Long-term therapeutic effects of corticoamygdalohippocampectomy for bilateral mesial temporal lobe epilepsy.

Background: Some cases of paradoxical mesial temporal lobe epilepsy (MTLE) are shown to be bilateral MTLE (BMTLE) by intracranial electrodes. The treatment for BMTLE is difficult, which poses several questions. Can corticoamygdalohippocampectomy (CAH) be applied to treat BMTLE? What are the long-term therapeutic effects if CAH is performed in BMTLE patients?

Methods: Four patients were shown to have BMTLE through bilateral intracranial electrode implantation. CAH was performed on the side with relatively more seizure originations. These patients were followed-up at 6 months, 1 year, 2 years and longer, in some cases, after the CAH. The postoperative seizure frequency was recorded. Preoperative and postoperative clinical memory tests and a postoperative 4-hour video electroencephalography (EEG) were conducted in the hospital at different follow-up times. The average seizure frequencies and memory quotient scores were analyzed.

Results: The average seizure frequency significantly decreased by 80.8%, 83.5%, and 84.3% at different postoperative times. Although no patient was seizure free, the intensity of the seizures was reduced in all cases. The postoperative average memory quotient score was moderately decreased by 15.8%, 11.7%, and 16.6% at different postoperative times. Both the average values of the postoperative seizure frequency (5.5, 4.75, and 4.5 per month) and the average values of the postoperative memory quotient (73.7, 77.3, and 73) at different postoperative times were approximately the same.

Conclusions: CAH reduced the seizure frequency and intensity in these BMTLE patients. Mild hypomnesis occurred in every case. We observed the long-term treatment effects at 6 months after the CAH and showed that the effects did not change at that time or over the next few years.