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Perianaesthetic management on a child with Lennox-Gastaut Syndrome for vagus nerve stimulation (VNS) placement

Yeap TB, Koo TH, Ang SY, Ab Mukmin L

BMJ Case Rep, 2023 Nov 27;16(11).
PMID: 38011949 DOI: 10.1136/bcr-2023-255897

Vagus nerve stimulation (VNS) is a neurostimulatory modality in treating patients with medically resistant epilepsy (MRE). It was introduced in 1997 and has been proven to reduce patients' dependency on antiepileptic drugs and seizure frequency. However, the usage of VNS in children with MRE has been limited, especially those with Lennox Gastaut Syndrome (LGS). Our teenage boy with this syndrome developed MRE and successfully underwent VNS placement. We discuss the perianaesthetic challenges, a brief description of VNS and the reported successes in patients with LGS.

Matched MeSH terms: Vagus Nerve Stimulation*
Perianaesthetic challenges in patients undergoing vagus nerve stimulation (VNS) placement

Yeap TB, Ab Mukmin L, Ang SY, Ghani AR

BMJ Case Rep, 2023 Feb 07;16(2).
PMID: 36750294 DOI: 10.1136/bcr-2022-252692

Patients with medically refractory epilepsy (MRE) are indicated for vagus nerve stimulation (VNS) placement. Anaesthesia for VNS placement is extremely challenging and requires several considerations. We present a man in his 20s with MRE who successfully underwent VNS placement. We review the mechanism of action of VNS, anaesthetic challenges and measures to prevent seizures.

Matched MeSH terms: Vagus Nerve Stimulation*
The strange case of the ear and the heart: The auricular vagus nerve and its influence on cardiac control

Murray AR, Atkinson L, Mahadi MK, Deuchars SA, Deuchars J

Auton Neurosci, 2016 08;199:48-53.
PMID: 27388046 DOI: 10.1016/j.autneu.2016.06.004

The human ear seems an unlikely candidate for therapies aimed at improving cardiac function, but the ear and the heart share a common connection: the vagus nerve. In recent years there has been increasing interest in the auricular branch of the vagus nerve (ABVN), a unique cutaneous subdivision of the vagus distributed to the external ear. Non-invasive electrical stimulation of this nerve through the skin may offer a simple, cost-effective alternative to the established method of vagus nerve stimulation (VNS), which requires a surgical procedure and has generated mixed results in a number of clinical trials for heart failure. This review discusses the available evidence in support of modulating cardiac activity using this strange auricular nerve.

Matched MeSH terms: Vagus Nerve/physiology*; Vagus Nerve/physiopathology
Fulltext Coughing on palpation: a rare complication of vagal schwannoma

Samarakkody, Z.M., Sayuti, K.A., Mat Zin, A.A., Wan Abdul Wahab, W.N.N., Mohamad, I.

Malaysian Family Physician, 2018;13(3):40-43.
MyJurnal

Cervical vagal schwannoma is an uncommon, benign neoplasm. It is usually asymptomatic and
presents as a painless, palpable mass in the neck. However, large schwannomas can cause dysphagia,
dysphonia or dyspnea as a result of compression. We report a case of an extremely rare complication
of vagal schwannoma in which neck palpation induced the patient to cough. As the patient refused
any surgical intervention, conservative management was used.

Matched MeSH terms: Vagus Nerve
Cardiovascular autonomic effects of transcutaneous auricular nerve stimulation via the tragus in the rat involve spinal cervical sensory afferent pathways

Mahadi KM, Lall VK, Deuchars SA, Deuchars J

Brain Stimul, 2019 05 06;12(5):1151-1158.
PMID: 31129152 DOI: 10.1016/j.brs.2019.05.002

