Lingual Branch Research Articles

Lingual nerve revisited-A comprehensive review Part I: Anatomy and variations.

The lingual nerve (LN) is a branch of the mandibular division of the fifth cranial nerve, the trigeminal. It primarily carries sensory fibers from the lingual gingiva, mucous membranes of the floor of the mouth, sublingual gland, and the anterior two-thirds of the tongue. Recent studies have explored and reclassified the five branches of the LN as branches to the isthmus of the fauces, lingual branches, sublingual nerves, posterior branch to the submandibular ganglion, and branches to the sublingual ganglion. The knowledge of the LN anatomy and its variants is clinically relevant to avoid its injury during oral procedures. The objective of this paper is to review the literature on the LN and to describe the anatomy, its course, and its functions.

The Clinical Relevance of the Lingual Branch in Ridge Augmentation of the Posterior Mandible: A Pilot Cadaver Study.

Guided bone regeneration (GBR) requires a tension-free flap without damaging the collateral circulation in order to secure better surgical outcomes. Topographic knowledge regarding the neurovascular bundles in the posterior aspect of the mandible can prevent complications during lingual flap design. The lingual branch (LB) of the inferior alveolar or maxillary arteries is not sufficiently illustrated or described in the literature. Nevertheless, it has an intimate relationship with the lingual nerve (LN) during ridge augmentation and implant-related posterior mandible surgery. Therefore, this study aimed to clarify the morphology and topography of the LB related to GBR surgeries. In the present human cadaveric study, the LB was analyzed in 12 hemimandibles using latex injection and corrosion casting. Two types of LB were identified based on their origin and course. The LB was found in a common connective tissue sheath close to the LN. The LB assembled several anastomoses on the posterior lingual aspect of the mandible and retromolar area. The LB acted as an anatomical landmark in identifying LN at the posterior lingual aspect of the mandible.

The sublingual branch of the lingual nerve: Anatomical study and suggestion for a new terminology.

The lingual nerve carries somatosensory fibers from the anterior two-thirds of tongue. The parasympathetic preganglionic fibers arising from the chorda tympani also travel with the lingual nerve in the infratemporal fossa to synapse in the submandibular ganglion to innervate the sublingual gland. However, only a few studies have investigated the specific nerve that innervates the sublingual gland and surrounding tissue i.e., the so-called sublingual nerve. Therefore, this study aimed to clarify the anatomy and definition of the sublingual nerves. Thirty sides from formalin fixed cadaveric hemiheads underwent microsurgical dissection of the sublingual nerves. The sublingual nerves were found on all sides and categorized into three branches, i.e., branches to the sublingual gland, branches to the mucosa of the floor of the mouth, and gingival branches. Additionally, branches to the sublingual gland were subcategorized into types I and II based on the origin of the sublingual nerve. We suggest that the lingual nerve branches should be categorized into five branches, i.e., branches to the isthmus of the fauces, sublingual nerves, lingual branches, posterior branch to the submandibular ganglion, and branches to the sublingual ganglion.

O062 Acquired carotid-jugular fistulas following carotid endarterectomy: a narrative review

Abstract Introduction Acquired arterio-venous fistulas (AVF) involving the carotid artery are most commonly the result of trauma and catheterisation of the neck vessels. Left untreated, carotid-jugular fistulas (CJF) may precipitate ischaemic neurological symptoms due to thromboembolism or shunting of blood through the AVF. Methods A literature review was performed to determine the incidence and outcomes of acquired carotid-jugular AVFs following carotid endarterectomy (CEA). Electronic searches were performed using three databases, PubMed, EMBASE, and Google Scholar. Results Three case studies met inclusion criteria for analysis. The first case occurred 4-months following a left CEA. CT-angiography and duplex ultrasound identified a pseudoaneurysm arising from the proximal internal carotid artery. A CJF was identified on re-intervention and carotid ligation was performed following unsuccessful attempts to repair the defect. The patient has ongoing mild dysphonia with no other complications at 18 months follow-up. The second case occurred 6 years following right CEA. Catheter angiography revealed an AVF between the right external carotid artery (ECA) and internal jugular vein, treated with coil embolization. The patient made complete neurological recovery and had no further complications at 2 years follow-up. The third case occurred 4 years following right CEA. Catheter angiography identified fistulisation between the lingual branch of the right ECA and right retromandibular vein, treated with transarterial particle embolization. The patient made a complete neurological recovery. Conclusion Carotid-jugular AVFs are rare following CEA. This review proposes that carotid-jugular AVFs may be amenable to both open and endovascular intervention with durable outcomes. Proceduralists should be cognisant of this complication. Take-home message Carotid-jugular arteriovenous fistulas are rare following carotid endarterectomy and may be amenable to both open and endovascular intervention with durable outcomes.

