Technique Nuances for Functional Preservation of Lower Cranial Nerves during Surgical Management of Ventral Foramen Magnum Meningiomas Via a Dorsal Lateral Approach.

BACKGROUND: This study established novel technique nuances in surgery for ventral foramen magnum meningiomas (vFMMs) via a dorsal lateral approach. METHODS: From July 2012 to July 2019, 37 patients with vFMMs underwent tumor resection surgery and were operated on with a dorsal lateral approach. Two safe zones were selected as the entrance of the surgical corridor. Safe zone I was located between the dural attachment of the first dental ligament (FDL) and the branches of C1; safe zone II lay between the dural attachment of the FDL and the jugular foramen. The tumor was debulked first through safe zone I and then through safe zone II. The tumor was removed through a trajectory from the caudal to cephalad to allow tumor debulking from below and downward delivery, away from the brainstem and lower cranial nerves. RESULTS: Thirty-three patients underwent gross total resection, and 4 patients underwent subtotal resection. Four patients transiently required a nasogastric feeding tube. All patients recovered within 3 months postoperatively. Three patients (8.1%) developed permanent mild hoarseness and dysphagia as a result of postoperative damage of cranial nerves IX and X. One patient underwent tracheotomy. No patient experienced tumor recurrence during the follow-up period. CONCLUSIONS: We established a minimal retraction principle, in which the selection of 2 safe zones as the entrance of the surgical corridor, tumor removal from the inferior to superior direction, and debulking followed by devascularization were the key elements to implement the minimal retraction principle in vFMM surgery.

Intraoperative mapping and monitoring of sensory vagal fibers during vagal schwannoma resection.

Vagal schwannomas are rare, benign tumors. Intermittent intraoperative neuromonitoring via selective stimulation of splayed motor fibers running on the schwannoma surface to elicit a compound muscle action potential has been previously reported as a method of preserving vagal motor fibers. In this case report, vagal sensory fibers are mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes. Laryngoscope, 129:E434-E436, 2019.

Close relationship between cardiovagal function and sural sensory nerve action potential in type 2 diabetes.

OBJECTIVE: Both diabetic distal symmetrical polyneuropathy (DSPN) and cardiac autonomic neuropathy (CAN) indicate the length-dependent pattern of disease. Decreased parasympathetic activity has been found in the early phase of CAN and sural sensory nerve action potential (SNAP) imply axonal loss in DSPN. METHOD: All patients with type 2 diabetes underwent cardiovascular autonomic function and nerve conduction studies (NCS). We constructed modified composite autonomic scoring scale (CASS) and composite score of NCS to measure the severity of CAN and DSPN, respectively. RESULTS: Patients with a longer duration of diabetes had a lower heart rate response to deep breathing (HR_DB), Valsalva ratio (VR), and baroreflex sensitivity (BRS), higher CASS, a higher percentage of CAN, lower sural SNAP, higher composite score of NCS, and a higher percentage of DSPN. Multiple linear regression analysis showed that only sural SNAPs were independently associated with mean HR_DB. CONCLUSION: Sural SNAP was closely correlated with parameters of cardiovagal functions in patients with different durations of diabetes. The percentage and severity of CAN and DSPN increase with longer duration of diabetes. SIGNIFICANCE: The independent association of sural sensory nerve action potential amplitude and heart rate response to deep breathing with type 2 diabetes is important because combined testing increases diagnostic sensitivity and specificity.

Vagal Nerve Palsy After Transarterial Embolization of Transverse-Sigmoid Dural Arteriovenous Fistula Using Onyx.