BACKGROUND: Electrical stimulation on select areas of the external auricular dermatome influences the autonomic nervous system. It has been postulated that activation of the Auricular Branch of the Vagus Nerve (ABVN) mediates such autonomic changes. However, the underlying neural pathways mediating these effects are unknown and, further, our understanding of the anatomical distribution of the ABVN in the auricle has now been questioned.
OBJECTIVE: To investigate the effects of electrical stimulation of the tragus on autonomic outputs in the rat and probe the underlying neural pathways.
METHODS: Central neuronal projections from nerves innervating the external auricle were investigated by injections of the transganglionic tracer cholera toxin B chain (CTB) into the right tragus of Wistar rats. Physiological recordings of heart rate, perfusion pressure, respiratory rate and sympathetic nerve activity were made in an anaesthetic free Working Heart Brainstem Preparation (WHBP) of the rat and changes in response to electrical stimulation of the tragus analysed.
RESULTS: Neuronal tracing from the tragus revealed that the densest CTB labelling was within laminae III-IV of the dorsal horn of the upper cervical spinal cord, ipsilateral to the injection sites. In the medulla oblongata, CTB labelled afferents were observed in the paratrigeminal nucleus, spinal trigeminal tract and cuneate nucleus. Surprisingly, only sparse labelling was observed in the vagal afferent termination site, the nucleus tractus solitarius. Recordings made from rats at night time revealed more robust sympathetic activity in comparison to day time rats, thus subsequent experiments were conducted in rats at night time. Electrical stimulation was delivered across the tragus for 5 min. Direct recording from the sympathetic chain revealed a central sympathoinhibition by up to 36% following tragus stimulation. Sympathoinhibition remained following sectioning of the cervical vagus nerve ipsilateral to the stimulation site, but was attenuated by sectioning of the upper cervical afferent nerve roots.
CONCLUSIONS: Inhibition of the sympathetic nervous system activity upon electrical stimulation of the tragus in the rat is mediated at least in part through sensory afferent projections to the upper cervical spinal cord. This challenges the notion that tragal stimulation is mediated by the auricular branch of the vagus nerve and suggests that alternative mechanisms may be involved.

Matched MeSH terms: Vagus Nerve/physiology*; Vagus Nerve Stimulation/methods
Fulltext Coughing on palpation: A rare complication of vagal schwannoma

Samarakkody ZM, Sayuti KA, Mat Zin AA, Wan Abdul Wahab W, Mohamad I

Malays Fam Physician, 2018;13(3):40-43.
PMID: 30800234

Cervical vagal schwannoma is an uncommon, benign neoplasm. It is usually asymptomatic and presents as a painless, palpable mass in the neck. However, large schwannomas can cause dysphagia, dysphonia or dyspnea as a result of compression. We report a case of an extremely rare complication of vagal schwannoma in which neck palpation induced the patient to cough. As the patient refused any surgical intervention, conservative management was used.

Matched MeSH terms: Vagus Nerve
Fulltext Epilepsy Surgery in Hospital Universiti Sains Malaysia: Our Experiences since 2004

Yee AS, Tharakan J, Idris Z, Bhaskar S, Halim SA, Razak SA, et al.

Malays J Med Sci, 2017 Dec;24(6):97-102.
PMID: 29379392 DOI: 10.21315/mjms2017.24.6.12

Epilepsy surgery has been performed by a few centres in Malaysia, including Hospital Universiti Sains Malaysia (HUSM). To date, a total of 15 patients have undergone epilepsy surgery in HUSM. The epilepsy surgery included anterior temporal lobectomy (ATL) with amygdalohippocampectomy (AH) and Vagal nerve stimulation (VNS). The surgical outcomes of the patients were assessed using the International League Against Epilepsy (ILAE) outcome scale. The ILAE scores for patients who underwent ATL with AH were comparatively better than those who underwent VNS. One of the patient who underwent ATL with AH and frontal lesionectomy was found to have psychosis during follow up. Epilepsy surgery has proven to be an important treatment for medically resistant epilepsy. Thus it is important to raise public awareness regarding epilepsy and its treatment.

