Intraoperative Ultrasound-Guided Selective Glossopharyngeal Nerve Block for Post-tonsillectomy Analgesia: A Case Report.

Tonsillectomy can lead to significant postoperative pain, which can impact the recovery process. Traditional analgesic approaches may entail risks due to medication use. Considering that the tonsils are innervated by the glossopharyngeal and maxillary nerves, implementing glossopharyngeal and maxillary nerve blocks can provide analgesia. Ultrasound guidance may improve its effectiveness and safety. A woman in her 30s with recurrent tonsillitis underwent tonsillectomy under general anesthesia. After induction, we performed an ultrasound-guided selective glossopharyngeal nerve block and an ultrasound-guided maxillary nerve block with ropivacaine. No analgesics were required during the six-day hospitalization period. There were no complications from the nerve blocks such as dysphagia or upper airway obstruction. The findings from this case indicated that the ultrasound-guided selective glossopharyngeal nerve block and ultrasound-guided maxillary nerve block provided effective analgesia after tonsillectomy without complications.

Long-Term Follow-Up of Ultrasound-Guided Glossopharyngeal Nerve Block Treatment for Glossopharyngeal Neuralgia: A Retrospective Clinical Study of 43 Cases.

Background: Glossopharyngeal neuralgia (GPN) is a rare chronic neuropathic pain disorder that significantly impacts quality of life. Ultrasound-guided glossopharyngeal nerve blocks (UGPNB) have gained popularity due to their various advantages. However, there have been no studies reporting the long-term outcomes of UGPNB in a larger cohort of GPN patients. Aim: This study aims to evaluate the efficacy and safety of UGPNB in patients with GPN. Methods: We reviewed the electronic medical records of patients with GPN who received UGPNB at the Department of Pain Medicine of the First Medical Center, PLA General Hospital between June 1, 2011, and June 1, 2022. The effect of UGPNB was evaluated using the Barrow Neurological Institute (BNI) scale. Improvement was defined as a reduction in pain category by comparing pain categories before and after therapy. Recovery was defined as achieving BNI I after treatment. Patients who responded to treatment but then regressed to the category before therapy were considered to have experienced pain relapse. Results: A total of 43 patients with GPN who received UGPNB were included in the analysis. At discharge, 35 (81.4%) patients experienced pain improvement after treatment, and among them, 13 (30.2%) patients achieved recovery. After discharge, 13 patients (37.1%) out of the 35 effective patients experienced pain relapse at different time intervals: 0.5, 0.7, 1, 1, 3, 3, 4, 12, 15, 36, 45, 63, and 96 months. The cumulative recurrence-free survival rates were 88.85% at month 1, 82.83% at month 3, 77.04% at month 12, 70.31% at month 36, and 54.66% at month 120. Among the 13 patients who experienced relapse, four patients received a second UGPNB treatment, and pain improved in two patients (50%). No severe adverse reactions were documented. Conclusion: UGPNB is an effective, repeatable, safe, and minimally invasive treatment for patients with GPN. It may be preferable to consider UGPNB before undergoing invasive intracranial surgery or neurodestructive methods.

Case Report: Inflamed Jacobson nerve: an uncommon cause of persisting otalgia after an acute otitis media.

Introduction: Otalgia can have multiple causes. Mostly otalgia is caused by a tubal dysfunction or an acute middle ear infection. This case describes a patient with an inflammation of the Jacobson's nerve causing severe persistent otalgia after an acute otitis media. The patients complaints completely disappeared after neurolysis of the Jacobson's nerve. Case presentation: We describe a case of a 21-year-old female caucasian patient with acute otitis media and persistent intractable otalgia. Infection was first successfully controlled by antibiotics. But the patient reported a persistent otalgia not responding to analgetics. We performed a CT scan, which exhibited a regular aerated middle ear finding, and a diagnostic tympanoscopy to examine the middle ear structures particularly the tympanic Jacobson's nerve as a possible cause for persistent pain. The following neurolysis of Jacobson's nerve under general anaesthesia led to a resolution of otalgia. Conclusion: An inflamed tympanic Jacobson's nerve is a rare observation and a persisting otalgia after an acute otitis media not responding to conservative treatment can be treated by a neurolysis.

