scholarly journals Vestibular Organ and Cochlear Implantation–A Synchrotron and Micro-CT Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Hao Li ◽  
Nadine Schart-Moren ◽  
Gunesh Rajan ◽  
Jeremy Shaw ◽  
Seyed Alireza Rohani ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Round Window ◽  
Surgical Approaches ◽  
Basal Region ◽  
Micro Ct ◽  
Contrast Imaging ◽  
Tissue Segmentation ◽  
Vestibular Organ ◽  
Temporal Bones ◽  
3D Anatomy

Background: Reports vary on the incidence of vestibular dysfunction and dizziness in patients following cochlear implantation (CI). Disequilibrium may be caused by surgery at the cochlear base, leading to functional disturbances of the vestibular receptors and endolymphatic duct system (EDS) which are located nearby. Here, we analyzed the three-dimensional (3D) anatomy of this region, aiming to optimize surgical approaches to limit damage to the vestibular organ.Material and Methods: A total of 22 fresh-frozen human temporal bones underwent synchrotron radiation phase-contrast imaging (SR-PCI). One temporal bone underwent micro-computed tomography (micro-CT) after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue contrast. We used volume-rendering software to create 3D reconstructions and tissue segmentation that allowed precise assessment of anatomical relationships and topography. Macerated human ears belonging to the Uppsala collection were also used. Drilling and insertion of CI electrodes was performed with metric analyses of different trajectories.Results and Conclusions: SR-PCI and micro-CT imaging demonstrated the complex 3D anatomy of the basal region of the human cochlea, vestibular apparatus, and EDS. Drilling of a cochleostomy may disturb vestibular organ function by injuring the endolymphatic space and disrupting fluid barriers. The saccule is at particular risk due to its proximity to the surgical area and may explain immediate and long-term post-operative vertigo. Round window insertion may be less traumatic to the inner ear, however it may affect the vestibular receptors.

The role of preoperative imaging for auditory implants in children

2020 ◽  
Vol 74 (6) ◽  
pp. 1-5
Author(s):  
Małgorzata Burzyńska-Makuch ◽  
Józef Mierzwiński ◽  
Karolina Haber
Keyword(s):  
Inner Ear ◽  
Cochlear Implantation ◽  
Preoperative Imaging ◽  
Surgical Approaches ◽  
Clinical Decisions ◽  
Imaging Studies ◽  
Inner Ear Malformations ◽  
Ear Malformations ◽  
Cochlear Ossification ◽  
Temporal Bones

<b>Introduction:</b> Preoperative imaging, besides audiological evaluation, plays a major role in evaluation of candidacy for auditory implants, and in particular cochlear implants. It is essential to assess whether the basic criteria necessary for implantation are met. Diagnostic imaging is crucial not only in determining candidacy, but also determining the feasibility of cochlear implantation as it allow to anticipate surgical difficulties which could preclude or complicate the implantation of the device. The aim of the study is to present the protocol for the evaluation of preoperative imaging studies with particular focus on the factors potentially affecting clinical decisions in children qualified for cochlear implantation. <br><b>Material and method:</b> Preoperative imaging studies of 111 children performed prior to cochlear implantation were analyzed: high-resolution computed tomography (HRCT) of temporal bones and MRI. The assessment was made according to the presented protocol. <br><b>Results:</b> Pathologies and anomalies identified during the assessment of preoperative imaging studies significantly altered clinical decisions in 30% of patients. In the study group, in 17% of patients inner ear malformations were identified. 2.7% of children were disqualified from a cochlear implantation due to severe congenital inner ear malformations. 9% of the patients have had bacterial meningitis. In 50% of them difficulties related to complete or progressive cochlear ossification occurred. In 4.5% of patients less common surgical approaches other than mastoidectomy with a posterior tympanotomy were applied. <br><b>Discussion:</b> Preoperative imaging allow for the identification of significant pathologies and anomalies affecting qualification decisions and further treatment. HRCT and MRI are complementary to each other for preoperative imaging. The two modalities in combination allow accurate and optimal evaluation of the anatomical structures prior to implantation. Inner ear malformations and cochlear ossification following meningitis are relatively frequently encountered in children qualified for a cochlear implant.

