A novel implantable vagus nerve stimulation system (ADNS-300) for combined stimulation and recording of the vagus nerve: pilot trial at Ghent University Hospital.
OBJECTIVE
Vagus nerve stimulation (VNS) is an established treatment for refractory epilepsy. The ADNS-300 is a new system for VNS that includes a rechargeable stimulus generator and an electrode for combined stimulation and recording. In this feasibility study, three patients were implanted with ADNS-300 for therapeutic VNS. In addition, compound action potentials (CAPs) were recorded to evaluate activation of the vagus nerve in response to VNS.


METHODS
Three patients were implanted with a cuff-electrode around the left vagus nerve, that was connected to a rechargeable pulse generator under the left clavicula. Two weeks after surgery, therapeutic VNS (0.25-1.25 mA, 500 μs, 30s on, 10 min off and 30Hz) was initiated and stimulus-induced CAPs were recorded.


RESULTS
The ADNS-300 system was successfully implanted in all three patients and patients were appropriately stimulated during six months of follow-up. A reduction in seizure frequency was demonstrated in two patients (43% and 40% in patients 1 and 3, respectively), while in patient 2 seizure frequency remained unchanged. CAPs could be recorded in patients 1 and 2, proving stimulation-induced activation of the vagus nerve.


CONCLUSIONS
This feasibility study demonstrates that the ADNS-300 system can be used for combined therapeutic stimulation (in 3/3 patients) and recording of CAPs in response to VNS (in 2/3 patients) up to three weeks after surgery. Implantation in a larger number of patients will lead to a better understanding of the electrophysiology of the vagus nerve, which in turn could result in more adequate and individualized VNS parameter choice.
Reference Centre for Refractory Epilepsy, Department of Neurology, Ghent University Hospital, De Pintelaan 185, K12IA, Gent 9000, Belgium. Riem.Eltahry@ugent.be
Riëm
R
El Tahry
Robrecht
R
Raedt
Lies
L
Mollet
Veerle
V
De Herdt
Tine
T
Wyckhuys
Tine
T
Wyckuys
Annelies
A
Van Dycke
Alfred
A
Meurs
Frank
F
Dewaele
Dirk
D
Van Roost
Pascal
P
Doguet
Jean
J
Delbeke
Wytse
W
Wadman
Kristl
K
Vonck
Paul
P
Boon
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004567:Electrodes, Implanted; D004827:Epilepsy / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000502:physiology* / Q000503:physiopathology*; D055536:Vagus Nerve Stimulation / Q000295:instrumentation / Q000379:methods*