Ultrasound-Guided Selective Glossopharyngeal Nerve Block for Severe Gag Reflex During Dental Treatment: A Report of Two Cases.

The ultrasound-guided selective glossopharyngeal nerve block (UGSGNB) has been developed as an approach to overcome the drawbacks of the conventional glossopharyngeal nerve block. The UGSGNB may be performed when a gag reflex occurs during dental treatment. Case 1 involved a 67-year-old man with a medical history of cervical spondylosis and dilated cardiomyopathy. Dental treatment with conscious sedation and the UGSGNB was performed three times. Case 2 involved a 25-year-old woman who was scheduled for dental treatment under general anesthesia because of dental phobia and gagging. Because the patient experienced severe tooth pain and desired urgent treatment, anesthesia was induced with intravenous sedation and the UGSGNB. In both cases, treatments were completed without intraoperative gagging or any complications. Our observations indicate that the UGSGNB can suppress the gag reflex during dental treatment; it may allow surgeons to avoid inducing general anesthesia and deep sedation in patients with a severe gag reflex.

Lingual Taste Nerve Transection Alters Food Selection, Relative Macronutrient Intake, and Meal Patterns in Rats Consuming a Cafeteria Diet without Changing Total Energy Intake.

The control of ingestive behavior is complex and involves input from many different sources, including the gustatory system. Signals transmitted via the taste nerves trigger responses that promote or discourage ingestion. The lingual taste nerves innervate 70% of taste buds, yet their role in the control of food selection and intake remarkably remains relatively underinvestigated. Here we used our custom five-item Food Choice Monitor to compare postsurgical behavioral responses to chow and a five-choice cafeteria diet (CAF) between male rats that had sham surgery (SHAM) or histologically verified transection of the chorda tympani and glossopharyngeal nerves (2NX). Compared with SHAM rats, 2NX rats ate significantly more of the high-fat CAF foods. The altered food choices led to dramatically increased fat intake and substantially reduced carbohydrate intake by 2NX vs SHAM rats. Furthermore, whether offered chow or CAF, 2NX rats ate fewer, larger meals each day. Eating rates implied that, compared with SHAM, 2NX rats were equally motivated to consume CAF but less motivated to eat chow. Even with these differences, energy intake and weight gain trajectories remained similar between SHAM and 2NX rats. Although some rats experienced CAF before surgery, contrary to our expectations, the effects of prior CAF experience on postsurgical eating were minimal. In conclusion, although total energy intake was unaffected, our results clearly indicate that information from one or both lingual taste nerves has a critical role in food selection, regulation of macronutrient intake, and meal termination but not long-term energy balance.

Characteristic Video Laryngeal Endoscopic "Pharyngeal Rotation" in Unilateral Pharyngeal Constrictor Muscle Paresis: A Case of Herpes Zoster Pharyngitis.

Herpes zoster pharyngitis (HZP) is a rare condition that should be considered as a differential diagnosis of acute dysphagia secondary to unilateral glossopharyngeal and/or vagal nerve palsy. Although early treatment is important to avoid adverse sequelae, serological diagnosis of varicella zoster virus (VZV) takes over a few days. Therefore, it is important to actively suspect VZV infection based on physical findings. Mucocutaneous lesions, curtain signs, and laryngeal palsy are well-known characteristic physical findings. In addition to these findings, the video laryngeal endoscopic finding that the pharyngeal constrictor muscles contract on only one side during swallowing, showing an appearance of "pharyngeal rotation", is one of the characteristic findings of glossopharyngeal/vagal nerve palsy and can support the diagnosis. We report the case of an 82-year-old Asian female who presented with acute dysphagia, sore throat, left ear pain, and fever that persisted for several days. Initial video laryngeal endoscopy revealed a markedly decreased pharyngeal reflex and significant salivary retention without mucosal vesicular lesions. Repeat videoendoscopic evaluation of swallowing revealed characteristic pharyngeal rotation, which was helpful in diagnosing unilateral pharyngeal constrictor muscle paresis, thus suggesting unilateral glossopharyngeal/vagal nerve palsy. An increase in serum antibody titers (IgG and IgM) against VZV was observed. Bilateral differences and rotation of the pharynx during pharyngeal contraction can be detected endoscopically in pharyngeal constrictor muscle paresis caused by glossopharyngeal/vagal nerve palsy and should be evaluated during video laryngeal endoscopy in patients with dysphagia.

