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BackgroundThe chorda tympani nerve (CTN) is a mixed nerve, which carries sensory and parasympathetic fibres. The sensory component supplies the taste sensation of the anterior two-thirds of the ipsilateral side of the tongue. During middle ear surgery the CTN is exposed and frequently stretched or sacrificed, because it lacks a bony covering as it passes through the middle ear. Injury may cause hypogeusia, ageusia or altered taste sensation of the ipsilateral side of the tongue. To date, there is no consensus regarding which type of CTN injury (sacrificing or stretching), during middle ear surgery, leads to the least burden for the patient.MethodsA double-blind prospective prognostic association study was designed in a single medical centre in the Netherlands to determine the effect of CTN injury on postoperative taste disturbance and quality of life. 154 patients, who will undergo primary stapes surgery or cochlear implantation will be included. The taste sensation, food preferences and quality of life of these patients will be evaluated preoperatively and at one week, six weeks and six months postoperatively using the Taste Strip Test, Electrogustometry, supplementary questionnaire on taste disturbance, Macronutrient and Taste Preference Ranking Task, Appetite, Hunger and Sensory Perception questionnaire and Questionnaire of Olfactory Disorders to assess the association of these outcomes with CTN injury. Evaluation of olfactory function will only take place preoperatively and at one week postoperatively using the Sniffin' Sticks. The patient and outcome assessor are blinded to the presence or absence of CTN injury.DiscussionThis study is the first to validate and quantify the effect of chorda tympani nerve injury on taste function. The findings of this study may lead to evidence-based proof of the effect of chorda tympani injury on taste function with consequences for surgical strategies.Trial registrationNetherlands Trial Register NL9791. Registered on 10 October 2021.

Introduction Otosclerosis is a common cause of acquired conductive hearing loss and can be treated using hearing aids or surgically. Surgical success rates or surgical results are usually reported using pure-tone audiometric thresholds and/or speech discrimination scores. Audiometric results and patient-reported quality of life after stapes surgery do not seem to correlate well. It is therefore our opinion that health-related quality of life measurements should be implemented as an additional outcome measure after stapes surgery. So far, there is a lack of a valid, reliable and clinically feasible measuring tool for determining health-related quality of life in Dutch patients with otosclerosis who undergo stapes surgery.Methods and analysis A prospective validation study was designed to translate and validate the disease-specific Stapesplasty Outcome Test 25 (SPOT-25) in a population of Dutch patients with otosclerosis who undergo primary stapes surgery. A total of 125 patients with otosclerosis who will be undergoing primary stapes surgery and 50 healthy controls will be included. The patients with otosclerosis will fulfil several questionnaires preoperatively, 6 to 8 weeks postoperatively and 8 to 10 weeks postoperatively with a 2-week interval between the postoperative administrations. The patients’ audiometric results, which are measured routinely before and after undergoing primary stapes surgery, will also be used. The healthy controls will fulfil the translated SPOT-25 once. First, the original SPOT-25 will be translated from German to Dutch in a six-step process. Second, the translated SPOT-25 will be pilot-tested in a subset of patients. Lastly, validity, reliability and responsiveness of the translated SPOT-25 will be analysed.Ethics and dissemination The research protocol was approved by the Institutional Review Board of the University Medical Center Utrecht (protocol 18–768/C; V.1, November 2018). Initially, we planned to include 50 patients. At a later stage we decided to increase the sample size to 100 patients. We notified the Institutional Review Board of this change to the protocol. The trial results will be disseminated through peer-reviewed medical journals and presented at scientific conferences.Trial registration number NL7586.