Rehabilitation of Persistent Symptoms and Neurocognitive Deficits Following Sports-Related Concussion in a Professional Hockey Player: Case Study

To demonstrate decreased post-concussive symptomatology and neurocognitive improvements in a professional hockey player following a multimodal, functional neurology approach to neurorehabilitation. Hockey is one of the top 3 sports in which concussions occur and has one of the top 10 highest participation numbers of sports in the northern hemisphere. The investigation of treatment modalities is warranted given the prevalence of hockey throughout society. This case study presents a 31-year-old male professional hockey athlete who had sustained 5 diagnosed concussions with additional suspected concussions throughout his career. His symptoms remained after independently receiving physical therapy and vestibular rehabilitation, causing an inability to continue playing hockey at a professional level. The patient was prescribed 10 treatment sessions over 5 contiguous days at an outpatient neurorehabilitation center specializing in functional neurology. The C3Logix neurocognitive assessment and graded symptom checklist were utilized at intake and discharge. Multimodal treatment interventions included transcranial photobiomodulation, non-invasive neuromodulation of the lingual branch of the trigeminal nerve, hand-eye coordination training, vestibular rehabilitation utilizing a three-axis whole-body off-axis rotational device, and cognitive training. On intake, their composite symptom score was reported as 16/162, Trail Making Test Part B was 24.1 seconds, Simple Reaction Time was 274 milliseconds, and Choice Reaction Time was 496 milliseconds. On discharge, the patient experienced an 81% in self-reported symptoms, Trail Making Test Part B improved to 17 seconds (+29.46%), Simple Reaction Time was 252 milliseconds (8% faster), and Choice Reaction Time was 465 milliseconds (24% faster). The present case study results demonstrated meaningful improvements in both self-rated concussion symptoms and neurocognitive performance for this patient. The Press suggest further investigation into functional neurology-based, multimodal, intensive approaches to decrease chronic post-concussion symptoms and improve neurocognitive performance in athletes that engage in hockey.

Rehabilitation of Persistent Neurocognitive Deficits Following Sports-Related Concussion in an Amateur Football Athlete: Case Study

Demonstrate neurocognitive improvements in an inactive, amateur football athlete following a functional neurology approach to multimodal neurorehabilitation. American Football has been reported to have one of the highest incidences of concussion in all contact sports. Given the high rate of concussive blows during play, the investigation of treatment modalities is warranted. This case study presents a 23-year-old male amateur football player who has sustained 3 diagnosed concussions with additional suspected concussions throughout his time participating in football. In addition, his symptoms persisted years after ceasing participation in all contact sports. The athlete was prescribed 10 treatment sessions over 5 consecutive days at an outpatient neurorehabilitation center specializing in functional neurology. The C3Logix neurocognitive assessment and Graded Symptom Checklist were utilized on intake and discharge. Multimodal treatment interventions included transcranial photobiomodulation, non-invasive neuromodulation of the lingual branch of the trigeminal nerve, neuromuscular reeducation of the limbs bilaterally, hand-eye coordination training, vestibular rehabilitation utilizing a three-axis whole-body off-axis rotational device, and cognitive training. On intake, composite symptom score was reported as 10/162, Trails Making Test Part A was 20.8 seconds, Part B was 41.9 seconds, Digit Symbol Matching score was 53, Simple Reaction Time was 277 milliseconds, and Choice Reaction Time was 412 milliseconds. On discharge, the patient experienced a 70% in self-reported symptoms, Trails A improved to 14.8 seconds (+29%), Trails B improved to 30.3 seconds (+28%), Simple Reaction Time was 248 milliseconds (10% faster), and Choice Reaction Time was 340 milliseconds (17% faster). The present case study demonstrates a meaningful improvement in symptoms and neurocognitive performance of a patient with multiple sports-related concussions. Therefore, the Press suggest further investigation into a functional neurology approach to multi-modal, intensive care to improve neurocognitive impairment in athletes that sustained concussions participating in footballs.

