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Regression analysis comparing BTL with 2TL (n = 68) using a straight line equation y = mx + b. R2 = 0.92, p = 0.018.
Source publication
Hypothesis:
Using a linear measurement of the cochlea on a single radiographic image can reliably estimate the complete and two-turn cochlear duct length (CDL) in a normal human temporal bone.
Background:
CDL is measured from the middle of the round window to the helicotrema. Histologic studies have shown the length of the organ of Corti (OC) to...
Contexts in source publication
Context 1
... measurements of CDL were performed at the level of the OC. The results are shown in Figures 3 and 4, where Figure 3 shows the relationship of the basal turn length (BTL) to CDL (oc) and Figure 4 shows the relationship of BTL to 2TL. For CDL, the regression analysis yielded an equation CDL = 1.71(BTL) + 0.18, with an r 2 value of 0.79 ( p = 0.086) (Fig. 3). ...
Context 2
... OC. The results are shown in Figures 3 and 4, where Figure 3 shows the relationship of the basal turn length (BTL) to CDL (oc) and Figure 4 shows the relationship of BTL to 2TL. For CDL, the regression analysis yielded an equation CDL = 1.71(BTL) + 0.18, with an r 2 value of 0.79 ( p = 0.086) (Fig. 3). For 2TL, the regression analysis yielded an (Fig. ...
Citations
... Disparities in cochlear volume [6], combined with individual anatomical variations in the normal cochlea, directly influence its size and length. Histologic studies report discrepancies in the length of the organ of Corti that range from 25 to 35 mm [7]. Consequently, selecting an optimal electrode requires the use of a transparent and reliable tool, for assisting the surgeon in scrutinizing the inner ear's morphology and precisely measuring cochlear dimensions. ...
Auditory impairment stands as a pervasive global issue, exerting significant effects on individuals’ daily functioning and interpersonal engagements. Cochlear implants (CIs) have risen as a cutting-edge solution for severe to profound hearing loss, directly stimulating the auditory nerve with electrical signals. The success of CI procedures hinges on precise pre-operative planning and post-operative evaluation, highlighting the significance of advanced three-dimensional (3D) inner ear reconstruction software. Accurate pre-operative imaging is vital for identifying anatomical landmarks and assessing cochlear deformities. Tools like 3D Slicer, Amira and OTOPLAN provide detailed depictions of cochlear anatomy, aiding surgeons in simulating implantation scenarios and refining surgical approaches. Post-operative scans play a crucial role in detecting complications and ensuring CI longevity. Despite technological advancements, challenges such as standardization and optimization persist. This review explores the role of 3D inner ear reconstruction software in patient selection, surgical planning, and post-operative assessment, tracing its evolution and emphasizing features like image segmentation and virtual simulation. It addresses software limitations and proposes solutions, advocating for their integration into clinical practice. Ultimately, this review underscores the impact of 3D inner ear reconstruction software on cochlear implantation, connecting innovation with precision medicine.
... The normal anatomy of the inner ear varies in size (36). Although assessing the preoperative images for cochlear size measurement is an effort, considering the concept that one length electrode would fit every cochlea will result in different insertion depths in the cochlea of different sizes ( Figures 3A-C). ...
