Selective subtemporal amygdalohippocampectomy for refractory temporal lobe epilepsy: operative and neuropsychological outcomes

Object. The authors evaluated operative, neuropathological, and neuropsychological results after selective subtemporal amygdalohippocampectomy for refractory temporal lobe epilepsy in patients who were observed for at least 2 years after surgery. Methods. Twenty-six consecutive patients underwent selective subtemporal amygdalohippocampectomy for nonlesional, medically refractory temporal lobe epilepsy. Neuropsychological evaluation using the Wechsler Adult Intelligence Scale was done before surgery in all patients, 2 months after surgery in 24 patients, and at 2-year follow up in 19 patients. A verbal paired associates learning test was administered before surgery and 2 months after surgery in 19 patients. The data were compared between the 13 patients in whom the language-dominant hemisphere was surgically treated and the six patients in whom the language-nondominant hemisphere was treated. After surgery, 84% of the patients attained either Engel Class I or R seizure outcome. There were no permanent subjective complications except postoperative memory impairment in one patient. Neuropathological examination confirmed hippocampal sclerosis in 19 patients. No significant differences in IQ and verbal memory test scores were observed between the patients in whom the language-dominant hemisphere was treated and those in whom the language-nondominant hemisphere was treated. Significant postoperative increases in verbal IQ, performance IQ, and full-scale IQ were observed over time. No significant differences were found between pre- and postoperative verbal memory test scores, and no subjective visual field loss was marked in any patient. Conclusions. Subtemporal selective amygdalohippocampectomy provides favorable surgical and neuropsychological outcomes and does not cause significant postoperative decline of verbal memory if performed on the language-dominant side.