scholarly journals HRCT Correlation with Round Window Identification during Cochlear Implantation in Children

2014 ◽  
Vol 4 ◽  
pp. 70 ◽  
Author(s):  
Sai Kiran Pendem ◽  
Rajeswaran Rangasami ◽  
Ravi Kumar Arunachalam ◽  
Venkata Sai Pulivadulu Mohanarangam ◽  
Paarthipan Natarajan
Keyword(s):  
Temporal Bone ◽  
Cochlear Implantation ◽  
Round Window ◽  
Oval Window ◽  
Significant Difference ◽  
Posterior Tympanotomy ◽  
Hrct Temporal Bone ◽  
Round Window Niche ◽  
The Right ◽  
A Prospective Study

Objective: To determine the accuracy of High Resolution Computer Tomography (HRCT) temporal bone measurements in predicting the actual visualization of round window niche as viewed through posterior tympanotomy (i.e. facial recess). Materials and Methods: This is a prospective study of 37 cochlear implant candidates, aged between 1and 6 years, who were referred for HRCT temporal bone during the period December 2013 to July 2014. Cochlear implantation was done in 37 children (25 in the right ear and 12 in the left ear). The distance between the short process of incus and the round window niche and the distance between the oval window and the round window niche were measured preoperatively on sub-millimeter (0.7 mm) HRCT images. We classified the visibility of round window niche based on the surgical view (i.e. through posterior tympanotomy) during surgery into three types: 1) Type 1- fully visible, 2) Type 2- partially visible, and 3) Type 3- difficult to visualize. The preoperative HRCT measurements were used to predict the type of visualization of round window niche before surgery and correlated with the findings during surgery. Results: The mean and standard deviation for the distance between the short process of incus and the round window niche and for the distance between the oval window and the round window niche for Types 1, 2, and 3 were 8.5 ± 0.2 mm and 3.2 ± 0.2 mm, 8.0 ± 0.4 mm and 3.8 ± 0.2 mm, 7.5 ± 0.2 mm and 4.4 ± 0.2 mm respectively, and showed statistically significant difference (P < 0.01) between them. The preoperative HRCT measurements had a sensitivity and specificity of 92.3% and 96.2%, respectively, in determining the actual visualization of round window niche. Conclusion: This study shows preoperative HRCT temporal bone measurements are useful in predicting the actual visualization of round window niche as viewed through posterior tympanotomy.

Surgical considerations during cochlear implantation: the utility of temporal bone computed tomography

2021 ◽  
pp. 1-8
Author(s):  
Beomcho Jun ◽  
Sunwha Song
Keyword(s):  
Computed Tomography ◽  
Temporal Bone ◽  
Cochlear Implantation ◽  
Round Window ◽  
Three Dimensional ◽  
Electrode Placement ◽  
Posterior Tympanotomy ◽  
Electrode Insertion ◽  
Window Approach ◽  
Bone Structures

Abstract Objective This paper describes the construction of portals for electrode placement during cochlear implantation and emphasises the utility of pre-operative temporal bone three-dimensional computed tomography. Methods Temporal bone three-dimensional computed tomography was used to plan portal creation for electrode insertion. Results Pre-operative temporal bone three-dimensional computed tomography can be used to determine the orientation of temporal bone structures, which is important for mastoidectomy, posterior tympanotomy and cochleostomy, and when using the round window approach. Conclusion It is essential to create appropriate portals (from the mastoid cortex to the cochlea) in a step-by-step manner, to ensure the safe insertion of electrodes into the scala tympani. Pre-operative three-dimensional temporal bone computed tomography is invaluable in this respect.

scholarly journals Comparison of Round Window Anatomy between Pediatric and Adult Population: A Perspective from Cochlear Implantation Surgery

2020 ◽  
Vol 42 (3) ◽  
pp. 23-25
Author(s):  
Rabindra B Pradhananga ◽  
Bigyan R Gyawali ◽  
Pabina Rayamajhi
Keyword(s):  
Cochlear Implantation ◽  
Adult Population ◽  
Round Window ◽  
Round Window Membrane ◽  
Institute Of Medicine ◽  
Statistical Association ◽  
Complex Anatomy ◽  
Wide Range ◽  
Posterior Tympanotomy ◽  
Round Window Niche

Introduction The round window is thought to be an ideal port for inserting electrodes during cochlear implantation. Considering its complex anatomy with an individual variation, this study aims to review the anatomy of round window based on the visibility of round window niche and round window membrane via posterior tympanotomy in pediatric and adult population who underwent cochlear implantation. MethodsThis was a retrospective observational study conducted at the Department of ENT-HNS, Institute of Medicine, Kathmandu, Nepal. Surgical notes of adult (>15 years) and pediatric cases (<15years) who underwent primary cochlear implantation from January 2015 to January 2018 were assessed for different grading of round window niche and round window membrane visibility via posterior tympanotomy. Cases with revision surgery and with incomplete documentation of intra-operative findings were excluded from the study. Statistical analysis was done using SPSS software version 25. We used Chi-square and Fisher’s exact tests to analyze the statistical association. ResultsType B round window niche (partially visible) was the most common variant seen in the pediatric group while in adults, both Type B (partially visible) and Type C (fully visible) round window niche were common. Compared to the adults, the pediatric group had good visibility of RWM. However, there was no statistical association between these observations. ConclusionThe round window has a wide range of anatomical variations with different levels of visibility of RWN and RWM in the different age groups. Although statistically insignificant, RWM visibility seemed to be better in pediatric cases compared to adults.