The optimal placement of a cochlear implant (CI) electrode inside the scala tympani compartment to create an effective electrode–neural interface is the base for a successful CI treatment. The characteristics of an effective electrode design include (a) electrode matching every possible variation in the inner ear size, shape, and anatomy, (b) electrically covering most of the neuronal elements, and (c) preserving intra-cochlear structures, even in non-hearing preservation surgeries. Flexible electrode arrays of various lengths are required to reach an angular insertion depth of 680° to which neuronal cell bodies are angularly distributed and to minimize the rate of electrode scalar deviation. At the time of writing this article, the current scientific evidence indicates that straight lateral wall electrode outperforms perimodiolar electrode by preventing electrode tip fold-over and scalar deviation. Most of the available literature on electrode insertion depth and hearing outcomes supports the practice of physically placing an electrode to cover both the basal and middle turns of the cochlea. This is only achievable with longer straight lateral wall electrodes as single-sized and pre-shaped perimodiolar electrodes have limitations in reaching beyond the basal turn of the cochlea and in offering consistent modiolar hugging placement in every cochlea. For malformed inner ear anatomies that lack a central modiolar trunk, the perimodiolar electrode is not an effective electrode choice. Most of the literature has failed to demonstrate superiority in hearing outcomes when comparing perimodiolar electrodes with straight lateral wall electrodes from single CI manufacturers. In summary, flexible and straight lateral wall electrode type is reported to be gentle to intra-cochlear structures and has the potential to electrically stimulate most of the neuronal elements, which are necessary in bringing full benefit of the CI device to recipients.
... Dabei ist die interindividuelle Streubreite erheblich, im eigenen Krankengut variierte die CDL zwischen 30,4-40,2 mm mit im Mittel 36,2 ± 1,8 mm [12]. In der Vergangenheit sind hier unterschiedliche Messverfahren zum Einsatz gekommen, heutzutage ist es möglich über die Software "OTOPLAN" von CAScination [14], basierend auf den Untersuchungen von Alexiades [15], relativ einfach die Felsenbeinanatomie präoperativ anhand von CT-/MRT-Bildern dreidimensional darzustellen, einzelne Parameter auszumessen und damit die Größe der Cochlea abzuschätzen sowie einzelne operationsrelevante Details zu betrachten. OTOPLAN Schonende OP-Techniken: "Hearing and Structure Preservation Techniques" ...
Cochlear implantation is the gold standard of hearing rehabilitation for patients with severe to profound sensorineural hearing loss. Cochlear Implants (CI) are nowadays essential for these patients. Adapted to rapid developments and the resulting expansion of indications, the implantation principles have consequently been subtly refined and further developed. For the established indications like bimodal or bilateral CI care and CI for single-sided deafness, the detailed developments that raised primarily from the observations that residual hearing after the procedure can be preserved. This also played a significant role in the diversification of Cochlear Implantation. Since the audiological criteria for cochlear implants have also been expanded due to the results achieved with the CI compared to optimal fitted hearing aids, CI´s are also suitable for patients with, in some cases, substantial, residual hearing. This current overview summarizes developments that are receiving more attention and increasing application in everyday clinical practice.
... • The Adopted Escudé formula [15] The Escudé formula, in its original form, relies on the cochlear diameter (A) to project the length of the cochlear lateral wall at various angles (Ɵ). The formula adopted for predicting electrode insertion length, as integrated into the software, presupposes that the lateral wall electrode is positioned beneath the organ of Corti, specifically 0.5 mm from the lateral wall. ...
Introduction
Round window approach and cochleostomy approach can have different depth of electrode insertion during cochlear implantation which itself can alter the audiological outcomes in cochlear implant.
Objective
The current study was conducted to determine the difference in the depth of electrode insertion via cochleostomy and round widow approach when done serially in same temporal bone.
Methodology
This is a cross-sectional study conducted in the Department of Otorhinolaryngology in conjunction with Department of Anatomy and Department of Diagnostic and Interventional Radiology over a period of 1 year. 12-electrode array insertion was performed via either approach (cochleostomy or round window) in the cadaveric temporal bone. HRCT temporal bone scan of the implanted temporal bone was done and depth of insertion and various cochlear parameters were calculated.
Result
A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892 mm; the alpha and beta angles were 58.175° and 8.350°, respectively. The mean angular depth of electrode insertion via round window was found to be 325.2° (SD = 150.5842) and via cochleostomy 327.350 (SD = 112.79) degree and the mean linear depth of electrode insertion via round window was found to be 18.80 (SD = 4.4962) mm via cochleostomy 19.650 (SD = 3.8087) mm, which was calculated using OTOPLAN 1.5.0 software. There was a statically significant difference in linear depth of insertion between round window and cochleostomy. Although the angular depth of insertion was higher in CS group, there was no statistically significant difference with round window type of insertion.
