Right-sided vagus nerve stimulation as a treatment for refractory epilepsy in humans.
OBJECTIVE
We present three children who underwent right-sided vagus nerve stimulation (R-VNS). This treatment option for people with refractory epilepsy has not been described in children.


METHODS
We reviewed our database of >350 patients implanted with vagus nerve stimulators and now describe our experience in three patients with R-VNS for the treatment of intractable seizures. All three patients improved dramatically with left-sided vagus nerve stimulation (L-VNS), but the devices had to be removed because of infection. The patients were thought to be at high risk for nerve injury if they were reapproached for L-VNSs; therefore R-VNSs were implanted.


RESULTS
All three patients with an R-VNS had a reduction in seizures. Our first patient has had an R-VNS for 5 years; he has been seizure free for >2 years on R-VNS monotherapy. The second patient had an R-VNS for 8 months. His seizure control improved slightly, but not as dramatically as with L-VNS. The third child has had an R-VNS for >7 months and has cessation of his most disabling seizure type (generalized tonic-clonic seizures). None of the patients had cardiac side effects from therapeutic R-VNS. However, two of the three patients had respiratory events with R-VNS.


CONCLUSIONS
VNS is known to be an effective treatment in pharmacoresistant epilepsy. R-VNS should be considered if a patient has significant benefit from L-VNS but is unable to continue with L-VNS. R-VNS appears also to have antiepilepsy effects. Additionally, our case report suggests that in some patients, a differential response is found regarding seizure control with R-VNS or L-VNS, raising the question whether L-VNS failures should pursue a trial of R-VNS. Patients should be cautioned and monitored for reactive airway disease if they undergo R-VNS. More research is needed to compare the effects of right- and left-sided VNS on cardiac and pulmonary function in humans and to determine which has the best antiseizure effect.
McGregor
Amy
A
Department of Neurology, Texas Comprehensive Epilepsy Program, University of Texas-Houston, Houston, Texas 77030, USA.
Wheless
James
J
Baumgartner
James
J
Bettis
David
D
D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D004599:Electric Stimulation Therapy / Q000379:methods*; D004827:Epilepsy / Q000188:drug therapy / Q000628:therapy*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000502:physiology*
D000927:Anticonvulsants