Nerve fiber analysis of the lingual branch of the glossopharyngeal nerve in human adult subjects.

Fibers of the glossopharyngeal part of the superior constrictor muscle are connected with fibers of the transverse lingual muscle, forming a ring of muscle at the base of the tongue. This group of muscles constrict the midpharyngeal cavity during retrusive movement of the tongue. The purpose of this study is to identify the contribution of the lingual branch of the glossopharyngeal nerve to the neuro-motor control of three muscles: the glossopharyngeal part of the superior pharyngeal constrictor muscle, the palatopharyngeal and the palatoglossus muscles. Six en bloc samples (9 sides), including the tissue from the skull base to the hyoid bone were obtained from adult human cadavers. Nerve fiber of the lingual branch of the glossopharyngeal nerve (main root of the glossopharyngeal nerve) was examined by the use of a binocular stereomicroscope. We observed that, after branching to the stylopharyngeal muscle, the lingual branch of the glossopharyngeal nerve branched to the glossopharyngeal part of the superior pharyngeal constrictor muscle, the palatopharyngeal and the palatoglossus muscles before inserting into the space between the muscle layers of the superior and middle pharyngeal constrictors. These neuromuscular arrangements may suggest the presence of specialized constrictive movements of the midpharygeal cavity at the level of the base of the tongue with the retrusive movement of the tongue. The simultaneous contraction of the palatopharyngeal and palatoglossus muscles on the pharyngeal stage of deglutition may aid in the passage of bolus from the oral cavity to the midpharyngeal cavity by increasing pharyngeal pressure.

Glossopharyngeal neuralgia due to exposed glossopharyngeal nerve post tonsillectomy and transoral styloidectomy

<p>Glossopharyngeal neuralgia (GN) is a rare facial pain syndrome, characterized by paroxysm of excruciating radiating pain in the sensory distribution of the auricular and pharyngeal branches of glossopharyngeal and vagus nerves. In relation to the tonsil, the glossopharyngeal nerve passes deep to the styloid process and related muscles attaching to styloid process. The lingual branch of the glossopharyngeal nerve provides sensation to the posterior tongue and enters the tongue base by traveling through the constrictor muscles in the area of the lingulotonsillar sulcus. Post tonsillectomy fossa with exposed nerve causing intractable pain is a rare entity. We report a case of 64 year male patient, post tonsillectomy and transoral styloidectomy, with complaint of severe throat pain on left side for 2 years, radiating upwards to the ipsilateral ear, face and eye. Glossopharyngeal nerve and its branches were found exposed in the posterior and inferior aspect of tonsillar bed. Surgical resection of exposed glossopharyngeal nerve and its branches was carried out in view of failure to respond to oral carbamazepine. Patient was symptom free during 10 months of follow up visit. GN is a rare condition following tonsillectomy and styloidectomy. Radical dissection of tonsillar bed during tonsillectomy and not suturing tonsillar bed properly after styloidectomy can lead to exposure of glossopharyngeal nerve and its branches, resulting in intractable GN.</p>

Anatomic Landmarks in Transoral Oropharyngeal Surgery.

Minimally invasive transoral surgery for oropharyngeal cancer is a challenge for head and neck surgeons because of the inside-out anatomic presentation and the confined workspace. This study was performed to describe the main neurovascular and muscular landmarks in a transoral approach. The authors propose an anatomic stratification for this surgery. Lateral wall of the oropharynx and base of the tongue of 15 formalin-fixed heads (30 sides) and 5 fresh cadaveric heads (10 sides) sagittal sectioned were dissected from the inside outwards. Dissection of 7 fresh cadaveric heads via an endoscopic transoral approach was also performed. The lateral oropharyngeal wall was divided into 3 layers from medial to lateral, based in the styloid muscle diaphragm. The first layer, medial to styloid muscles, includes the tonsillar vascularization and the lingual branch of the glossopharyngeal nerve. The second layer, lateral to constrictor muscles, includes the pharyngeal venous plexus, the glossopharyngeal nerve, and the lingual artery. The third layer, lateral to styloid diaphragm, includes the parapharyngeal and submandibular spaces, the carotid vessels and lingual, vagus, glossopharyngeal and hypoglossal nerves. The base of the tongue was divided into central and lateral parts, which contain the lingual artery and lingual branches of the glossopharyngeal nerve. The main landmarks to find the neurovascular structures in each layer are described. The authors propose an anatomic division, which helps to plan oropharynx and base of the tongue surgery. This anatomic stratification is useful to surgeons when performing a reconstruction of the oropharynx with a transoral approach.