Microsurgical anatomy of the glossopharyngeal nerve.

The glossopharyngeal nerve is a complicated and mixed nerve including sensory, motor, parasympathetic, and visceral fibers. It mediates taste, salivation, and swallowing. The low cranial nerves, including IXth, Xth, and XIth, are closely related, sharing some nuclei in the brainstem. The glossopharyngeal nerve arises from the spinal trigeminal nucleus and tract, solitary tract and nucleus, nucleus ambiguous, and inferior salivatory nucleus in the brainstem. There are communicating branches forming a neural anastomotic network between low cranial nerves. Comprehensive knowledge of the anatomy of the glossopharyngeal nerve is crucial for performing surgical procedures without significant complications. This review describes the microsurgical anatomy of the glossopharyngeal nerve and illustrates some pictures involving the glossopharyngeal nerve and its connective and neurovascular structures.

Ultrasound-guided selective glossopharyngeal nerve block: posterior mandibular ramus approach.

OBJECTIVE: Glossopharyngeal nerve block is a useful interventional technique for pain management of the head and neck. It is performed with landmark techniques or ultrasound guidance. We propose a novel ultrasound-guided glossopharyngeal nerve block technique. METHODS: This new approach was performed in 3 patients in their twenties and thirties. A needle was inserted deeply under the stylohyoid muscle through the sternocleidomastoid muscle. Subsequently, an ultrasound-guided nerve block was performed with 1 mL of 1% xylocaine. The performance of our technique was evaluated with 2 tests: a cold sensitivity test and a gag reflex test. RESULTS: The effect of the nerve block was observed in the posterior third of the tongue on both sides, the tonsils, and the pharyngeal region. The effect lasted for approximately 1.5 hour. Motor efferent block was not observed. CONCLUSIONS: We designated the technique as ultrasound-guided selective glossopharyngeal nerve block: posterior mandibular ramus approach. No complications occurred during the bilateral application. This novel approach can be performed at a very shallow position, compared with conventional methods. There is no damage to tissues other than the muscles, which reduces postoperative complications and patient distress. Although our technique requires further safety assessments and technical refinements, it could represent a simpler alternative to conventional methods in daily clinical practice.

Topohistology of the cranial nerves IX-XII at the cranial base and upper parapharyngeal space: A histological study using human fetuses.

The topographical relationships among the lower cranial nerves, internal carotid artery (ICA), and internal jugular vein (IJV) in the upper parapharyngeal neurovascular bundle remain obscure. Thus, details of the anatomy were examined in human fetus histology. We observed the horizontal histological sections from 20 midterm (9-18 weeks) and 12 near-term (28-40 weeks) fetuses. At the external skull base, the glossopharyngeal nerve crosses the anterior aspect of the IJV to reach the medially located Hyrtl's fissure in the petrous temporal bone. The nerve crossed the anterior aspect of the ICA medially near or below the first cervical nerve root. Below the hypoglossal nerve canal, the accessory nerve crosses the anterior or posterior aspects of the IJV and moves laterally. During the half-spiral course, the hypoglossal nerve was tightly attached to the posterolateral-anterior aspects of the vagus nerve and surrounded by a common nerve sheath. The glossopharyngeal ganglia sometimes extended inferiorly to the level of the hypoglossal nerve canal but were absent along the inferior course. The inferior vagal ganglion rarely extends above the occipital condyle. The superior cervical sympathetic ganglion occasionally extends above the first cervical nerve root. The IJV (or ICA) descends to the lateral (or medial) margins of the parapharyngeal neurovascular bundle. The glossopharyngeal (or accessory) nerve crosses the ICA (or IJV) to exit the bundle at the base of the skull (or below the hypoglossal nerve canal). The glossopharyngeal and vagus inferior ganglia differ at each site.