Abstract Background Prednisolone has been suggested as a treatment for olfactory disorders after COVID-19, but evidence is scarce. Hence, we aimed to determine the efficacy of a short oral prednisolone treatment on patients with persistent olfactory disorders after COVID-19. Methods We performed a randomized, double-blind, placebo-controlled, single-centered trial in the Netherlands. Patients were included if they were > 18 years old and if they had persistent (> 4 weeks) olfactory disorders within 12 weeks after a confirmed COVID-19 test. The treatment group received oral prednisolone 40 mg once daily for 10 days and the placebo group received matching placebo. In addition, all patients performed olfactory training. The primary outcome was the objective olfactory function on Sniffin’ Sticks Test (SST) 12 weeks after the start of treatment, measured in Threshold-Discrimination-Identification (TDI) score. Secondary outcomes were objective gustatory function assessed by the Taste Strip Test (TST) and subjective self-reported outcomes on questionnaires about olfactory, gustatory and trigeminal function, quality of life, and nasal symptoms. The CONSORT 2010 guideline was performed. Results Between November 2021 and February 2022, we included 115 eligible patients, randomly assigned to the treatment (n = 58) or placebo group (n = 57). No difference in olfactory function between groups was obtained after 12 weeks. Median TDI score on SST was 26.8 (IQR 23.6-29.3) in the placebo group and 28.8 (IQR 24.0-30.9) in the prednisolone group, with a median difference of - 1.5 (-3.0 to 0.25). There was similar improvement on olfactory function in both groups after 12 weeks. Furthermore, on secondary outcomes, we obtained no differences between groups. Conclusions This trial shows that prednisolone does not improve olfactory function after COVID-19. Therefore, we recommend not prescribing prednisolone for patients with persistent olfactory disorders after COVID-19. Trial registration This trial is registered on the ISRCTN registry with trial ID ISRCTN70794078.

ObjectivesTo investigate the feasibility of the endoscopic approach vs. microscopic approach during stapes surgery, focusing on the visualization of the important anatomical structures of the middle ear, the volume of the resected scutum and chorda tympani (CT) injury.MethodsFresh frozen human cadaveric heads underwent two stapes surgeries using an operating microscope on one ear and an endoscope on the other ear. The surgeon documented the visualization of critical landmarks, as well as exposure and injury of the CT. The volume of resected scutum was evaluated using cone beam computed tomography scanning and three-dimensional imaging.ResultsWe performed endoscopic stapes surgery in 10 ears and microscopic stapes surgery in 11 ears. A stapes prosthesis was placed in all ears. The volume of bony scutum resection was significantly lower in the endoscopic group (median = 2.20 mm3, IQR = 4.17) than in the microscopic group (median 13.25 mm3, IQR = 8.71). No scutum was removed in two endoscopic ears, while scutum was removed in all microscopic ears. The endoscopic and microscopic group had similar CT injury.ConclusionsThis study showed that the endoscopic stapes surgery procedure is feasible and might be less invasive than microscopic stapes surgery. Future clinical prospective and functional studies will be needed to support our findings.

Abstract Objective What are the electrogustometer's (EGM) validity, reliability, and diagnostic accuracy in assessing taste sensation in adults compared to other taste tests? Data Sources PubMed Medline, Elseviers's Embase, and the six databases of Cochrane Library. Methods We conducted a systematic search on December 20, 2022, consisting of synonyms for EGM. We considered randomized controlled trials and observational studies with original data for inclusion if they included adults who underwent electrogustometry. Articles were excluded if no analysis regarding validity, reliability, or diagnostic accuracy had been performed or if these analyses could not be performed with the published data. Results Nineteen articles discussing 18 studies were included for data extraction. The included studies carry a high risk of bias. Overall, the association between a variety of reference taste tests and EGM was moderate or weak with correlation coefficients ranging from −0.51 to 0.40 with one outlier of −0.74 found in one study correlating EGM and taste solutions. Test–retest reliability was good with reported correlation coefficients between 0.78 and 1.0. The sensitivity, specificity, PPV, and NPV of EGM in identifying abnormal taste function varied widely between the four studies on diagnostic accuracy. Conclusion The included studies in this review lack the required standards regarding study design to draw firm conclusions about the validity, reliability, and diagnostic accuracy of the EGM. Future research is needed to assess these measurement properties. Based on the reported results, we would not recommend using the EGM as a screening test for taste disturbance in clinical practice. Level of Evidence NA.