Comparison of Microfissures between the Oval and Round Window Niche Areas in Human Temporal Bone.

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.

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Direct measurement of the round window niche dimensions using a 3-dimensional moulding technique - a human cadaveric temporal bone study

Clinical Otolaryngology ◽

10.1111/coa.12438 ◽

2015 ◽

Vol 40 (6) ◽

pp. 657-661 ◽

Cited By ~ 2

Author(s):

M. Shakeel ◽

P.M. Spielmann ◽

S.E. Jones ◽

S.S.M. Hussain

Keyword(s):

Temporal Bone ◽

Direct Measurement ◽

Round Window ◽

3 Dimensional ◽

Round Window Niche

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HRCT Correlation with Round Window Identification during Cochlear Implantation in Children

Journal of Clinical Imaging Science ◽

10.4103/2156-7514.148264 ◽

2014 ◽

Vol 4 ◽

pp. 70 ◽

Cited By ~ 4

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.

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Microfissure in the Oval Window Area

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948109000217 ◽

1981 ◽

Vol 90 (2) ◽

pp. 174-180 ◽

Cited By ~ 21

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.

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Radiographic Imaging of the Cochlear Implant Candidate: Preliminary Results

Otolaryngology ◽

10.1177/019459988609500513 ◽

1986 ◽

Vol 95 (5) ◽

pp. 592-597 ◽

Cited By ~ 12

Author(s):

Thomas J. Balkany ◽

James N. Dreisbach ◽

Charles E. Seibert

Keyword(s):

Cochlear Implant ◽

Temporal Bone ◽

Round Window ◽

Parietal Bone ◽

Systematic Evaluation ◽

Preoperative Imaging ◽

Radiographic Imaging ◽

Anatomic Structure ◽

Basal Turn ◽

Round Window Niche

Preoperative radiographic imaging of the temporal bone is well accepted in otology for both the diagnosis of disease and the delineation of anatomic structure for surgical planning. Until recently radiographic techniques have unfortunately failed to demonstrate fibrous or bony obstruction of the basal turn of the cochlea, which may cause difficulties during cochlear implantation. Intraoperative findings have been correlated with preoperative imaging in a consecutive group of six cochlear implant recipients and a series of consistent radiographic signs that may indicate the presence of obstruction of the scala tympani have been identified. A classification system has been developed. Based on thin-section high-resolution computerized tomography (HRCT), the system has been used preoperatively on six cochlear implant recipients. In addition, a systematic evaluation of the temporal bone has been developed for precochlear implant evaluation. This includes (1) the thickness of the parietal bone for seating of the receiving device, (2) the degree of pneumatization of the mastoid, (3) the measurement of the size of the facial recess, (4) the description of the size and orientation of the round window niche, and (5) the patency of the basal turn of the cochlea.

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

The Journal of Laryngology & Otology ◽

10.1017/s0022215119001269 ◽

2019 ◽

Vol 133 (7) ◽

pp. 575-579 ◽

Cited By ~ 3

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.

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Mucopolysaccharidosis I-H (Hurler's Syndrome) and Human Temporal Bone Histopathology

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948409300115 ◽

1984 ◽

Vol 93 (1) ◽

pp. 65-69 ◽

Cited By ~ 27

Author(s):

P. A. Schachern ◽

D. A. Shea ◽

M. M. Paparella

Keyword(s):

Otitis Media ◽

Stria Vascularis ◽

Round Window ◽

Enzyme Analysis ◽

Mucopolysaccharidosis I ◽

Human Temporal Bone ◽

Hurler’S Syndrome ◽

Round Window Niche ◽

Temporal Bones ◽

Histopathologic Findings

Six temporal bones from three patients with mucopolysaccharidosis I-H are described. All three patients were diagnosed as having mucopolysaccharidosis I-H by enzyme analysis, and all fit the phenotypic criteria of this disease. Family histories of the three cases described were negative for mycopolysaccharide-storage diseases. All three of the patients suffered chronic recurrent otitis media from infancy through death. Common histopathologic findings include otitis media, residual mesenchyme in the round window niche, partial occlusion of the middle ear cavity, and basophilic concretions within the stria vascularis. The common severe histopathologic changes observed in this study and similar findings in the temporal bones described in other studies lead the authors to believe that ear involvement in this disease may be more common than was previously suspected.

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

Ear Nose & Throat Journal ◽

10.1177/01455613211009141 ◽

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

The Journal of Laryngology & Otology ◽

10.1017/s0022215121000232 ◽

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.

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