Acute Taste Dysfunction in Oropharyngeal Cancer Patients after Transoral Robotic Surgery.

OBJECTIVES: To compare taste changes after transoral robotic surgery (TORS) to taste changes in healthy controls. METHODS: Oropharyngeal cancer patients receiving TORS and healthy controls were recruited. Participants underwent posterolateral and whole-mouth psychophysical taste testing (identification, intensity, and hedonics) at baseline and at 2 weeks postoperatively (patients) or follow-up (controls). Surgeons reported suspension time and glossopharyngeal nerve injury (GNI) based on the identification and sacrifice of the nerve. A Clinical Global Impression (CGI) of taste symptoms was completed at each session ("My sense of taste bothers me" on a 5-point scale from Never [1] to Always [5]). A taste disorder (TD) was a CGI of 3 (Sometimes) or worse. Within-subject changes in CGI and psychophysical scores were computed. "Worsened taste" was a CGI increase by ≥1 point at follow-up. RESULTS: Of 69 participants, most (33/37 tumor, 31/32 controls) had normal baseline taste (CGI < 3). 14/33 (42%) TORS patients and no controls developed new TDs at follow-up. More smokers (7/9) had worsened taste than nonsmokers (19/60, difference = 46% [95% CI 16%-76%]). More patients without GNI (6/22) than with GNI (0/15) had postoperative phantogeusia (difference = 27% [95% CI 9-45%]). Tumor-ipsilateral taste identification (TI) decreased more in patients (-11.3%) than controls (0.8%, difference = 12.2% [95% CI 5.0-19.3%]). Suspension time was not associated with worsened taste symptoms or psychophysical changes. CONCLUSIONS: Patient-reported taste changes after TORS are frequent. Compared to healthy controls, TORS patients have decreased tumor-ipsilateral TI. Suspension time and GNI are unlikely to cause symptomatic TDs. Further investigations of the etiology and long-term symptom burden of TORS-associated TDs will aid in the management of oropharyngeal cancer patients. LEVEL OF EVIDENCE: 3 (non-randomized controlled cohort study) Laryngoscope, 133:3520-3528, 2023.

Glossopharyngeal schwannoma a rare case report: Diagnostic and surgical approach.

INTRODUCTION AND IMPORTANCE: Schwannomas are tumors of the nerve sheath that consist of Schwann cells that are often described as slow-growing. Glossopharyngeal schwannomas are rare tumors present in the region of the posterior fossa, with limited case reports present in literature. While patients may present asymptomatically, some present with vestibulocochlear symptoms or lower cranial nerve dysfunction. CLINICAL PRESENTATION: We report an extremely rare case of a left para-pharyngeal carotid space glossopharyngeal schwannoma in a 26-year-old female. The presentation was a 3-month left sided neck swelling and a hoarse voice. Radiological investigations were completed (neck ultrasound; CT; MRI scans). Investigations revealed a solid lesion measuring about 29 × 10 mm. The final decision was to excise the mass under microsurgery. CLINICAL DISCUSSION: CN 9-11 schwannomas are often called jugular foramen schwannomas. Intraoperatively, these get differentiated as glossopharyngeal schwannomas. Diagnosis involves a physical examination, a detailed history, audiological assessments, and radiological investigations. While MRI scans are known as the most effective pre-operative diagnostic test, cases are in majority discovered intra-operatively. Surgical excision is the recommended approach. Post-operative recurrence is rare. Pre-operative diagnosis is often difficult due to the rarity and similarly presenting differential diagnoses. CONCLUSION: Schwannomas of the glossopharyngeal nerve are extremely rare tumors that may present with lower cranial nerve or vestibulocochlear deficits. Magnetic resonance imaging is a useful tool in diagnosing this unordinary tumor. This case report intends to provide further data regarding the clinical presentation, the patient population, and the diagnostic and surgical approach in dealing with this incredibly rare tumor.

