Mental and Lingual Nerve Paresthesia Following Infiltration Anesthesia for Dental Implant Placement in a Patient With Guillain-Barré Syndrome.

Guillain-Barré syndrome (GBS) is a rare rapid onset autoimmune peripheral polyneuropathy, most commonly characterized by inflammatory demyelination of peripheral nerves. Patients with GBS are considered higher risk for anesthetic-induced neurotoxicity caused by demyelination. In the present report, a case is described of a 56-year-old man with GBS who experienced mental and lingual nerve paresthesia following infiltration anesthesia for dental implant placement in the posterior mandible. The pareshesia lasted 5 months postoperatively and subsided spontaneously without any intervention. The patient was successfully restored with fixed partial dental prosthesis without any other complication. This is considered the first report of such complication in patient with GBS after local anesthesia in the oral and maxillofacial region. Possible pathogenic mechanism of the complication and clinical implications are discussed.

Plunging ranula with lingual nerve tether: Case report and literature review.

Plunging ranulas are most often treated surgically; various surgical approaches may be necessary depending on the unique characteristics of each case. Here, we present the case of a plunging ranula noted on imaging to have a cordlike tether, which was revealed intraoperatively to be the lingual nerve. This case illustrates the importance of preoperative imaging for surgical planning, and when a transcervical approach may be the best choice for plunging ranulas.

Perineural Invasion and Perineural Tumor Spread in Head and Neck Cancer.

Perineural invasion (PNI), the neoplastic invasion of nerves, is a common pathologic finding in head and neck cancer that is associated with poor clinical outcomes. PNI is a histologic finding of tumor cell infiltration and is distinct from perineural tumor spread (PNTS), which is macroscopic tumor involvement along a nerve extending from the primary tumor that is by definition more advanced, being radiologically or clinically apparent. Despite widespread acknowledgment of the prognostic significance of PNI and PNTS, the mechanisms underlying its pathogenesis remain largely unknown, and specific therapies targeting nerve invasion are lacking. The use of radiation therapy for PNI and PNTS can improve local control and reduce devastating failures at the skull base. However, the optimal volumes to be delineated with respect to targeting cranial nerve pathways are not well defined, and radiation can carry risks of major toxicity secondary to the location of adjacent critical structures. Here we examine the pathogenesis of these phenomena, analyze the role of radiation in PNI and PNTS, and propose guidelines for radiation treatment design based on the best available evidence and the authors' collective experience to advance understanding and therapy of this ominous cancer phenotype.

Lingual Nerve Entrapment in Fused Submandibular and Sublingual Salivary Glands: A Unique Finding.

Lingual nerve (LN) is one among the 3 branches of posterior division of mandibular nerve. It might get entrapped in the infratemporal fossa by lateral pterygoid muscle, pterygospinous ligament, or lateral pterygoid plate. Its entrapment in the submandibular region has not been reported yet. A unique entrapment of LN in the fused submandibular and sublingual salivary glands in a cadaver was reported. The deep parts of the submandibular and sublingual salivary glands were completely fused with each other. The LN passed through the center of the fused part. Histologically both submandibular and sublingual salivary glands had both mucous and serous acini. Though this entrapment might not cause any functional problems, it might get injured during various surgical procedures of the submandibular region.

[Clinical application of the combined radical operation without breaking lower lip and mandible for tongue and lingual root carcinoma].

OBJECTIVE: To investigate the clinical applicability and outcomes of the combined radical operation without breaking the lower lip and mandible with one-stage reconstruction using free anterolateral thigh flap for tongue and lingual root carcinoma. METHODS: The operation with or without breaking lower lip and mandible was performed respectively in 245 patients (experimental group) and 120 patients (control group). RESULTS: Removal of tumor and neck dissection were conducted successfully in all patients of two groups with no serious postoperative complication. With the follows-up of 6 to 36 months, in the patients of experimental group there was no recurrence for primary sites but 3 cases with neck lymphnode recurrence, the functions of chewing, swallowing and speaking were good, there was no damage to appearance, and no osteoradionecrosis occurred in the lymphnode positive cases after radiotherapy; in the patients of experimental group there was no recurrence for primary sites but 4 cases with neck lymphnode recurrence, the functions of chewing, swallowing and speaking were good, but there was apparent scar in neck and face, and osteoradionecrosis occurred in 11 of lymphnode positive cases. CONCLUSIONS: The combined radical operation without breaking the lower lip and mandible with one-stage reconstruction using free anterolateral thigh flap is feasible for tongue and lingual root carcinoma (T2-T3), which reduces the risk for osteoradionecrosis in lymphnode positive cases after radiotherapy and keeps good appearance for patients.

