Far lateral disc excision at L5-S1 complicated by iliolumbar artery incursion: case report

OBJECTIVE AND IMPORTANCE: Paramedial approaches to far lateral discs at the L5-S1 space joint have advantages but may also bring the surgical space closer to large branch arteries of the internal iliac artery. I report incursion into an iliolumbar artery that required laparotomy to control hemorrhage. Surgeons performing extraforaminal disc explorations at L5-S1 need to evaluate preoperative magnetic resonance imaging scans for an enlarged iliolumbar artery near the disc space. CLINICAL PRESENTATION: The patient presented with a right L5 radiculopathy and a far lateral disc at L5-S1, as indicated by analysis of her magnetic resonance imaging scan. INTERVENTION: A midline incision and an extraforaminal exposure were performed. Arterial bleeding occurred when an anular disc fragment was removed with a pituitary rongeur under direct vision with microscopic magnification. Emergency laparotomy demonstrated hemorrhage from a branch of the internal iliac artery 2 cm from its origin. CONCLUSION: Iliolumbar artery variants may be at the margins of extraforaminal disc exposure at L5-S1. Preoperative magnetic resonance imaging scans should be evaluated for this vasculature structure.