OBJECTIVE: We report a case of a 70-year-old man who developed a transverse-sigmoid dural arteriovenous fistula (TS-DAVF) that was successfully treated by transarterial embolization (TAE) with Onyx. CASE PRESENTATION: The patient presented with sudden and progressive disturbance of consciousness and left hemiparesis. Magnetic resonance imaging (MRI) revealed venous infarction and hemorrhagic changes with brain swelling in the right parietal lobe. Angiography revealed a right TS-DAVF and multiple occlusions with retrograde leptomeningeal venous drainage into the cortical veins. The TS-DAVF was graded as Borden type III and Cognard type IIa+b. Because of its progressive clinical nature and wide distribution of DAVF in the occluded sinus wall, he underwent emergent TAE with liquid embolic materials including n-butyl cyanoacrylate and Onyx under informed consent by his family. Complete obliteration of the TS-DAVF was achieved, leading to a marked amelioration of symptoms, and MRI after treatment confirmed a decrease in the brain swelling. However, he suffered transient dysphagia due to right vagal nerve palsy caused by occlusion of vasa nervorum of ascending pharyngeal artery. He returned home 5 months later with a modified Rankin Scale of 1. CONCLUSIONS: TAE with Onyx appears to be effective for aggressive TS-DAVF with a widely distributed shunt. However, the blood supply to the cranial nerves and potentially dangerous anastomoses between the external-internal carotid artery and vertebral artery should be taken into account to avoid serious complications.

Tos persistente y neuropatía laríngea / Persistent cough and laryngeal neuropathy

RESUMEN La tos persistente es un síntoma de consulta frecuente, de origen multifactorial, que involucra a diferentes especialidades como la neumología, la gastroenterología y la otorrinolaringología. Sus causas más frecuentes son la descarga nasal posterior, tos como variante del asma y reflujo gastroesofágico/faringolaríngeo. Una vez descartadas dichas causas, cobran importancia los trastornos sensoriales del nervio vago, una entidad relativamente nueva que también es conocida como neuropatía laríngea sensitiva. En la neuropatía laríngea, una injuria a nivel neuronal aferente del reflejo de la tos produce un estado de hipersensibilidad laríngea en la que estímulos normalmente ignorados (que no producen respuesta tusígena) comienzan a gatillar el reflejo. Las características clínicas de la tos y el descarte de las causas más frecuentes permite llegar a este diagnóstico. Su tratamiento tiene como objetivo la modulación de las vías neuronales alteradas basándose en 3 pilares: educación sobre la patología, recomendaciones conductuales (higiene vocal, estrategias de reducción de tos) y los fármacos entre los que se usan los inhibidores de bomba de protones, mucolíticos y neuromoduladores.

ABSTRACT Persistent cough is a common symptom for medical consultation, it is of multifactorial origin and involves different specialties such as pneumology gastroenterology and otorhinolaryngology. The most frequent causes are postnasal drip, cough variant asthma and gastroesophageal/pharyngolaryngeal reflux. Once these causes are discarded the vagus nerve sensory disorder becomes of importance, it is a relatively new entity also known as laryngeal sensitive neuropathy. In the laryngeal neuropathy, an injury in the afferent neuronal pathway of the cough reflex produces laryngeal hypersensitivity in which normally ignored stimulus (i.e. do not cause cough) start to trigger the reflex. The clinical features of the cough and the rule out of the most frequent causes allow the diagnosis. The objective of the treatment is to modulate the altered neuronal pathways based on 3 pillars: education regarding the pathology, behavioral recommendations (vocal hygiene, cough reduction strategies) and drugs among which proton pump inhibitors, mucolytics and neuromodulators are used.

Impaired vagus function in rats suppresses bile acid synthesis in the liver by disrupting tight junctions and activating Fxr-Fgf15 signaling in the intestine.

Bile acids (BAs) circulate between the liver and intestine, and regulate the homeostasis of glucose, lipid, and energy. Recent studies demonstrated an essential role of BAs in neurological diseases, suggesting an interaction between BAs and the nervous system. In the present study, we showed that impaired vagus function in rats induced by vagotomy resulted in an increase in bile flow without causing liver injury. The concentrations of unconjugated and glycine-conjugated BAs were increased in both serum and bile of rats after vagotomy, which was due to impaired tight junctions and thus increased passive absorption of BAs in the intestine. Vagotomy markedly suppressed the expression of the rate-limiting BA synthetic enzyme Cyp7a1, which was not due to activation of Fxr-Shp signaling in the liver, but due to activation of Fxr-Fgf15 signaling in the intestine. Furthermore, vagotomy produced a BA profile in the bile favorable for Fxr activation by decreasing tauro-ß-muricholic acid, a natural Fxr antagonist, and increasing glyco-chenodeoxycholic acid, a natural Fxr agonist. In summary, the present study provides the first comprehensive analysis of the critical role of the vagus nerve in regulating BA metabolism and signaling pathway.

