Postoperative Seizures following Endoscopic Endonasal Surgery of the Skull Base

Objective: Endoscopic endonasal surgery (EES) permits resection of intracranial skull base lesions with minimal brain manipulation, theoretically reducing the incidence of postoperative seizures. However, the incidence of postoperative seizures in this population is unknown.

Methods: All patients with suspected seizure activity routinely receive EEG monitoring. The charts of adult patients undergoing EES or craniotomy for extra-axial lesions from 2007 to 2014 who also received EEGs were retrospectively reviewed. Inclusion criteria were electrographic seizures or witnessed seizure activity. Exclusion criteria were preoperative seizures, combined approaches, and extradural location.

Results: Of 827 patients undergoing EES with intradural involvement, 8 (0.97%) patients met criteria for postoperative seizures: 2 meningiomas, 1 esthesioneuroblastoma, 1 pituitary adenoma, 1 spontaneous cerebrospinal fluid leak, 1 epidermoid, 1 chondrosarcoma, and 1 squamous cell carcinoma. Prophylactic anticonvulsants were not used in this group. Except for two patients with meningiomas, all patients had at least one complication including hematoma (1), meningitis (3), postoperative CSF leak (2), pneumocephalus (2), or abscess (1). Patients were managed with anticonvulsants without fatalities during the study period (mean follow-up = 41 months). Patients undergoing craniotomy for extra-axial tumors (792) during the same time period had a higher incidence of postoperative seizure (3.0%, p = 0.006), despite the routine use of prophylactic anticonvulsants.

Conclusion: The incidence of seizures following uncomplicated EES is minimal, and significantly lower than the risk associated with craniotomy for extra-axial tumors. These results confirm that anticonvulsant prophylaxis is unnecessary following EES and suggest that there is an impact of brain manipulation via craniotomy not seen with EES.