Morphological Features of the Branching Pattern of the Hypoglossal Nerve.

The hypoglossal or twelfth cranial nerve is the motor nerve to the extrinsic and intrinsic muscles of the tongue, and the superior root of the ansa cervicalis and the thyrohyoid and geniohyoid branches are delivered through the nerve. This study investigated the muscular branches of the hypoglossal nerve to clarify their spatial relationships with the muscles of the tongue and the neighboring structures. The muscles and the nerve were gross anatomically examined in 42 cadavers. The superior root and the thyrohyoid branch left the nerve near the occipital and lingual arteries, respectively. The extrinsic muscles consisted of some components, and the geniohyoid branch and the lingual branches arose on the hyoglossus. The ascending lingual branches formed a plexus on the anterior part of the hyoglossus and were divided into the proximal and distal groups. They supplied the two parts of the hyoglossus, the three bundles of the styloglossus and the superior and inferior longitudinal muscles and communicated with the lingual nerve. The descending lingual branches supplied the inferior part of the genioglossus, and the terminal branches gave intramuscular twigs to its main part and the transverse and vertical muscles. The findings indicated that the branching pattern of the hypoglossal nerve is characterized by the positional relationships to the components of the extrinsic muscles. The hyoid bone can be an effective marker to identify the branches and affected position if it was used in combination with the morphology of the extrinsic muscles, and the knowledge of their variations is also beneficial. Anat Rec, 302:558-567, 2019. © 2018 Wiley Periodicals, Inc.

Post-tonsillectomy taste dysfunction: Myth or reality?

Lingual branches of the glossopharyngeal nerve (CN Ⅸ) are at risk of injury during tonsillectomy due to their proximity to the muscle layer of the palatine tonsillar bed. However, it is unclear how often this common surgery leads to taste disturbances. We conducted a literature search using PubMed, Embase, Cochrane Library, Google Scholar, PsychInfo, and Ovid Medline to evaluate the available literature on post-tonsillectomy taste disorders. Studies denoting self-reported dysfunction, as well as those employing quantitative testing, i.e., chemogustometry and electrogustometry, were identified. Case reports were excluded. Of the 8 original articles that met our inclusion criteria, only 5 employed quantitative taste tests. The highest prevalence of self-reported taste disturbances occurred two weeks after surgery (32%). Two studies reported post-operative chemical gustometry scores consistent with hypogeusia. However, in the two studies that compared pre- and post-tonsillectomy test scores, one found no difference and the other found a significant difference only for the left rear of the tongue 14 days post-op. In the two studies that employed electrogustometry, elevated post-operative thresholds were noted, although only one compared pre- and post-operative thresholds. This study found no significant differences. No study employed a normal control group to assess the influences of repeated testing on the sensory measures. Overall, this review indicates that studies on post-tonsillectomy taste disorders are limited and ambiguous. Future research employing appropriate control groups and taste testing procedures are needed to define the prevalence, duration, and nature of post-tonsillectomy taste disorders.

The sensory trigeminal complex and the organization of its primary afferents in the zebra finch (Taeniopygia guttata).

Our knowledge of the avian sensory trigeminal system has been largely restricted to the principal trigeminal nucleus (PrV) and its ascending projections to the forebrain. Studies addressing the cytoarchitecture and organization of afferent input to the sensory trigeminal complex, which includes both the PrV and the nuclei of the descending trigeminal tract (nTTD), have only been performed in pigeons and ducks. Here we extend such an analysis to a songbird, the zebra finch (Taeniopygia guttata). We describe the cytoarchitecture of the sensory trigeminal complex, the patterns of calbindin-like and substance P-like immunoreactivity, and the organization of afferents from the three branches of the trigeminal nerve and from the lingual branch of the hypoglossal nerve. On the basis of cytoarchitecture and immunohistochemistry, the sensory trigeminal column can be subdivided from caudal to rostral, as in other species, into cervical dorsal horn, subnucleus caudalis, subnucleus interpolaris, subnucleus oralis, and nucleus principalis. The relative positions of the terminal fields of the three trigeminal branches move from medial to lateral in the dorsal horn to dorsomedial to ventrolateral in nTTD, whereas in PrV there is considerable overlap of mandibular and ophthalmic terminal fields, with only a small maxillary input ventrally. The hypoglossal afferents, which terminate medially in the dorsal horn and dorsolaterally in nTTD, terminate in specific cell groups in the dorsolateral nTTDo and in PrV. This work sets the grounds for further analyses of the ascending connections of the nTTD and the afferents from the syrinx to the trigeminal sensory column.

