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/OBJECTIVES: Taste perception is influenced by both nutritional factors and psychological factors. This study was undertaken to measure the 4 basic taste perceptions, nutrient intake, and mental health, and to examine the factors that affect insensitive taste perception in young Japanese women. SUBJECTS/METHODS: Young women in their late teens and twenties were enrolled as subjects. Taste perception was measured by applying the filter-paper disc method over areas of the chorda tympani nerve. Nutritional status was evaluated using brief, self-administered diet history questionnaires. The index of nutritional status was based on the 2015 Japanese dietary reference intakes. Mental health was assessed using the Japanese translation of the Profile of Mood States short version. This study was approved by the ethical committee at Osaka University. RESULTS: The normal taste perception group (four basic tastes [sweet, salty, sour, and bitter] identified as normal taste perception) comprised 55.4% of the subjects, while the abnormal taste perception group (more than 1 abnormal taste perception was perceived, regardless of flavor) comprised 44.6% of the subjects. There were no significant differences in nutrient intake (except manganese) and mental health between the normal and abnormal taste perception groups. Subjects who took 5 mg to less than 7.1 mg zinc per day were at significantly decreased risk of insensitive taste perception compared to subjects who consumed less than 5 mg zinc per day [Regression coefficient 0.831, 95% confidence interval 0.694–0.996]. CONCLUSION: The present results suggest that insensitive taste perception could be associated with zinc deficiency in young women in their late teens and twenties.
Adolescent ; Asian Continental Ancestry Group ; Chorda Tympani Nerve ; Diet ; Female ; Humans ; Mental Health ; Methods ; Nutritional Status ; Psychology ; Recommended Dietary Allowances ; Taste Perception ; Zinc

OBJECTIVE: To explore the characteristic changes of the peripheral chorda tympanic nerve (CT) electrophysiological responses to salty stimulus and other taste stimuli in rats with the conditioned taste aversion to saltiness. METHODS: Fourteen adult SD male rats were divided into a conditioned taste aversion to salty group (CTA) and a control group (Ctrl) (n=7/group). On the first day of the experiment, rats were given a 0.1 mol/L NaCl intake for 30 min, then, the rats in CTA and Ctrl groups were injected intraperitoneally with 2 ml of 0.15 mol/L LiCl and the same amount of saline respectively. On day 2, 3 and 4, the 30 min consumption of NaCl and distilled water was measured for both groups of rats. On the 4th day after the behavioral test of that day, CT electrophysiological recording experiments were performed on CTA rats and control rats. RESULTS: Compared with the rats in Ctrl group, the electrophysiological characteristics of CT in CTA group rats did not change significantly the responses to the series of NaCl and other four basic taste stimuli (P＞0.05). The amiloride, the epithelial sodium channel blocker, strongly inhibited the response of CT to NaCl in CTA and Ctrl group rats (P＜0.01). CONCLUSION The electrophysiological responses of CT to various gustatory stimuli do not significantly change in rats after the establishment of conditional taste aversion to the saltiness.
Amiloride ; pharmacology ; Animals ; Chorda Tympani Nerve ; physiology ; Conditioning, Classical ; Electrophysiological Phenomena ; Male ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride ; Taste ; physiology

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*

Adolescent ; Child ; Child, Preschool ; Chorda Tympani Nerve ; diagnostic imaging ; surgery ; Cochlear Implantation ; methods ; Female ; Humans ; Male ; Radiography ; Young Adult

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

OBJECTIVE: To investigate the effect of hyalinized chorda tympani nerve canal in mastoid segment to landmark facial nerve in middle ear surgery by means of observing the location relationship between hyalinized chorda tympani nerve canal and facial nerve. METHOD: 118 cases of cholesteatoma otitis media in our hospital undergoing tympanoplasty from 2008 to 2011 were retrospectively analyzed. In all the cases, the position of horizontal semicircular and fossa incus as well as the hyalinized chorda tympani nerve canal were used for landmark the height of facial ridge and vertical segment of facial nerve. RESULT: The chorda tympani nerve of 99 patients were higher than the vertical segment of the facial nerve which were not exposed, and the vertical segment of the facial nerve in 9 patients, which were exposed, were 1-2 mm lower and 2-3 mm ahead or backward than the chorda tympani nerve. The horizontal semicircular and fossa incus were broken in 9 patients, of whom the vertical segments of the facial nerve were 1-2 mm lower and 2-3 mm ahead or backward than the chorda tympani nerve. The chorda tympani nerve of 1 patient were lower than the exposed vertical segment of facial nerve. CONCLUSION The hyalinized chorda tympani nerve canal in mastoid segment can landmark the positon of facial ridge, and it would be the complement to the traditional method of landmarking vertical segment of facial nerve, especially for those whose horizontal semicircular canal and fossa incus had been broken.
Adult ; Aged ; Cholesteatoma, Middle Ear ; surgery ; Chorda Tympani Nerve ; surgery ; Female ; Humans ; Male ; Mastoid ; surgery ; Middle Aged ; Otologic Surgical Procedures ; methods ; Retrospective Studies ; Young Adult

