Extent of Mesiobasal Resection Determines Outcome after Temporal Lobectomy for Intractable Complex Partial Seizures

Abstract

The extent of resection was assessed in 94 patients who underwent temporal lobectomy for medically intractable complex partial seizures originating from a unilateral seizure focus in the anteromesial temporal lobe. Postoperative magnetic resonance imaging in the coronal plane was used to quantify the extent of resection of lateral and mesiobasal structures according to a 20-compartment model of the temporal lobe. Successful seizure outcome (≥90% reduction in seizure frequency) was accomplished in 83% of the patients (all followed up for more than 1 year; mean duration of follow-up, 25.2 months) and correlated significantly (P<0.05) with the extent of mesiobasal resection, regardless of the extent of resection of lateral structures. Successful seizure outcome was accomplished in 81% of the patients with no structural lesions, and also correlated significantly (P<0.05) with the extent of mesiobasal resection regardless of the extent of lateral resection. A successful seizure outcome was accomplished in 90% of the 21 patients with structural lesions documented by neuroimaging studies. Two patients who underwent extensive lobectomy without resection of the structural lesion had no reduction in seizure frequency postoperatively. We conclude that the most important factor in determining the outcome of temporal lobectomy in patients with unilateral anteromesial temporal lobe epileptogenicity is the extent of resection of structures in the mesiobasal temporal lobe. In patients with structural lesions, lesion resection may be an added contributor to successful seizure outcome. (Neurosurgery 29:55-61, 1991)

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).…”

Neurosurgical Management of Intractable Temporal Lobe Epilepsy by Amygdalohippocampectomy Plus Anterior Temporal Lobectomy: Report of Initial Three Pediatric Cases with Short Literature Review

“…Size of the lesion, possibility of different pathology, narrow space through trans-sylvian route and possibility of manipulation and damage of critical vessels and neural structures and most importantly less familiarity of the approach along with less success rate of amygdalohippocampectomy in controlling epilepsy helped us to take decision in favour of trans middle temporal gyrus approach amygdalohippocampectomy with lesionectomy plus standard anterior temporal lobectomy instead of selective amygdalohippocampectomy in the hope to cure epilepsy as well as the lesion. It has been suggested that the amount of tissue resected in mesiotemporal operations is crucial for surgical success in mesial TLE 4,5,6,7 . In a randomized, prospective study comparing the trans-sylvian with the transcortical approach, seizure outcome was similar 8,9 .…”

“…In certain developmental tumors, e.g., ganglioglioma and dysembryoplastic neuroepithelial tumor that usually occurs in pediatric patient can be treated with excellent seizure-control and disease control rates in most patients 6 . Seizure control rate in MTS after surgery is excellent 2,3 .…”

Standardization of Amygdalohippocampectomy with Intraoperative Magnetic Resonance Imaging: Preliminary Experience

“…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). Whether this approach actually confers a higher rate of seizure freedom or a greater amount of visual field or neuropsychological impairment than electrographically tailored resections has never been tested in a randomized prospective fashion.…”

“…In spite of the increased visibility provided by the operating microscope, careful evaluation of the postoperative MRI has indicated that the extent of the hippocampal resection is often overestimated by the operating surgeon (14,(16)(17)(18)(19). Recently several surgeons integrated frameless stereotaxy into the surgical approach to the medial temporal lobe (20)(21)(22)(23)(24).…”