Change of somatosensory function of the tongue caused by chorda tympani nerve disorder after stapes surgery

Background: To investigate whether endoscopic stapes surgery is safer and less invasive than conventional stapes surgery using an operating microscope.Methods: The subjects were 60 patients who were divided consecutively into group A undergoing microscopic stapedotomy and group B undergoing endoscopic stapedotomy. The procedures for endoscopic surgery were fundamentally the same as those for microscopic surgery, except for post aural incision used in some patients in microscopic group. The two surgical techniques were compared with respect to the operating time, approach, drilling of posterosuperior canal, manipulation of chorda tympani, visualisation of anterior crus, postoperative hearing, postoperative pain, and complications. Results: There were no differences of operating time or postoperative hearing between the endoscopic and microscopic groups. There was very little postoperative pain in the endoscopic group. Drilling at the posterosuperior part of the external auditory canal was less extensive in the endoscopic group than in the microscopic group. Visualisation of anterior crus of stapes was good in endoscopic group.Conclusions: Endoscopic stapes surgeries are technically feasible, safe and promising. The main advantages were: easy access, virtually no trauma to the chorda tympani nerve and excellent vision. The disadvantages were the lack of stereoscopic vision, having to work with one hand only and the learning curve.

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Synaptic reformation between salt-sensitive taste cells and axons after denervation of mouse chorda tympani nerve and recovery of behavioral discriminability between sodium and potassium salts

Neuroscience Research ◽

10.1016/s0168-0102(00)80994-3 ◽

2000 ◽

Vol 38 ◽

pp. S24

Author(s):

K Yasumatsu

Keyword(s):

Chorda Tympani ◽

Chorda Tympani Nerve ◽

Potassium Salts ◽

Taste Cells ◽

Sodium And Potassium

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Cell non-autonomous requirement of p75 in the development of geniculate oral sensory neurons

Scientific Reports ◽

10.1038/s41598-020-78816-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tao Tang ◽

Christopher R. Donnelly ◽

Amol A. Shah ◽

Robert M. Bradley ◽

Charlotte M. Mistretta ◽

...

Keyword(s):

Sensory Neurons ◽

Significant Loss ◽

Taste Buds ◽

Neurotrophin Receptor ◽

P75 Neurotrophin Receptor ◽

Chorda Tympani ◽

Chorda Tympani Nerve ◽

Tactile Stimuli ◽

Oral Sensory ◽

Nerve Recordings

AbstractDuring development of the peripheral taste system, oral sensory neurons of the geniculate ganglion project via the chorda tympani nerve to innervate taste buds in fungiform papillae. Germline deletion of the p75 neurotrophin receptor causes dramatic axon guidance and branching deficits, leading to a loss of geniculate neurons. To determine whether the developmental functions of p75 in geniculate neurons are cell autonomous, we deleted p75 specifically in Phox2b + oral sensory neurons (Phox2b-Cre; p75fx/fx) or in neural crest-derived cells (P0-Cre; p75fx/fx) and examined geniculate neuron development. In germline p75−/− mice half of all geniculate neurons were lost. The proportion of Phox2b + neurons, as compared to Phox2b-pinna-projecting neurons, was not altered, indicating that both populations were affected similarly. Chorda tympani nerve recordings demonstrated that p75−/− mice exhibit profound deficits in responses to taste and tactile stimuli. In contrast to p75−/− mice, there was no loss of geniculate neurons in either Phox2b-Cre; p75fx/fx or P0-Cre; p75fx/fx mice. Electrophysiological analyses demonstrated that Phox2b-Cre; p75fx/fx mice had normal taste and oral tactile responses. There was a modest but significant loss of fungiform taste buds in Phox2b-Cre; p75fx/fx mice, although there was not a loss of chemosensory innervation of the remaining fungiform taste buds. Overall, these data suggest that the developmental functions of p75 are largely cell non-autonomous and require p75 expression in other cell types of the chorda tympani circuit.

