Abstracts

To evaluate the benefits and safety of vagus nerve stimulation (VNS) in intractable childhood epilepsy through review of our experiences. Twelve patients who underwent VNS at two centers and could be followed up for more than 3 months were included. We retrospectively reviewed records for clinical features, therapeutic outcomes, side-effects, developmental progress and EEG changes. The mean ([plusmn] SD) age at the start of VNS were 9 yrs. 9 mo. ([plusmn] 60.5 mo.) (2 yrs. 9 mo. [ndash] 17 yrs. 10 mo.). The mean follow-up period was 21.6 ([plusmn] 23.3) mo. In five patients, follow-up period was over 12 mo., while in seven patients, it was less than 12 mo. Nine patients were classified as Lennox-Gastaut syndrome (LGS), including one patient whose problem originated from previous encephalitis, one patient who was evolved from infantile spasms combined with tuberous sclerosis, and one patient with unknown specific underlying causes. Three patients presented with partial seizure disorder, including one with gelastic seizure caused by hypothalamic harmatoma. At 3 mo. after VNS insertion, eight patients showed more than 50% reduction in seizure frequency, and two patients with LGS became seizure-free after 3 mo. Of the five patients who could be followed up for more than 12 mo., one patient with partial seizure disorder exhibited more than 50% reduction in seizure frequency 3 mo. after VNS insertion, and over 90% reduction at 12 mo. and afterwards. One patient with LGS from previous encephalitis showed more than 50% reduction in seizure frequency after 3 mo. and over 75% after 12 mo., with maintained effect, while one patient with cryptogenic LGS showed over 50% seizure reduction after 3 mo. with maintained effect. Two patients who presented with gelastic seizure and cryptogenic LGS, however, didn[apos]t show any improvement in seizure frequency. Side effects such as hoarseness, drooling, frequent aspiration and dyspnea during sleep could be controlled by adjustment of output current. Wound infection in one patient was controlled after wound revision. In two patients who were seizure free at 3 mo. post-surgically, dramatic improvements of EEG findings were seen. Of the five patients who were followed-up for more than 12 mo., ultimate cognitive outcome was not satisfactory. VNS may be an effective adjunctive therapy for intractable childhood epilepsy and transient side effects can be controlled without discontinuation of VNS therapy.