Abstracts

Rationale: Temporal lobe epilepsy surgery is the most common surgical procedure to treat pharmacoresistant epilepsy. Several temporal surgical procedures had been described including anterior temporal lobectomy (ATL) and selective amygdalo-hipppocampectomy (SAH) with 50-70% seizure free rates. The parahippocampal gyrus has a relevant role in the output gate in the temporal mesial structures and is involved in the epileptogenic pathways of mesial temporal epilepsy (mTLE). We proposed that the parahippocampectomy (PHC) has similar long-term epilepsy efficacy control with a better neuro-psychological (verbal and visual memory) and visual field outcomes compared to ATL and AH. Methods: Comparative and prospective non-randomized clinical trial that included adult patients who underwent mTLE surgery due to hippocampal sclerosis; Trans-T3 resection approach and PHC (subiculum as upper limit, PHC), ATL and SAH through a trans-T3 approach were performed. We described clinical socio-demographic characteristics. Also, epilepsy outcome, visual fields and neuro-psychological profiles were evaluated at baseline, 1 and 5 years of follow-up with Engel scale, Goldman perimeter and Barcelona test (semantic-episodic memory and Rey complex figure sub-test). We used descriptive statistics, Kruskal-Wallis and Mann-Whitney tests, statistical significance was p ≤ 0.05.  The Ethics Committee of our institution approved this study. Results: Forty-nine patients with mean 35.8 (range 18-56) years-old, 39% male and 61% female were analyzed:  15 PHC, 18 ALT and 16 SAH. (Table 1). Free-seizure (Engel IA) at the follow-up at 1 and 5 years was; 46.7%, PHC, 72.2%, ATL and 56.3% SAH (p= 0.325) 26.7% PHC, 55.6% ATL and 53.3% SAH (p= 0.204), respectively. Engel I outcome at 1 and 5 years of follow-up was: 80% PHC, 94.4% ATL and 93.8% SAH (p= 0.329); 53.3% PHC, 66.7% ATL and 66.7% SAH (p= 0.682). Table 2, show the Engel I comparative analysis between the surgical techniques at 1 and 5 years of follow-up without any statistical significance.                                                                                                                  Visual field defects (partial or complete homonymous quadrantanopia) were seen post-operatively in: 0% PHC, 100% ALT and 50% SAH (p= 0.001).                 Verbal and/or visual memory worsening were present in: 20% PHC, 27.8% ATL and 26.7% SAH (p= 0.865). Conclusions: Parahippocampectomy had similar efficacy in the control of seizure compared to ATL and SAH, with less affected verbal and visual memory and without visual fields deficits. Funding: Any