scholarly journals Radiological and surgical aspects of round window visibility during cochlear implantation: a retrospective analysis

2021 ◽  
Author(s):  
Saad Jwair ◽  
Job J. M. van Eijden ◽  
Esther E. Blijleven ◽  
Jan Willem Dankbaar ◽  
Hans G. X. M. Thomeer
Keyword(s):  
Cochlear Implant ◽  
Round Window ◽  
Ct Scans ◽  
Round Window Membrane ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Cochlear Implant Surgery ◽  
Window Approach ◽  
Almost All ◽  
Surgical Aspects

Abstract Purpose The round window approach has become the most preferred option for cochlear implant (CI) insertion, however, sometimes it may not be possible due to the (in)visibility of the round window membrane (RWM). We addressed the prevalence, consequences and indicators of difficult detection of the RWM in cochlear implant surgery. Methods This study retrospectively analysed the operative reports and preoperative high resolution axial-computed tomography (CT) scans of a consecutive cohort of patients who underwent a CI insertion. The main outcomes were surgical outcomes of the RW approach, and assessment of radiological markers. Results The operative reports showed that RWM insertion was feasible in 151 out of 153 patients. In 18% of the patients the RWM was difficult to visualize. All these patients had at least one intraoperative event. The chorda tympani nerve (CTN) or posterior canal wall was affected in 8% of the 153 patients and the fallopian canal in 6%. These patients had a facial-chorda tympani nerve distance on the CT scan that was considerably smaller than normal patients (1.5 mm vs 2.3 mm). In addition, a prediction line towards the anterolateral side of the RWM was found to be more prevalent in these patients’ CT scans (sensitivity 81%, specificity 63%). Conclusion The RW approach is feasible in almost all patients undergoing CI surgery. Difficult visualisation of the RWM seems to lead to at least one intraoperative event. Radiological measures showed that these patients had a smaller facial recess and a more anteriorly placed facial nerve, which can be used to better plan a safe insertion approach.

scholarly journals Retaining Chorda Tympani Nerve Integrity During Cochlear Implant Surgery

2015 ◽  
Vol 128 (15) ◽  
pp. 2115-2118 ◽  
Author(s):  
Lin-E Wang ◽  
Jiao Xia ◽  
Xi-Xi Shen ◽  
Zhen-Xiao Wang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Implant Surgery ◽  
Cochlear Implant Surgery

Effect of Round Window Opening Size on Residual Hearing Preservation in Cochlear Implantation

2020 ◽  
Vol 163 (2) ◽  
pp. 375-381
Author(s):  
Giselle L. Gotamco ◽  
Chuan-Hung Sun ◽  
Yi-Fan Chou ◽  
Chuan-Jen Hsu ◽  
Hung-Pin Wu
Keyword(s):  
Cochlear Implantation ◽  
Round Window ◽  
Hearing Preservation ◽  
Round Window Membrane ◽  
Tertiary Referral ◽  
Tertiary Referral Center ◽  
Window Technique ◽  
Cochlear Implant Surgery ◽  
Window Opening ◽  
Window Approach

Objectives This study aims to compare the hearing preservation outcomes in cochlear implant surgery following slit versus full opening of the round window membrane. Setting Tertiary referral center. Study Design Comparative study. Subjects and Methods Seventy patients (mean, 26.3 years; range, 2-69 years) who underwent cochlear implantation via the round window approach were included in the study. Thirty-five subjects were prospectively enrolled for cochlear implantation via the open round window technique between August 2018 and January 2019. Thirty-five patients who underwent cochlear implantation from January 2017 to July 2018 via the slit round window opening, frequency matched by sex and age, were retrospectively enrolled. Pre- and postoperative thresholds were obtained. The percentage of hearing preservation was computed with the HEARRING Network formula and classified into complete, partial, and minimal hearing preservation. The results between the groups were compared and analyzed at 6 months postoperatively. Results The rate of complete hearing preservation in the open group was statistically significant ( P = .030) at 71.4% (n = 25) as compared with 45.7% (n = 16) in the slit group. Conclusions The widely opened round window may be an optional technique that surgeons can utilize to improve hearing preservation outcomes.

