Delayed Retroperitoneal Hematoma Due to Rupture of a Renal Artery Branch after Oblique Lumbar Interbody Fusion: A Case Report

Retroperitoneal hematoma is an uncommon complication of oblique lumbar interbody fusion (OLIF); delayed hemorrhage from a renal arterial branch is rarely reported.A 78-year-old woman with atrial fibrillation and hypertension underwent OLIF with posterior pedicle screw fixation at L3-4 and L4-5; rivaroxaban was discontinued 2 days before surgery and resumed on postoperative day 5. Her early postoperative course was uneventful, but on postoperative day 17, she developed sudden, atypical left flank pain accompanied by a decrease in hemoglobin from 8.7 to 6.8 g/dL despite stable vital signs.Computed tomography showed a large left perinephric hematoma and active extravasation at the lower pole of the left kidney; angiography confirmed a lower-pole segmental/capsular renal branch as the bleeding source.Superselective coil embolization achieved hemostasis, and persistent anemia was treated with transfusion.Gross hematuria resolved within 5 days without deterioration of renal function.The delay in presentation likely reflects an initially contained occult arterial injury followed by disruption; pseudoaneurysm formation is possible but remains unconfirmed, and postoperative anticoagulation may have contributed to the delayed presentation or greater severity of hemorrhage.Preoperative imaging confirmed that the lower renal pole lay close to the OLIF corridor.Surgeons should recognize this anatomical risk and maintain vigilance for delayed vascular injury, especially in anticoagulated patients.