Oral Anatomy.

With regard to oral cavity, it is known that jaw bone morphology greatly changes with tooth loss. Therefore, it is necessary to consider the muscles attached to the jaw bone and the surrounding vessels and nerves, in connection with the jaw bone morphology after tooth loss. As an example, the height of the mandibular bone decreases to the position of the mylohyoid line after tooth loss. By this marked morphological change in the alveolar area, the lingual nerve and the lingual artery branches running in the sublingual area on the mandibular inner surface becomes located in the area almost the same as the alveolar crest.

Anatomical and prospective clinical study of variant distribution of the glossopharyngeal nerve

Background: Removal of lesions involving the jugular foramen region requires detailed knowledgeof the anatomy and anatomical landmarks of the related area, especially the lower cranial nerves. Theglossopharyngeal nerve (GPhN) courses along the uppermost part of the jugular foramen and is wellhidden in the deep layers of the neck, making this nerve is the most difficult one to identify duringsurgery. The glossopharyngeal nerve can be compromised iatrogenically during the surgical procedures.Aim of the work: Is to investigate the topography and branching pattern of the GPhN and to define theimportant landmarks that can help to identify this nerve during surgery. It also designed to evaluate thepost-tonsillectomy pain and the role of the different patterns of distribution of the glossopharyngeal nervebranches within the tonsillar fossa in the perception of pain in the postoperative period.Materials and Methods: Thirty glossopharyngeal nerves in fifteen cadaveric necks were dissected. Theanatomic relation between the GPhN and the nearby structures, distribution and branching pattern of theGPhN were studied. Regarding the GPhN in the tonsilar fossa two anatomic distances were measured:A) distance from the posterosuperior tonsillar fossa to the main trunk of the GPhN and B) distance fromthe posteroinferior tonsillar fossa to the closest lingual branch of the glossopharyngeal nerve (LBG). Thelevel of the post-operative pain was estimated in 70 patients at one and three hours, and one week aftertonsillectomyby numeric pain intensity scale Technique of anesthesia was similar for all patients. At theend of the procedure, a 1 ml mixture of Xylocain- Marcaine solution was infiltrated in the lower tonsillarpole on both sides.Results: The GPhN can be divided into three portions: cisternal, jugular foramen and extracranial part.Tough dural septum separates the jugular part of the GPhN from both vagus and accessory nerves in 20%of the cadaveric specimens. The GPhN was anastomosed with the hypoglossal nerve in 40% and withthe lingual nerve in 50%. The lingual branch of the glossopharygeal nerve (LBG) entered the tongueobliquely bifurcated into medial and lateral primary branches, with the former innervating most ofthe circumvallate papillae. In 30% the medial branches of LBG extended anteriorly beyond the sulcusterminalis and the circumvallate papillae. Tonsillar branches were originating from the GPhN in 60% andfrom the LBG in 40%. The mean distance from the posterosuperior tonsillar fossa and the main trunkof the glossopharyngeal nerve was 9.3 mm, and the mean distance from the posteroinferior tonsillarfossa and the closest lingual branch of the glossopharyngeal nerve was6.7 mm. Results of the clinicalstudy showed statistically significant lower pain scores (according to VAS score) in the recovery room,1and 3hours after surgery in the group that received local anesthetic infiltration compared with the othergroup that didn’t receive any local anesthetic infiltration. Also 1 week postoperatively there was again astatistically significant lower pain scores in the group that received local anesthetic infiltration.Conclusions: Accurate identification and exposure of the GPhN allow for its preservation during surgicalresection of any pathological entities along its course. The results of the anatomical dissection study donepoints to the crucial role the glossopharyngeal nerve branching patterns in determining the level of thepostoperative pain perception after tonsillectomy operation.

A description of the anatomy of the glossopharyngeal nerve as encountered in transoral surgery.

