Vagus nerve stimulation for refractory epilepsy: long term efficacy and side-effects.
BACKGROUND
In general vagus nerve stimulation (VNS) can serve as an adjunctive treatment for patients with refractory partial-onset seizures. And we evaluated the long-term efficacy and safety of VNS in a group of Chinese patients with refractory epilepsy.


METHODS
Of 127 patients with refractory epilepsy, 13 patients who were not eligible for surgical intervention were implanted with the Cyberonics VNS system. Seizure frequency, physical examination and side effects profile were recorded at follow-up visits for a minimum of 18 months.


RESULTS
Mean duration of treatment was 47.4 months, and the longest follow-up period was 71 months. Mean baseline seizure frequency was 26.6 seizures per month. The mean percentage reductions in convulsions were 33.2%, 47.1% and 40.0% at 6, 12 and 18 months, respectively. One patient became seizure free, and six (46%) had 50% or more reduction in seizure frequency. Response was poor (< 20% reduction) in five patients (39%). Side effects were uncommon.


CONCLUSIONS
The effectiveness of VNS was sustained and was well tolerated but benefited only a sub-group of patients with intractable convulsions.
Hui
Andrew Che Fai
AC
Division of Neurology, Department of Medicine, Prince of Wales Hospital, the Chinese University of Hong Kong, Hong Kong Special Administrative Region, China. cfhui@cuhk.edu.hk
Lam
Joseph Man Kuen
JM
Wong
Ka Shing
KS
Kay
Richard
R
Poon
Wai Sing
WS
D000293:Adolescent; D000328:Adult; D004599:Electric Stimulation Therapy / Q000379:methods*; D004827:Epilepsy / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D019736:Prostheses and Implants; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000502:physiology*