scholarly journals Radiographic Measurement of Cochlear Duct Length in an Indian Cadaveric Population - Importance of Custom Fit Cochlear Implant Electrodes

2020 ◽  
Vol 24 (04) ◽  
pp. e492-e495
Author(s):  
Anup Singh ◽  
Rajeev Kumar ◽  
Smita Manchanda ◽  
Ashu Seith Bhalla ◽  
Prem Sagar ◽  
...  
Keyword(s):  
High Resolution ◽  
Cochlear Implant ◽  
Radiographic Measurement ◽  
High Resolution Computed Tomography ◽  
Insertion Depth ◽  
Cochlear Duct ◽  
Basal Turn ◽  
Significant Difference ◽  
Cochlear Duct Length ◽  
Temporal Bones

Abstract Introduction Successful cochlear implantation requires an appropriate insertion depth of the electrode, which depends on cochlear duct length CDL). The CDL can vary due to ethnic factors. Objective The objective of the current study was to determine the CDL in an Indian adult cadaveric population. Methods The present was a cadaveric study using the temporal bones obtained after permission of the Institutional Review Board. The temporal bones were subjected to high-resolution computed tomography (HRCT), and the double oblique reformatted CT images were reconstructed through the basal turn of the cochlea. The reformatted images were then viewed in the minimum-intensity projection (minIP) mode, and the ‘A’ value (the diameter of the basal turn of the cochlea) was calculated. The CDL was then measured using the formula CDL = 4.16A - 4 (Alexiades et al). The data analysis was performed using the Microsoft Excel software, version 2016. Results A total of 51 temporal bones were included for imaging analysis. The CDL varied from 27.6 mm to 33.4 mm, with a mean length of 30.7 mm. There was no statistically significant difference between the two sides. Conclusion The CDL can be calculated with preoperative high-resolution CT, and can provide a roadmap for effective cochlear implant electrode insertion. The population-based anatomical variability needs to be taken into account to offer the most efficient and least traumatic insertion of the electrode.

scholarly journals Cone beam CT for perioperative imaging in hearing preservation Cochlear implantation – a human cadaveric study

2019 ◽  
Vol 48 (1) ◽  
Author(s):  
Kayvan Nateghifard ◽  
David Low ◽  
Lola Awofala ◽  
Dilakshan Srikanthan ◽  
Jafri Kuthubutheen ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Cochlear Implantation ◽  
Lateral Wall ◽  
Cone Beam ◽  
Insertion Depth ◽  
Cochlear Duct ◽  
Low Radiation Dose ◽  
A Value ◽  
Cochlear Duct Length ◽  
Temporal Bones

Abstract Background Knowledge of the cochlear implant array’s precise position is important because of the correlation between electrode position and speech understanding. Several groups have provided recent image processing evidence to determine scalar translocation, angular insertion depth, and cochlear duct length (CDL); all of which are being used for patient-specific programming. Cone beam computed tomography (CBCT) is increasingly used in otology due to its superior resolution and low radiation dose. Our objectives are as followed: Validate CBCT by measuring cochlear metrics, including basal turn diameter (A-value) and lateral wall cochlear duct length at different angular intervals and comparing it against microcomputed CT (uCT).Explore the relationship between measured lateral wall cochlear duct length at different angular intervals and insertion depth among 3 different length electrodes using CBCT. Methods The study was performed using fixed human cadaveric temporal bones in a tertiary academic centre. Ten temporal bones were subjected to the standard facial recess approach for cochlear implantation and imaged by CBCT followed by uCT. Measurements were performed on a three-dimensional reconstructed model of the cochlea. Sequential insertion of 3 electrodes (Med-El Flex24, 28 and Soft) was then performed in 5 bones and reimaged by CBCT. Statistical analysis was performed using Pearson’s correlation. Results There was good agreement between CBCT and uCT for cochlear metrics, validating the precision of CBCT against the current gold standard uCT in imaging. The A-value recorded by both modalities showed a high degree of linear correlation and did not differ by more than 0.23 mm in absolute values. For the measurement of lateral wall CDL at various points along the cochlea, there was a good correlation between both modalities at 360 deg and 720 deg (r = 0.85, p < 0.01 and r = 0.79, p < 0.01). The Flex24 electrode displayed consistent insertion depth across different bones. Conclusions CBCT reliably performs cochlear metrics and measures electrode insertion depth. The low radiation dose, fast acquisition time, diminished metallic artifacts and portability of CBCT make it a valid option for imaging in cochlear implant surgery.

