The impact of injury of the chorda tympani nerve during primary stapes surgery or cochlear implantation on taste function, quality of life and food preferences:A study protocol for a double-blind prospective prognostic association study

BACKGROUND: The 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.METHODS: A 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.DISCUSSION: This 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 REGISTRATION: Netherlands Trial Register NL9791. Registered on 10 October 2021.</p

Cochlear implant positioning:development and validation of an automatic method using computed tomography image analysis

The aim of this study was to preoperatively asses the feasibility of drilling a bony recess for the fixation of a cochlear implant in the temporal bone. Even though complications are rare with cochlear implantations, drilling at the site of implantation have resulted in hematoma or cerebrospinal fluid leakage. Mainly in cases with a reduced temporal bone thickness, the risk for complications has increased, such as in paediatric patients.Methods An in-house designed semi-automatic algorithm was developed to analyse a 3D model of the skull. The feasibility of drilling the recess was determined by a gradient descent method to search for the thickest part of the temporal bone. Feasibility was determined by the residual bone thickness which was calculated after a simulated drilling of the recess at the thickest position. An initial validation of the algorithm was performed by measuring the accuracy of the algorithm on five 3D models with known thickest locations for the recess. The accuracy was determined by a part comparison between the known position and algorithm provided position.Results In four of the five validation models a standard deviation for accuracy below the predetermined cut-off value of 4.2 mm was achieved between the actual thickest position and the position determined by the algorithm. Furthermore, the residual thickness calculated by the algorithm showed a high agreement (max. 0.02 mm difference) with the actual thickness.Conclusion With the developed algorithm, a semi-automatic method was created to analyse the temporal bone thickness within a specified region of interest on the skull. Thereby, providing indications for surgical feasibility, potential risks for anatomical structures and impact on procedure time of cochlear implantation. This method could be a valuable research tool to objectively assess feasibility of drilling a recess in patients with thin temporal bones preoperatively

Cochlear implant positioning: development and validation of an automatic method using computed tomography image analysis

The aim of this study was to preoperatively asses the feasibility of drilling a bony recess for the fixation of a cochlear implant in the temporal bone. Even though complications are rare with cochlear implantations, drilling at the site of implantation have resulted in hematoma or cerebrospinal fluid leakage. Mainly in cases with a reduced temporal bone thickness, the risk for complications has increased, such as in paediatric patients.MethodsAn in-house designed semi-automatic algorithm was developed to analyse a 3D model of the skull. The feasibility of drilling the recess was determined by a gradient descent method to search for the thickest part of the temporal bone. Feasibility was determined by the residual bone thickness which was calculated after a simulated drilling of the recess at the thickest position. An initial validation of the algorithm was performed by measuring the accuracy of the algorithm on five 3D models with known thickest locations for the recess. The accuracy was determined by a part comparison between the known position and algorithm provided position.ResultsIn four of the five validation models a standard deviation for accuracy below the predetermined cut-off value of 4.2 mm was achieved between the actual thickest position and the position determined by the algorithm. Furthermore, the residual thickness calculated by the algorithm showed a high agreement (max. 0.02 mm difference) with the actual thickness.ConclusionWith the developed algorithm, a semi-automatic method was created to analyse the temporal bone thickness within a specified region of interest on the skull. Thereby, providing indications for surgical feasibility, potential risks for anatomical structures and impact on procedure time of cochlear implantation. This method could be a valuable research tool to objectively assess feasibility of drilling a recess in patients with thin temporal bones preoperatively

Variability in surgical techniques for cochlear implantation: an international survey study

Objective: This study aimed to gain insight into current practices regarding the surgical techniques used for positioning and fixation of internal components of the cochlear implant. Methods: A questionnaire focused on surgical techniques used for cochlear implantation was distributed among 441 cochlear implant surgeons. Descriptive statistics were reported. Results: The questionnaire was completed by 59 surgeons working in 13 different countries. The most preferred incision shapes were the S-shape (41%) and the C-shape (36%). The preferred implantation angle for the receiver/stimulator device was either 45° (64%) or 60° (30%), relative to the Frankfurter Horizontal Plane. Most respondents used a drilled bony well with (42%) or without a subperiosteal pocket (31%) to fixate the receiver/stimulator device. All respondents used the facial recess approach. Most used the round window insertion technique to enter the scala tympani (73%). Approximately half of the respondents preferred the lateral wall electrode array, whereas the other half preferred the perimodiolar electrode array. During their career, most (86%) changed their technique towards structure preservation and minimizing trauma. Conclusion: This study indicates variability in the surgical techniques used to position and fixate the internal components of the cochlear implant. Additionally, surgical preference transits towards structure preservation and minimal invasiveness

