gms | German Medical Science

Objective: Seizure-free outcome in patients undergoing resective surgery for pharmacoresistant focal epilepsy can be achieved in around 80%. Here we report on a series of patients with persistent or relapsing seizures after initial epilepsy surgery, undergoing repeated presurgical evaluation with video-EEG-monitoring for tailored reoperation.

Methods: From 2015 to 2019, a cohort of 23 consecutive patients with pharmacoresistant focal epilepsy were reevaluated after unsuccessful initial epilepsy surgery. 19 Patients were examined with scalp EEG, 16 had invasive EEG recording using stereotactically implanted depth electrodes. All patients had repeated MRI scans, 10 had ictal SPECT and 8 had FDG-EPT scans for reevaluation. Image processing was used for coregistration and combined 3D visualization of all imaging modalities to localize the epileptogenic zone (EZ) and eloquent areas in the context of the patients' individual brain surface anatomy. Individual 3D maps of the EZ were used to guide subsequent tailored focus resection. The outcome (f/u >6months, n=21) was rated according to the Engel and the ILAE classification.

Results: Median age was 31 yrs [0.8-74]. After initial epilepsy surgery, 10 patients showed reduced but persistent seizure activity; 13 patients were initially seizure free but developed relapsing seizure activity within a median of 3,5 yrs [3 months – 25 yrs]. Time between initial and second resection was in median 70 months [6-340] with a median follow-up of 14 months [6-44] thereafter. The EZ was adjacent to the initially resected EZ in 16 patients and distant in 7. Surgical procedures included unilobar resections (n=13), multilobar resections (n=5), hemispherectomy/disconnection (n=4) and callosotomy (n=1). Seizure-free outcome (Engel class I A-C, ILAE class 1-2) was achieved in 81% of the study cohort. Outcome was similar for patients with lesional or non-lesional (n=11, 82% vs n=10, 80%), temporal or extratemporal (n=7, 86% vs n=14, 79%), right- or left-hemispheric epilepsy (n=8 87% vs n=13, 77%) and with an EZ adjacent or distant from eloquent cortex (n=12, 75% vs n=9, 88%).

Conclusion: Repeated surgery after unsuccessful initial epilepsy surgery can achieve seizure free outcome comparable to the rate obtained with initial focus resection. Reoperations should therefore be considered in all patients with persistent or relapsing pharmacoresistant seizures.