BACKGROUND AND OBJECTIVES: After bilateral mastoidectomy, taste change is common because of injury to chorda tympani nerve. We aimed to understand about the appropriate interval of sequential bilateral mastoidectomy. SUBJECTS AND METHOD: Retrospective review was carried out for 25 patients who underwent sequential bilateral mastoidectomy from March 2004 to November 2011. RESULTS: Among the 25 patients, there were 19 patients whose chorda tympani nerve was injured after bilateral mastoidectomy, and eight of those 19 patients complained of taste disturbance. The rates of dysfunction according to operation interval were within 6 month (55%, 5/9), between 6 and 12 months (33%, 2/6), and above 12 months (10%, 1/10). Compared to canal wall up mastoidectomy, for canal wall down mastoidectomy, taste disturbance was more common (p=0.001). CONCLUSION: The result supports that at least 6 months interoperative period for bilateral chronic otitis media may be needed to avoid taste disturbance. A further large study may validate this result.
Chorda Tympani Nerve ; Dysgeusia ; Humans ; Otitis Media ; Retrospective Studies

Schwannoma is benign tumor that is originated from the schwann cell. It rarely occurs in the middle ear. Schwannomas of the middle ear may originate from the nerves of the middle ear cavity or by extensions from its neighboring structures. Most schwannomas arising from the middle ear are facial nerve schwannomas. We present a case of a 16-year-old male patient with primary middle ear schwannoma believed to arise from Jacobson's nerves. The tumor was easily dissected from the facial nerve and the chorda tympani nerve. The mass was successfully removed by canal down mastoidectomy, while preserving the hearing and facial nerve functions of the patient.
Adolescent ; Chorda Tympani Nerve ; Ear, Middle ; Facial Nerve ; Hearing ; Humans ; Male ; Neurilemmoma

The classic surgical technique for cochlear implantation was first introduced by House in 1961. This technique includes a mastoidectomy and a posterior tympanotomy, which has been most widely used for cochlear implantation. However, this approach may result in the injury of the chorda tympani nerve or the facial nerve. To avoid the risk of the neural injury, several alternative surgical methods have been developed. The endomeatal approach is one of the several alternative techniques. We present, along with a review of literatures, a case of cochlear implantation using the endomeatal approach performed in a child with an extremely hypoplastic mastoid.
Child* ; Chorda Tympani Nerve ; Cochlear Implantation* ; Cochlear Implants* ; Facial Nerve ; Humans ; Mastoid*

Schwannoma is a benign nerve sheath tumor composed of schwann cells. Most schwannoma arising in the middle ear are facial nerve schwannoma. In very rare occasions, schwannoma of the middle ear can arise from chorda tympani nerve. Hearing loss and tinnitus are the most common symptoms of patients with schwannoma of chorda tympani nerve and it can be treated by surgical excision. Recently, we treated a male patient with schwannoma of the chorda tympani nerve. This is the first case of schwannoma of the chorda tympani nerve reported in Korea. Herein, we present the case in detail with a review of the related literature.
Chorda Tympani Nerve ; Ear, Middle ; Facial Nerve ; Hearing Loss ; Humans ; Korea ; Male ; Neurilemmoma ; Schwann Cells ; Tinnitus

BACKGROUND AND OBJECTIVES: During middle ear surgery, surgeons manipulate the chorda tympani nerve (CTN) at various degrees and warn the post-operative taste changes to patients preoperatively. The purpose of this study is to assess how many patients suffer from taste disturbance after surgery and the characteristics of their disease factors and surgical factors in patients complaining of it. In addition, it was designed to evaluate the clinical availability of electrogustometry (EGM)compared with subjective taste symptoms. SUBJECTS AND METHOD: One hundred thirty-one patients underwent middle ear surgery. Patients were divided to three groups, only tympanoplasty, tympano-ossiculoplasty without mastoidectomy and tympanoplasty with mastoidectomy. They were analysed by operative findings of CTN preserved, stretched, cut. The CTN function was measured at one day before surgery and one month after surgery by EGM. Taste questionnaires were given to all patients before and after surgery for one year. The results of EGM and questionnaires were compared with each other. RESULTS: In pre-operative EGM results of unilateral surgery, the lesion side of tongue had more elevated threshold of EGM than the contralateral side. In the post-operative EGM, any statistical factor was not significant and EGM results was not correlated with subjective symptoms. The results of the test questionnaraires was that thirty-three patients (25%) reported taste change. In tympanoplasty-preserved CTN group, more patients suffered from taste change than mastoidedctomy-cut CTN group. Symptoms were decreased taste sensation, dysgeusia, and decreased general sensation of tongue. Subjective recovery time was on the average of 2.7 months (two weeks to one year) after surgery. CONCLUSION: EGM was not correlated with subjective symptoms after surgery. Iatrogenic CTN injury in advanced middle ear infection may not cause taste disturbance. Surgeons should have efforts to preserve CTN in even mild middle ear diseases.
Chorda Tympani Nerve ; Diterpenes ; Dysgeusia ; Ear, Middle ; Humans ; Otitis Media ; Surveys and Questionnaires ; Sensation ; Tongue ; Tympanoplasty

