Assessment of anatomic variations and measurements in high resolution computed tomography related to round window visibility in cochlear implantation

2021 ◽  
Author(s):  
Eduarda Maria Marinho Pinto
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Cochlear Implantation ◽  
Round Window ◽  
Anatomic Variations ◽  
High Resolution Computed Tomography

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 < 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.

The Crista Fenestra and Its Impact on the Surgical Approach to the Scala Tympani during Cochlear Implantation

2017 ◽  
Vol 22 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Roberto D. Angeli ◽  
Joel Lavinsky ◽  
Enio T. Setogutti ◽  
Luiz Lavinsky
Keyword(s):  
High Resolution ◽  
Cochlear Implantation ◽  
Round Window ◽  
Ct Scanning ◽  
Round Window Membrane ◽  
Scala Tympani ◽  
High Resolution Computed Tomography ◽  
High Resolution Ct ◽  
Round Window Niche ◽  
Temporal Bones

Objective: The aim of this work was to describe the dimensions of the crista fenestra and determine its presence by means of high-resolution computed tomography (CT) for the purpose of cochlear implantation via the round window approach. Methods: A series of 10 adult human temporal bones underwent high-resolution CT scanning and were further dissected for microscopic study of the round window niche. Results: In all of the specimens, the round window membrane was fully visualized after the complete removal of bony overhangs. The crista fenestra was identified as a sharp bony crest located in the anterior and inferior borders of the niche; its area ranged from 0.28 to 0.80 mm2 (mean 0.51 ± 0.18). The proportion of the area occupied by the crista fenestra in the whole circumference of the round window ranged from 23 to 50% (mean 36%). We found a moderate positive correlation between the area of the niche and the dimensions of the crista fenestra (Spearman rho: 0.491). In every case, high-resolution CT scanning was unable to determine the presence of the crista fenestra. Conclusion: The crista fenestra occupies a variable but expressive area within the bony round window niche. Narrower round window niches tended to house smaller crests. The presence of the crista fenestra is an important obstacle to adequate access to the scala tympani. Nevertheless, a high-resolution CT scan provides no additional preoperative information with regard to its presence for the purpose of surgical access to the scala tympani via the round window niche.

Predicting Round Window Niche Visibility via the Facial Recess Using High-Resolution Computed Tomography

2015 ◽  
Vol 36 (1) ◽  
pp. e18-e23 ◽  
Author(s):  
Akinori Kashio ◽  
Takashi Sakamoto ◽  
Shotaro Karino ◽  
Akinobu Kakigi ◽  
Shinichi Iwasaki ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Round Window ◽  
High Resolution Computed Tomography ◽  
Facial Recess ◽  
Round Window Niche

Comparative evaluation of round window niche accessibility pre-operatively on high-resolution computed tomography of the temporal bone with intra-operative findings

2019 ◽  
Vol 133 (7) ◽  
pp. 575-579 ◽  
Author(s):  
R Sharma ◽  
R Meher ◽  
J C Passey ◽  
J Kumar ◽  
A Gupta ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Temporal Bone ◽  
Round Window ◽  
Type I ◽  
Significant Finding ◽  
High Resolution Computed Tomography ◽  
Posterior Tympanotomy ◽  
Round Window Niche ◽  
Operative Findings

AbstractObjectiveTo compare round window niche visibility as seen endoscopically during cochlear implant surgery with pre-operative high-resolution computed tomography of the temporal bone.MethodsNineteen patients scheduled for cochlear implantation, aged 2–20 years, were referred for computed tomography from October 2016 to March 2018. Angles were measured between the lines passing through the mid-sagittal plane and cochlear basal turn on the scans. Endoscopic round window niche visibility during posterior tympanotomy was categorised as: type I = 100 per cent, type IIa = more than 50 per cent, type IIb = less than 50 per cent or type III = 0 per cent. Pre-operative computed tomography measurements were used to predict round window niche visibility before surgery and correlated with intra-operative findings.ResultsThe mean (range) of pre-operative angles on computed tomography for endoscopic visibility types I, IIa and IIb, were 64.06° (61.16–69.37°), 63.81° (58.61–71.35°) and 56.48° (50.37–59.05°), respectively, a statistically significant finding (one-way analysis of variance test, p = 0.016).ConclusionPre-operative high-resolution temporal bone computed tomography measurements are useful in predicting round window niche visualisation as viewed endoscopically during posterior tympanotomy. The angle was more acute in type IIb compared to type I.

Temporal Bone Computed Tomography in the Preoperative Evaluation for Cochlear Implantation

1989 ◽  
Vol 98 (5) ◽  
pp. 346-349 ◽  
Author(s):  
Donald P. Mueller ◽  
Kenneth D. Dolan ◽  
Bruce J. Gantz
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Temporal Bone ◽  
Cochlear Implantation ◽  
Preoperative Evaluation ◽  
Operative Procedure ◽  
High Resolution Computed Tomography ◽  
Adequate Knowledge ◽  
Temporal Bone Ct ◽  
Selection Of

High resolution computed tomography of the temporal bone is performed routinely in the preoperative evaluation for cochlear implantation. A retrospective review was performed to determine the effect of these studies. The clinical significance was determined through consultation with the referring otolaryngologist and review of the operative reports. Twelve examinations were reviewed. Abnormalities were identified in 12 of the 24 ears examined (eight of 12 patients studied). In two patients the CT examination strongly influenced the selection of the ear to be implanted. In four additional cases information felt to be useful in preoperative planning was provided. Useful information related to potential complications with the mechanical insertion of the electrode apparatus. We conclude that temporal bone abnormalities are common in the population undergoing cochlear implantation and that high resolution temporal bone CT is essential in preoperative evaluation. The CT scan should be interpreted with adequate knowledge of the operative procedure to evaluate any possible barriers to the mechanical insertion of the internal components of the system.

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