neurogenic and venous TOS can exist together in perhaps 10% of cases. Similarly, patients who have had rib resection for venous TOS can later present with neurologic symptoms, and vice-versa. These concepts are important as they will alter the goals of surgery and hence, in many cases, the surgical approach used for decompression.