scholarly journals Herniation of the Mastoid Segment of the Facial Nerve During Cochlear Implantation Surgery

2021 ◽  
pp. 014556132110516
Author(s):  
Mohammad Almohammad ◽  
Tala Tasabehji ◽  
Abdulrahman Awad ◽  
Ibrahem Hanafi
Keyword(s):  
Facial Nerve ◽  
Hearing Aids ◽  
Cochlear Implantation ◽  
Round Window ◽  
Posterior Wall ◽  
Case Presentation ◽  
Posterior Tympanotomy ◽  
Bilateral Sensorineural Hearing Loss ◽  
The Right ◽  
Electrical Stimuli

Background: We aim to report a rare case of a herniated mastoid segment of the facial nerve that was accidently discovered during cochlear implantation surgery and how altering the surgery plan could achieve the implantation while preserving the nerve. Case presentation: A four-year-old girl presented with profound bilateral sensorineural hearing loss that did not completely resolve after 2 years of using hearing aids was scheduled for cochlear implantation surgery in the right ear. During surgery, a herniated mastoid segment of the facial nerve took an anterior course and obstructed the access to the round window. Conclusion: When a traditional posterior tympanotomy approach in cochlear implantation surgery is limited in cases of a herniated facial nerve, a tunnel created near the inferior part of the posterior wall of the auditory canal provided safe insertion of the electrode. It also permitted placement of a piece of fascia between the electrode and the facial nerve, therefore, protecting the facial nerve from electrical stimuli.

Locating the scala media in the fixed human temporal bone for therapeutic access: a preliminary study

2006 ◽  
Vol 120 (11) ◽  
pp. 914-915 ◽  
Author(s):  
H Pau ◽  
P Fagan ◽  
S Oleskevich
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Oval Window ◽  
Horizontal Line ◽  
Point Of Entry ◽  
Anterior Edge ◽  
Human Temporal Bone ◽  
Round Window Niche ◽  
Temporal Bones ◽  
A Site

Objective: To investigate the location of the scala media in relation to the round window niche in human temporal bones.Design: Ten human temporal bones were investigated by radical mastoidectomy and promontory drill-out.Setting: Temporal bone laboratory.Outcome measures: The distance from the scala media to the anterior edge of the round window niche, measured by Fisch's stapedectomy measuring cylinders.Results: The scala media was identified at the transection point of a vertical line 1.6 to 2.2 mm (mean=1.8 mm; standard deviation=0.2) anterior to the anterior edge of the round window niche and a horizontal line 0.2 mm inferior to the lower border of the oval window.Conclusion: This report demonstrates the point of entry into the scala media via the promontory in fixed temporal bone models, which may provide a site of entry for stem cells and gene therapy insertion.

scholarly journals Surgical anatomy of the round window with special reference to cochlear implantation

1987 ◽  
Vol 101 (2) ◽  
pp. 97-102 ◽  
Author(s):  
Burkhard K. H. Franz ◽  
Graeme M. Clark ◽  
David M. Bloom
Keyword(s):  
Cochlear Implant ◽  
Special Reference ◽  
Cochlear Implantation ◽  
Round Window ◽  
Surgical Anatomy ◽  
Round Window Membrane ◽  
Scala Tympani ◽  
Good View ◽  
Posterior Tympanotomy ◽  
Round Window Niche

AbstractWhen the multi-channel cochlear implant electrode is inserted into the scala tympani through the round window the operation is best performed via a posterior tympanotomy. The view of the round window membrane, however, is incomplete because of its orientation and the fact that it has a conical shape. Nevertheless, a good view along the basal turn is obtained after the antero-inferior overhang of the round window niche and the crista fenestrae have been removed. It might be damaging to drill away the postero-superior overhang as the osseous spiral lamina lies extremely close to the round window membrane.

