Implanted vagus nerve stimulation in 126 patients: surgical technique and complications

Introduction: Vagus nerve stimulation is a palliative treatment for patients with refractory epilepsy to reduce the frequency and intensity of seizures. A bipolar helical electrode is placed around the left vagus nerve at the cervical level and is connected to the pulse generator placed in a subcutaneous pocket, most commonly in the subclavian region. Methods: Between March 1998 and October 2019, we performed 196 procedures related to the vagal nerve stimulation at the Neurosurgery Department in Motol University Hospital. Of these, 126 patients were vagal nerve stimulator implantation surgeries for intractable epilepsy. The cases included 69 female and 57 male patients with mean age at the time of the implantation surgery 22±12.4 years (range 2.1−58.4 years). Results: Nine patients (7.1%) were afflicted by complications related to implantation. Surgical complications included postoperative infection in 1.6%, VNS-associated arrhythmias in 1.6%, jugular vein bleeding in 0.8% and vocal cord paresis in 2.4%. One patient with vocal cord palsy also suffered from severe dysphagia. One patient (0.8%) did not tolerate extra stimulation with magnet due to a prolonged spasm in his throat. The extra added benefit of vagus stimulation in one patient was a significant reduction of previously regular severe headaches. Conclusion: Vagus nerve stimulation is an appropriate treatment for patients with drug-resistant epilepsy who are not candidates for focal resective surgery. Implantation of the vagus nerve stimulator is a relatively safe operative procedure.

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Self-inflicted vocal cord paralysis in two patients with vagus nerve stimulators

Journal of Neurosurgery ◽

10.3171/jns.2002.96.5.0949 ◽

2002 ◽

Vol 96 (5) ◽

pp. 949-951 ◽

Cited By ~ 19

Author(s):

James G. Kalkanis ◽

Priya Krishna ◽

Jose A. Espinosa ◽

Dean K. Naritoku

Keyword(s):

Vagus Nerve ◽

Vocal Cord ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Pulse Generator ◽

Vocal Cord Paralysis ◽

Cardiac Pacemakers ◽

Content Type ◽

Vagus Nerve Stimulator ◽

Disabled Patients

✓ Vagus nerve stimulation for treatment of epilepsy is considered safe; reports of severe complications are rare. The authors report on two developmentally disabled patients who experienced vocal cord paralysis weeks after placement of a vagus nerve stimulator. In both cases, traction injury to the vagus nerve resulting in vocal cord paralysis was caused by rotation of the pulse generator at the subclavicular pocket by the patient. Traumatic vagus nerve injury caused by patients tampering with their device has never been reported and may be analogous to a similar phenomenon reported for cardiac pacemakers in the literature. As the use of vagus nerve stimulation becomes widespread it is important to consider the potential for this adverse event.

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Is Vagus Nerve Stimulation Brain Washing?

10.1101/733410 ◽

2019 ◽

Author(s):

Kevin P. Cheng ◽

Sarah K. Brodnick ◽

Stephan L. Blanz ◽

Weifeng Zeng ◽

Jack Kegel ◽

...

Keyword(s):

Cerebrospinal Fluid ◽

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Intractable Epilepsy ◽

Brain Parenchyma ◽

Vagal Nerve ◽

Waste Products ◽

Adrenergic Signaling ◽

The Brain

AbstractVagal nerve stimulation (VNS) is an FDA approved treatment method for intractable epilepsy, treatment resistant depression, cluster headaches and migraine with over 100,000 patients having received vagal nerve implants to date. Moreover, evidence in the literature has led to a growing list of possible clinical indications, with several small clinical trials applying VNS to treat conditions ranging from neurodegenerative diseases to arthritis, anxiety disorders, and obesity. Despite the growing list of therapeutic applications, the fundamental mechanisms by which VNS achieves its beneficial effects are poorly understood and an area of active research. In parallel, the glymphatic and meningeal lymphatic systems have recently been proposed and experimentally validated to explain how the brain maintains a healthy homeostasis without a traditionally defined lymphatic system. In particular, the glymphatic system relates to the interchange of cerebrospinal fluid (CSF) and interstitial fluid (ISF) whose net effect is to wash through the brain parenchyma removing metabolic waste products and misfolded proteins from the interstitium. Of note, clearance is sensitive to adrenergic signaling, and a primary driver of CSF influx into the parenchyma appears to be cerebral arterial pulsations and respiration. As VNS has well-documented effects on cardiovascular and respiratory physiology as well as brain adrenergic signaling, we hypothesized that VNS delivered at clinically derived parameters would increase CSF influx in the brain. To test this hypothesis, we injected a low molecular weight (3 kD) lysine-fixable fluorescent tracer (TxRed) into the CSF system of mice with a cervical vagus nerve cuff implant and measured the amount of CSF penetrance following VNS. We found that the clinical VNS group showed a significant increase in CSF dye penetrance as compared to the naïve control and sham groups. This study demonstrates that VNS therapeutic strategies already being applied in the clinic today may induce intended effects and/or unwanted side effects by altering CSF/ISF exchange in the brain. This may have broad ranging implications in the treatment of various CNS pathologies.One Sentence SummaryCervical vagus nerve stimulation using clinically derived parameters enhances movement of cerebrospinal fluid into the brain parenchyma presenting a previously unreported effect of vagus nerve stimulation with potential clinical utility.

