Left Sixth Nerve Palsy and Subdural Hygroma Following Intrathecal Morphine Pump Placement: A Case Report

Case Diagnosis: A 59-year-old male, with chronic, intractable low back pain and lumbar radiculopathy had a left sixth nerve palsy and subdural hygroma following intrathecal Morphine pump placement

Case Description or Program Description: The patient underwent an IT morphine pump implant for treatment of his chronic, intractable low back pain. However, approximately one week following the procedure, he developed a persistent headache and diplopia. He was found to have left lateral rectus palsy, in which his left eye was unable to deviate to the side. Following the ophthalmology consult, the patient had a spinal tap, which was normal, however, he was found to have low opening pressure. A blood patch was subsequently performed, with no improvement in headache or visual symptoms. About two months following the procedure, he had a repeat CT scan that showed the development of bilateral subdural hygromas. He underwent exploratory surgery, in which the CSF leak was identified and the dura was sutured around the IT catheter to prevent further CSF leaks. Two weeks later, he was found to have a large postoperative seroma and elected to have the pump and catheter removed.

Setting: Out-patient surgery center

Assessment/Results: On a follow-up appointment following pump removal, he reported the resolution of his headache and left lateral rectus palsy.

Discussion (relevance): After an extensive literature search and review, to our knowledge, this is the first reported case of sixth nerve palsy and subdural hygromas following the implant of a drug-delivery system.

Conclusions: Despite its rarity, headache, and diplopia following this procedure must be actively pursued, as cranial nerve palsy should be ruled out immediately. Treatment is on a case-by-case basis, however, it may take several months for the symptoms to resolve.