Related Experiment Videos
Factors predictive of suboptimal seizure control following selective amygdalohippocampectomy
Aviva Abosch1, Neda Bernasconi, Warren Boling
1Department of Neurosurgery and Neurology, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada. aabosch@emory.edu
Object:
Selective amygdalohippocampectomy (SelAH) is used in the treatment of mesial temporal lobe epilepsy (MTLE). The goal of this study was to determine factors predictive of poor postoperative seizure control (Engel Class III or IV) following SelAH.
Methods:
A retrospective study was conducted of 27 patients with poor seizure control postoperatively (Engel III/IV group), in comparison with 27 patients who were free from seizures after surgery (Engel I/II group). The results of electroencephalography, magnetic resonance (MR) imaging, and pathological studies were reviewed, and volumetric MR image analysis was used to compare the extent of the mesial structures that had been resected. In 56% of patients in the Engel III/IV group, significant bitemporal abnormalities were displayed on preoperative EEG studies, compared with 24% of patients in the Engel I/II group (p < 0.05). An analysis of preoperative MR images disclosed five patients (19%) in the Engel III/IV group and no patient in the Engel I/II group with normal hippocampal volumes bilaterally. Thirteen patients in the Engel III/IV group subsequently underwent either extension of the SelAH (six cases) or a corticoamygdalohippocampectomy (seven patients). Three patients from the former and one patient from the latter subgroup subsequently became seizure free (four patients total [34%]). The remaining nine patients did not improve despite the fact that they had undergone near-total resection of mesial structures.
Conclusions:
The majority of patients receiving suboptimal seizure control following SelAH did not meet the criteria for unilateral MTLE, based on EEG, MR imaging, and/or histopathological studies. These patients were therefore unlikely to benefit from additional resection of mesial structures. With the benefits of modern imaging, and by strict adherence to selection criteria, SelAH can be predicted to yield excellent postoperative seizure control for nearly all patients with unilateral MTLE. There remains a subpopulation, however, that meets the criteria for MTLE, but does not become free from seizure following SelAH.
Insights
Selective amygdalohippocampectomy (SelAH) for mesial temporal lobe epilepsy (MTLE) may not improve seizure control if patients have bilateral abnormalities or normal hippocampal volumes. Careful patient selection is crucial for successful outcomes.
Area of Science:
- Neurosurgery
- Epileptology
- Neuroradiology
Background:
- Selective amygdalohippocampectomy (SelAH) is a surgical treatment for mesial temporal lobe epilepsy (MTLE).
- Predicting postoperative seizure control after SelAH is essential for patient management.
Purpose of the Study:
- To identify factors associated with poor seizure control (Engel Class III or IV) after SelAH.
- To evaluate the utility of further surgical intervention in patients with suboptimal outcomes.
Main Methods:
- Retrospective analysis of 54 patients (27 Engel III/IV, 27 Engel I/II).
- Review of electroencephalography (EEG), magnetic resonance (MR) imaging, and histopathology.
- Volumetric MR imaging to assess resection extent and hippocampal volumes.
Main Results:
- 56% of Engel III/IV patients had preoperative bitemporal abnormalities on EEG, versus 24% in Engel I/II (p < 0.05).
- 19% of Engel III/IV patients had normal bilateral hippocampal volumes on MR imaging, versus 0% in Engel I/II.
- Further resection in 13 Engel III/IV patients yielded seizure freedom in only 34% (4/13).
Conclusions:
- Many patients with poor outcomes after SelAH do not meet criteria for unilateral MTLE.
- These patients are unlikely to benefit from additional mesial structure resection.
- Strict adherence to selection criteria and modern imaging can optimize SelAH outcomes for unilateral MTLE, though a refractory subpopulation exists.