Second operation after the failure of previous resection for epilepsy

Abstract

We present our surgical experience with second operations in 15 patients with recurrent intractable partial seizures after resection for epilepsy. The interval from the first operation until the first recurrence of seizures ranged from 1 day to 7 months (mean, 62 days). The interval between the first and second operations ranged from 3 months to 12 years (mean, 38 months). Detailed video-electroencephalographic interictal and ictal recording was performed in all patients (invasive electrodes were used in 11 patients). Ictal onset was shown to be remote from the zone of previous resection in 3 of 15 cases (all 3 extratemporal and in the ipsilateral hemisphere). Recurrent seizures arose from the area of previous extratemporal resection in 2 of 15 patients, and from the area of previous temporal resection in 10 of 15 patients. Both cases of extratemporal recurrences and 3 of the 10 cases of temporal lobe recurrences in the area of previous resection were associated with residual unresected structural lesion. Of the 10 patients with local temporal recurrence, 6 had proven epileptogenicity in the residual mesial structures, and 4 had residual epileptogenicity in the unresected lateral temporal lobe. The patients have been monitored for 8 to 82 months (mean, 18 months) after the second operation: 7 patients (47%) have remained seizure-free and another 5 (33%) have achieved a reduction in seizure frequency of more than 90%. There was no mortality or significant morbidity in this series. We conclude that the extent and distribution of residual epileptogenicity after failed epilepsy surgery are highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Optimizing Epilepsy Surgery with Intraoperative MR Imaging

“…Several authors suggested that amygdala and hippocampus removal is essential in achieving a good surgical outcome (8)(9)(10)12,13,21,22). In a trial randomizing the extent of hippocampus resection while maintaining controlled lateral temporal resection in 70 patients, Wyler et al (9,13) showed that complete hippocampectomy (to the level of the colliculus) was associated with significantly better seizure control (69% seizure free at 1 year vs. 38%) than partial hippocampectomy (to the anterior edge of the cerebral peduncle).…”

“…Despite reasonable seizure control achieved with temporal structure resections, there still remains a 20-60% recurrence rate, varying in onset from the perioperative phase to several years after surgery (9)(10)(11)(12). Potential reasons for failures include nonfocal or bitemporal lobe epilepsy, unresected lesion, perilesional or postsurgical gliosis, extratemporal lesions, or diffuse cerebral disease, as may be present after meningitis or encephalitis (8).…”

“…More recently several authors suggested that seizure recurrence may be due to a conservative and inadequate resection of the medial temporal structures, primarily the amygdala and hippocampus (8)(9)(10)13). Magnetic resonance (MR) imaging has assisted greatly in defining residual lesions and incomplete media.…”

Standardization of Amygdalohippocampectomy with Intraoperative Magnetic Resonance Imaging: Preliminary Experience

“…Finally, because the PoleStar N-10 has a built in neuronavigational system, we often used its "optical wand" to locate the temporal horn of the lateral ventricle after the brain had shifted, rendering standard neuronavigational systems inaccurate. The role of IMRI also may be critical for reoperations when the surgical anatomy is distorted and the risk of complications slightly higher (11). Another potential use for IMRI would be to determine intraoperatively the extent of division of the corpus callosum after callosotomy, which has already been reported by Nimsky et al (39).…”

“…As a result of depth-electrode studies, investigators have demonstrated ictal onsets arising not only from the anterior hippocampus but also from the posterior hippocampus, amygdala, and parahippocampal gyrus (5)(6)(7)(8). Studies using high-resolution postoperative magnetic resonance imaging (MRI) to correlate residual medial temporal lobe structures with outcome have demonstrated the impact of residual hippocampus and parahippocampal gyrus in recurrent seizures after medial temporal lobe resections (9)(10)(11)(12). Several retrospective and prospective studies also confirmed a higher seizurefree rate after a more extensive hippocampal resection, and many surgeons now perform a radical amygdalohippocampectomy as an integral part of their temporal lobe resections (13)(14)(15)(16).…”