Delayed retroperitoneal haematoma after failed lumbar plexus block.

A 72-yr-old patient was to undergo a left lumbar plexus block by the posterior approach to achieve postoperative analgesia after hip replacement. The block failed after three unsuccessful attempts to identify nerve structures and a fascia iliaca compartment block was performed. Postoperatively the patient received enoxaparin and then phenylindanedione for thromboprophylaxis. She was re-admitted 2 weeks after surgery because of a lower limb motor deficit and a left retroperitoneal haematoma requiring blood transfusion. Clinicians need to be aware of this potential complication of lumbar plexus block in patients receiving thrombphylaxis.