Eagle's syndrome associated with lingual nerve paresthesia: a case report.

Eagle's syndrome is characterized by a variety of symptoms, including throat pain, sensation of a foreign body in the pharynx, dysphagia, referred otalgia, and neck and throat pain exacerbated by head rotation. Any styloid process longer than 25 mm should be considered elongated and will usually be responsible for Eagle's syndrome. Surgical resection of the elongated styloid is a routine treatment and can be accomplished using a transoral or an extraoral approach. We report a patient with a rare giant styloid process that was approximately 81.7 mm. He complained of a rare symptom: hemitongue paresthesia. After removal of the elongated styloid process using the extraoral approach, his symptoms, including the hemitongue paresthesia, were alleviated. We concluded that if the styloid process displays medium to severe elongation, the extraoral approach will be appropriate.

Maxillary-fronto-temporal approach for removal of recurrent malignant infratemporal fossa tumors: Anatomical and clinical study.

PURPOSE: For recurrent malignant tumors occurring in the infratemporal fossa, it is difficult to select a proper surgical approach. We explore the efficiency of a new approach for removal of recurrent malignant tumors involving the infratemporal fossa based on the measurement on three-dimension CT, observation of six cadaveric specimens, and our surgical experience. MATERIALS AND METHODS: The distances between the surgical landmarks in the infratemporal fossa were measured using CT data to determine the safe distance. And anatomy observation was examined on 6 formalin-fixed cadaveric specimens. Data from seven patients with recurrent malignant infratemporal fossa tumors were retrospectively analyzed. RESULTS: The mean distance of the medial pterygoid plate from the zygoma was 52.12 mm. The maxillary artery can be found between the deep surface of the condyle and the sphenomandibular ligament, with mean distance of 8.25 ± 3.22 mm to the inferior border of the capsule of the temporomandibular joint. All tumors got gross resection using the maxillary-fronto-temporal approach with minor complication. CONCLUSIONS: The advantages of the new approach include adequate protection of facial nerve with extended operation field; the exposed temporal muscle could be used to fill the dead space. This technique is especially useful to remove recurrent malignant infratemporal tumors safely.

Schwannoma derived from lingual nerve occurring in floor of mouth.

A schwannoma is a benign tumor composed of schwann cells which forms on the periphery of nerves. We report a case of a schwannoma derived from a lingual nerve occurring in the floor of the mouth. The patient was a 27-year-old woman who presented with the complaint of a swelling in the floor of the mouth. It is difficult to distinguish a swelling from a sublingual gland tumor, cyst, or malignant tumor by MRI alone. Therefore, a biopsy and cytological examination were performed one week prior to surgery to determine whether the growth represented a malignancy. The results revealed a class II growth which was suspected to be a schwannoma. Intraoperatively, it became clear that the tumor and lingual nerve were inseparable, making excision of the nerve unavoidable. On the other hand, there was a clear border between the tumor and the sublingual gland, so it was possible to preserve the sublingual gland. In the postoperative pathological diagnosis, a definitive diagnosis was difficult based solely on H-E staining. Therefore, immunohistochemical staining was performed, resulting in a diagnosis of schwannoma. Currently, the patient is still being followed up. The results of this case indicate that preoperative aspiration biopsy cytology is useful in deciding the operative method to be employed.

Correlation of Nav1.8 and Nav1.9 sodium channel expression with neuropathic pain in human subjects with lingual nerve neuromas.