Cochlear Implant Surgery Through Round Window Approach Is Always Possible

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 38S-44S ◽  
Author(s):  
Seong-Cheon Bae ◽  
You-Ree Shin ◽  
Young-Myoung Chun
Keyword(s):  
Cochlear Implant ◽  
Standard Procedure ◽  
Round Window ◽  
Lateral Wall ◽  
Anatomical Variations ◽  
Implant Surgery ◽  
Cochlear Implant Surgery ◽  
Alternative Procedures ◽  
Electrode Insertion ◽  
Window Approach

Objectives: The benefit of round window (RW) approach for cochlear implant (CI) has been well studied. Because the RW represents a natural door to scala tympani, it facilitates precise electrode insertion. Atraumatic electrode insertion can also be performed without drilling the cochlear lateral wall. However, the RW approach has several limitations. The purpose of this study is to describe successful CI surgeries utilizing the RW approach except for severe cases of temporal bone anomaly. The authors’ successful surgical solution for cases involving difficult RW access is also described. Materials and Methods: We retrospectively analyzed 377 consecutive surgeries of cochlear implantation performed between June 2010 and December 2018 by a single experienced surgeon. Standard and alternative procedures were used according to anatomical variations. Standard procedures included modified techniques of mastoidectomy in the RW approach, opening of facial recess, exposure of RW membrane, and electrode insertion. Difficult cases involving severe rotated cochlea or hypoplastic mastoid were successfully treated with RW insertion using alternative procedures such as external auditory canal (EAC) wall mobilization and endomeatal approach. Results: We performed CI surgery through a reproducible RW technique in two cases involving endomeatal approach and three cases of EAC mobilization. Other cases were treated using the standard procedure. Conclusion: Cochlear implant surgery through RW is reliable, safe, and effective. The RW technique is reproducible via several surgical procedures in most CI cases. Identification and safe exposure of RW membrane is a prerequisite for successful electrode insertion in cochlear implant surgery.

scholarly journals The Effects of Round Window Membrane Injury and the Use of a Model Electrode Application on Hearing in Rats

2021 ◽  
pp. 014556132199018
Author(s):  
Murat Koc ◽  
Abdullah Dalgic ◽  
Mehmet Ziya Ozuer
Keyword(s):  
Hearing Loss ◽  
Cochlear Implant ◽  
Round Window ◽  
Mechanical Trauma ◽  
Round Window Membrane ◽  
Albino Rats ◽  
Topical Steroids ◽  
Distortion Product ◽  
Significant Difference ◽  
Group 3

Objective: To investigate the effects of the mechanical trauma to the round window, a model electrode inserted into the scala tympani on the cochlear reserve, and the efficacy of topical steroids in preventing hearing loss. Materials and Methods: 21 male Wistar Albino rats were equally categorized into three groups. In all groups an initial mechanical injury to round window was created. Only subsequent dexamethasone injection was administrated into the cochlea in the subjects of group 2 while a multichannel cochlear implant guide inserted into the cochlea prior to dexamethasone administration for group 3. Distortion product otoacoustic emissions (DPOAEs) were obtained prior to and immediately after the surgical injury, eventually on postoperative seventh day (d 7). Mean signal/noise ratios (S/Ns) obtained at 2000, 3000, and 4000 Hz were calculated. Data sets were compared with non-parametric statistical tests. Results: The early intraoperative mean S/Ns were significantly less than preoperative measurements for group 1 and 2; however, preoperative and postoperative d 7 average S/Ns did not differ. There was statistically significant difference between preoperative, intraoperative and postoperative d 7 average S/Ns for group 3. Conclusion: We observed that hearing was restored approximately to the preoperative levels following early postoperative repair. However, an electrode insertion into the cochlea via round window subsequent to mechanical trauma seems to cause a progressive hearing loss. Therefore, a special care must be taken to avoid the injury to the round window membrane in the course of the placement of a cochlear implant electrode and surgery for the chronic otitis media.

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