A rare case of bilateral vagus nerve schwanomatosis.

Schwanomatosis is the third most common form of neurofibromatosis. Schwanomatosis affecting the vagus nerve is particularly rare. In this report, we describe an extremely rare case bilateral vagus nerve schwanomatosis in a 45-year-old male patient. The patient initially presented with bilateral neck tumors and hoarseness arising after thoracic surgery. We performed left neck surgery in order to diagnose and resect the remaining tumors followed by laryngeal framework surgery to improve vocal cord closure and symptoms of hoarseness. Voice recovery was successfully achieved after surgery. An appropriate diagnosis and surgical tumor resection followed by phonosurgery improved patient quality of life in this rare case.

A 68-year-old with cranial nerve neuropathies and a troponin rise.

In this case study, we summarise the inpatient investigations and management of a 68-year-old woman with Takotsubo cardiomyopathy secondary to a Varicella zoster encephalitis and the difficulties inherent with making this diagnosis. She presented with evolving cranial nerve neuropathies, which started with a vagal nerve mononeuritis and eventually included left-sided sensorineural hearing loss and a facial nerve palsy. These symptoms were concomitant with a variety of cardiac abnormalities, including fast atrial fibrillation and electrocardiographic changes. We summarise some of the current understanding of Takotsubo cardiomyopathy and the criteria for its diagnosis. Although left ventricular apical ballooning has been described in association with severe infections and states of high stress, we have not seen it reported in association with a Varicella zoster encephalitis.

Nonverbal behaviors are associated with increased vagal activity in major depressive disorder: Implications for the polyvagal theory.

BACKGROUND: Major depressive disorder (MDD) is associated with impairments in nonverbal behaviors (NVBs) and vagal activity. The polyvagal theory proposes that vagal activity regulates heart rate and NVBs by modulating a common anatomically and neurophysiologically discrete social engagement system. However, the association between these putative endophenotypes has not yet been explored. We hypothesize that in MDD, NVBs indicating positive affects and social interest and those indicating negative feelings and social disinterest could be associated with different patterns of vagal activity. METHODS: For this cross-sectional study we recruited 50 antidepressant-free participants with moderate-to-severe MDD. Vagal activity was indexed by heart rate variability (HRV) measures, and positive and negative nonverbal behaviors (NVBs) by a validated ethogram. Associations between NVBs and HRV were explored by bivariate analyses and multivariable models were adjusted by age, gender, depression severity, and self-reported positive and negative affects. RESULTS: HRV measures indicative of higher vagal activity were positively correlated with positive NVBs exhibited during the clinical interview. Conversely, NVBs related to negative affects, low energy and social disinterest were not associated with HRV. LIMITATIONS: Absence of a control group. CONCLUSIONS: The findings highlight that the examined depression endophenotypes (nonverbal behaviors and vagal activity) are related, shedding light on MDD pathophysiology in the context of the polyvagal theory.

Postviral Vagal Neuropathy: What Is the Role of Laryngeal Electromyography in Improving Diagnostic Accuracy?

OBJECTIVES: To investigate the convenience of laryngeal electromyography (EMG) findings in patients with chronic cough thought to be postviral vagal neuropathy (PVVN) with the clinical symptoms. STUDY DESIGN: Prospective cohort study. METHODS: We applied PVVN questionnaire and chronic cough quality of life (QoL) questionnaire, which is for determining the effect of chronic cough on the QoL, to 20 chronic cough applicants who has no explanatory cause in differential diagnosis. We also carried out videolaryngostroboscopy (VLS) and laryngeal needle EMG in these patients. RESULTS: The mean duration of persisting cough was 1.875 months (SD ±0.825). The overall mean symptom score of chronic cough questionnaire was 58.80 (SD ±9.89). There was a significant positive correlation between total EMG score and chronic cough score (Spearman r, 0.489, P < 0.05). The correlation between VLS findings and either chronic cough scores or EMG scores did not reach statistical significance. CONCLUSIONS: Cranial nerves might be affected by inflammatory processes as occur in the PVVN, which must be considered in the etiology of chronic cough. We showed that the laryngeal EMG can be used as an appropriate diagnostic tool for these patients.