A study on modelling cochlear duct mid-scalar length based on high-resolution computed tomography, and its effect on peri-modiolar and mid-scalar implant selection

2019 ◽  
Vol 133 (09) ◽  
pp. 764-769
Author(s):  
G Pamuk ◽  
A E Pamuk ◽  
A Akgöz ◽  
E Öztürk ◽  
M D Bajin ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Round Window ◽  
Chronic Otitis Media ◽  
Lateral Wall ◽  
High Resolution Computed Tomography ◽  
Cochlear Duct ◽  
Implant Selection ◽  
Cochlear Duct Length ◽  
Implant Length

AbstractObjectiveTo determine cochlear duct mid-scalar length in normal cochleae and its role in selecting the correct peri-modiolar and mid-scalar implant length.MethodsThe study included 40 patients with chronic otitis media who underwent high-resolution computed tomography of the temporal bone. The length and height of the basal turn, mid-modiolar height of the cochlea, mid-scalar and lateral wall length of the cochlear duct, and the ‘X’ line (the largest distance from mid-point of the round window to the mid-scalar point of the cochlear canal) were measured.ResultsCochlear duct lateral wall length (28.88 mm) was higher than cochlear duct mid-scalar length (20.08 mm) (p &lt; 0.001). The simple linear regression equation for estimating complete cochlear duct length was: cochlear duct length = 0.2 + 2.85 × X line.ConclusionUsing the mid-scalar point as the reference point (rather than the lateral wall) for measuring cochlear duct mid-scalar length, when deciding on the length of mid-scalar or peri-modiolar electrode, increases measurement accuracy. Mean cochlear duct mid-scalar length was compatible with peri-modiolar and mid-scalar implant lengths. The measurement method described herein may be useful for pre-operative peri-modiolar or mid-scalar implant selection.

Evaluating Intracochlear Trauma after Cochlear Implant Electrode Insertion through Middle Fossa Approach in Temporal Bones

2017 ◽  
Vol 158 (2) ◽  
pp. 350-357 ◽  
Author(s):  
Juan Carlos Cisneros Lesser ◽  
Rubens de Brito ◽  
Graziela de Souza Queiroz Martins ◽  
Eloisa Maria Mello Santiago Gebrim ◽  
Ricardo Ferreira Bento
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Middle Cranial Fossa ◽  
Middle Fossa ◽  
Insertion Depth ◽  
Middle Fossa Approach ◽  
Basal Turn ◽  
Fresh Frozen ◽  
Electrode Insertion ◽  
Temporal Bones

Objective To evaluate cochlear trauma after cochlear implant insertion through a middle fossa approach by means of histologic and imaging studies in temporal bones. Study Design Prospective cadaveric study. Setting University-based temporal bone laboratory. Subjects and Methods Twenty fresh-frozen temporal bones were implanted through a middle cranial fossa basal turn cochleostomy. Ten received a straight electrode and 10 a perimodiolar electrode. Samples were fixed in epoxy resin. Computed tomography (CT) scans determined direction, depth of insertion, and the cochleostomy to round window distance. The samples were polished by a microgrinding technique and microscopically visualized to evaluate intracochlear trauma. Descriptive and analytic statistics were performed to compare both groups. Results The CT scan showed intracochlear insertions in every bone, 10 directed to the middle/apical turn and 10 to the basal turn. In the straight electrode group, the average number of inserted electrodes was 12.3 vs 15.1 for the perimodiolar group ( U = 78, P = .0001). The median insertion depth was larger for the perimodiolar group (14.4 mm vs 12.5 mm, U = 66, P = .021). Only 1 nontraumatic insertion was achieved and 14 samples (70%) had important trauma (Eshraghi grades 3 and 4). No differences were identified comparing position or trauma grades for the 2 electrode models or when comparing trauma depending on the direction of insertion. Conclusion The surgical technique allows a proper intracochlear insertion, but it does not guarantee a correct scala tympani position and carries the risk of important trauma to cochlear microstructures.

Cochlear duct length and cochlear distance on preoperative CT: imaging markers for estimating insertion depth angle of cochlear implant electrode

2021 ◽  
Vol 31 (3) ◽  
pp. 1260-1267 ◽  
Author(s):  
Jiseon Oh ◽  
Jung-Eun Cheon ◽  
Junghoan Park ◽  
Young Hun Choi ◽  
Yeon Jin Cho ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Ct Imaging ◽  
Insertion Depth ◽  
Cochlear Duct ◽  
Preoperative Ct ◽  
Cochlear Duct Length ◽  
Imaging Markers

scholarly journals The Effect of Cochlear Size on Cochlear Implantation Outcomes

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jafri Kuthubutheen ◽  
Amandeep Grewal ◽  
Sean Symons ◽  
Julian Nedzelski ◽  
David Shipp ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Outer Wall ◽  
X Rays ◽  
Speech Discrimination ◽  
Insertion Depth ◽  
Basal Diameter ◽  
Cochlear Duct ◽  
Significant Difference ◽  
Cochlear Duct Length ◽  
Electrode Insertion