To illustrate detailed anatomy of the extracranial portion of the glossopharyngeal nerve in the parapharyngeal space as encountered during transoral surgery. Prospective cadaveric dissection. All dissections were performed transorally and confirmed with transcervical dissection. Eight color-injected cadaveric heads (16 sides) were dissected to demonstrate the course and anatomy of the glossopharyngeal nerve. Conventional external dissections were performed to verify our anatomic measurements. Anatomical measurements of the glossopharyngeal nerve, including segments, branches in each segment, relationship with stylopharyngeus muscle, internal carotid artery, and pharyngeal branch of Vagus were recorded and analyzed. The glossopharyngeal nerve was separated into three segments according to the relationship with the stylopharyngeus muscle. Total lengths of the glossopharyngeal nerve are 32.6 ± 3.1 (left side) and 30.6 ± 3.7 (right side) mm, respectively. The average number of branches in the upper, middle, and lower segments is 3 (range 1-3), 4 (range 2-4), and 3 (range 1-3), respectively. The total number of branches is 8 (range 6-9). The average diameter of the main trunk of the glossopharyngeal nerve is 1.2 ± 0.3 mm, and the average diameter of the lingual branch of the glossopharyngeal nerve is approximately 0.6 ± 0.2 mm. In 75% of cases, pharyngeal branch of Vagus crosses the glossopharyngeal nerve, whereas in 25% of cases it parallels the course of the glossopharyngeal nerve to form the pharyngeal nerve plexus to innervate the pharyngeal wall. Understanding the precise and detailed anatomy of the glossopharyngeal nerve in the parapharyngeal space is important in transoral surgery for indications such as transoral robotic surgery or transoral laser microsurgery tumor resection, lingual tonsillectomy, glossopharyngeal neuralgia, glossopharyngeal nerve block, and internal carotid artery dissection. N/A. Laryngoscope, 126:2010-2015, 2016.

Incidence of Visualization of the Glossopharyngeal Nerve after Pediatric Tonsillectomy.

The objective was to determine the incidence of exposure of the lingual branch of the glossopharyngeal nerve during tonsillectomy with a retrospective review of surgical findings in 138 children who underwent total tonsillectomy at a tertiary medical center. Age, sex, surgical indication, tonsil size, congenital abnormalities, operative time, and surgical findings indicating the presence or absence of the glossopharyngeal nerve in the tonsillar fossa were recorded. Statistical analysis was performed with z test, t test, and Fisher's exact test. Thirty-seven nerves were observed in 28 patients, with preponderance for the left fossa (24 of 37 vs 13 of 37; P = .01). In a comparison of children with and without exposed nerves, there was no statistically significant difference in mean age (6.89 vs 7.08; P = .84), proportion of males (14 of 28 vs 54 of 110; P = 1), or proportion of 3 to 4+ tonsils (20 of 28 vs 73 of 110; P = .66). In approximately 20% of children undergoing tonsillectomy, the lateral pharyngeal musculature incompletely protected the lingual branch of the glossopharyngeal nerve from the tonsil capsule.

Taste disturbance after tonsillectomy: a rare but significant complication- a case report

Introduction: Tonsillectomy is the most commonly performed procedure and generally regarded as a safe surgery. Taste disturbance is a very rare complication after tonsillectomy, with very few reports in the literature. The most possible cause of this rare complication is direct or indirect damage to the glossopharyngeal nerve or its lingual branch (LBGN). Aim: To report a very rare complication of the most commonly performed procedure i.e. tonsillectomy. Case Report: The case is a 32 years old lady who complained of taste disturbance following tonsillectomy that was performed for chronic tonsillitis. As treatment patient was given Trifluoparazine Hydrochloride a Phenothiazine derivatives and Vit B6 + Vit B12. Patient recovered after 4 months postoperatively. Conclusion: Tonsillectomy should be performed with minimal trauma to the tonsillar bed to avoid injury to the Glossopharyngeal nerve or its lingual branch (LBGN) and all patients should be informed of the risk of post-operative taste disturbance after tonsillectomy. DOI: http://dx.doi.org/10.3329/jafmc.v10i1.22935 Journal of Armed Forces Medical College Bangladesh Vol.10(1) 2014

A ganglion cell cluster along the glossopharyngeal nerve near the human palatine tonsil

