Abstracts

Vagal Nerve Stimulation (VNS), Responsive Neurostimulation (RNS), and Deep Brain Stimulation (DBS) have been shown to decrease seizure frequency and provide additional epilepsy control in medically refractory cases. The expansion of neuromodulation devices makes decision-making increasingly challenging for patients, neurologists, and neurosurgeons. We sought to evaluate our utilization of neuromodulation for medically refractory focal epilepsy.

All adult epilepsy patients who underwent VNS, RNS, or DBS for focal or generalized epilepsy at Indiana University from September 2019 to November 2021 were identified via ICD and CPT codes. Data were collected retrospectively via chart review under IRB approval. Statistics were performed in SPSS 27.

VNS was the most common operation (n=90), followed by RNS (n=10), and DBS (n=6).  Pre-operative demographics were similar (Table 1); most patients reported one to three seizures per month (25.5%) or one to six seizures per week (38.7%) (Figure 1). Average time between diagnosis and surgery was 10 years. At one year visit following initial operation, overall, Engel I (seizure free) and Engel II (≥50% improvement) seizure reduction was achieved in 62.3% of patients and 13.2% of patients achieved reduction in the number of medications (by 50% on average). Engel I+II rates for DBS, VNS and RNS were 83.4%, 61.2% and 60% respectively (Figure 2). Among patients in Engel class II-IV, resolution of seizures with impaired awareness, including FIAS, GTCS, and FBTCS, was achieved in 12 cases (13.3%). During the follow-up period, the most common adverse events included headache (38.7%), accidental injury (34.9%), and pain (32.1%). There were three superficial surgical site infections (2.8%), none requiring explant, and no mortalities.

At on year follow-up, VNS, RNS, and DBS provided similar rates of seizure reduction in our population. There were no serious adverse events and therapy was well tolerated.