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

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

Perspectives in Surgery ◽

10.33699/pis.2020.99.7.304-310 ◽

2020 ◽

Vol 99 (7) ◽

Keyword(s):

Vagus Nerve ◽

Vocal Cord ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Pulse Generator ◽

Operative Procedure ◽

Intractable Epilepsy ◽

Vagal Nerve ◽

University Hospital ◽

Nerve Stimulator

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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Complete Atrioventricular Nodal Block in Patient Undergoing Left Vagus Nerve Stimulation: A case report

Korean Journal of Anesthesiology ◽

10.4097/kjae.2005.49.4.578 ◽

2005 ◽

Vol 49 (4) ◽

pp. 578

Author(s):

Young Kug Kim ◽

Gyu Sam Hwang ◽

In Young Huh ◽

Hyung Seok Seo ◽

Su Jin Kang ◽

...

Keyword(s):

Case Report ◽

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Complete Atrioventricular ◽

Left Vagus

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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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REFRACTORY EPILEPSY AND VAGUS NERVE STIMULATION: THE WAY FORWARD

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v5i3.1837 ◽

2021 ◽

Vol 5 (3) ◽

Author(s):

Bhupendra Chaudhary ◽

Ansh Chaudhary

Keyword(s):

Vagus Nerve ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Pulse Generator ◽

Refractory Epilepsy ◽

Cardiac Innervation ◽

On Demand ◽

The Poor ◽

Us Fda ◽

Left Vagus

Vagus Nerve Stimulation (VNS) an efficacious neurophysiological modality of treatment for both medically & surgically refractory epilepsy was first implanted in 1988 & later approved by US FDA in 1997. In clinical practice, trains of current are applied intermittently to the left vagus using a pacemaker or AICD like device 'the VNS device'. The device has four components pulse generator, lead, spiral electrodes & a magnet. The pulse generator is implanted beneath left clavicle by a simple surgical method & attached to left vagus nerve via lead & spiral electrodes.[1] The magnet provides an extra edge to control the aura or impending seizure by providing 'On Demand' stimulations. The poor cardiac innervation by left vagus helps to minimize the unwanted or at time dangerous side effects like severe bradycardia, brady arrythmia, or even cardiac asystole.[2]

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LEFT VAGUS NERVE STIMULATION SIGNIFICANTLY ATTENUATES VENTRICULAR DYSFUNCTION AND INFARCT SIZE THROUGH PREVENTION OF MITOCHONDRIAL DYSFUNCTION DURING ACUTE ISCHEMIA-REPERFUSION INJURY IN SWINE

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(13)60069-8 ◽

2013 ◽

Vol 61 (10) ◽

pp. E68

Author(s):

Krekwit Shinlapawittayatorn ◽

Kreokkiat Chinda ◽

Siripong Palee ◽

Sirirat Surinkaew ◽

Kittiya Thunsiri ◽

...

Keyword(s):

Infarct Size ◽

Vagus Nerve ◽

Reperfusion Injury ◽

Nerve Stimulation ◽

Vagus Nerve Stimulation ◽

Ventricular Dysfunction ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Acute Ischemia ◽

Left Vagus

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Alternative Paradigm of Selective Vagus Nerve Stimulation Tested on an Isolated Porcine Vagus Nerve

The Scientific World JOURNAL ◽

10.1155/2014/310283 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Polona Pečlin ◽

Janez Rozman

Keyword(s):

Vagus Nerve ◽

Nerve Stimulation ◽

Fibre Type ◽

Vagus Nerve Stimulation ◽

Experimental Testing ◽

Present Stage ◽

Stage Of Development ◽

Isolated Segment ◽

Left Vagus ◽

Stimulation Of

Alternative paradigm for spatial and fibre-type selective vagus nerve stimulation (VNS) was developed using realistic structural topography and tested in an isolated segment of a porcine cervical left vagus nerve (LVN). A spiral cuff (cuff) containing a matrix of ninety-nine electrodes was developed for selective VNS. A quasitrapezoidal stimulating pulse (stimulus) was applied to the LVN via an appointed group of three electrodes (triplet). The triplet and stimulus were configured to predominantly stimulate the B-fibres, minimizing stimulation of the A-fibres and by-passing the stimulation of the C-fibres. To assess which fibres made the most probable contribution to the neural response (NR) during selective VNS, the distribution of conduction velocity (CV) within the LVN was considered. Experimental testing of the paradigm showed the existence of certain parameters and waveforms of the stimulus, for which the contribution of the A-fibres to the NR was slightly reduced and that of the B-fibres was slightly enlarged. The cuff provided satisfactory fascicle discrimination in selective VNS as well as satisfactory fascicle discrimination during NR recording. However, in the present stage of development, fibre-type VNS remained rather limited.

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