Conclusion
The depth of electrode insertion is one of the parameters that influences the hearing outcome. Linear depth of electrode insertion was found to be more in case of cochleostomy compared to round window approach (p = 0.075) and difference in case of angular depth of electrode insertion existed but not significant (p = 0.529).
... This measure is similar to the cochlear width (long) parameter in the present study. Alexiades et al. [12] used the A value to calculate the basal and middle turns only (2TL) instead of the cochlear duct length because they found a significant correlation between the diameter of the basal turn (A) and 2TL, and 2TL varied less than the cochlea duct length [12,13]. The apical region is more Jun/Song variable; thus, its contribution to cochlear duct length renders assessments less accurate than estimation of the 2TL alone. ...
... This measure is similar to the cochlear width (long) parameter in the present study. Alexiades et al. [12] used the A value to calculate the basal and middle turns only (2TL) instead of the cochlear duct length because they found a significant correlation between the diameter of the basal turn (A) and 2TL, and 2TL varied less than the cochlea duct length [12,13]. The apical region is more Jun/Song variable; thus, its contribution to cochlear duct length renders assessments less accurate than estimation of the 2TL alone. ...
b> Introduction: Preoperative evaluation of cochlear morphology is important for successful cochlear implantation. This study analyzed the cochlear canal by three-dimensional reconstructions of temporal bones using computed tomography (CT). Methods: Fifty temporal bones from 25 patients aged 42–74 years were evaluated. The inner spaces of the bony cochlea were reconstructed using a surface rendering technique on the CT images. Eight angular points (P0–P7) every 90° were selected from 0° to 630° from the center of the round window using the reconstructed cochlear canal images. The radius (R) and thickness (T) of the cochlear canal at each point were measured. The cochlear canal length (CoCL) was estimated using an equation based on the radius at each point. The cochlear width and height based on multiplanar CT images were also measured and compared with the length and volume of the cochlear canal. Results: The mean CoCL from 0° to 630° was 31.5 mm, and the cochlear volume was 55.9 mm<sup>3</sup>. The CoCL to P7 was correlated with the cochlear volume ( r = 0.77), coiling ratios (R4/R0, r = 0.47; R5/R1, r = 0.384), cochlear width (long) ( r = 0.539), cochlear height ( r = 0.385), and total thickness at each point ( r = 0.475). The cochlear volume was correlated with CoCL (630°) ( r = 0.77), coiling ratio (R4/R0, r = 0.367), cochlear width (long) ( r = 0.616), cochlear height ( r = 0.447), and total T ( r = 0.566). Conclusion: Preoperative evaluation using three-dimensional reconstruction can elucidate the size and shape of the cochlear canal before cochlear implantation.
... Currently, the most clinically viable methods to estimate the CDL www.nature.com/scientificreports/ and angular insertion depth are dependent only on cochlear basal turn parameters, which can be measured by different methods described in the literature [12][13][14][15] . The basal turn of the cochlea, while readily identifiable, does not provide a comprehensive representation of the cochlear structure due to its highly variable nature among individuals 16 . ...