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Effect of defibrillation on the performance of an implantable vagus nerve stimulation system

Bioelectronic Medicine ◽

10.1186/s42234-021-00064-w ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Imad Libbus ◽

Scott R. Stubbs ◽

Scott T. Mazar ◽

Scott Mindrebo ◽

Bruce H. KenKnight ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Function ◽

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Pulse Generator ◽

High Energy ◽

Implantable Pulse Generator ◽

Defibrillation Pulse ◽

Stimulation System

Abstract Background Vagus Nerve Stimulation (VNS) delivers Autonomic Regulation Therapy (ART) for heart failure (HF), and has been associated with improvement in cardiac function and heart failure symptoms. VNS is delivered using an implantable pulse generator (IPG) and lead with electrodes placed around the cervical vagus nerve. Because HF patients may receive concomitant cardiac defibrillation therapy, testing was conducted to determine the effect of defibrillation (DF) on the VNS system. Methods DF testing was conducted on three ART IPGs (LivaNova USA, Inc.) according to international standard ISO14708-1, which evaluated whether DF had any permanent effects on the system. Each IPG was connected to a defibrillation pulse generator and subjected to a series of high-energy pulses. Results The specified series of pulses were successfully delivered to each of the three devices. All three IPGs passed factory electrical tests, and interrogation confirmed that software and data were unchanged from the pre-programmed values. No shifts in parameters or failures were observed. Conclusions Implantable VNS systems were tested for immunity to defibrillation, and were found to be unaffected by a series of high-energy defibrillation pulses. These results suggest that this VNS system can be used safely and continue to function after patients have been defibrillated.

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Vagus nerve stimulation for complex partial seizures: surgical technique, safety, and efficacy

Journal of Neurosurgery ◽

10.3171/jns.1993.78.1.0026 ◽

1993 ◽

Vol 78 (1) ◽

pp. 26-31 ◽

Cited By ~ 79

Author(s):

Howard J. Landy ◽

R. Eugene Ramsay ◽

Jeremy Slater ◽

Roy R. Casiano ◽

Robert Morgan

Keyword(s):

Vagus Nerve ◽

Vocal Cord ◽

Seizure Frequency ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Vocal Cord Dysfunction ◽

High Current ◽

Partial Seizures ◽

Complex Partial Seizures ◽

Stimulation Group

✓ Electrical stimulation of the vagus nerve has shown efficacy in controlling seizures in experimental models, and early clinical trials have suggested possible benefit in humans. Eleven patients with complex partial seizures were subjected to implantation of vagus nerve stimulators. Electrode contacts embedded in silicone rubber spirals were placed on the left vagus nerve in the low cervical area. A transcutaneously programmable stimulator module was placed in an infraclavicular subcutaneous pocket and connected to the electrode. One patient required replacement of the system due to electrode fracture. Another patient developed delayed ipsilateral vocal-cord paralysis; the technique was then modified to allow more tolerance for postoperative nerve edema. A third patient showed asymptomatic vocal-cord paresis on immediate postoperative laryngoscopy. Vagus nerve stimulation produces transient vocal-cord dysfunction while the current is on. Nine patients were randomly assigned to receive either high- or low-current stimulation, and seizure frequency was recorded. The high-current stimulation group showed a median reduction in seizure frequency of 27.7% compared to the preimplantation baseline, while the low-current stimulation group showed a median increase of 6.3%. This difference approached statistical significance. The entire population then received maximally tolerable stimulation. The high-current stimulation group showed a further 14.3% reduction, while the low-current stimulation group showed a 25.4% reduction compared to the blinded period. The efficacy of vagus nerve stimulation seemed to depend on stimulus parameters, and a cumulative effect was evident. These results are encouraging, and further study of this modality as an adjunct treatment for epilepsy is warranted.