Matched MeSH terms: Vagus Nerve Stimulation
Laryngeal paralysis in organophosphorous poisoning

Indudharan R, Win MN, Noor AR

J Laryngol Otol, 1998 Jan;112(1):81-2.
PMID: 9538454

Organophosphorous poisoning causing isolated laryngeal paralysis has only been rarely reported before. We describe a case of difficult extubation in a patient with organophosphorous poisoning, the cause of which was found to be bilateral vocal fold palsy. This is a type of intermediate paralysis that recovers with time. Such a condition should be thought of as a cause of dyspnoea or difficult extubation in patients with organophosphorous poisoning.

Matched MeSH terms: Vagus Nerve/drug effects
Fulltext Mediation of Cardiac Macrophage Activity via Auricular Vagal Nerve Stimulation Ameliorates Cardiac Ischemia/Reperfusion Injury

Chung CH, Bretherton B, Zainalabidin S, Deuchars SA, Deuchars J, Mahadi MK

Front Neurosci, 2020;14:906.
PMID: 33013299 DOI: 10.3389/fnins.2020.00906

Background: Myocardial infarction (MI) reperfusion therapy causes paradoxical cardiac complications. Following restoration of blood flow to infarcted regions, a multitude of inflammatory cells are recruited to the site of injury for tissue repair. Continual progression of cardiac inflammatory responses does, however, lead to adverse cardiac remodeling, inevitably causing heart failure.
Main Body: Increasing evidence of the cardioprotective effects of both invasive and non-invasive vagal nerve stimulation (VNS) suggests that these may be feasible methods to treat myocardial ischemia/reperfusion injury via anti-inflammatory regulation. The mechanisms through which auricular VNS controls inflammation are yet to be explored. In this review, we discuss the potential of autonomic nervous system modulation, particularly via the parasympathetic branch, in ameliorating MI. Novel insights are provided about the activation of the cholinergic anti-inflammatory pathway on cardiac macrophages. Acetylcholine binding to the α7 nicotinic acetylcholine receptor (α7nAChR) expressed on macrophages polarizes the pro-inflammatory into anti-inflammatory subtypes. Activation of the α7nAChR stimulates the signal transducer and activator of transcription 3 (STAT3) signaling pathway. This inhibits the secretion of pro-inflammatory cytokines, limiting ischemic injury in the myocardium and initiating efficient reparative mechanisms. We highlight recent developments in the controversial auricular vagal neuro-circuitry and how they may relate to activation of the cholinergic anti-inflammatory pathway.
Conclusion: Emerging published data suggest that auricular VNS is an inexpensive healthcare modality, mediating the dynamic balance between pro- and anti-inflammatory responses in cardiac macrophages and ameliorating cardiac ischemia/reperfusion injury.

Matched MeSH terms: Vagus Nerve; Vagus Nerve Stimulation
Fulltext Mechanisms underpinning sympathetic nervous activity and its modulation using transcutaneous vagus nerve stimulation

Deuchars SA, Lall VK, Clancy J, Mahadi M, Murray A, Peers L, et al.

Exp Physiol, 2018 Mar 01;103(3):326-331.
PMID: 29205954 DOI: 10.1113/EP086433

What is the topic of this review? This review briefly considers what modulates sympathetic nerve activity and how it may change as we age or in pathological conditions. It then focuses on transcutaneous vagus nerve stimulation, a method of neuromodulation in autonomic cardiovascular control. What advances does it highlight? The review considers the pathways involved in eliciting the changes in autonomic balance seen with transcutaneous vagus nerve stimulation in relationship to other neuromodulatory techniques. The autonomic nervous system, consisting of the sympathetic and parasympathetic branches, is a major contributor to the maintenance of cardiovascular variables within homeostatic limits. As we age or in certain pathological conditions, the balance between the two branches changes such that sympathetic activity is more dominant, and this change in dominance is negatively correlated with prognosis in conditions such as heart failure. We have shown that non-invasive stimulation of the tragus of the ear increases parasympathetic activity and reduces sympathetic activity and that the extent of this effect is correlated with the baseline cardiovascular parameters of different subjects. The effects could be attributable to activation of the afferent branch of the vagus and, potentially, other sensory nerves in that region. This indicates that tragus stimulation may be a viable treatment in disorders where autonomic activity to the heart is compromised.