BACKGROUND: Voltage-gated sodium channels Nav1.8 and Nav1.9 are expressed preferentially in small diameter sensory neurons, and are thought to play a role in the generation of ectopic activity in neuronal cell bodies and/or their axons following peripheral nerve injury. The expression of Nav1.8 and Nav1.9 has been quantified in human lingual nerves that have been previously injured inadvertently during lower third molar removal, and any correlation between the expression of these ion channels and the presence or absence of dysaesthesia investigated. RESULTS: Immunohistochemical processing and quantitative image analysis revealed that Nav1.8 and Nav1.9 were expressed in human lingual nerve neuromas from patients with or without symptoms of dysaesthesia. The level of Nav1.8 expression was significantly higher in patients reporting pain compared with no pain, and a significant positive correlation was observed between levels of Nav1.8 expression and VAS scores for the symptom of tingling. No significant differences were recorded in the level of expression of Nav1.9 between patients with or without pain. CONCLUSIONS: These results demonstrate that Nav1.8 and Nav1.9 are present in human lingual nerve neuromas, with significant correlations between the level of expression of Nav1.8 and symptoms of pain. These data provide further evidence that changes in expression of Nav1.8 are important in the development and/or maintenance of nerve injury-induced pain, and suggest that Nav1.8 may be a potential therapeutic target.

Treatment of recurrent lingual nerve end-neuroma: A case report.

A neuroma is a collection of disorganized nerve sprouts emanating from an interruption of axonal continuity, forming within a collagen scar as the nerve attempts to regenerate. Lingual neuroma formation secondary to iatrogenic trauma to the tongue is likely not uncommon; however, we could not find a report in the literature of treatment of a distal tongue end-neuroma treated by resection and implantation into muscle. Here we describe a patient who experienced debilitating chronic tongue pain after excision of a benign mass. After failing conservative management, the patient was taken to the operating room where an end-neuroma of the lingual nerve was identified and successfully treated by excision and burying of the free proximal stump in the mylohyoid muscle. At 17 months postoperatively, she remains pain free without dysesthesias.

Functional anatomy of the mandibular nerve: consequences of nerve injury and entrapment.

Various anatomic structures including bone, muscle, or fibrous bands may entrap and potentially compress branches of the mandibular nerve (MN). The infratemporal fossa is a common location for MN compression and one of the most difficult regions of the skull to access surgically. Other potential sites for entrapment of the MN and its branches include, a totally or partially ossified pterygospinous or pterygoalar ligament, a large lamina of the lateral plate of the pterygoid process, the medial fibers of the lower belly of the lateral pterygoid muscle and the inner fibers of the medial pterygoid muscle. The clinical consequences of MN entrapment are dependent upon which branches are compressed. Compression of the MN motor branches can lead to paresis or weakness in the innervated muscles, whereas compression of the sensory branches can provoke neuralgia or paresthesia. Compression of one of the major branches of the MN, the lingual nerve (LN), is associated with numbness, hypoesthesia, or even anesthesia of the tongue, loss of taste in the anterior two thirds of the tongue, anesthesia of the lingual gums, pain, and speech articulation disorders. The aim of this article is to review, the anatomy of the MN and its major branches with relation to their vulnerability to entrapment. Because the LN expresses an increased vulnerability to entrapment neuropathies as a result of its anatomical location, frequent variations, as well as from irregular osseous, fibrous, or muscular irregularities in the region of the infratemporal fossa, particular emphasis is placed on the LN.

Lingual nerve entrapment in muscular and osseous structures.

Running through the infratemporal fossa is the lingual nerve (i.e. the third branch of the posterior trunk of the mandibular nerve). Due to its location, there are various anatomic structures that might entrap and potentially compress the lingual nerve. These anatomical sites of entrapment are: (a) the partially or completely ossified pterygospinous or pterygoalar ligaments; (b) the large lamina of the lateral plate of the pterygoid process; and (c) the medial fibers of the anterior region of the lateral pterygoid muscle. Due to the connection between these nerve and anatomic structures, a contraction of the lateral pterygoid muscle, for example, might cause a compression of the lingual nerve. Any variations in the course of the lingual nerve can be of clinical significance to surgeons and neurologists because of the significant complications that might occur. To name a few of such complications, lingual nerve entrapment can lead to: (a) numbness, hypoesthesia or even anesthesia of the tongue's mucous glands; (b) anesthesia and loss of taste in the anterior two-thirds of the tongue; (c) anesthesia of the lingual gums; and (d) pain related to speech articulation disorder. Dentists should, therefore, be alert to possible signs of neurovascular compression in regions where the lingual nerve is distributed.