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Complete section of the left vagus nerve does not preclude the efficacy of vagus nerve stimulation: illustrative case

Journal of Neurosurgery: Case Lessons ◽

10.3171/case21128 ◽

2021 ◽

Vol 2 (3) ◽

Author(s):

Alice Noris ◽

Paolo Roncon ◽

Simone Peraio ◽

Anna Zicca ◽

Matteo Lenge ◽

...

Keyword(s):

Vagus Nerve ◽

Vocal Cord ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Neurological Deficits ◽

Vocal Cord Dysfunction ◽

Illustrative Case ◽

Nerve Section ◽

Complete Section ◽

Left Vagus

BACKGROUND Vagus nerve stimulation (VNS) represents a valid therapeutic option for patients with medically intractable seizures who are not candidates for epilepsy surgery. Even when complete section of the nerve occurs, stimulation applied cranially to the involved nerve segment does not preclude the efficacy of VNS. Complete vagus nerve section with neuroma causing definitive left vocal cord palsy has never been previously reported in the literature. OBSERVATIONS Eight years after VNS implant, the patient experienced worsening of seizures; the interrogation of the generator revealed high impedance requiring surgical revision. On surgical exploration, complete left vagus nerve section and a neuroma were found. Vocal cord atrophy was found at immediate postoperative laryngeal inspection as a confirmation of a longstanding lesion. Both of these events might have been caused by direct nerve injury during VNS surgery, and they presented in a delayed fashion. LESSONS VNS surgery may be complicated by direct damage to the left vagus nerve, resulting in permanent neurological deficits. A complete section of the nerve also enables an efficacious stimulation if applied cranially to the involved segment. Laryngeal examination should be routinely performed before each VNS surgery to rule out preexisting vocal cord dysfunction.

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Vagus Nerve Stimulation for Intractable Epilepsy

Youmans Neurological Surgery ◽

10.1016/b978-1-4160-5316-3.00069-1 ◽

2011 ◽

pp. 807-812

Author(s):

James E. Baumgartner ◽

Gretchen K. Von Allmen

Keyword(s):

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Intractable Epilepsy

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Long term effect of vagus nerve stimulation in pediatric intractable epilepsy: an extended follow-up

Child s Nervous System ◽

10.1007/s00381-015-3004-z ◽

2016 ◽

Vol 32 (4) ◽

pp. 641-646 ◽

Cited By ~ 24

Author(s):

Ayse Serdaroglu ◽

Ebru Arhan ◽

Gökhan Kurt ◽

Atilla Erdem ◽

Tugba Hirfanoglu ◽

...

Keyword(s):

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Intractable Epilepsy ◽

Term Effect ◽

Long Term Effect

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P.018 Forced normalization after vagal nerve stimulation in a case of intractable Lennox-Gastaut syndrome

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/cjn.2018.120 ◽

2018 ◽

Vol 45 (s2) ◽

pp. S20-S20

Author(s):

A Denton ◽

A Vitali ◽

K Waterhouse ◽

J Tellez-Zenteno

Keyword(s):

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Psychiatric Symptoms ◽

Intractable Epilepsy ◽

Complex Case ◽

Drop Attacks ◽

Intractable Seizures ◽

Forced Normalization ◽

Clonic Seizures

Background: Forced normalization is the development of psychiatric symptoms in a patient experiencing remission of intractable seizures. The mechanism of this phenomenon is unknown. We present a complex case of Lennox Gastaut syndrome that experiences forced normalization after vagus nerve stimulation (VNS). Methods: This case details a 31-year-old male with seizures since early childhood. The patient has intractable epilepsy and failed AEDs, VNS, and a partial callosotomy. Results: The patient was in remission from 2-12 years old, when seizures returned at a frequency of 2-5 per day. He has multiple types of seizures including drop attacks, absences, and tonic-clonic seizures. Patient experienced status epilepticus multiple times. Twelve AEDs were failed before VNS was started in 2010, which helped curb the severity of seizures and the potential for clusters. Forced normalization developed over the course of treatment with VNS. The patient behavior was characterized by aggression, paranoia, and hallucinations. VNS was turned off late in 2010 and then re-started in January of 2011. Patient proceeded to cycle between several days of seizures without psychiatric symptoms and several days of psychosis without seizures. Conclusions: Vagus nerve stimulation gave way to forced normalization, characterized here as aggressive behaviour and psychosis. Forced normalization is seen commonly after epilepsy surgery, but rarely following VNS.

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