The lingual nerve (LN) is a branch of the mandibular division of the trigeminal nerve, and its injury is one of the major complications during oral surgery. This study aims to investigate the anatomy of the LN in the lower third molar area. Twenty sides from ten fresh-frozen adult cadaveric Caucasian heads were examined to measure the diameter of the LN. The mean diameter of the LN was 2.20±0.37 mm (range, 1.61–2.95 mm). There were no statistically significant differences in the measurements between sexes, sides, or tooth status (dentulous or edentulous). Understanding the anatomical features of the LN is essential for performing any surgical procedure in the oral region.
Adult ; Cadaver ; Head ; Humans ; Lingual Nerve ; Mandibular Nerve ; Molar, Third ; Surgery, Oral ; Tooth ; Trigeminal Nerve

Trigeminal nerve injury as a consequence of lower third molar surgery is a notorious complication and may affect the patient in long term. Inferior alveolar nerve (IAN) and lingual nerve (LN) injury result in different degree of neurosensory deficit and also other neurological symptoms. The long term effects may include persistent sensory loss, chronic pain and depression. It is crucial to understand the pathophysiology of the nerve injury from lower third molar surgery. Surgery remains the most promising treatment in moderate-to-severe nerve injuries. There are limitations in the current treatment methods and full recovery is not commonly achievable. It is better to prevent nerve injury than to treat with unpredictable results. Coronectomy has been proved to be effective in reducing IAN injury and carries minimal long-term morbidity. New technologies, like the roles of erythropoietin and stem cell therapy, are being investigated for neuroprotection and neural regeneration. Breakthroughs in basic and translational research are required to improve the clinical outcomes of the current treatment modalities of third molar surgery-related nerve injury.
Chronic Pain ; Depression ; Erythropoietin ; Humans ; Lingual Nerve ; Mandibular Nerve ; Molar, Third ; Neuroprotection ; Postoperative Complications ; Regeneration ; Stem Cells ; Translational Medical Research ; Trigeminal Nerve Injuries ; Trigeminal Nerve

Lingual nerve injury is a rare complication of general anesthesia. The causes of lingual nerve injury following general anesthesia are multifactorial; possible mechanisms may include difficult laryngoscopy, prolonged anterior mandibular displacement, improper placement of the oropharyngeal airway, macroglossia and tongue compression. In this report, we have described a case of bilateral lingual nerve injury that was associated with orotracheal intubation for open reduction and internal fixation of the left distal radius fracture in a 61-year-old woman. In this case, early treatment with dexamethasone effectively aided the recovery of the injured lingual nerve.
Anesthesia, General ; Dexamethasone ; Female ; Humans ; Intubation ; Laryngoscopy ; Lingual Nerve Injuries ; Lingual Nerve ; Macroglossia ; Middle Aged ; Radius Fractures ; Tongue

Neurilemmomas are well-encapsulated, benign, slow-growing tumors originating from Schwann cells of the nerve sheath surrounding cranial, peripheral, or autonomic nerves. Intraoral neurilemmomas are relatively rare and have a wide variety of morphologic and radiologic features. This makes differential diagnosis difficult, and only histopathological features can lead to a definitive neurilemmoma diagnosis. In this report, we present the case of a 30-year-old woman whose chief complaint was a solitary, nodular mass on the right floor of the mouth. After computed tomography and magnetic resonance imaging, we performed an incisional biopsy that showed the typical characteristics of a neurilemmoma. The mass was removed completely through an intraoral surgical approach. Despite losing a portion of the lingual nerve, the patient did not complain of any specific discomfort. Wound healing was uneventful and there were no signs or symptoms of recurrence.
Adult ; Autonomic Pathways ; Biopsy ; Diagnosis ; Diagnosis, Differential ; Female ; Humans ; Lingual Nerve ; Magnetic Resonance Imaging ; Mouth* ; Neurilemmoma* ; Recurrence ; Schwann Cells ; Sublingual Gland ; Wound Healing

