Vagus nerve stimulation

Lulic, Dzenan; Ahmadian, Amir; Baaj, Ali A.; Benbadis, Selim R.; Vale, Fernando Ĺ.

doi:10.3171/2009.6.focus09126

Cited by 59 publications

(40 citation statements)

References 35 publications

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“…10,11,14 Studies in the 1990s demonstrated a mean 25%-30% decrease in seizure frequency in epilepsy patients following VNS, which led to US FDA approval in 1997 for the treatment of intractable partial epilepsy in patients older than 12 years of age. 4,9,21 To date, many more retrospective and nonrandomized studies have confirmed the effectiveness of VNS in children 7 and adults afflicted with treatment-resistant epilepsy.…”

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confidence: 99%

Vagus nerve stimulation after lead revision

Dlouhy¹,

Viljoen²,

Kung³

et al. 2012

FOC

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Object Vagus nerve stimulation (VNS) has demonstrated benefit in patients with medically intractable partial epilepsy. As in other therapies with mechanical devices, hardware failure occurs, most notably within the VNS lead, requiring replacement. However, the spiral-designed lead electrodes wrapped around the vagus nerve are often encased in dense scar tissue hampering dissection and removal. The objective in this study was to characterize VNS lead failure and lead revision surgery and to examine VNS efficacy after placement of a new electrode on the previously used segment of vagus nerve. Methods The authors reviewed all VNS lead revisions performed between October 2001 and August 2011 at the University of Iowa Hospitals and Clinics. Twenty-four patients underwent 25 lead revisions. In all cases, the helical electrodes were removed, and a new lead was placed on the previously used segment of vagus nerve. All inpatient and outpatient records of the 25 lead revisions were retrospectively reviewed. Results Four cases were second lead revisions, and 21 cases were first lead revisions. The average time to any revision was 5 years (range 1.8–11.1 years), with essentially no difference between a first and second lead revision. The most common reason for a revision was intrinsic lead failure resulting in high impedance (64%), and the most common symptom was increased seizure frequency (72%). The average duration of surgery for the initial implantation in the 15 patients whose VNS system was initially implanted at the authors' institution was much shorter (94 minutes) than the average duration of lead revision surgery (173 minutes). However, there was a significant trend toward shorter surgical times as more revision surgeries were performed. Sixteen of the 25 cases of lead revision were followed up for more than 3 months. In 15 of these 16 cases, the revision was as effective as the previous VNS lead. In most of these cases, both the severity and frequency of seizures were decreased to levels similar to those following the previous implantation procedure. Only 1 complication occurred, and there were no postoperative infections. Conclusions Lead revision surgery involving the placement of a new electrode at the previously used segment of vagus nerve is effective at decreasing the seizure burden to an extent similar to that obtained following the initial VNS implantation. Even with multiple lead revisions, patients can obtain VNS efficacy similar to that following the initial lead implantation. There is a learning curve with revision surgery, and overall the duration of surgery is longer than for the initial implantation. Note, however, that complications and infection are rare.

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confidence: 99%

Vagus nerve stimulation after lead revision

Dlouhy¹,

Viljoen²,

Kung³

et al. 2012

FOC

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“…The ability of such external excitatory stimuli to terminate seizures and/or paroxysmal activity may depend upon identifiable parameters, which, at present, are not understood. 10,11,[21][22][23][24][25] In this work, we present two models of brain function, particularly of working memory, although they may be interpreted more broadly as producing activity involved and useful for many cognitive and motor functions. We examine the models' nonlinear dynamic behavior in normal (i.e., working memory) and pathological (i.e., seizure) states.…”

Section: Introductionmentioning

confidence: 99%

From cognitive networks to seizures: Stimulus evoked dynamics in a coupled cortical network

