Effect of VNS Generator Depletion on Seizure Frequency
Abstract number :
3.318
Submission category :
9. Surgery / 9C. All Ages
Year :
2023
Submission ID :
746
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Vanessa Lessa, MD – Santa Casa da Misericordia de São Paulo
Julia Vieira, MD – Clinica Cukiert; João Paulo Oliveira, MD – Clinica Cukiert; Rafael Guimaraes, MD – Clinica Cukiert; José Burattini, MD – Clinica Cukiert; Cristine Cukiert, MD, MsC – Clinica Cukiert; Arthur Cukiert, PhD, MD, MsC – Clinica Cukiert
Rationale: VNS generators may require replacement, which is currently performed when its charge gets to below 12.5% or is depleted. Information related to the effect of battery reduction on seizure control is scarce. We evaluated the clinical effects resulting from VNS battery depletion.
Methods: We studied 27 patients who were submitted to VNS generator replacement between 2014 and 2022. Seizure frequency data were obtained through chart reviews, seizure diaries and phone interviews. Mean seizure frequency before battery depletion was considered as baseline and compared to the seizure frequency recorded during the period without adequate stimulation prior to generator replacement.
Results: The average age at seizure onset was 4.3 years and 13.8 years at VNS implantation. The mean follow-up time was 8.1 years. A total of 59% of the patients had some developmental delay. A total of 88,8% had generalized seizures; 37% had normal MRI; 37% had generalized and 30% had multifocal discharges in EEG. A total of 10 patients had a worsening in seizure frequency and duration after battery reduction or depletion. In those patients, battery level was below 25% in four, below 12.5% in four and totally depleted in two. A total of 17 individuals did not notice any seizure frequency increase; in 3 (18%) the generator battery was below 50%, in 10 (59%) below 25% and in 4 (23%) it was totally depleted.
Conclusions: A total of 37% of the patients with VNS battery depletion showed an increase in seizure frequency. This might happen upon total depletion but could also happen by the time the battery is not totally depleted suggesting that adequate stimulation might not be achieved in a low battery charge setting. More frequent visits should be advised when battery levels are below 25% and generator replacement should be performed at least below 12.5%. The different responses associated with battery levels may indicate possible distinct effects of neuromodulation and further studies should be encouraged to seek biomarkers of better therapeutic response.
Funding: None
Surgery