Schwannomas are benign peripheral nerve sheath tumors. It is found rarely in the oral cavity but most commonly in the tongue followed by the palate, floor of mouth, buccal mucosa, and mandible. Because schwannoma of the base of tongue is exceedingly rare, it is often not immediately included in the differential diagnosis, causing delay in identification and treatment. We report here, with a review of the literature, a case of schwannoma of the base of tongue, which was misdiagnosed as a lingual thyroid. A 28-year-old man presented with a base of tongue mass, which was first detected a month ago. The preoperative diagnosis was lingual thyroid on the basis of the physical findings and computerized tomographic findings. The permanent pathologic report of the mass was schwannoma. Postoperatively, the patient showed no problem with tongue function and wound healing.
Adult ; Diagnosis ; Diagnosis, Differential ; Humans ; Lingual Thyroid ; Mandible ; Mouth ; Mouth Floor ; Mouth Mucosa ; Nerve Sheath Neoplasms ; Neurilemmoma* ; Palate ; Tongue* ; Wound Healing

INTRODUCTIONThe lingual, inferior alveolar and auriculotemporal nerves, being branches of the posterior division of the mandibular nerve, mainly innervate the mandibular teeth and all the major salivary glands. Anomalous communications among these branches are widely reported due to their significance to various treatment procedures undertaken in the region. This study was performed as detailed exploration of the functional perspectives of such communicating branches would further enhance the scope of these procedures.

METHODSA total of 36 specimens were dissected to examine the infratemporal region. The branches from the posterior division of the mandibular nerve--namely the lingual, inferior alveolar and auriculotemporal nerves--were carefully dissected, and their branches were studied and analysed for abnormal course.

RESULTSCommunication between branches of the posterior division of the mandibular nerve was observed in four specimens. In two of the four specimens, communication between the mylohyoid and lingual nerves was observed. A rare and seldom reported type of communication between the auriculotemporal and inferior alveolar nerves is described in this study. This communicating nerve split into two to form a buttonhole for the passage of the mylohyoid nerve.

CONCLUSIONSuch communicating branches between nerves found in this study are developmental in origin and thought to maintain functional integrity through an alternative route.

Cadaver ; Female ; Humans ; Lingual Nerve ; anatomy & histology ; Male ; Mandibular Nerve ; anatomy & histology ; Neck Muscles ; innervation ; Tongue

Stimulation of the trigeminal nerve can elicit various cardiovascular and autonomic responses; however, the effects of anesthesia with pentobarbital sodium on these responses are unclear. Pentobarbital sodium was infused intravenously at a nominal rate and the lingual nerve was electrically stimulated at each infusion rate. Increases in systolic blood pressure (SBP) and heart rate (HR) were evoked by lingual nerve stimulation at an infusion rate between 5 and 7 mg·kg(-1)·h(-1). This response was associated with an increase in the low-frequency band of SBP variability (SBP-LF). As the infusion rate increased to 10 mg·kg(-1)·h(-1) or more, decreases in SBP and HR were observed. This response was associated with the reduction of SBP-LF. In conclusion, lingual nerve stimulation has both sympathomimetic and sympathoinhibitory effects, depending on the depth of pentobarbital anesthesia. The reaction pattern seems to be closely related to the autonomic balance produced by pentobarbital anesthesia.
Adjuvants, Anesthesia ; administration & dosage ; pharmacology ; Adrenergic alpha-Antagonists ; pharmacology ; Animals ; Autonomic Nervous System ; drug effects ; Cats ; Dose-Response Relationship, Drug ; Electric Stimulation ; Electrocardiography ; drug effects ; Hemodynamics ; drug effects ; Hexamethonium ; pharmacology ; Hypnotics and Sedatives ; administration & dosage ; pharmacology ; Infusions, Intravenous ; Lingual Nerve ; drug effects ; physiology ; Male ; Neural Inhibition ; Phentolamine ; pharmacology ; Trigeminal Nerve ; drug effects ; physiology