Role of capsaicin-sensitive peripheral sensory neurons in anorexic responses to intravenous infusions of cholecystokinin, peptide YY-(3-36), and glucagon-like peptide-1 in rats.

Cholecystokinin (CCK)-induced suppression of feeding is mediated by vagal sensory neurons that are destroyed by the neurotoxin capsaicin (CAP). Here we determined whether CAP-sensitive neurons mediate anorexic responses to intravenous infusions of gut hormones peptide YY-(3-36) [PYY-(3-36)] and glucagon-like peptide-1 (GLP-1). Rats received three intraperitoneal injections of CAP or vehicle (VEH) in 24 h. After recovery, non-food-deprived rats received at dark onset a 3-h intravenous infusion of CCK-8 (5, 17 pmol·kg⁻¹·min⁻¹), PYY-(3-36) (5, 17, 50 pmol·kg⁻¹·min⁻¹), or GLP-1 (17, 50 pmol·kg⁻¹·min⁻¹). CCK-8 was much less effective in reducing food intake in CAP vs. VEH rats. CCK-8 at 5 and 17 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 39 and 71% in VEH rats and 7 and 18% in CAP rats. In contrast, PYY-(3-36) and GLP-1 were similarly effective in reducing food intake in VEH and CAP rats. PYY-(3-36) at 5, 17, and 50 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 15, 33, and 70% in VEH rats and 13, 30, and 33% in CAP rats. GLP-1 at 17 and 50 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 48 and 60% in VEH rats and 30 and 52% in CAP rats. These results suggest that anorexic responses to PYY-(3-36) and GLP-1 are not primarily mediated by the CAP-sensitive peripheral sensory neurons (presumably vagal) that mediate CCK-8-induced anorexia.

The role of vagus nerve overactivity in the increased incidence of pneumonia following traumatic brain injury.

Nosocomial infections, pneumonia in particular, are well-known complications of traumatic brain injury (TBI), which are associated with a worse neurological outcome. This review aims to explore the role of vagus nerve activity in immunomodulation as a causative factor. A MEDLINE search revealed numerous reports published over the last decade describing the "cholinergic anti-inflammatory pathway" between the vagus nucleus and leukocyte activity. Using a combination of lipopolysaccharide stimulation and vagotomy, it has been shown that the parasympathetic fibres terminating in the spleen reduce tumour necrosis factor production. Further pharmacological and receptor knockout studies have identified the α7 subtype of nicotinic receptors as the likely target for this. Vagal activity also induces changes in neutrophil chemotaxis through altered expression of the CD11b integrin which is abolished by splenectomy. By extrapolating this evidence we suggest a possible mechanism for immunosuppression following TBI which also has the potential to be targeted to reduce the incidence of pneumonia. Whilst there is strong supporting evidence for the role of vagal nerve overactivity in post-TBI pneumonia, there have yet to be any clinical investigations and further study is required.

18F-FDG PET/CT diagnosis of vagus nerve neurolymphomatosis.

A 62-year-old woman was in remission from previously treated stage IV diffuse large B-cell lymphoma with cranial involvement. She presented with new-onset hoarseness of voice and choking; MRI of the brain showed disease recurrence in the left cavernous sinus. She was subsequently referred for F-FDG PET/CT with contrast for further evaluation of lymphomatous recurrence. F-FDG PET/CT not only revealed hypermetabolic activity in the left cavernous sinus correlating to the MRI findings but also showed an interesting manifestation explaining the patient's hoarseness of voice, being neurolymphomatosis along the left vagus nerve.