Conclusion: The lingual branches of the glossopharyngeal nerve were most likely to bring not only gustatory nerves to the postsulcal part of the tongue but also autonomic nerves to the small glands and vessels. Tonsillectomy may injure the ganglion or reduce its function due to scar formation after surgery. Objectives: To determine the topographical anatomy of a suggested ganglion cluster along the lingual branches of the glossopharyngeal nerve and to identify the incidence. Methods: In the human pharynges of 12 donated cadavers, we studied the ganglia using routine procedures for paraffin-embedded histology and immunohistochemistry. Results: Near the palatine tonsil, the lingual branches of the glossopharyngeal nerve often contained ganglion cells (in 9 of 12 specimens). The ganglion cells, 20–40 µ in diameter, were sparsely distributed along a 0.5–3.0 mm length of the nerve course attached to the posterolateral aspect of the superior pharyngeal constrictor. Most of these cells were positive for neuronal nitric oxide synthase, while some were positive for tyrosine hydroxylase. Thus, the ganglion was composed of a mixed population of sympathetic and parasympathetic neurons.

Anesthetic considerations in patients with large obstructing vocal process granuloma

Dangerous problems can arise during the induction of general anesthesia in patients with huge vocal process granuloma, due to airway obstruction [1]. A 54 year-old female patient was referred to our institution from a local clinic due to persistent hoarseness and severe dyspnea, over the last 3 months after subtotal gastrectomy with a diagnosis of a postintubation granuloma. She was scheduled for a laryngomicroscopic surgery under general anesthesia. We decided to use direct larygoscope for endotracheal intubation with patient's cooperation. She was kept awake with conscious sedation during intubation with remifentanil 0.1 µg/kg/min IV. The topical anesthesia with two to three sprays of aerosolized 10% xylocaine was performed onto the backside of the tongue, the soft palate, the pharynx and the larynx in the oral cavity. This was followed by an injection of 2 ml of 2% lidocaine to block the lingual branch of the superior laryngeal nerves. Direct laryngoscope was applied. We confirmed there was space on the left side on the vocal cord during patient's deep expiration, and the granuloma was not fixed. An assistant put aside the granuloma in the space to the right by the suction tip. An anesthesiologist inserted an endotracheal tube with an inner diameter of 5.0 mm into which a stylet was inserted during patient's deep expiration. The tube was carefully inserted not to cut off the mass into the trachea (Fig. 1). No fragments of damaged tissue were found. After successful intubation, propofol 120 mg and rocuronium 30 mg were injected intravenously, and anesthesia was maintained with sevoflurane 2 vol% and remifentanil 0.1-0.2 µg/kg/min. Dexamethasone 10 mg was administered to prevent postoperative laryngeal edema. Surgeon performed a laryngomicroscopic excision for granuloma mass, which continued for 15 min.

A survey of oral cavity afferents to the rat nucleus tractus solitarii

Visualization of myelinated fiber arrangements, cytoarchitecture, and projection fields of afferent fibers in tandem revealed input target selectivity in identified subdivisions of the nucleus tractus solitarii (NTS). The central fibers of the chorda tympani (CT), greater superficial petrosal nerve (GSP), and glossopharyngeal nerve (IX), three nerves that innervate taste buds in the oral cavity, prominently occupy the gustatory-sensitive rostrocentral subdivision. In addition, CT and IX innervate and overlap in the rostrolateral subdivision, which is primarily targeted by the lingual branch of the trigeminal nerve (LV). In the rostrocentral subdivision, compared with the CT terminal field, GSP appeared more rostral and medial, and IX was more dorsal and caudal. Whereas IX and LV filled the rostrolateral subdivision diffusely, CT projected only to the dorsal and medial portions. The intermediate lateral subdivision received input from IX and LV but not CT or GSP. In the caudal NTS, the ventrolateral subdivision received notable innervation from CT, GSP, and LV, but not IX. No caudal subnuclei medial to the solitary tract contained labeled afferent fibers. The data indicate selectivity of fiber populations within each nerve for functionally distinct subdivisions of the NTS, highlighting the possibility of equally distinct functions for CT in the rostrolateral NTS, and CT and GSP in the caudal NTS. Further, this provides a useful anatomical template to study the role of oral cavity afferents in the taste-responsive subdivision of the NTS as well as in subdivisions that regulate ingestion and other oromotor behaviors.