The glossopharyngeal nerve (IX cranial nerve pair): anatomical considerations and neuralgia: literature review / O nervo glossofaringeo (IX par de nervo craniano): considerações anatômicas e neuralgia: revisão da literatura

The glossopharyngeal nerve (IX cranial nerve) is a mixed nerve, with both motor and sensory function. This relates to the tongue and pharynx. Glossopharyngeal neuralgia is a rare nervous neuropathy, with poristic, lancinating and paritary crises, usually unilateral. The aim of the study was to review the literature on glossopharyngeal neuralgia of the nerve (IX cranial nerve), highlighting the anatomical aspects of this nerve and the possible causes and complications of neuralgia as well as forms of treatment. A literature review was carried out in the international Pubmed database. The literature review included 72 articles from 2015 to 2021. The keywords used were: "anatomy of glossopharyngeal neuralgia". Of the 72 articles, 7 were used for this literature review. Uncommon as nervous/glossophingeal etiologies and pathologies are neurological abnormalities/neurovarises and pathologies are neurovascular/neurovariseal lesions. Pharmacological treatment approaches mentioned in the literature were therapy with antiepileptics and antidepressants such as carbamazepine and gabapentin; a microvascular decompression; and gamma knife radiosurgery(AU)

O nervo glossofaríngeo (IX par de nervo craniano) é um nervo misto, contendo função tanto motora como sensitiva. Este nervo relaciona-se com a língua e com a faringe. A neuralgia do nervo glossofaríngeo é uma neurapatia rara, sendo caracterizada por crises dolorosas, lancinantes e paroxísticas, geralmente unilaterais. O objetivo do estudo foi realizar uma revisão de literatura sobre a neuralgia do nervo glossofaríngeo (IX par de nervo craniano), destacando os aspectos anatômicos deste nervo e as possíveis causas e complicações da neuralgia bem como formas de tratamento. Foi realizada uma revisão da literatura na base de dados internacional Pubmed. A revisão da literatura incluiu 72 artigos no período de 2015 a 2021. As palavras-chave utilizadas foram: "anatomia da neuralgia do glossofaríngeo". Dos 72 artigos, 7 foram utilizados para esta revisão de literatura. Verificouse que a neuralgia do nervo glossofaríngeo é incomum e as etiologias mais encontradas foram compressão neurovascular/variações vasculares, patologias e traumas. As abordagens dos tratamentos mencionadas na literatura foram a terapia farmacológica da área com antiepilépticos e antidepressivos, como carbamazepina e gabapentina; a descompressão microvascular; e radiocirurgia com faca gama(AU)

Trigeminal Function in Sino-Nasal Health and Disease.

The upper airway (nasal passages, paranasal sinuses, pharynx, and glottis) provides the sentinel portion of the human respiratory tract, with the combined senses of olfaction (cranial nerve I) and trigeminal sensation (cranial nerve V) signaling the quality of inspired air. Trigeminal function also complements the sense of taste (in turn mediated by cranial nerves VII, IX and X), and participates in the genesis of taste aversions. The ability of trigeminal stimulation in the upper aero-digestive tract to trigger a variety of respiratory and behavioral reflexes has long been recognized. In this context, the last three decades has seen a proliferation of observations at a molecular level regarding the mechanisms of olfaction, irritation, and gustation. Concurrently, an ever-widening network of physiological interactions between olfaction, taste, and trigeminal function has been uncovered. The objective of this review is to summarize the relatively recent expansion of research in this sub-field of sensory science, and to explore the clinical and therapeutic implications thereof.

Expression of the cellular prion protein by mast cells in the human carotid body.

Prion diseases are fatal neurologic disorders that can be transmitted by blood transfusion. The route for neuroinvasion following exposure to infected blood is not known. Carotid bodies (CBs) are specialized chemosensitive structures that detect the concentration of blood gasses and provide feedback for the neural control of respiration. Sensory cells of the CB are highly perfused and densely innervated by nerves that are synaptically connected to the brainstem and thoracic spinal cord, known to be areas of early prion deposition following oral infection. Given their direct exposure to blood and neural connections to central nervous system (CNS) areas involved in prion neuroinvasion, we sought to determine if there were cells in the human CB that express the cellular prion protein (PrPC), a characteristic that would support CBs serving as a route for prion neuroinvasion. We collected CBs from cadaver donor bodies and determined that mast cells located in the carotid bodies express PrPC and that these cells are in close proximity to blood vessels, nerves, and nerve terminals that are synaptically connected to the brainstem and spinal cord.

