Evaluation of facial nerve course, posterior tympanotomy width and visibility of round window in patients with cochlear implantation by performing oblique sagittal cut computed tomographic scan temporal bone

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

Ear Nose & Throat Journal ◽

10.1177/01455613211051655 ◽

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.

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Surgeon Oriented Preoperative Radiologic Evaluation in Cochlear Implantation - Our experience with a Proposed Checklist

International Archives of Otorhinolaryngology ◽

10.1055/s-0038-1648247 ◽

2018 ◽

Vol 23 (02) ◽

pp. 137-141 ◽

Cited By ~ 1

Author(s):

Mahmoud Mandour ◽

Mohammed Tomoum ◽

Saad El Zayat ◽

Hisham Hamad ◽

Mohamed Amer

Keyword(s):

Facial Nerve ◽

Temporal Bone ◽

Cochlear Implantation ◽

Round Window ◽

Special Focus ◽

Radiologic Evaluation ◽

Cortical Mastoidectomy ◽

Temporal Bone Ct ◽

Operative Findings ◽

Key Steps

Introduction Preoperative temporal bone imaging studies have been routinely performed prior to cochlear implantation. Radiologists need to report these examinations with special focus on the surgeon's expectations. Objectives To provide a basic structured format, in the form of a checklist, for reporting preoperative computed tomography (CT) and to its clinical impact on operative findings. Methods The preoperative temporal bone CT scans of 47 patients were analyzed and reported according to the proposed checklist. Intraoperative assessment of mastoidectomy, posterior tympanotomy and round window access was done by the surgeon in a blinded fashion and were correlated with the radiological findings to assess its significance. Results The proposed radiological checklist was reliable in assessing operative difficulty during cochlear implantation. Contracted mastoid and lower tegmen position were associated with a greater difficulty of the cortical mastoidectomy. Presence of an air cell around the facial nerve (FN) was predictive of easier facial recess access exposure. Facial nerve location and posterior external auditory canal (EAC) wall inclination were predictive of difficult round window (RW) accessibility. Conclusion Certain parameters on the preoperative temporal bone CT scan may be useful in predicting potential difficulties encountered during the key steps involved in cochlear implant surgery.

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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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Az emberi halántékcsontnak a csecsemő- és kisgyermekkori cochlearis implantáció szempontjából kiemelkedően fontos dimenziói. Klinikoradiológiai vizsgálat

Orvosi Hetilap ◽

10.1556/650.2019.31389 ◽

2019 ◽

Vol 160 (24) ◽

pp. 936-943 ◽

Cited By ~ 1

Author(s):

Ádám Perényi ◽

József Jóri ◽

Miklós Csanády ◽

László Rovó

Keyword(s):

Temporal Bone ◽

Cochlear Implantation ◽

Soft Tissues ◽

Round Window ◽

Young Age ◽

Mastoid Cavity ◽

Tomographic Images ◽

Computed Tomographic ◽

Facial Recess ◽

Young Subjects

Abstract: Introduction: Early cochlear implantation enables prelingual deaf individuals to become full members of the hearing society. Although early diagnostics are widely accessible and enable early rehabilitation, implant surgery often may be delayed due to a candidate’s young age. Aim: The authors’ objectives were to determine the anatomical parameters of the pediatric and adult temporal bone that are relevant to cochlear implantation and to ascertain the differences between them in order to assess whether the anatomical differences could influence the surgical technique and the timing of surgery. Method: Along with a survey of the literature, findings from the authors own cochlear implantees were assessed with respect to the most relevant dimensions of the internal electronic package, including the stimulating electrode of the cochlear implant, by measuring the squama of the temporal bone, the mastoid cavity and the facial recess on high resolution computed tomographic images. Results: The skull and the overlying soft tissues proved to be thinner and the mastoid cavity was less developed in children than in adults, while no significant changes were noted in the size of the facial recess. Conclusions: It is recommended to choose modern, thin implants that do not require sinking the implant package into a bone bed. Less bone work in infants and children enables excellent visualization of the round window through the underdeveloped mastoid cavity, which makes the procedure less time-consuming and minimally invasive. Indeed, a young age should alert ear surgeons to be cautious, but no higher risk of injury to important structures is predicted for young subjects than those that might occur in adults. Orv Hetil. 2019; 160(24): 936–943.

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

Journal of Institute of Medicine ◽

10.3126/jiom.v42i3.37573 ◽

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.

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Preoperative Evaluation and Surgical Outcome of Cochlear Implantation in NIENT

Bangladesh Journal of Otorhinolaryngology ◽

10.3329/bjo.v26i2.50640 ◽

2020 ◽

Vol 26 (2) ◽

pp. 128-135

Author(s):

Md Zakaria Sarker ◽

Muhammad Rafiqul Islam ◽

Utpal Kumar Dutta ◽

Debabrota Roy ◽

AHM Ferdows Nur ◽

...

Keyword(s):

Hearing Loss ◽

Facial Nerve ◽

Psychosocial Development ◽

Cochlear Implantation ◽

Preoperative Evaluation ◽

Round Window ◽

Round Window Membrane ◽

Safe Procedure ◽

Female Ratio ◽

Facial Recess

Background: Sensory neural hearing loss (SNHL) is the most common congenital sensory deficit, with an incidence of one to three per 1000 live births. Acoustic deprivation during the first 3 years of life can hinder speech and language acquisition with significant negative consequences on a child’s educational and psychosocial development. The gold standard intervention for permanent severe to profound hearing loss is cochlear implantation. Cochlear implant (CI); is a semi implantable electronic device that bypass the cochlea. Objectives: An observational study was carried out on 40 cases of pre-lingual deaf to find out the causes of pre-lingual deaf, to evaluate the preoperative procedures to set ideal criteria for pre -lingual cochlear implantation and to evaluate surgical procedure and outcome of cochlear implantations. Methods: Evaluation of the candidates included patient medical history, general health checkup, ENT examination, audiometric evaluation, CT and MRI scans, psychological profile of the candidate. A limited cortical mastoidectomy was performed. The facial recess was opened using the fossa of incudis as an initial landmark. The round window niche was visualized through the facial recess about 2 mm inferior to the stapes. A cochleostomy created by drilling over the basal turn of the cochlea anterior and inferior to the annulus of the round window membrane. The electrode array was then carefully inserted through the fenestra into the scala tympani of the cochlea. Electrophysiological testing (Neural Response Telemetry: NRT) was performed to verify the correct placement of active electrodes. Resulst: Among them 22 (55%) were male and 18 (45%) were female. Male female ratio was 1.2:1. Age distribution at implantation was 3.3±1.054(SD). Average hearing loss was 96.4±5.3(SD) dB and in aided audiogram was 63.7±4.6(SD) dB. Overall complications occurred in 10 (25%) cases. Transient facial nerve paresis in 2 (5%), injury of tympanic membrane in 1(2.5%), seroma 4(10%) and delayed otitis media in 1(2.5%) were observed. Major postoperative complications occurred in 2 cases including facial nerve palsy in 1(2.5%) case and spontaneous device failure in 1(2.5%) case. Conclusion: The result of this survey was find out the risk factor of congenital hearing loss. With a thorough preoperative evaluation, we can select proper candidates for CI which is a reliable and safe procedure with a low percentage of severe complication. Bangladesh J Otorhinolaryngol; October 2020; 26(2): 128-135

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

The Journal of Laryngology & Otology ◽

10.1017/s0022215100101343 ◽

1987 ◽

Vol 101 (2) ◽

pp. 97-102 ◽

Cited By ~ 37

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.

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