Anatomy of the Round Window Region With Relation to Selection of Entry Site Into the Scala Tympani

Pringle, Märit; Konieczny, Katarzyna

doi:10.1002/lary.28738

Cited by 4 publications

(2 citation statements)

References 29 publications

(88 reference statements)

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“…It requires precise identi cation of topographic points, an essential one being the round window niche (RWN) and, after removal of the bony overhang, the round window membrane (RWM). Cochlear access through the round window (RW) is currently preferred as less traumatic with lower risk of electrode translocation to the scala vestibuli [1][2][3] and better preservation of vestibular function [4]. Access to the round window assessed by CT scanning is crucial in planning both classic and robotic cochlear implant surgery.…”

Section: Introductionmentioning

confidence: 99%

Objective evaluation of the round window access in computed tomography for cochlear implantation

Amernik,

Mielnik,

Gostyński

et al. 2023

Preprint

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Objective The aim of this study was to determine what kind of radiological parameters are the best for assessing RW approach for CI surgery. Material and Methods Patients undergoing cochlear implantation between 2015 and 2022 were eligible for the study. Radiological assessment was performed according to parameters proposed in literature. Clinical assessment was made intraoperative. The difference in the assessment of accessibility to the round window niche and the round window membrane (RWN - RWM) indicated the clinical assessment of the size of the overhang over the round window. Results Computed tomography images of 57 ears in 52 patients were analyzed in terms of round window access. The study group included 26 women and 26 men, ranging in age from 1 year to 80 years, with a mean age of 36.2. In clinical assessment RW visibility was rated as 5 after removal of the bony overhang in 69% of patients. Cochlear access through the round window was performed in 39 patients, extended access through the round window in 13 cases and cochleostomy in 5 patients. Statistically significant correlations describing RW access were found for parameters proposed by Chen and by us. From parameters describing bony overhang of the RW positive correlation was found for Sarafaz and Mehanna parameters. Conclusion Radiological measurements describing access to the RW, determining the angle based on the anatomy of the posterior wall of the auditory canal and the position of the facial nerve, are of the highest value. Clinical relevance statement In the future, the use of algorithms for CT evaluation and robotic surgery will require parameters for assessing RW access to plan surgical access and the type of electrodes. The parameters proposed by various authors are summarized, which allows us to assess their usefulness in further clinical practice.

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Section: Introductionmentioning

confidence: 99%

Objective evaluation of the round window access in computed tomography for cochlear implantation

Amernik,

Mielnik,

Gostyński

et al. 2023

Preprint

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“…The scala tympani, the favored intra-cochlear lumen for implant placement, can be accessed through a RW or extended RW approach or a RW-related cochleostomy ( 12 , 13 ). A favorable trajectory directed into the scala tympani, without targeting the osseous spiral lamina and the lateral wall of the basal portion, must pass through the canonus of the niche ( 14 ). Removal of the canonus (canonectomy) or creation of an opening in the canonus (canonostomy) may cause trauma to the hook region, where the osseous spiral lamina, the spiral ligament and the basilar membrane fuse ( 10 ).…”

Section: Introductionmentioning

confidence: 99%

Image-Based Planning of Minimally Traumatic Inner Ear Access for Robotic Cochlear Implantation

et al. 2021

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Objective: During robotic cochlear implantation, an image-guided robotic system provides keyhole access to the scala tympani of the cochlea to allow insertion of the cochlear implant array. To standardize minimally traumatic robotic access to the cochlea, additional hard and soft constraints for inner ear access were proposed during trajectory planning. This extension of the planning strategy aims to provide a trajectory that preserves the anatomical and functional integrity of critical intra-cochlear structures during robotic execution and allows implantation with minimal insertion angles and risk of scala deviation.Methods: The OpenEar dataset consists of a library with eight three-dimensional models of the human temporal bone based on computed tomography and micro-slicing. Soft constraints for inner ear access planning were introduced that aim to minimize the angle of cochlear approach, minimize the risk of scala deviation and maximize the distance to critical intra-cochlear structures such as the osseous spiral lamina. For all cases, a solution space of Pareto-optimal trajectories to the round window was generated. The trajectories satisfy the hard constraints, specifically the anatomical safety margins, and optimize the aforementioned soft constraints. With user-defined priorities, a trajectory was parameterized and analyzed in a virtual surgical procedure.Results: In seven out of eight cases, a solution space was found with the trajectories safely passing through the facial recess. The solution space was Pareto-optimal with respect to the soft constraints of the inner ear access. In one case, the facial recess was too narrow to plan a trajectory that would pass the nerves at a sufficient distance with the intended drill diameter. With the soft constraints introduced, the optimal target region was determined to be in the antero-inferior region of the round window membrane.Conclusion: A trend could be identified that a position between the antero-inferior border and the center of the round window membrane appears to be a favorable target position for cochlear tunnel-based access through the facial recess. The planning concept presented and the results obtained therewith have implications for planning strategies for robotic surgical procedures to the inner ear that aim for minimally traumatic cochlear access and electrode array implantation.

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In vivo endoscopic study of the variations of anatomical structures in the hidden spaces of the middle ear during endoscopic ear surgery

Moneir,

Ibraheem,

Eladl

et al. 2023

Egypt J Otolaryngol

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Objective The middle ear has compartments with the presence of anatomic variations. Transcanal endoscopic middle ear surgery facilitates the exploration of every single compartment with the least possible tissue dissection. Methods This study was conducted on 250 middle ears of patients who had endoscopic ear surgery (tympanoplasty and stapedotomy) at the period of the study with endoscopic recording of the data. Intraoperative examination of the pro, retro, and hypotympanum was performed with 0, 30, and 45° endoscopes and data was collected, processed, and analyzed with Statistical Package for Social Sciences (SPSS). Results Quadrangular conformation (64%), type B (shallow subtensor recess) (64.8%), and type A protinuculum (ridge) were the commonest in the protympanum. Type A jugular bulb which lies below the level of the bony annulus was the commonest finding (75.6%) in the hypotympanum. Type A (ridge) variant was the commonest finding of ponticulus, subiculum, and finiculus 88.4%, 64.8%, and 72.8% respectively in the retrotympanum. Type B (deep) ST 53.6% was the commonest regarding sinus tympani. Type A (present) subcochlear canaliculus, type B (oblique) fustis and type B (absent) RW membrane were the most common regarding the round window region. Conclusion Good knowledge of the anatomical variations of the middle ear has great surgical importance. The study showed variations of the known structures from other studies that can be attributed to being an in vivo study, racial differences, and a larger sample size.

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Anatomy of the Round Window Region With Relation to Selection of Entry Site Into the Scala Tympani

Cited by 4 publications

References 29 publications

Objective evaluation of the round window access in computed tomography for cochlear implantation

Objective evaluation of the round window access in computed tomography for cochlear implantation

Image-Based Planning of Minimally Traumatic Inner Ear Access for Robotic Cochlear Implantation

In vivo endoscopic study of the variations of anatomical structures in the hidden spaces of the middle ear during endoscopic ear surgery

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