INTRODUCTION: This study evaluated nerve recovery through retrospective study of patients with lingual nerve damage. PATIENTS AND METHODS: The patients who visited Seoul National University Dental Hospital for an injury to the lingual nerve from April 1988 to August 2009 were enrolled in this study (n=41). The relevance of various factors including the causes of damage, age, etc. was analyzed by the subjective improvement based upon questionnaires and the clinical records. The evaluation variants were a subjective assessment and neurosensory examination composed of the direction, contact threshold, two-point discrimination, pin prick, thermal discrimination and current perception threshold. RESULTS: The causes of lingual nerve damage were an extraction of the lower third molar (75.6%), local anesthesia (9.7%), incision and drainage (4.88%), trauma (2.44%). The evaluation of subjective prognosis exhibited no difference in sensory improvement depending on the cause, age and gender. Based upon the subjective evaluation, 44.7% of patients showed sensory improvement. The first hospital visit from injury was shorter in the group showing subjective improvement (3.41 months) than those showing no improvement (5.24 months) (P=0.301). Thirty six out of 41 patients were treated with only conservative therapy and 5 patients were treated by surgical intervention. Neurosensory examinations revealed improvement, although not statistically significant, and the degree was higher in the subjectively improved group. The contact threshold discrimination showed the highest correlation with subjective improvement (P=0.069). Most of the sensory recovery was gained within 12 months and the degree of improvement at the tip of the tongue was higher than that of the dorsum (P<0.001). CONCLUSION: The damaged lingual nerve improved at a rate of 44.7% and mostly within 12 months after the incident. There was no difference between the subjective prognosis and neurosensory examination depending on the cause of damage, age and gender, whereas the contact threshold discrimination was the best variant that reflected the subjective prognosis statistically.
Anesthesia, Local ; Discrimination (Psychology) ; Drainage ; Humans ; Lingual Nerve ; Molar, Third ; Prognosis ; Surveys and Questionnaires ; Retrospective Studies ; Tongue

The extraction of an impacted third molar tooth is associated with many complications during the procedure and postoperative care. These complications include bleeding, swelling, pain, infection, as well as root fracture, proximal tooth injury, alveolar bone fracture, lingual nerve and inferior alveolar nerve injury etc. With the exception of a fractured root dislocation in the submandibular space, no direct submandibular gland injury related to extraction surgery has been reported until now. A 40 year old man visited the department of oromaxillofacial surgery at Yeouido St. Mary's Hospital for an extraction of the right mandible third molar. A partial third molar impaction was diagnosed by a clinical and radiographic examination. A surgical tooth extraction was practiced including buccal cortical bone osteotomy. During socket curettage, an encapsulated cyst-like lesion and a verified 3x3 cm neoplasm in the apically lingual direction were found during process of dissection. A biopsy confirmed that the neoplasm involved the submandibular gland and nerve trunk. This unusual anatomical organ injury during the surgical tooth extraction procedure is reported as a new complication during impacted third molar extraction.
Biopsy ; Curettage ; Dislocations ; Fractures, Bone ; Hemorrhage ; Intraoperative Complications ; Lingual Nerve ; Mandible ; Mandibular Nerve ; Molar, Third ; Osteotomy ; Postoperative Care ; Submandibular Gland ; Tooth ; Tooth Extraction ; Tooth Injuries

Schwannoma is a relatively slow-growing, encapsulated benign tumor that is derived from the Schwann cell of the nerve sheath. We report here on a case of schwannoma of the mouth floor with a review of the literature. A 67-year-old woman presented with a right mouth floor mass, which was first detected 5 years ago. The preoperative diagnosis was ranula on the basis of the physical findings and the computerized tomographic findings. However, the mass was found to be a true neoplastic lesion rather than a cystic lesion in the course of surgical dissection. The permanent pathologic report of the mass was schwannoma. Postoperatively, although the patient had no problem with taste, the pain-sense, speech and swallowing, she had mild deviation of the tongue towards the same side of the mass, which means that the function of the hypoglossal nerve was somewhat impaired. Her tongue deviation was spontaneously resolved within 6 weeks postoperatively.
Aged ; Deglutition ; Female ; Humans ; Hypoglossal Nerve ; Lingual Nerve ; Mouth ; Mouth Floor ; Neurilemmoma ; Ranula ; Tongue