Refractory epilepsy in tuberous sclerosis: vagus nerve stimulation with or without subsequent resective surgery.

Abstract

OBJECTIVE:

The goal of the work described here was to assess the efficacy and safety of vagus nerve stimulation in a cohort of patients with tuberous sclerosis complex with refractory epilepsy. Furthermore, we examined the impact of vagus nerve stimulation failure on the ultimate outcome following subsequent intracranial epilepsy surgery.

METHODS:

A retrospective review was performed on 19 patients with refractory epilepsy and TSC who underwent vagus nerve stimulator (VNS) implantation. There were 11 (58%) females and 8 (42%) males aged 2 to 44 years when the VNS was implanted (mean: 14.7+/-12 years). Twelve patients underwent primary VNS implantation after having failed a mean of 7.1 antiepileptic drugs. Two patients (17%) had generalized epilepsy, one had a single seizure focus, three (25%) had multifocal epilepsy, and six (50%) had multifocal and generalized epilepsy. Seven patients were referred for device removal and evaluation for intracranial procedures. One patient in the primary implantation group was lost to follow-up and excluded from outcome analysis.

RESULTS:

All implantations and removals were performed without permanent complications. The duration of treatment for primary VNS implants varied from 8.5 months to 9.6 years (mean: 4.9 years). Mean seizure frequency significantly improved following VNS implantation (mean reduction: 72%, P<0.002). Two patients had Engel Class I (18%), one had Class II (9%), seven had Class III (64%), and one had Class IV (9%) outcome. Three patients with poor response to vagus nerve stimulation therapy at our center underwent resection of one or more seizure foci (Engel Class I, two patients; Engel Class III, one patient). Seven patients referred to our center for VNS removal and craniotomy underwent seizure focus resection (6) or corpus callosotomy (1) (Engel Class II: 2, Engel III: 2; Engel IV: 3). In total, 8 of 10 (80%) patients experienced improved seizure control following intracranial surgery (mean reduction: 65%, range: 0-100%, P<0.05).

CONCLUSIONS:

VNS is a safe and effective treatment option for medically refractory epilepsy in patients with tuberous sclerosis complex. Nine of 11 patients (82%) experienced at least a 67% reduction in seizure burden. Lack of response to vagus nerve stimulation does not preclude subsequent improvement in seizure burden with intracranial epilepsy surgery.

• Authors: Robert E Elliott, Chad Carlson, Stephen P Kalhorn, Yaron A Moshel, Howard L Weiner, Orrin Devinsky, Werner K Doyle
• Journal: Epilepsy & behavior : E&B (Epilepsy Behav) Vol. 16 Issue 3 Pg. 454-60 (Nov 2009) ISSN: 1525-5069 [Electronic] United States
• PMID: 19767244 (Publication Type: Clinical Trial, Comparative Study, Journal Article)

Topics

• Adolescent
• Adult
• Child
• Child, Preschool
• Electroencephalography
• Epilepsy (etiology, therapy)
• Female
• Humans
• Male
• Neurosurgery (methods)
• Outcome Assessment, Health Care
• Retrospective Studies
• Tuberous Sclerosis (complications, therapy)
• Vagus Nerve Stimulation (methods)
• Young Adult