Estimating insertion depth, cochlear duct length (CDL), and other inner ear parameters is vital to optimizing cochlear implantation outcomes. Most current formulas use only the basal turn dimensions for CDL prediction. In this study, we investigated the importance of the second turn parameters in estimating CDL. Two experienced neuro-otologists blindly used segmentation software to measure (in mm) cochlear parameters, including basal turn diameter (A), basal turn width (B), second-turn diameter (A2), second-turn width (B2), CDL, first-turn length, and second-turn length (STL). These readings were taken from 33 computed tomography (CT) images of temporal bones from anatomically normal ears. We constructed regression models using A, B, A2, and B2 values fitted to CDL, two-turn length, and five-fold cross-validation to ensure model validity. CDL, A value, and STL were longer in males than in females. The mean B2/A2 ratio was 0.91 ± 0.06. Adding A2 and B2 values improved CDL prediction accuracy to 86.11%. Therefore, we propose a new formula for more accurate CDL estimation using A, B, A2, and B2 values. In conclusion, the findings of this study revealed a notable improvement in the prediction of two-turn length (2TL), and CDL by clinically appreciable margins upon adding A2 and B2 values to the prediction formulas.
... It is necessary to enter the electrode array model according to its length, Flex28 in the present study, and the software automatically identifies the central points of each of the electrodes, giving them a central frequency according to the position, as well as the degree of insertion and the length in millimeters reached by each of them. For the calculation of central tonotopic frequencies, as already described by Mertens et al. (2022), the software initially uses the equations of Alexiades et al. (2015) and the elliptic-circular approximation method to estimate the complete and two-turn cochlear duct length (Schurzig et al., 2018), to calculate the total length of the organ of Corti and the depth of insertion of the electrode along the length of the organ of Corti (θ). These parameters are applied to the Greenwood function to calculate the tonotopic center frequencies (Hz) for each electrode contact (Canfarotta et al., 2019). ...
Introduction
Personalization of treatment is a growing trend in various fields of medicine, and this includes cochlear implantation. Both the precise choice of the length and shape of the electrode array to fit a particular cochlear anatomy, as well as an individualized fitting setting have been suggested to improve hearing outcomes with a cochlear implant (CI). The aim of this study was to compare anatomy-based fitting (ABF) vs. default fitting in terms of frequency-to-place mismatch, speech discrimination, and subjective outcomes in MED-EL CI users.
Methods
Eight adult CI users implanted with a Synchrony ST Flex28 were enrolled prospectively. Insertion depth and tonotopic distribution of each electrode was calculated using the Otoplan software. The mismatch was calculated for each fitting strategy relative to the electrodes' tonotopic place-frequency. Speech tests and patient preference was evaluated after 9 months with ABF and 1 month after default fitting.
Results
Median angular insertion of the most apical active electrode was 594° (interquartile range 143°). ABF showed lower mismatches than default fitting in all patients (p ≤ 0.01). Mean speech discrimination score with ABF and default fitting was 73 ± 11% and 72 ± 16%, respectively ( p = 0.672). Mean speech reception threshold with ABF and default fitting was 3.6 ± 3.4 dB and 4.2 ± 5.0 dB, respectively ( p = 0.401). All patients except one preferred ABF when they were asked about their preference.
Conclusion
ABF maps have a lower frequency-to-place mismatch than default fitting maps. In spite of similar hearing outcomes most patients prefer ABF. More data are necessary to corroborate the benefit of the ABF over default fitting in speech and subjective tests.
... HRCT was utilized to measure the CDL utilizing the formula proposed by Alexiades et al. 11 CDL=(4.16A)-4. Cochlear Length (A) (CLA), was measured from the center of round window to the most distant point on the wall of cochlea on the opposite site i.e., helicotrema, which passed through modiolus. ...
Objectives
To analyze the gender, age and side association of cochlear duct length in Pakistani-Asian cochlear implant recipient population based on computed tomography imaging study.
Methods
Current study retrospectively studied charts of cases who underwent cochlear implantation at the Department of Otolaryngology & Auditory Implant Centre, Capital Hospital Islamabad, over a period of two years from 1st May 2017 to 30th April 2019. These included 200 cases of both genders and of any age. In addition to basic demographic data, computed tomography findings of the temporal bone were utilized to measure the cochlear duct length. Data was analyzed using SPSS Version 23.