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Systematic Review and Meta-analysis of Endoscopic vs Microscopic Stapes Surgery for Stapes Fixation

Otolaryngology ◽

10.1177/0194599821990669 ◽

2021 ◽

pp. 019459982199066

Author(s):

Sandra Ho ◽

Prayag Patel ◽

Daniel Ballard ◽

Richard Rosenfeld ◽

Sujana Chandrasekhar

Keyword(s):

Postoperative Complications ◽

Meta Analysis ◽

Stapes Surgery ◽

Chorda Tympani Nerve ◽

Stapes Fixation ◽

Operative Outcomes ◽

Significant Difference ◽

The Mean ◽

Postoperative Vertigo ◽

Hearing Outcomes

Objective To systematically review the current literature regarding the operative outcomes of stapes surgery for stapes fixation via the endoscopic and microscopic approaches. Data Sources PubMed, Embase, and Web of Science. Review Methods An electronic search was conducted with the keywords “endoscop* or microscop*” and “stapes surgery or stapedectomy or stapedotomy or otosclerosis or stapes fixation.” Studies were included if they compared endoscopy with microscopy for stapes surgery performed for stapes fixation and evaluated hearing outcomes and postoperative complications. Articles focusing on stapes surgery other than for stapes fixation were excluded. Results The database search yielded 1317 studies; 12 remained after dual-investigator screening for quantitative analysis. The mean MINORS score was 18 of 24, indicating a low risk of bias. A meta-analysis demonstrated no statistically significant difference between the groups with regard to operative time, chorda tympani nerve manipulation or sacrifice, or postoperative vertigo. There was a 2.6-dB mean improvement in the change in air-bone gap in favor of endoscopic stapes surgery and a 15.2% increased incidence in postoperative dysgeusia in the microscopic group, but the studies are heterogeneous. Conclusions Endoscopic stapes surgery appears to be a reasonable alternative to microscopic stapes surgery, with similar operative times, complications, and hearing outcomes. Superior visibility with the endoscope was consistently reported in all the studies. Future studies should have standardized methods of reporting visibility, hearing outcomes, and postoperative complications to truly establish if endoscopic stapes surgery is equivalent or superior to microscopic stapes surgery.

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Rate of Recovery of Taste Function after Preservation of Chorda Tympani Nerve in Middle Ear Surgery with Special Reference to Type of Disease

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348940311200111 ◽

2003 ◽

Vol 112 (1) ◽

pp. 52-56 ◽

Cited By ~ 33

Author(s):

Masafumi Sakagami ◽

Mieko Sone ◽

Keijiro Fukazawa ◽

Kojiro Tsuji ◽

Yasuo Mishiro

Keyword(s):

Recovery Of Function ◽

Inflammatory Diseases ◽

Chronic Otitis Media ◽

Normal Function ◽

Middle Ear Surgery ◽

Chorda Tympani ◽

Chorda Tympani Nerve ◽

Taste Disturbance ◽

Postoperative Symptoms ◽

Rate Of Recovery

To study the recovery of function of the chorda tympani nerve, we examined by electrogustometry 79 patients (83 ears) with both preoperative normal function of the nerve and operative preservation of the nerve, every 2 days during hospitalization and at 6 months after surgery. For symptoms such as tongue numbness and taste disturbance, patients with noninflammmatory (NI) diseases (13/20 or 65.0%) showed a significantly higher rate of symptoms than did patients with chronic otitis media (COM; 13/35 or 37.1%) at 2 weeks after surgery (p = .032). The patients with NI diseases (5/20 or 25.0%) tended to show a higher rate of symptoms than did the COM patients (2/35 or 5.7%) or cholesteatoma patients (2/28 or 7.1%) at 6 months after surgery. The rate of recovery of the EGM threshold to normal at 2 weeks after surgery was significantly lower in NI disease patients (6/20 or 30.0%) than in COM patients (23/ 35 or 62.9%) or cholesteatoma patients (19/28 or 67.9%; p = .015 and .008, respectively). Thus, the patients with NI diseases had postoperative symptoms and elevation of EGM threshold more frequently than did the patients with inflammatory diseases.

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