Matched MeSH terms: Vagus Nerve Stimulation*
Fulltext Bilateral Carotid Body Tumours

Amran, A.R., Jayaram, G., Kumar, G.

International Medical Journal Malaysia, 2006;5(1):1-6.
MyJurnal

Paragangliomas are slow growing hypervascular tumour arising from neural crest cell derivatives throughout the body. In the head and neck region, the major paraganglial cells are located at the carotid bifurcation (carotid body), along the ganglia of the vagus nerve and along the nerves supplying the middle ear and jugular bulb. Less common locations include the larynx, orbit, nose and the aortic arch. Carotid body tumours are very rare neoplasms constituting less than 0.5% of all tumours. The true nature of the tumour is established at the time of attempted biopsy or surgical resection, sometimes with disastrous consequences. Only a few of the more than 500 cases reported in the literature have been studied and diagnosed preoperatively. These tumours must be considered in the evaluation of any lateral neck mass, even one located far from the carotid bifurcation. We report a case of bilateral carotid body tumours detected using 16-slice MDHCT in a patient who presented with pulsatile neck swelling for two years. This tumour is rarely malignant; however it produces serious problems by its progressive enlargement and impairment of adjacent structures in the neck. The treatment of choice is surgical resection; preferably to excise this lesion when it is small, because large, very vascular tumours are intimately attached to the carotid vessels and make surgical resection more hazardous. Pre-operative embolization can be performed in large tumours, as to facilitates surgery and reduce complication. In most of the cases, there is strong attachment of the tumour to the carotid arteries. When this is the situation, removal of the tumour means complete excision of both great arteries as well, and the mortality rate is 40 to 45 %. When surgical removal is not feasible, radiotherapy may help to control the tumour growth, although the results have not been encouraging. As it is very slow growing tumour with the growth rate of less than 5 mm per year tumours in old patients with significant risk factors for surgical intervention can be managed by observation alone.

Matched MeSH terms: Vagus Nerve
Fulltext An extensive cervical vagal nerve schwannoma: a case report

Chiun KC, Tang IP, Prepageran N, Jayalakshmi P

Med J Malaysia, 2012 Jun;67(3):342-4.
PMID: 23082434 MyJurnal

Vagal nerve schwannoma is extremely rare. The majority of cases present with a slow growing neck swelling without neurological deficit. Magnetic resonance imaging is the gold standard investigation to establish a pre-operative diagnosis. We report a case of a 32-year-old man with an extensive right vagal nerve schwannoma involving the right jugular foramen and parapharyngeal space. The tumour was resected via a transcervical approach. Complete excision of the tumour is the key to prevent recurrence.

Matched MeSH terms: Vagus Nerve
Immediate selective laryngeal reinnervation in vagal paraganglioma patients

Mat Baki M, Clarke P, Birchall MA

J Laryngol Otol, 2018 Sep;132(9):846-851.
PMID: 30180919 DOI: 10.1017/S0022215118000476

OBJECTIVE: This prospective case series aimed to present the outcomes of immediate selective laryngeal reinnervation.
METHODS: Two middle-aged women with vagal paraganglioma undergoing an excision operation underwent immediate selective laryngeal reinnervation using the phrenic nerve and ansa cervicalis as the donor nerve. Multidimensional outcome measures were employed pre-operatively, and at 1, 6 and 12 months post-operatively.
RESULTS: The voice handicap index-10 score improved from 23 (patient 1) and 18 (patient 2) at 1 month post-operation, to 5 (patient 1) and 1 (patient 2) at 12 months. The Eating Assessment Tool 10 score improved from 20 (patient 1) and 24 (patient 2) at 1 month post-operation, to 3 (patient 1) and 1 (patient 2) at 12 months. There was slight vocal fold abduction observed in patient one and no obvious abduction in patient two.
CONCLUSION: Selective reinnervation is safe to perform following vagal paraganglioma excision conducted on the same side. Voice and swallowing improvements were demonstrated, but no significant vocal fold abduction was achieved.

Matched MeSH terms: Vagus Nerve Diseases/pathology