Iliac vein compression syndrome from anterior perforation of a pedicle screw.

May-Thurner syndrome is an anatomic variant where the right common iliac artery compresses the left common iliac vein. The variant exists in a significant portion of the population, but is usually asymptomatic; however, clinically significant stenosis can occur by iatrogenic means. In this report, we describe a patient who presents with left lower extremity pain and swelling.