Abstracts

Rationale: To evaluate effectiveness, safety, and related findings following stereotactic laser amygdalohippocampotomy (SLAH), a minimally invasive option to open anterior temporal lobectomy and selective amygdalohippocampectomy for mesial temporal lobe epilepsy (MTLE). Methods: Data from 7 centers enrolling 66 adult subjects with medically resistant MTLE that underwent SLAH (Visualase, Houston, TX) at least 6 mo prior was collected via validated case report forms (CRFs); 44 subjects reached 12 mo follow-up. Only subjects with completed data are reported: 11 and 6 subjects had incomplete data at 6 and 12 mo follow-up, respectively, due to late patient visits or the site not collecting 6 mo data. Each center had IRB approval for its respective single-center, investigator-initiated study. Screening and follow-up visits were arranged per protocol at a given center, with some variation per center. Demographic, medical history, and medical/surgical care data were also gathered, along with seizure outcome. Results: For the subjects with data available, age was 43±14 (range 19-75). 66% were female. Mesial temporal sclerosis (MTS) was reported in 70%. Duration of epilepsy was 25±18 years (range 2-68, n=43), and subjects had taken a median of 6 anti-epileptic drugs (range 2-11, n=43) prior to SLAH. The most common pre-ablation seizure type was complex partial, with some exhibiting simple partial and secondarily generalized seizures as well. At 6-mo follow-up of all available subjects since the beginning of SLAH being performed (8/2011), 53% of subjects (n=55) were Engel I (free of disabling seizures). At one-year follow-up, analysis of all available reported adult data showed 55% subjects achieving Engel I status (n=38); 7 had non-disabling simple partial seizures (Engel Ib) with 1 occurring only within the first month post-ablation. Seizure-free rates were 61% in subjects with MTS and 53% in those without at 6 mo, but this was not statistically significant (p=0.28, two-tailed Fisher's exact test). Two hemorrhages occurred: 1 subdural hematoma with no transient or permanent neurological deficit; 1 temporal lobe hematoma with visual field deficit that recovered. Overall there were 4 visual field deficit & transient subjective diplopia (1); transient confusion/difficulty with expression (3), anxiety (5) and other psychological problems of uncertain relation to ablation, superficial skin erythema, and headache (8 episodes in 7 subjects), among other reported events of uncertain relation to ablation. Steroids were given post-operative period ranging from 4 to 15 days at most centers. Median length of stay was 1 day. Anti-epileptic medications were kept constant throughout the one-year course by most centers, and altered based upon high blood levels or seizure activity. Conclusions: SLAH achieved Engel 1 outcome in the majority of subjects at 6- and 12-month follow-up, with acceptable saftey. Further prospective study, with greater numbers of subjects, will help elucidate and/or strengthen these findings.