POSTERIOR AURICULAR NERVE – A NOVEL LANDMARK FOR IDENTIFICATION OF THE FACIAL NERVE IN SUPERFICIAL PAROTIDECTOMY

ABSTRACT Background-Facial nerve identification and preservation is the most critical step in parotid surgery. Though there are described landmarks to locate the facial nerve trunk, they have individual variations. The posterior auricular nerve (PAN) is a branch of the facial nerve and is always present, it can be followed to reach the facial nerve trunk. MATERIALS AND METHODS A retrospective cohort study in which analysis of parotidectomy performed from January 2017 to November 2018 at our tertiary referral center was done. RESULTS A total of 23 parotidectomies were performed, of which 18 cases were pleomorphic adenoma. In four cases of pleomorphic adenoma we could clearly identify and preserve the PAN. Using PAN as the landmark the facial nerve trunk was located, all its peripheral branches were dissected and preserved. PAN identification narrows down the target area of dissection to identify the facial nerve trunk. CONCLUSION The posterior auricular branch of the facial nerve can be used as a standard landmark in parotid surgeries, that almost always leads to the facial nerve trunk. CLINICAL SIGNIFICANCE Though identification of PAN may be difficult in all cases, effort must be made to identify it under magnification. If done meticulously PAN can be an ideal landmark to identify facial nerve in parotid surgery. KEYWORDS Parotid surgery, Superficial Parotidectomy, Posterior auricular nerve, Facial nerve.

The application of vagus nerve stimulation in individuals with misophonia

Stimulating the Vagus nerve helps maintain the autonomic tone, indicating stabilising any hyperactivity in the nervous system. The vagus nerve stimulation is applied in individuals with seizures, depression, sepsis, pain, obesity, cardiovascular disease, lung disease, diabetes, stroke, and traumatic brain injury. Auditory neuroscience has been widely applied in individuals with tinnitus and has been demonstrated as a successful neuromodulation technique. Individuals with peripheral lesions of the hair cells induce a maladaptive change in the plasticity resulting in hyperactivity in the auditory and non-auditory structures. In order to reduce this hyperactivity, neuromodulation techniques such as; transcranial magnetic stimulation, transcranial direct current stimulation, transcranial alternating current stimulation, transcranial random noise stimulation, neurofeedback, epidural and subdural cortical and deep brain stimulation. The vagus nerve stimulation is also one form of neuromodulation technique considered to reduce the symptoms of tinnitus. It is believed that the ramus Auricularis Nervi vagi, an afferent sensory branch of the vagus nerve, innervates the afferent sensory branch of the vagus nerve, the ramus auricularis nervi vagi also innervate the outer ear canal and parts of the auricle. This auricular branch of the vagus nerve also called Arnold's nerve, which gives a projection to the nucleus of the solitary tract. The vagus nerve stimulation in individuals with tinnitus works to activate the auricular branch of the vagus nerve to reduce its symptoms. A similar principle of vagus nerve stimulation can be tried upon in individuals with misophonia. Literatures states that individuals with misophonia have hyperactivity in their non-classical auditory pathway that can be suppressed with the help of vagus nerve stimulation. The article discusses the possible effects of vagus nerve stimulation in individuals with misophonia.

First-in-Neonate Use of Noninvasive Transcutaneous Auricular Vagus Nerve Stimulation: 18-Month Development and Sensory Processing Follow-Up

Date Presented 04/23/21 Infants discharged with gastrostomy tubes are more likely to have lower scores in all neurodevelopment outcomes than full-feed infants. A noninvasive application of vagal nerve stimulation (VNS), transcutaneous auricular VNS (taVNS), stimulates the auricular branch of the vagal nerve. Yet, the long-term impact of the application of taVNS remains unknown. Early findings from this study reveal that taVNS could have a positive impact on children's neurodevelopmental and sensory performance observed at 18 months follow-up evaluation. Primary Author and Speaker: Turki Khaild Aljuhani

Recognizing emotions in bodies: Vagus nerve stimulation enhances recognition of anger while impairing sadness

According to the Polyvagal theory, the vagus nerve is the key phylogenetic substrate that supports efficient emotion recognition for promoting safety and survival. Previous studies showed that the vagus nerve affects people’s ability to recognize emotions based on eye regions and whole facial images, but not static bodies. The purpose of this study was to verify whether the previously suggested causal link between vagal activity and emotion recognition can be generalized to situations in which emotions must be inferred from images of whole moving bodies. We employed transcutaneous vagus nerve stimulation (tVNS), a noninvasive brain stimulation technique that stimulates the vagus nerve by a mild electrical stimulation to the auricular branch of the vagus, located in the anterior protuberance of the outer ear. In two sessions, participants received active or sham tVNS before and while performing three emotion recognition tasks, aimed at indexing their ability to recognize emotions from static or moving bodily expressions by actors. Active tVNS, compared to sham stimulation, enhanced the recognition of anger but reduced the ability to recognize sadness, regardless of the type of stimulus (static vs. moving). Convergent with the idea of hierarchical involvement of the vagus in establishing safety, as put forward by the Polyvagal theory, we argue that our findings may be explained by vagus-evoked differential adjustment strategies to emotional expressions. Taken together, our findings fit with an evolutionary perspective on the vagus nerve and its involvement in emotion recognition for the benefit of survival.

International Consensus Based Review and Recommendations for Minimum Reporting Standards in Research on Transcutaneous Vagus Nerve Stimulation (Version 2020)

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation (tVNS) across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation(VNS) and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice.

Unusual Symptomatology in Eagle Syndrome

A 20-year-old female presented a history of isolate left external ear pain. ENT valuation showed no alteration of the district, but an aberrant styloid process was tender to palpation in the left tonsillar fossa. Computer tomography was performed and confirmed it. Thereafter, the diagnosis of Eagle syndrome was made. The auricular branch of the vagal nerve (ABVN) was pressed by the styloid process causing the pain. This case pointed out the importance to consider anatomical alteration as elongated styloid process as a possible cause of external ear pain.