Cochlear Implant Fixation Techniques: A Systematic Review of the Literature

OBJECTIVE: Given the lack of consensus on fixation techniques of the cochlear implant, this review aims to create an up-to-date overview of intra- and postoperative complications, focusing on migration of the internal receiver/stimulator (R/S) device and the electrode array. DATA SOURCES: On June 29, 2020 we conducted a search in PubMed, Embase, Cochrane, Web of Science, and CINAHL. Keywords were "Cochlear implant," "complication," "migration," and synonyms. STUDY SELECTION: Studies were considered if: 1) the adult study population consisted of ≥ 10 patients, 2) the R/S device was fixated using the bony well or tight subperiostal pocket technique without bone-anchoring sutures or screws on the implant, and 3) migration of the R/S device or displacement of the electrode array were described as outcomes. DATA EXTRACTION: Study characteristics, interventions, follow-up, and outcomes were extracted. For critical appraisal, an adapted version of the Newcastle-Ottawa quality assessment scale for cohort studies was used. DATA SYNTHESIS: Seven studies were included (n = 430 patients). Migration of the R/S device was reported by three studies. Two studies applying the tight pocket technique reported migration rates ranging from 9.0 to 69.2%. One study using the bony bed technique reported migration of 100%, with an average of 2.5 mm. All studies lacked the required standard for comparability, assessment of outcome, and follow-up. CONCLUSIONS AND RELEVANCE: There is currently no evidence of a difference between the bony bed- and tight pocket fixation technique, regarding migration of the R/S device or the electrode array, in adult patients

Cochlear Implant Receiver Location and Migration: Experimental Validation Pilot Study of a Clinically Applicable Screening Method

Objectives: Postoperative follow-up after cochlear implantation lacks a reliable screening method to detect cochlear implant receiver device migration. This study aims to validate a clinically applicable method to assess the position and migration of the cochlear implant receiver device. Study design: Validation study. Setting: Tertiary university medical center. Participants and method: To assess the cochlear implant receiver device location, round markers representing the external magnet were placed on both sides of the head of volunteers. Four independent clinicians took measurements of the distances between reference points on the head and the center of the marker. The reference points were: the lateral canthus (LC), tragus tip (TT), the mastoid angle (MA), and the mandibular angle (AM). Main outcome measures: The inter-clinician reliability was determined by calculating the intraclass correlation coefficient (ICC) and confidence interval (CI) with a two-way mixed model and both consistency and absolute agreement types for each distance. Results: Eight volunteers were included resulting in 16 individual cases. The consistency type ICC's for each reference point were: LC 0.90 (CI = 0.80, 0.96), TT 0.83 (CI = 0.69, 0.93), MA 0.75 (CI = 0.56, 0.89), and AM 0.29 (CI = 0.05, 0.59). The absolute agreement ICC's were: LC 0.87 (CI = 0.73, 0.95), TT 0.83 (CI = 0.68, 0.93), MA 0.68 (CI = 0.42, 0.86), and AM 0.18 (CI = 0.01, 0.46). The inter-clinician reliability was good to excellent for the lateral canthus and tragus tip reference points. Conclusions: The cochlear receiver device location can be assessed reliably by measuring the distance between the LC, TT, and the external magnet. This method can be used to registrate implant receiver location after implantation and detect implant migration postoperatively

Angina Bullosa Hemorrhagica: Post-traumatic Swelling in the Oral Cavity-A Case Report

Contains fulltext : 220019.pdf (Publisher’s version ) (Open Access

Click Stimulus Electrocochleography Versus MRI With Intratympanic Contrast in Meniere's Disease: A Systematic Review

Objective: To evaluate the diagnostic value of electrocochleography compared with magnetic resonance imaging (MRI) with intratympanic gadolinium administration to diagnose endolymphatic hydrops in patients with Ménière's disease. Data Sources: An electronic search was performed in the PubMed, EMBASE, and Cochrane databases on September 15, 2015. A systematic search was conducted. Articles were included if written in English, Dutch, German, or French language. Study Selection: Original studies reporting on the diagnostic value of electrocochleography compared with MRI with intratympanic gadolinium administration, were included. Data Extraction: The methodological quality of the studies was independently assessed by two reviewers using an adjusted version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. The results of the diagnostic values of both tests were extracted. Data Synthesis: We performed analyses for the sensitivity, specificity, positive predictive value, and negative predictive value of compared electrocochleography with MRI with intratympanic gadolinium administration in patients with definite Ménière's disease. Conclusion: The results of this systematic review, based on a very low number of patients, show there is a relative low sensitivity and negative predictive value for click stimulus electrocochleography compared with MRI with intratympanic gadolinium administration for detecting endolymphatic hydrops in patients with definite Ménière's disease