Ipsilateral Double May-Thurner Syndrome With a Congenital Double Left Common Iliac Vein: A Case Report of an Unprecedented Anatomical Variant and Hemodynamic Interaction.

This case report describes a unique presentation of May-Thurner syndrome (MTS) in a 28-year-old woman, characterized by the congenital bifurcation of the left common iliac vein (LCIV) into the outer (OLCIV) and inner (ILCIV) segments. Both veins experienced significant compression - OLCIV proximally and ILCIV medially - due to the overlying right common iliac artery (RCIA) and lumbar spine. The patient presented with bilateral spider veins, lower extremity swelling, pelvic discomfort, and bilateral leg cramping. Detailed imaging with venous duplex ultrasound, venography, and intravascular ultrasound (IVUS) revealed not only chronic venous insufficiency in the greater saphenous veins but also this rare vascular anomaly. Interventional treatment involved the strategic deployment of two stents to address the dual venous compression. A 16 mm x 90 mm stent was placed in the OLCIV at the site of proximal compression, followed by the insertion of a 16 mm x 60 mm stent in the ILCIV to relieve the medial compression. The successful resolution of venous obstruction was confirmed by post-procedural venography and IVUS. This case underscores the critical role of comprehensive anatomical evaluation, including advanced imaging techniques, in the diagnosis and management of complex venous disorders. The effective use of stenting in this rare "double May-Thurner syndrome" demonstrates the potential for targeted endovascular interventions in similarly challenging cases.