Microfissure in the Oval Window Area

1981 ◽  
Vol 90 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Takehiko Harada ◽  
Isamu Sando ◽  
Eugene N. Myers
Keyword(s):  
Temporal Bone ◽  
Round Window ◽  
Vertical Plane ◽  
Careful Analysis ◽  
Oval Window ◽  
Annular Ligament ◽  
Round Window Niche ◽  
Window Area ◽  
Most Probable Explanation ◽  
Temporal Bones

Examination of 331 human temporal bones revealed the presence of a microfissure in the oval window area in 25%. The youngest temporal bone in which the microfissure was observed was from a child eight years old and the oldest temporal bone was from an individual 102 years old. It appears that the microfissure in this area occurs extremely rarely before 10 years of age, that it begins to be observed after the age of 10, and that the incidence of this fissure increases sharply at about age 40. In 61% of the bones in which the microfissure was observed, it was present both superior and inferior to the oval window in almost the same vertical plane. In none of the bones, however, did it extend beyond the annular ligament to the footplate. The histological appearance of the microfissure in this area was quite similar to that of the microfissure between the posterior canal ampulla and round window niche, although the latter appeared to be wider in general. The histogenesis of the microfissure is still unknown, but upon careful analysis of the results of this study and literature review, the authors consider nontraumatic spontaneous fracture by mechanical stress to be the most probable explanation for its occurrence. Possible clinical significance of the microfissure is also discussed.

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.

scholarly journals Endoscopic-assisted epitympanic approach: a feasible technique for cochlear implantation

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Mohamed Mostafa Badr-El-dine ◽  
Mohamed Fawzy Fathalla ◽  
Mohamed Eid ◽  
Ahmed Mohamed Mehanna
Keyword(s):  
Cochlear Implantation ◽  
Comparison Group ◽  
Round Window ◽  
Management Strategies ◽  
Insertion Depth ◽  
Statistical Significant Difference ◽  
Endoscopic Control ◽  
Significant Difference ◽  
Posterior Tympanotomy ◽  
Safe Approach

Abstract Background The aim of this study is to discuss the detailed surgical steps of the endoscopic-assisted epi-tympanic approach (EAEA) to the round window (RW) as a safe, precise, and reliable approach for cochlear implantation (CI) and also to evaluate possible problems and limitations faced, their management strategies, and how to overcome. Results This study was carried on 40 patients admitted for cochlear implantation (CI). The patients were divided into two equal groups; the first group underwent CI via the endoscopic-assisted epitympanic approach (EAEA), while the second group was a comparison group and underwent CI via the classic posterior tympanotomy. There was a statistical significant difference as regards scalar location of CI electrodes; all EAEA cases were inserted through ST in comparison to 45% of conventional cases. There was no statistical significant difference as regards linear and angular insertion depth between the two groups. The EAEA group needed shorter time to finish the procedure taking from 90 to 195 min, whereas the conventional group consumed longer time ranging from 120 to 185 min; a difference that was found to be statistically significant. No facial nerve injury was reported in the endoscopic approach. Conclusions Endoscope-assisted epitympanic approach (EAEA) is a reliable and safe approach for soft surgery CI. Visualization of the RW and insertion of the electrode under endoscopic control was significantly reliable and successful in all cases.

scholarly journals Cochlear Implantation Following Explorative Tympanotomy in Patients With Sudden Sensorineural Hearing Loss: Surgical Features and Audiological Outcomes

2021 ◽  
pp. 014556132110091
Author(s):  
Robin Rupp ◽  
Joachim Hornung ◽  
Matthias Balk ◽  
Matti Sievert ◽  
Sarina Müller ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Connective Tissue ◽  
Sensorineural Hearing Loss ◽  
Cochlear Implantation ◽  
Round Window ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
Round Window Membrane ◽  
Hearing Results ◽  
Round Window Niche

Objective: To investigate the anatomical status of the round window niche and hearing outcome of cochlear implantation (CI) after explorative tympanotomy (ExT) with sealing of the round window membrane in patients with sudden sensorineural hearing loss at a tertiary referral medical center. Methods: Between January 1, 2007, and July 30, 2020, 1602 patients underwent CI at our department. Out of these, all patients previously treated by ExT with sealing of the round window membrane because of unilateral sudden hearing loss were included in the study. A retrospective chart review was conducted concerning method of round window membrane sealing, intraoperative findings during CI, postoperative imaging, and hearing results. Results: Twenty one patients (9 females; 8 right ears; 54.3 years [± 12.9 years]) underwent ExT with sealing of the round window membrane with subsequent CI after 26.6 months (± 32.9 mo) on average. During CI, in 76% of cases (n = 16), the round window niche was blocked by connective tissue due to the previous intervention but could be removed completely in all cases. The connective tissue itself and its removal had no detrimental effects on the round window membrane. Postoperative computed tomography scan showed no electrode dislocation. Mean postoperative word recognition score after 3 months was 57.4% (± 17.2%) and improved significantly to 73.1% (± 16.4%, P = .005) after 2 years. Conclusion: Performing CI after preceding ExT, connective tissue has to be expected blocking the round window niche. Remaining tissue can be removed safely and does not alter the round window membrane allowing for a proper electrode insertion. Short- and long-term hearing results are satisfactory. Consequently, ExT with sealing of the round window membrane in patients with sudden sensorineural hearing loss does not impede subsequent CI that can still be performed safely.

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