Objectives. To determine if cochlear duct length and cochlear basal diameter, measured using routinely available radiology software, affect hearing outcomes after cochlear implantation with two different length electrodes. Methods. 55 patients who received a Med-El Flex electrode were retrospectively reviewed. 34 patients received the Flex 31 electrode (31mm) and 21 patients received the Flex 28 electrode (28mm). Preoperative high-resolution CT scans of the temporal bone were reformatted in the axial and coronal plane. The basal diameter of the cochlear (A-value) and the outer-wall lengths of the cochlear duct were measured using readily available imaging software. Postoperative plane X-rays were used to determine the degree of electrode insertion and the number of electrodes within the cochlea and speech discrimination scores at 6 months were evaluated. Results. The cochlear metrics obtained were comparable with those previously published in the literature. There was no significant difference in the degree of insertion or speech outcomes between the two electrode lengths. However, when the group who had received the shorter electrode were analysed, there was an association seen between both cochlear duct length and cochlear diameter and speech outcomes. Conclusions. Cochlear size may be a factor in determining speech outcomes that cannot be explained solely by insertion depth or degrees of insertion. Further studies are required to determine if cochlear duct length is an independent predictor of speech outcomes.

scholarly journals The Role of Transthoracic Ultrasound in the Study of Interstitial Lung Diseases: High-Resolution Computed Tomography Versus Ultrasound Patterns: Our Preliminary Experience

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 439
Author(s):  
Donato Lacedonia ◽  
Giulia Scioscia ◽  
Angelamaria Giardinelli ◽  
Carla Maria Irene Quarato ◽  
Ennio Vincenzo Sassani ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Lung Diseases ◽  
Interstitial Lung Diseases ◽  
High Resolution Computed Tomography ◽  
Pleural Line ◽  
Complementary Role ◽  
Number Of Patients ◽  
Significant Difference ◽  
Transthoracic Ultrasound

Transthoracic ultrasound (TUS) is a readily available imaging tool that can provide a quick real-time evaluation. The aim of this preliminary study was to establish a complementary role for this imaging method in the approach of interstitial lung diseases (ILDs). TUS examination was performed in 43 consecutive patients with pulmonary fibrosis and TUS findings were compared with the corresponding high-resolution computed tomography (HRCT) scans. All patients showed a thickened hyperechoic pleural line, despite no difference between dominant HRCT patterns (ground glass, honeycombing, mixed pattern) being recorded (p > 0.05). However, pleural lines’ thickening showed a significant difference between different HRCT degree of fibrosis (p < 0.001) and a negative correlation with functional parameters. The presence of >3 B-lines and subpleural nodules was also assessed in a large number of patients, although they did not demonstrate any particular association with a specific HRCT finding or fibrotic degree. Results allow us to suggest a complementary role for TUS in facilitating an early diagnosis of ILD or helping to detect a possible disease progression or eventual complications during routine clinical practice (with pleural line measurements and subpleural nodules), although HRCT remains the gold standard in the definition of ILD pattern, disease extent and follow-up.

scholarly journals Facial nerve anomalies in paediatric cochlear implant candidates: radiological evaluation

2016 ◽  
Vol 131 (1) ◽  
pp. 26-31 ◽  
Author(s):  
F B Palabiyik ◽  
K Hacikurt ◽  
Z Yazici
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Facial Nerve ◽  
Cochlear Implant ◽  
Inner Ear ◽  
Resonance Imaging ◽  
High Resolution Computed Tomography ◽  
Ear Anomalies

AbstractBackground:Pre-operative radiological identification of facial nerve anomalies can help prevent intra-operative facial nerve injury during cochlear implantation. This study aimed to evaluate the incidence and configuration of facial nerve anomalies and their concurrence with inner-ear anomalies in cochlear implant candidates.Methods:Inner-ear and concomitant facial nerve anomalies were evaluated by magnetic resonance imaging and temporal high-resolution computed tomography in 48 children with congenital sensorineural hearing loss who were cochlear implant candidates.Results:Inner-ear anomalies were present in 11 out of 48 patients (23 per cent) and concomitant facial nerve anomalies were present on 7 sides in 4 patients (7 per cent of the total). Facial nerve anomalies were accompanied by cochlear or vestibular malformation.Conclusion:Potential facial nerve abnormalities should always be considered in patients with inner-ear anomalies. Pre-operative facial nerve imaging can increase the surgeon's confidence to plan and perform cochlear implantation. Magnetic resonance imaging should be used to detect inner-ear anomalies; if these are identified, temporal high-resolution computed tomography should be used to evaluate the facial nerve.

