Authors :
Presenting Author: Juan Luis Alcala Zermeno, MD – Thomas Jefferson University
Michael Sperling, MD – Director, Jefferson Comprehensive Epilepsy Center, Neurology, Thomas Jefferson University; Marina Romozzi, MD – PhD student, Neurology, Università Cattolica del Sacro Cuore
Rationale:
Assessments of response to epilepsy surgery typically measure reduction in seizure frequency without regard to seizure type. However, tonic-clonic seizures (TC) are worthy of separate analysis, as these pose the greatest risk of injury, disability and SUDEP. All-or-none views of seizure reduction ignore the impact of tonic-clonic seizures and may drive surgery underutilization. To improve postoperative assessments and patient counseling, we studied the effect of resective epilepsy surgery on TC in patients undergoing single lobe resective surgery for management of DRE as well as the frequency of de novo tonic clonic seizures (dnTC).
Methods: A retrospective review of an institutional database with prospective follow up (1986-2022) was conducted. Cases with prior intracranial surgeries (excluding phase two monitoring), missing baseline or follow up information on seizure type, seizure frequency or having less than 13 months of follow-up were excluded. Patients with active TC before surgery were defined as at least one TC per year prior to surgery. Seizure freedom was defined as no seizures since surgery excluding auras. Breakthrough seizures in the immediate post-operative period, or with missed medications or intercurrent illness were not allowed in the seizure free category. DnTC were defined as patients with a postoperativeTC with clear documentation of no history of TC prior to surgery. When seizure freedom was not obtained, worthwhile improvement was defined as >80% seizure frequency reduction and/or elimination of TC seizures.
Results:
A total of 804 patients were included in the analysis. TC prior to epilepsy surgery were reported by 521 patients (65%) with 185 of them having active TC before resection (23%). Postoperative median follow up time was seven years (IQR 3-13). Seizure freedom was observed in 307 (38%), worthwhile improvement was observed in 415 (52%). (See Table 1.) Figure 1 depicts seizure outcomes. Of the patients who did not have TC prior to surgery (283, 35%), 17 developed dnTC (6%). Sixteen of them had >80% seizure frequency reduction (94%). In patients preoperative active TC, there was a significant TC frequency reduction after epilepsy surgery from a median of 12 TC per year (range 1-192) to 0.2 TC per year (range 0 – 122), p< 0.001.