BACKGROUND AND OBJECTIVES: Currently, the changes of taste sensation after unilateral injury of chorda tympani nerve during middle ear surgery remains unclear, particularly in objective methods, like threshold to each taste stimulus. This study aims to evaluate the objective changes of taste threshold according to the degrees of injury of chorda tympani nerve. MATERIALS AND METHODS: In 36 patients who underwent middle ear surgery, the degrees of injury were described as "intact", "stretched" and "sacrificed". The taste threshold to citric acid, NaCl, and sucrose were measured preoperatively, and 1 week, 1 month, 3 months after surgery. Subjective changes of taste sensation were questioned together. The amount of changes in threshold according to the degree of injury were statistically analyzed. RESULTS: There were no significant differences of threshold according to the degrees of injury in each taste. Several patients documented subjective taste changes, such as hypogeusia and parageusia. But there were no relationship between subjective and objective findings. CONCLUSION: These results suggest the probability of some compensatory mechanism after unilateral injury of chorda tympani nerve. There might be some discrepancy between taste threshold and real-world taste sensation.
Ageusia ; Chorda Tympani Nerve* ; Citric Acid ; Dysgeusia ; Ear, Middle* ; Humans ; Sensation ; Sucrose ; Taste Threshold

Salt signals in tongue are relayed to the nucleus of the solitary tract (NST). This signaling is very important to determine whether to swallow salt-related nutrition or not and suggests some implications in discrimination of salt concentration. Salt concentration-dependent electrical responses in the chorda tympani and the NST were well reported. But salt concentration-dependency and spatial distribution of c-Fos in the NST were not well established. In the present study, NaCl signaling in the NST was studied in urethane-anesthetized rats. The c-Fos immunoreactivity in the six different NST areas along the rostral-caudal axis and six subregions in each of bilateral NST were compared between applications of distilled water and different concentrations of NaCl to the tongue of experimental animals. From this study, salt stimulation with high concentration (1.0 M NaCl) induced significantly higher c-Fos expression in intermediate NST and dorsal-medial and dorsal-middle subregions of the NST compared to distilled water stimulation. The result represents the specific spatial distribution of salt taste perception in the NST.
Animals ; Axis, Cervical Vertebra ; Chorda Tympani Nerve ; Discrimination (Psychology) ; Rats ; Solitary Nucleus ; Taste Perception ; Tongue ; Water

Electrogustometry has become one of the most important and useful diagnostic methods as has audiometry and vestibular function tests in the otolaryngological field. Although much literature, concerning the facial nerve and gustatory function have appeared, still problems remain to be solved in future research. To these points of view, the anatomical relationships of the nerves associated with gustatory function were reviewed and discussed. And also the clinical importance and usability of electrogustometry is emphasized.
Chorda Tympani Nerve/anatomy & histology ; Facial Nerve/anatomy & histology* ; Facial Nerve/physiopathology ; Human ; Taste* ; Taste Disorders/physiopathology

Two major salivary glands, submandibular duct, lingual nerve, and vessels are situated beneath the mouth floor. Among these, passing through the pterygomandibular space, lingual nerve is innervated to the lingual gingiva and the mucosa of mouth floor, and is responsible for the general sensation of the anterior two thirds of the tongue. So, the injury of the lingual nerve during an anesthesia or surgery in the retromolar area may cause complications such as a numbness, a loss of taste of the tongue and the other dysfunctions. Therefore, to find out the morphology and the course of lingual nerve and to clarify the topographical relationships of lingual nerve at the infratemporal fossa and paralingual space area, 32 Korean hemi-sectioned heads were dissected macroscopically and microscopically with a viewpoint of clinical aspect in this study. This study demonstrated various anatomical characteristics with relation to the course and topography of the lingual nerve in Koreans. And clinical significances based on the anatomical variations through the topography of the courses and communications between the mandibular nerve branches were described in details.
Anesthesia ; Chorda Tympani Nerve ; Gingiva ; Head ; Hypesthesia ; Lingual Nerve* ; Mandibular Nerve ; Mouth Floor ; Mucous Membrane ; Salivary Glands ; Sensation ; Tongue

The sensor of the taste is the taste bud. The signals originated from the taste buds are transmitted to the central nervous system through the gustatory taste nerves. The chorda tympani nerve (innervating the taste buds of the anterior tongue) and glossopharyngeal nerve (innervating the taste buds of the posterior tongue) are the two primary gustatory nerves. The injuries of gustatory nerves cause their innervating taste buds atrophy, degenerate and disappear. The related taste function is also impaired. The impaired taste function can be restored after the gustatory nerves regeneration. The rat model of cross-regeneration of gustatory nerves is an important platform for research in the plasticity of the central nervous system. The animal behavioral responses and the electrophysiological properties of the gustatory nerves have changed a lot after the cross-regeneration of the gustatory nerves. The effects of the injury, regeneration and cross-regeneration of the gustatory nerves on the taste function in the animals will be discussed in this review. The prospective studies on the animal model of cross-regeneration of gustatory nerves are also discussed in this review. The study on the injury, regeneration and cross-regeneration of the gustatory nerves not only benefits the understanding of mechanism for neural plasticity in gustatory nervous system, but also will provide theoretical basis and new ideas for seeking methods and techniques to cure dysgeusia.
Animals ; Chorda Tympani Nerve ; physiology ; Glossopharyngeal Nerve ; physiology ; Nerve Regeneration ; Neuronal Plasticity ; Rats ; Taste ; physiology ; Taste Buds ; physiology ; Tongue ; innervation