Can Preoperative High Resolution Computed Tomography Be Rationalized in Adult Cochlear Implant Candidates?

2018 ◽  
Vol 39 (10) ◽  
pp. 1264-1270
Author(s):  
Peter Gaskell ◽  
Jameel Muzaffar ◽  
Steve Colley ◽  
Chris Coulson
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Cochlear Implant ◽  
High Resolution Computed Tomography

High resolution computed tomography and magnetic resonance imaging in the pre-operative assessment of cochlear implant patients

2003 ◽  
Vol 117 (9) ◽  
pp. 692-695 ◽  
Author(s):  
T. G. Gleeson ◽  
P. D. Lacy ◽  
M. Bresnihan ◽  
R. Gaffney ◽  
P. Brennan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Magnetic Resonance ◽  
Cochlear Implant ◽  
High Resolution Computed Tomography ◽  
Time Of Surgery ◽  
Surgical Access ◽  
Significant Difference ◽  
Mri Scans ◽  
Operative Assessment ◽  
Ct And Mri

Optimal imaging protocols for cochlear implantation have yet to be determined. Pre-operative computed tomography (CT) and magnetic resonance image (MRI) scans are used to assess cochlear anatomy and patency, to delineate surgical access, and to aid in choice of side for implantation. However, opinion still differs as to which modality provides more information in pre-operative assessment, or if, indeed, a combination of the two is superior.The first 88 patients on the Irish National Cochlear Implant Programme (NCIP) were retrospectively studied to determine the accuracy of pre-operative CT and MRI in predicting abnormalities at the time of surgery. Correlation with surgical findings was determined in three separate groups of patients (those who had CT only, those who had MRI only, and those who had both CT and MRI performed).Of the 24 patients that had both CT and MRI performed, both modalities had a 79 per cent correlation with surgical findings. CT and MRI reports concurred in 75 per cent of cases. Specificity and negative predictive value were high (86 per cent and 90 per cent, respectively). CT alone (47 cases) correlated with surgery in 39 cases (83 per cent); MRI alone (17 cases) correlated in 15 cases (88 per cent).The findings of this study suggest that CT and MRI are effective at predicting normal inner ear anatomy, and thus at predicting the patient and the cochlea most suitable for implantation. Both modalities are useful in determining the side of implantation, thus avoiding potential surgical difficulties in cases of unilateral abnormalities. There was no significant difference between the ability of MRI and CT to detect abnormalities at the time of surgery. In this series the combination of CT and MRI has not been shown to be superior to either modality used alone, although anecdotal evidence to the contrary was noted.

Labyrinthitis ossificans: How accurate is MRI in predicting cochlear obstruction?

2009 ◽  
Vol 140 (5) ◽  
pp. 692-696 ◽  
Author(s):  
Brandon Isaacson ◽  
Timothy Booth ◽  
Joe W. Kutz ◽  
Kenneth H. Lee ◽  
Peter S. Roland
Keyword(s):  
High Resolution ◽  
Bacterial Meningitis ◽  
Cochlear Implant ◽  
Tertiary Care ◽  
Fibrous Tissue ◽  
Case Series ◽  
Prior History ◽  
Basal Turn ◽  
Labyrinthitis Ossificans ◽  
History Of

Objective: To determine the accuracy of preoperative MRI in predicting cochlear obstruction in pediatric patients with a history of bacterial meningitis. Methods: A case series with chart review was performed at a tertiary care multidisciplinary cochlear implant program. Forty-five children with hearing loss that resulted from bacterial meningitis were implanted from 1991 to 2006. Twenty-five children had preoperative MRI with high-resolution axial T2-weighted images to assess for cochlear patency. Results: Seventeen of 25 patients (68%) had surgical evidence of cochlear obstruction. Six patients (37.5%) required circummodiolar drill-outs, and one patient (6.25%) underwent placement of a double array cochlear implant. The nine remaining patients (56%) with cochlear obstruction required removal of fibrous tissue or drilling of the inferior basal turn, but did not require manipulation of the ascending basal turn to achieve full electrode insertion. The sensitivity, specificity, and positive and negative predictive value of MRI predicting intraoperative cochlear obstruction with 95 percent confidence intervals was 94.1 percent (71–99), 87.5 percent (47–99), 94.1 percent (71–99) and 87.5 percent (47–99), respectively. Conclusion: Preoperative high-resolution T2 MRI may be useful in predicting cochlear obstruction in patients with a prior history of bacterial meningitis.

Sign in / Sign up

Export Citation Format

Share Document