Bilateral vagus nerve neurolymphomatosis diagnosed using PET/CT and diffusion-weighted MRI.

In neurolymphomatosis, malignant lymphocytes infiltrate the peripheral nervous system in the presence of a known or unknown hematological malignancy. This report describes the findings of diffusion-weighted MRI and F-FDG PET/CT in a 65-year-old man with hoarseness. Results revealed a mass with restricted diffusion on diffusion-weighted imaging in the right visceral vascular space, increased uptake of F-FDG, and other masses at distant peripheral nerves. Restaging PET/CT showed involvement of the right brachial plexus and right sciatic nerve. Biopsy and immunohistochemistry of the right vagus nerve and cervical lymphadenopathy revealed a diffuse large B-cell non-Hodgkin lymphoma.

Idiopathic cranial polyneuropathy with unilateral IX and X and contralateral XI nerve palsy in a 4-year-old boy.

A 4-year-old boy presented with a sudden onset of nasal escape of fluids, nasal speech, and difficulty placing his left arm through a sleeve. Neurologic examination indicated a unilateral cranial IX and X and contralateral XI nerve palsy that was considered idiopathic. Palsy of cranial nerves IX, X, and XI is rare in childhood, and few reports have described this condition. Our patient received prednisolone for 1 week and demonstrated complete recovery within several weeks. We suggest that aggressive therapy is unnecessary for patients with idiopathic cranial polyneuropathy. The pathogenesis of this condition may involve an immunologic mechanism.

Attention-deficit hyperactivity disorder and cardiac vagal control: a systematic review.

Attention-deficit hyperactivity disorder (ADHD) is characterized by behavioural disinhibition, deficient emotional self-regulation, inattention, and hyperactivity. The constellation of deficits found in children with ADHD implicates autonomic dysregulation characterized by deficient control of the heart by parasympathetic influences. While it is generally assumed that autonomic regulation of the heart is impaired during ADHD, the information pertaining to this dysregulation is limited. A systematic review of three databases was conducted between January and March 2012 for peer reviewed publications examining the relationship between cardiac vagal control (CVC) and ADHD without comorbid psychopathology. 19 articles were reviewed with only 6 meeting inclusion criteria. Findings were not unanimous but suggested that children with unmedicated ADHD experienced lower levels of CVC than did healthy controls. It was difficult to evaluate whether children with ADHD exhibited a different pattern of withdrawal and application of CVC than did normal controls. Findings suggested CVC reactivity depended on the task employed but children with ADHD experienced dampened CVC reactivity during tasks that involved self-regulation and emotion regulation. Finally, medication acted to correct the autonomic imbalance experienced by children with ADHD but did not bring this imbalance into normal levels. Given that so few studies were identified, no firm conclusions can be made, and there is a clear need for additional research in this area. Recommendations for future research are discussed.

Enucleation of vagal nerve schwannoma using intraoperative nerve monitoring.

Vagal nerve schwannomas are rare, benign, neural sheath tumors. The treatment of enlarging or symptomatic vagal nerve schwannomas is surgical resection. Transecting the vagus nerve results in significant morbidity, and attempts at nerve preservation should be made whenever possible. We introduce a nerve-sparing technique using meticulous microsurgical dissection and intraoperative nerve monitoring for vagal schwannomas. A 61-year old patient presented with an enlarging 2-cm right vagal nerve schwannoma. She underwent resection via a transcervical approach. The patient was intubated with an electromyographic (EMG) endotracheal tube that allowed for monitoring of the recurrent laryngeal nerve intraoperatively. A microsurgical subcapsular dissection was performed after branches of the vagus nerve were identified using a nerve probe and preserved. At the conclusion of the resection the nerve was intact and stimulated along its entire course. Postoperatively, the patient had normal vagal nerve function. We introduced the role of intraoperative nerve monitoring using an EMG endotracheal tube for successful enucleation of vagal schwannomas. In conjunction with meticulous microsurgical dissection, nerve monitoring allows for successful preservation of the vagus nerve and decreased postoperative morbidity.