Abstracts

Rationale: Epilepsy surgery is the best long-term treatment option for medically intractable seizures. Clear consensus for duration and type of anti-epilepsy drugs (AEDs) to be used in post-surgical patients is lacking. Four retrospective and two prospective studies have investigated this problem, and peri-operative and post-operative use of Levetiracetam (LEV) was found to have best seizure control possibly because of its “anti-epileptogenic” properties (Table 1). These studies did not include AEDs approved after 2008, specifically Lacosamide (LCS) which is now commonly used. We aim to compare the post-surgery efficacy of LEV and LCS in controlling seizures. Methods: Ours was a retrospective study that looked at AED use in adult patients who met ILAE definition of medically intractable epilepsy and underwent resective surgery between 2009 and 2015 at our Level 4 Epilepsy Center with a minimum follow-up of 6 months.  We included patients with both temporal and extra-temporal resection. Exclusion criteria were previous epilepsy surgery, resections for malignant brain tumors, and palliative procedures such as corpus callosotomy. In addition, patients on LEV & LCS simultaneously were excluded. Pearson's Chi-square test was performed to observe the significance between nominal variables and unpaired two-tailed t-test was performed for absolute variables. We also summarized available literature in this area (Table 1). Results: 45 patients met inclusion criteria out of which 16 were on LEV while 14 on LCS. Seven patients on both LEV & LCS and eight patients on other AEDs were not included in the analysis. Results are summarized in Table 2. LCS group had significantly more patients with normal presurgical brain MRI. Other variables did not show a statistical difference. There was no difference in seizure freedom rates between the two groups at six months, one year and two years. However, there was a strong trend (p=0.06) towards a higher proportion of patients with seizure freedom at 1 year with LEV group. Only one patient in either group was on monotherapy. Mean dose at 6 month was 2218 mg for LEV and 403 mg for LCS. Some form of temporal lobe resection was present in all except one patient in either group. Surprisingly, 8 out of 10 patients (with available data) who were seizure free at 6 months on LCS had failed LEV prior to surgery. Conclusions: LEV & LCS have similar efficacy for seizure freedom in post-surgical patients. While there is evidence in animal studies for anti-epileptogenic properties of LEV, such evidence is lacking for LCS. The trend towards worse outcome with LCS could be explained by the higher proportion of patients with normal MRI which is a known poor prognostic factor. Our study results would imply only to temporal lobe resections. Our study in its present form is limited by its retrospective nature and small sample size, especially as compared to other similar studies. Short follow-up is also a limitation as it is well known that post-surgical patients can have a waxing and waning course over many years. We aim to address these by including patients from 2006 to 2008 that will allow for a longer follow-up.Prior studies have shown LEV use to have benefit in post-surgical patients as compared to other AEDs. Preliminary data from our study show that LCS might have similar efficacy in this patient population and should be especially considered in patients who have failed LEV.  Funding: None