Patient-specific characteristics associated with favorable response to vagus nerve stimulation

Author: Robert A Riestenberg1, Alain E Sherman2, Austin J S Clark3, Kiarash Shahlaie3, Marike Zwienenberg3, Tord Alden4, S Kathleen Bandt2
Affiliation:
1 Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Address: 676 North St. Clair Street, Suite 2210, Chicago, IL 60611, USA; University of California, Davis, Department of Neurological Surgery, Address: 4860 Y Street Suite 3740, Sacramento, CA 95817, USA.
2 Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Address: 676 North St. Clair Street, Suite 2210, Chicago, IL 60611, USA.
3 University of California, Davis, Department of Neurological Surgery, Address: 4860 Y Street Suite 3740, Sacramento, CA 95817, USA.
4 Division of Pediatric Neurosurgery, Ann and Robert H. Lurie Children's Hospital of Chicago, Address: 225 E. Chicago Ave. Chicago, IL 60611, USA.
Conference/Journal: World Neurosurg
Date published: 2022 Feb 21
Other: Special Notes: doi: 10.1016/j.wneu.2022.02.055. , Word Count: 222


Objective:
The expansion in treatments for medically refractory epilepsy heightens the importance of identifying patients who are likely to benefit from vagus nerve stimulation (VNS). Here, we identify predictors of positive VNS response.

Methods:
We present a retrospective analysis of 158 patients with medically refractory epilepsy. Patients were categorized as VNS responders or non-responders. Baseline characteristics and time to VNS response were recorded. Univariate and multivariate Cox regression were used to identify predictors of response. Recursive partitioning analysis (RPA) was used to identify likely VNS responders.

Results:
Eighty-nine (56.3%) patients achieved ≥ 50% seizure frequency reduction. Left-hand dominance (HR = 1.703, p = 0.038), age at epilepsy onset ≥ 15 years (HR = 2.029, p = 0.005), duration of epilepsy ≥ 8 years (HR = 1.968, p = 0.007) and age at implantation ≥ 35 years (HR = 1.809, p = 0.020), and baseline seizure frequency < 5/month (HR = 1.569, p = 0.044) were significant univariate predictors of VNS response. Following multivariate Cox regression, left-hand dominance, age at epilepsy onset ≥ 15 years, and duration of epilepsy ≥ 8 years remained significant. With RPA, patients with either age at epilepsy onset ≥ 15 years, left-hand dominance, or baseline seizure frequency < 5/month were stratified into Group A and had a 73.9% responder rate; the remaining patients stratified into Group B had a 43.8% responder rate.

Conclusions:
Patients with age at epilepsy onset ≥ 15 years, left-hand dominance, or baseline seizure frequency < 5/month are ideal candidates for VNS.

Keywords: Vagus nerve stimulation; medically refractory epilepsy; prediction system.

PMID: 35202878 DOI: 10.1016/j.wneu.2022.02.055

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