Lee

Ermentrout

Bodner

2013

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Epilepsy is one of the most common neuropathologies worldwide. Seizures arising in epilepsy or in seizure disorders are characterized generally by uncontrolled spread of excitation and electrical activity to a limited region or even over the entire cortex. While it is generally accepted that abnormal excessive firing and synchronization of neuron populations lead to seizures, little is known about the precise mechanisms underlying human epileptic seizures, the mechanisms of transitions from normal to paroxysmal activity, or about how seizures spread. Further complication arises in that seizures do not occur with a single type of dynamics but as many different phenotypes and genotypes with a range of patterns, synchronous oscillations, and time courses. The concept of preventing, terminating, or modulating seizures and/or paroxysmal activity through stimulation of brain has also received considerable attention. The ability of such stimulation to prevent or modulate such pathological activity may depend on identifiable parameters. In this work, firing rate networks with inhibitory and excitatory populations were modeled. Network parameters were chosen to model normal working memory behaviors. Two different models of cognitive activity were developed. The first model consists of a single network corresponding to a local area of the brain. The second incorporates two networks connected through sparser recurrent excitatory connectivity with transmission delays ranging from approximately 3 ms within local populations to 15 ms between populations residing in different cortical areas. The effect of excitatory stimulation to activate working memory behavior through selective persistent activation of populations is examined in the models, and the conditions and transition mechanisms through which that selective activation breaks down producing spreading paroxysmal activity and seizure states are characterized. Specifically, we determine critical parameters and architectural changes that produce the different seizure dynamics in the networks. This provides possible mechanisms for seizure generation. Because seizures arise as attractors in a multi-state system, the system may possibly be returned to its baseline state through some particular stimulation. The ability of stimulation to terminate seizure dynamics in the local and distributed models is studied. We systematically examine when this may occur and the form of the stimulation necessary for the range of seizure dynamics. In both the local and distributed network models, termination is possible for all seizure types observed by stimulation possessing some particular configuration of spatial and temporal characteristics.

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“…Since the U.S. Food and Drug Administration approved this device for refractory epilepsy in adult and adolescents in July 1997, this modality is the most widely used nonpharmacological treatment for drug-resistant epilepsy now. However, the underlying mechanisms of VNS remain poorly understood [27]. Other neuromodulation methods, such as chronic anterior thalamic stimulation [28], and responsive neurostimulator [29] are under clinical trials and have shown promising efficacy preliminarily.…”

Section: Different Categories Of Epilepsy Surgerymentioning

confidence: 99%

The cultivation of epilepsy neurosurgeons: requirements and challenges

Zhang¹,

Zhang²,

Ma³

et al. 2016

Chin Neurosurg Jl

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Epilepsy surgery has been accepted as an effective treatment in drug-resistant focal epilepsy. However, the number of epilepsy neurosurgeons is not enough in China compared with the huge demand. The content of epilepsy neurosurgeon cultivation includes surgery itself as well as presurgical evaluation. In this article, we review not only different categories of epilepsy surgeries but also the presurgical evaluation approaches including non-invasive methods, such as semiology analysis, high-resolution structural and functional imaging techniques, scalp electroencephalography monitoring as well as invasive methods, such as electrocorticography (ECoG) and stereotactic electroencephalography (SEEG). We also discuss the importance of learning each method briefly. In addition, we suggest that epilepsy neurosurgeons should have a solid structural and functional anatomy basis as it plays pivotal role in localizing epileptogenic zone. Epilepsy neurosurgeons should also be familiar with the staged presurgical evaluation starting from the most preliminary examinations and progressing to more complex and invasive methods. During the diagnosis and therapeutic procedures, collaboration between epilepsy neurosurgeons and other specialists is essential. At last, the necessity of epilepsy neurosurgeon cultivation has been emphasized.

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Vagus nerve stimulation

Cited by 59 publications

References 35 publications

Vagus nerve stimulation after lead revision

Vagus nerve stimulation after lead revision

From cognitive networks to seizures: Stimulus evoked dynamics in a coupled cortical network

The cultivation of epilepsy neurosurgeons: requirements and challenges

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