Anterior and Posterior Tongue Regions and Taste Papillae: Distinct Roles and Regulatory Mechanisms with an Emphasis on Hedgehog Signaling and Antagonism.

Sensory receptors across the entire tongue are engaged during eating. However, the tongue has distinctive regions with taste (fungiform and circumvallate) and non-taste (filiform) organs that are composed of specialized epithelia, connective tissues, and innervation. The tissue regions and papillae are adapted in form and function for taste and somatosensation associated with eating. It follows that homeostasis and regeneration of distinctive papillae and taste buds with particular functional roles require tailored molecular pathways. Nonetheless, in the chemosensory field, generalizations are often made between mechanisms that regulate anterior tongue fungiform and posterior circumvallate taste papillae, without a clear distinction that highlights the singular taste cell types and receptors in the papillae. We compare and contrast signaling regulation in the tongue and emphasize the Hedgehog pathway and antagonists as prime examples of signaling differences in anterior and posterior taste and non-taste papillae. Only with more attention to the roles and regulatory signals for different taste cells in distinct tongue regions can optimal treatments for taste dysfunctions be designed. In summary, if tissues are studied from one tongue region only, with associated specialized gustatory and non-gustatory organs, an incomplete and potentially misleading picture will emerge of how lingual sensory systems are involved in eating and altered in disease.

Current advances in the surgical treatment of glossopharyngeal neuralgia.

Glossopharyngeal neuralgia (GPN) is a neurological condition characterized by paroxysmal, stabbing-like pain along the distribution of the glossopharyngeal nerve that lasts from a couple of seconds to minutes. Pharmacological treatment with anticonvulsants is the first line of treatment; however, about 25% of patients remain symptomatic and require surgical intervention, which is usually done via microvascular decompression (MVD) with or without rhizotomy. More recently, the use of stereotactic radiosurgery (SRS) has been utilized as an alternative treatment method to relieve patient symptoms by causing nerve ablation. We conducted a systematic review to analyze whether MVD without rhizotomy is an equally effective treatment for GPN as MVD with the use of concurrent rhizotomy. Moreover, we sought to explore if SRS, a minimally invasive alternative surgical option, achieves comparable outcomes. We included retrospective studies and case reports in our search. We consulted PubMed and Medline, including articles from the year 2000 onwards. A total of 36 articles were included for review. Of all included patients with glossopharyngeal neuralgia, the most common offending artery compressing the glossopharyngeal nerve was the posterior inferior cerebellar artery (PICA). MVD alone was successful achieving pain relief immediately postoperatively in about 85% of patients, and also long term in 65-90% of patients. The most common complication found on MVD surgery was found to be transient hoarseness and transient dysphagia. Rhizotomy alone shows an instant pain relief in 85-100% of the patients, but rate of long-term pain relief was lower compared to MVD. The most common adverse effects observed after a rhizotomy were dysphagia and dysesthesia along the distribution of the glossopharyngeal nerve. SRS had promising results in pain reduction when using 75 Gy radiation or higher; however, long-term rates of pain relief were lower. MVD, rhizotomy, and SRS are effective methods to treat GPN as they help achieve instant pain relief and the decrease use of medication. Patients with MVD alone presented with less adverse effects than the group that underwent MVD plus rhizotomy. Although SRS may be a viable alternative treatment for GPN, further studies must be done to evaluate long-term treatment efficacy.

Anatomy of small canals around the jugular foramen: Special reference to Jacobson's and Arnold's nerves.

