A lumbar spinal drainage catheter is placed to reduce the risk of paraplegia following thoracic endovascular aortic repair. Various complications related to the catheter placement can be seen. An 85-year-old patient who underwent thoracic endovascular aortic repair (TEVAR) developed motor deficit characterized by the loss of motor function in the left hip and knee (motor function 2/5), following the withdrawal of the lumbar spinal drainage catheter. Initially, the patient was suspected of having a spinal hematoma. However, the patient did not respond to the treatment and control magnetic resonance imaging in the postoperative period showed findings suggestive of ischemia in the left side of the medulla spinalis. The patient was monitored in the hospital for 25 days with the elevation of arterial blood pressure and was discharged home without any neurological deficits.