BACKGROUND: Cochlear morphology and cochlear duct length (CDL) play important roles in the selection of appropriate electrodes. Cochlear parameters such as diameter (A value) and width (B ...

The objective of this study was to determine the shape of cochlear basal turn through basic cochlear parameters measurement. The secondary aim was to overlay an image of the precurved electrode array on top of the three-dimensional (3D) image of the cochlea to determine which shape of the cochlear basal turn gives optimal electrode-to-modiolus proximity. Computed tomography (CT) preoperative image-data sets of 117 ears were made available for the measurements of cochlear parameters retrospectively. Three-dimensional slicer was used in the visualization and measurement of cochlear parameters from both 3D and 2D (2-dimensional) images of the inner ear. Cochlear parameters including basal turn diameter (A), width of the basal turn (B), and cochlear height (H) were measured from the appropriate planes. B/A ratio was made to investigate which ratios correspond to round and elliptical shape of the cochlear basal turn. The cochlear size as measured by A value ranged between 7.4 mm and 10 mm. The B value and the cochlear height (H) showed a weak positive linear relation with A value. The ratio between the B and A values anything above or below 0.75 could be an indicator for a more round- or elliptical shaped cochlear basal turn, respectively. One sized/shaped commercially available precurved electrode array would not offer a tight electrode-to-modiolus in the cochlea that has an elliptical shaped basal turn as identified by the B/A ratio of <0.75. Accurate measurement of cochlear parameters adds value to the overall understanding of the cochlear geometry before a cochlear implantation procedure. The shape of cochlear basal turn could have clinical implications when comes to electrode-to-modiolus proximity.

The A-value used in cochlear duct length (CDL) estimation does not take malformed cochleae into consideration. The objective was to determine the A-value reported in the literature, to assess the accuracy of the A-value measurement and to evaluate a novel cochlear measurement in distinguishing malformed cochlea. High resolution Computer Tomography images in the oblique coronal plane/cochlear view of 74 human temporal bones were analyzed. The A-value and novel C-value measurement were evaluated as predictors of inner ear malformation type. The proximity of the facial nerve to the basal turn was evaluated subjectively. 26 publications report on the A-value; but they do not distinguish normal vs. malformed cochleae. The A-values of the normal cochleae compared to the cochleae with cochlear hypoplasia, incomplete partition (IP) type I, -type II, and -type III were significantly different. The A-value does not predict the C-value. The C-values of the normal cochleae compared to the cochleae with IP type I and IP type III were significantly different. The proximity of the facial nerve to the basal turn did not relate to the type of malformation. The A-value is different in normal vs. malformed cochleae. The novel C-value could be used to predict malformed anatomy, although it does not distinguish all malformation types.

Background and Objectives: Electrode migration after cochlear implantation (CI) is a rare complication that accounts for 1to 15% of all revision surgery. This study is a systematic review of the literature for investigating the knowledge and approaches to the incidence of electrode migration after CI. Methods: A systematic electronic search of the literature was carried out using PubMed, Cochrane, Virtual Health Library, Scopus and Web of Science (ISI). All original articles that reported electrode migration after CI surgery were included. The Newcastle-Ottawa Scale and CARE checklist were utilized for the assessment of the risk of bias. Descriptive data analysis was performed using SPSS software. Results: A total of 26 studies including 4,316 patients were included. Out of them, 289 patients had electrode migration following CI. To diagnose electrode migration, traditional computed tomography scan was used in 13 studies, while cone-beam computed tomography was applied in three studies. In addition, electrode migration was detected during intraoperative exploration in eight studies. The most common presenting symptom was change in sound/poor performance (n = 43) followed by pain sensation (n = 15) and facial nerve stimulation (n = 10). Cholesteatoma was the most common associated pathology (n = 10) followed by infection (n = 9) and ossification of the basal turn of the cochlea (n = 8). Conclusion: Electrode migration is a major complication of CI and could be more common than previously thought. As it may occur with or without clinical complaints, long-term follow-up through routine radiological scanning is recommended. Further studies are warranted to identify the underlying mechanism of electrode extrusion and the appropriate fixation method.

Objectives: Hemangioma is a common soft tissue tumor that can be categorized mainly into cavernous, capillary, and venous subtypes. It usually develops in the head and neck and rarely in the external auditory canal (EAC). Methods: A systematic review of patients with capillary hemangioma of the EAC was performed. A computerized systematic search was conducted in PubMed, Scopus, and Web of Science to extract relevant studies for a qualitative review. Results: A total of 38 patients were included in the systematic review, and half of them were men. Hearing loss was the most common presenting feature (n = 19; 50%), followed by aural fullness (n = 15; 39.4%). Cavernous hemangioma was the predominant type (n = 22, 57.8%). Endaural and transcanal surgical approaches were the most frequent, with ten (26.3%) and nine (23.6%) cases, respectively. Most of the patients (n = 31; 81.5%) had no recurrence. Conclusions: Hemangioma of the EAC may not be uncommon as healthcare professionals may expect. Hearing loss, aural fullness, and tinnitus are possible symptoms, but many patients remain asymptomatic. Surgical excision is the main effective management option, and complete resolution is the most prevalent outcome. Computed tomography assists in the diagnosis, but histopathological examination after resection is mandatory for the definitive diagnosis.