Transient isolated lingual nerve neuropraxia associated with general anaesthesia and laryngeal mask use: two case reports and a review of the literature.

BACKGROUND: Transient, isolated lingual nerve neuropraxia is a rare complication following general anaesthesia. Reports implicate airway manipulation and we describe two new cases associated with laryngeal mask airway (LMA) and review the related English language literature. RESULTS: Unilateral numbness and loss of taste on the anterior tongue were the characteristic symptoms. Collation of literature data (median and range) with that from the new cases showed: patient age was 38 (20-61) years and female to male ratio was 1.2:1. Surgery time was 62.5 (20-150) min and symptom duration was 28 (7-120) days. CONCLUSION: Lingual neuropraxias reported have been transient and patients can be advised, despite disturbing symptoms, that recovery is anticipated in about 1 month. Lingual neuropraxia reports are becoming more frequent, perhaps associated with increasing LMA use. Research is recommended as modification to LMA cuff volume, pressure and/or position within the oral cavity might ameliorate the entity.

Solitary benign schwannomas in major nerve systems of the head and neck.

Solitary schwannomas of the head and neck are uncommon tumors arising from any cranial or autonomic nerve. Twenty-five percent to 45% of extracranial schwannomas occur in the head and neck. A total of 28 consecutive patients treated be tween January 2000 and August 2006 for solitary schwannomas in different major nerves of the head and neck were included in this study. Most affected trunks were cranial nerves in 14 patients (50%), cervical sympathetic chain in 7 (25%), and brachial plexus in 7 (25%). The most common sign was an isolated well-demarcated lesion placement at the lateral aspect of the neck for those tumors arising from vagus, lingual, and sympathetic nerves. Total resection with nerve conservation was the treatment of choice for these tumors. In 26 patients (94%), no functional sequels were detected; in 2 other patients (6%), Horner syndrome was a consequence of sympathetic chain resection. No relapse was detected in all 28 patients.

Overexpression of artemin in the tongue increases expression of TRPV1 and TRPA1 in trigeminal afferents and causes oral sensitivity to capsaicin and mustard oil.

Artemin, a member of the glial cell line-derived neurotrophic factor (GDNF) family, supports a subpopulation of trigeminal sensory neurons through activation of the Ret/GFRalpha3 receptor tyrosine kinase complex. In a previous study we showed that artemin is increased in inflamed skin of wildtype mice and that transgenic overexpression of artemin in skin increases TRPV1 and TRPA1 expression in dorsal root ganglia neurons. In this study we examined how transgenic overexpression of artemin in tongue epithelium affects the anatomy, gene expression and calcium handling properties of trigeminal sensory afferents. At the RNA level, trigeminal ganglia of artemin overexpresser mice (ART-OEs) had an 81% increase in GFRalpha3, a 190% increase in TRPV1 and a 403% increase in TRPA1 compared to wildtype (WT) controls. Myelinated and unmyelinated fibers of the lingual nerve were increased in diameter, as was the density of GFRalpha3 and TRPV1-positive innervation to the dorsal anterior tongue and fungiform papilla. Retrograde labeling of trigeminal afferents by WGA injection into the tip of the tongue showed an increased percentage of GFRalpha3, TRPV1 and isolectin B4 afferents in ART-OE mice. ART-OE afferents had larger calcium transients in response to ligands of TRPV1 (capsaicin) and TRPA1 (mustard oil). Behavioral sensitivity was also exhibited by ART-OE mice to capsaicin and mustard oil, measured using a two-choice drinking test. These results suggest a potential role for artemin-responsive GFRalpha3/TRPV1/TRPA1 sensory afferents in mediating sensitivity associated with tissue injury, chemical sensitivity or disease states such as burning mouth syndrome.