Posterior tympanotomy is a procedure performed to access the posterior mesotympanum through a mastoid exposure while preserving the posterior external auditory canal wall. It is dangereous to drill the the site of procedure, as it is surrounded by incuidal fossa superiorly, facial nerve posteriomedially, and chorda tympani nerve anterolaterally, and forms a very narrow pathway. There is always a risk of surgical trauma involving important surgical structures, especially facial nerve and chorda tympani nerve. The development of image-guided surgery (IGS) has significantly improved the performance of many surgical procedures by aiding the identification of surgical landmarks, improving surgical outcomes, rendering the procedure safer and more efficient, especially for beginner otologic surgery, in revision operations, in cases of massive bleeding and tumor of complex anatomy. To see how IGS could help otologic surgeons to identify fine, important structures during posterior tympanotomy, we report a case of posterior tympanotomy in chronic otitis media, which was done using the image-guided surgical technique.
Chorda Tympani Nerve ; Ear Canal ; Facial Nerve ; General Surgery ; Hemorrhage ; Mastoid ; Otitis Media* ; Otitis* ; Surgery, Computer-Assisted ; Wounds and Injuries

OBJECTIVE: To investigate the related parameters of temporal bone structure in the surgery of cochlear implantation through facial recess approach so as to offer a theoretical reference for the avoidance of facial nerve injury and the accurate localization. METHOD: In a surgical simulation experiment, twenty human temporal bones were studied. The correlation parameters were measured under surgical microscope. RESULT: Distance between suprameatal spine and short process of incus was (12.44 +/- 0.51) mm. Width from crotch of chorda tympani nerve to stylomastoid foramen was (2.67 +/- 0.51) mm. Distance between short process of incus and crotch of chorda tympani nerve was (15.22 +/- 0.83) mm. The location of maximal width of the facial recess into short process of incus, crotch of chorda tympani nerve were (6.28 +/- 0.41) mm, (9.81 +/- 0.71) mm, respectively. The maximal width of the facial recess was (2.73 +/- 0.20) mm. The value at level of stapes and round window were (2.48 +/- 0.20 mm) and (2.24 +/- 0.18) mm, respectively. Distance between pyramidalis eminence and anterior round window was (2.22 +/- 0.21) mm. Width from stapes to underneath round window was (2.16 +/- 0.14) mm. CONCLUSION These parameters provide a reference value to determine the position of cochlear inserting the electrode array into the scale tympani and opening facial recess firstly to avoid potential damage to facial nerve in surgery.
Anatomic Landmarks ; anatomy & histology ; Chorda Tympani Nerve ; anatomy & histology ; Cochlea ; anatomy & histology ; Cochlear Implantation ; methods ; Ear, Middle ; Facial Nerve Injuries ; prevention & control ; Humans ; Incus ; anatomy & histology ; Organ Sparing Treatments ; methods ; Round Window, Ear ; anatomy & histology ; Stapes ; anatomy & histology ; Temporal Bone ; anatomy & histology ; Tympanic Membrane ; anatomy & histology

OBJECTIVE: To report the way for searching the chorda tympani nerve and the significance for preserving the chorda tympani nerve during canal-wall-down mastoidectomy and tympanoplasty surgery. METHOD: Sixty-six cases with chronic suppurative otitis media underwent canal-wall-down mastoidectomy and tympanoplasty surgery. According to the marker of the short crus of incus, the posterior wall of auditory canal was lowered and crista of the chorda tympani nerve was found through tracing the facial nerve contour. The chorda tympani nerve was preserved after clearing the surrounding tissue. RESULT: Among the 66 cases, 24 cases had middle ear cholesteatoma, 42 cases had granulation in middle ear. The cholesteatoma and granulation on the surface of the chorda tympani nerve were cleared thoroughly. No neurotmesis or obvious change of taste occurred after operation. CONCLUSION Canal-wall-down mastoidectomy and tympanoplasty surgery preserving chorda tympani nerve integrality may preserve the structure and function of the chorda tympani nerve, reduce the risk of ossicle extrusion above the head of stapes and serve as a frame for transplanting fascia.
Adolescent ; Adult ; Aged ; Cholesteatoma, Middle Ear ; surgery ; Chorda Tympani Nerve ; surgery ; Female ; Humans ; Mastoid ; surgery ; Middle Aged ; Otitis Media, Suppurative ; surgery ; Tympanoplasty ; methods ; Young Adult