The jugular foramen harbors anatomically complex bony, venous and neural structures. It is closely associated with small canals including the mastoid, tympanic, and cochlear canaliculi, and the stylomastoid foramen. The minute intraosseous branches of Arnold's and Jacobson's nerves (<1 mm in length) remain difficult to study with current imaging techniques, and cadaveric dissection is the most reliable approach. Our aim was to examine the variations of Jacobson's and Arnold's canaliculi and nerves and to provide detailed cadaveric graphics. To reveal the anatomical structures of small canals around the jugular foramen, 25 sides of dry skulls and 14 sides of cadaveric heads were examined. Intraosseous branches varied more in Arnold's nerve than Jacobson's nerve. In our cadaveric dissection, all specimens formed a single canal for Jacobson's nerve connecting the jugular foramen to the tympanic cavity. The intraosseous course of Arnold's nerve varied in its communication with the facial nerve. A descending branch crossing the facial nerve was identified in five of 14 sides, an ascending branch in 13. In two specimens, an ascending branch clearly reached the base of the stapedius muscle. Classical anatomical studies of cadavers remain a supplementary tool for analyzing these tiny structures. The present study confirms Gray's findings of 1913. Variations of these nerves could be even more complex than previously reported. Our study provides additional information regarding the anatomy of Jacobson's and Arnold's nerves.

Glossopharyngeal Neuralgia.

Glossopharyngeal neuralgia (GPN) is a rare disease that must be differentiated from trigeminal neuralgia. The purpose of this article is to provide a comprehensive review of anatomy, pathophysiology, diagnostic criteria, and several options of treatment for GPN. Lessons learned through our experience of treating GPN are presented in detail, as well as cases of misdiagnosis and diagnostic pitfalls. Microvascular decompression (MVD) should be primarily considered for medically intractable GPN. Techniques employed in MVD for GPN are categorized and described. Especially, we underscore the advantages of the 'transposition' technique where insulating material is positioned 'off' the root entry zone (REZ), instead of 'on' it. We believe this 'off-the-REZ' technique can fundamentally prevent recurrence, if applicable. In addition, Gamma Knife radiosurgery can be an alternative option when a patient is ineligible for MVD, though it is categorized as a destructive procedure.

The Location of the Parasympathetic Fibres within the Vagus Nerve Rootlets: A Case Report and a Review of the Literature.

The vagus nerve has motor, sensory, and parasympathetic components. Understanding the nerve's internal anatomy, its variations, and relationship to the glossopharyngeal nerve are crucial for neurosurgeons decompressing the lower cranial nerves. We present a case report demonstrating the location of the parasympathetic fibres within the vagus nerve rootlets. A 47-year-old woman presented with a 1-year history of medically refractory left-sided glossopharyngeal neuralgia and a more recent history of left-sided hemi-laryngopharyngeal spasm. magnetic resonance imaging showed her left posterior inferior cerebellar artery distorting the lower cranial nerves on the affected left side. The patient consented to microvascular decompression of the lower cranial nerves with possible sectioning of the glossopharyngeal and upper sensory rootlets of the vagus nerve. During surgery, electrical stimulation of the most caudal rootlet of the vagus nerve triggered profound bradycardia. None of the more rostral rootlets had a similar parasympathetic response. This case is the first demonstration, to our knowledge, of the location of the cardiac parasympathetic fibres within the human vagus nerve rootlets. This new understanding of the vagus nerve rootlets' distribution of pure sensory (most rostral), motor/sensory (more caudal), and parasympathetic (most caudal) fibres may lead to a better understanding and diagnosis of the vagal rhizopathies. Approximately 20% of patients with glossopharyngeal neuralgia also have paroxysmal cough. This could be due to the anatomical juxtaposition of the IXth cranial nerve with the rostral vagal rootlets with pure sensory fibres (which mediate a tickling sensation in the lungs). A subgroup of patients with glossopharyngeal neuralgia have neuralgia-induced syncope. The cause of this rare condition, "vago-glossopharyngeal neuralgia," has been debated since it was first described by Riley in 1942. Our case supports the theory that this neuralgia-induced bradycardia is reflexively mediated through the brainstem with afferent impulses in the IXth and efferent impulses in the Xth cranial nerve. The rarer co-occurrence of glossopharyngeal neuralgia with hemi-laryngopharyngeal spasm (as seen in this case) may be explained by the proximity of the IXth nerve with the more caudal vagus rootlets which have motor (and probably sensory) supply to the throat. Finally, if there is a vagal rhizopathy related to compression of its parasympathetic fibres, one would expect it to be at the most caudal rootlet of the vagus nerve.