Vascular surgeon Robert W. Thompson, MD, performed the 1,000th operation at Barnes-Jewish Hospital to treat a rare type of thoracic outlet syndrome (TOS), a group of potentially disabling disorders that occur when blood vessels or nerves become compressed in the space between the collarbone and the first rib. Dr. Thompson is the only surgeon in the world to perform this number of procedures targeting venous TOS, which is caused by damage to the major veins in the lower neck and upper chest.