Retroperitoneal Hematoma Following Lumbar Injection in a Patient Receiving Clopidogrel: A Case Report

Lumbar spine injections are commonly used to manage spinal and radicular pain and have included techniques with varying anatomic depth and bleeding risk. Although hemorrhagic complications are rare, lumbar injections in patients receiving antiplatelet therapy-particularly when multiple deep lumbar procedures are performed-may result in clinically significant bleeding and neurologic injury. We report a case of a 56-year-old man receiving clopidogrel who underwent a lumbar medial branch block and a psoas compartment-related block during the same session at an outside hospital and subsequently developed a retroperitoneal hematoma. The patient experienced progressive flank pain, hemodynamic instability, and acute anemia. Angiography revealed active bleeding from the left iliolumbar artery, which was successfully managed with transcatheter embolization. Subsequently, he developed persistent weakness and sensory deficits in the left lower extremity, and electrodiagnostic studies confirmed upper lumbar plexopathy with incomplete motor recovery. Our case illustrates that combining high-bleeding-risk procedures, such as a psoas compartment block, with other lumbar interventions under uninterrupted clopidogrel therapy can lead to clinically significant retroperitoneal hemorrhage and enduring neurologic sequelae. It emphasizes the need for procedure-specific risk stratification, cumulative bleeding risk assessment, and long-term electrophysiological monitoring in patients undergoing lumbar injections while receiving antiplatelet therapy.