Results
Study revealed a mean Cochlear duct length of 29.935±2.173mm (range: 25.12 to 37.60) with significant (p<0.001) association with gender with longer cochlear duct in males compared to females on right (30.50±2.384 vs. 29.36±1.887) and on left side (30.50±2.236 vs.29.32±1.935). However, no significant difference was noted for side with slightly longer cochlear duct on the right side compared to left (29.95±2.224 vs.29.92±2.171). Also, no significant association with age was noted with p=0.578 & p=0.824 for right and left side respectively.
Conclusion
Pakistani population is characterized by a short mean CDL of 29.935±2.173 mm with significant association (p<0.001) with gender with longer cochlear duct length in males; and side with larger CDL on right side. However, no significant association with age was noted.
... HRCT was utilized to measure the CDL utilizing the formula proposed by Alexiades et al. 11 CDL=(4.16A)-4. Cochlear Length (A) (CLA), was measured from the center of round window to the most distant point on the wall of cochlea on the opposite site i.e., helicotrema, which passed through modiolus. ...
There is growing evidence of prescribing sodium glucose co-transporters-2 inhibitor (SGLT-2) to patients with/at high risk of atherosclerotic cardiovascular disease as first-line (instead of metformin). This is the first meta-analysis to compare SGLT-2 inhibitors regarding the same. We aimed to compare SGLT-2 inhibitors and metformin regarding heart failure, acute coronary syndrome, and ischemic stroke. We systematically searched PubMed and Cochrane Library for relevant articles from the first article up to August 2022. The following keywords were used: Metformin, Salt glucose co-transporters inhibitors, SGLT-2 inhibitors, empagliflozin, dapagliflozin, canagliflozin, and first-line. The retrieved data were exported to an excel sheet detailing the author’s names, the country of origin of the study, the number of patients and control subjects, the study duration, and the total number of events in the interventional and exercise groups.
Out of 108 articles screened, only three studies fulfilled the inclusion criteria, a databased study, and two cohorts with 10309 events and 86487 patients. The present meta-analysis showed that SGLT-2 inhibitors had lower rates of heart failure (odd ratio, 1.51, 95% CI, 1.10-2.08) and myocardial infarction (odd ratio, 1.45, 95% CI, 1.08-1.96) than metformin with a similar rate of stroke (odd ratio, 1.03, 95% CI, 0.66-1.61). Significant heterogeneity was observed. Sodium-glucose co-transporter inhibitors-2 as first-line therapy showed a lower heart failure and myocardial infarction compared to metformin. No significant difference was found between the two drugs regarding ischemic stroke. Further larger studies comparing the adverse event are needed.
... OTOPLAN adeptly localizes the modiolus, round window, and cochlear boundaries to calculate the CDL at the organ of Corti level, utilizing the elliptic-circular approximation (ECA) method [25]. Historically, CDL estimation has been approached through various methods, including direct and indirect strategies and 3D reconstructions, each employing a calculation of spiral coefficients with differing accuracy levels [26,27]. ...
The cochlear implant (CI) is a widely accepted option in patients with severe to profound hearing loss receiving limited benefit from traditional hearing aids. CI surgery uses a default setting for frequency allocation aiming to reproduce tonotopicity, thus mimicking the normal cochlea. One emerging instrument that may substantially help the surgeon before, during, and after the surgery is a surgical planning software product developed in collaboration by CASCINATION AG (Bern,
Switzerland) and MED-EL (Innsbruck Austria). The aim of this narrative review is to present an overview of the main features of this otological planning software, called OTOPLAN®. The literature was searched on the PubMed andWeb of Science databases. The search terms used were “OTOPLAN”, “cochlear planning software” “three-dimensional imaging”, “3D segmentation”, and “cochlear implant” combined into different queries. This strategy yielded 52 publications, and a total of 31 studies were included. The review of the literature revealed that OTOPLAN is a useful tool
for otologists and audiologists as it improves preoperative surgical planning both in adults and in children, guides the intraoperative procedure and allows postoperative evaluation of the CI.
