Abducens Nerve Palsy Following Lumbar Subarachnoid Drain Placement: A Case Report and Review of the Literature

Introduction: Abducens nerve palsy is a rare complication following lumbar dural puncture for spinal anesthesia, diagnostic cerebrospinal fluid (CSF) analysis, and lumboperitoneal shunting. We describe the first known case of abducens nerve palsy from lumbar subarachnoid drain placement during pituitary macroadenoma resection. Methods: An obese 65-year-old woman underwent uneventful transsphenoidal endoscopic resection of a large pituitary macroadenoma after fluoroscopic percutaneous placement of a lumbar subarachnoid drain. There was no evidence of significant bleeding or CSF leak during the case, and the drain was kept closed during the procedure. Immediately postoperatively, the patient was noted to have unilateral left sixth-nerve palsy. Postoperative CT and MRI revealed no structural causes. The sixth nerve palsy ultimately recovered completely over 3 months. A systematic review of the English literature was conducted. Results: Eleven studies, including 9 case reports and 2 case series were found. The total number of sixth nerve palsies in the literature following dural puncture procedures was 13. The proposed mechanism is nerve traction with local ischemia after loss of CSF. This is most likely to occur at the sixth nerve's acute angulation at the petroclival junction. Abducens nerve palsy has not been reported from temporary lumbar subarachnoid drain placement. Conclusion: Procedures potentially causing CSF hypotension carry a rare risk of sixth cranial nerve palsy. Abducens palsy following placement of lumbar drain for pituitary tumor resection has not been previously reported. As the use of endoscopic skull base procedures expands, knowledge of these rare complications is essential for skull base surgeons.