scholarly journals Anatomical Study of the Facial Recess with Implications in Round Window Visibility for Cochlear Implantation: Personal Observations and Review of the Literature

2019 ◽  
Vol 23 (03) ◽  
pp. e281-e291 ◽  
Author(s):  
Shraddha Jain ◽  
PT Deshmukh ◽  
Pooja Lakhotia ◽  
Sanika Kalambe ◽  
Deepshikha Chandravanshi ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Round Window ◽  
Round Window Membrane ◽  
Chorda Tympani Nerve ◽  
Maximum Width ◽  
Facial Recess ◽  
Average Maximum ◽  
Mean Width ◽  
The Mean ◽  
Temporal Bones

Introduction Posterior tympanotomy through facial recess (FR) is the conventional and most preferred approach to facilitate cochlear implantation, especially when the electrode is inserted through the round window. The complications of the FR approach can be minimized by proper understanding of the anatomy of the FR. Objective The present study was undertaken to assess the various parameters of FR and round window visibility, which may be of relevance for cochlear implant surgery. Methods Thirty-five normal wet human cadaveric temporal bones were studied by dissection for anatomy of FR and posterior tympanum. Photographs were taken with an 18 megapixels digital camera, which were then imported to a computer to determine various parameters. Results The mean distance from the take-off point/crotch of the chorda tympani nerve (CTN) to the stylomastoid foramen was 4.08 ± 0.8 mm (range of 2.06 - 5.5 mm). The variations in the course of the CTN included origin at the level of the lateral semicircular canal. The mean chorda-facial angle in our study was 26.91° ± 1.19°, with a range of 25° to 28.69°. The mean FR length ranged between 9.4 mm and 18.56 mm (mean of 12.41 ± 2.91mm) and varied with the origin of the CTN and pneumatization of temporal bone. The average maximum width of the FR was 2.93 ± 0.4 mm (range 2.24–3.45 mm) and the mean width of the FR at the level of the round window was 2.65 ± 0.41 mm. Conclusion The FR approach provides good access to the round window membrane in all cases. In some cases, table adjustment is required.

The Crista Fenestra and Its Impact on the Surgical Approach to the Scala Tympani during Cochlear Implantation

2017 ◽  
Vol 22 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Roberto D. Angeli ◽  
Joel Lavinsky ◽  
Enio T. Setogutti ◽  
Luiz Lavinsky
Keyword(s):  
High Resolution ◽  
Cochlear Implantation ◽  
Round Window ◽  
Ct Scanning ◽  
Round Window Membrane ◽  
Scala Tympani ◽  
High Resolution Computed Tomography ◽  
High Resolution Ct ◽  
Round Window Niche ◽  
Temporal Bones

Objective: The aim of this work was to describe the dimensions of the crista fenestra and determine its presence by means of high-resolution computed tomography (CT) for the purpose of cochlear implantation via the round window approach. Methods: A series of 10 adult human temporal bones underwent high-resolution CT scanning and were further dissected for microscopic study of the round window niche. Results: In all of the specimens, the round window membrane was fully visualized after the complete removal of bony overhangs. The crista fenestra was identified as a sharp bony crest located in the anterior and inferior borders of the niche; its area ranged from 0.28 to 0.80 mm2 (mean 0.51 ± 0.18). The proportion of the area occupied by the crista fenestra in the whole circumference of the round window ranged from 23 to 50% (mean 36%). We found a moderate positive correlation between the area of the niche and the dimensions of the crista fenestra (Spearman rho: 0.491). In every case, high-resolution CT scanning was unable to determine the presence of the crista fenestra. Conclusion: The crista fenestra occupies a variable but expressive area within the bony round window niche. Narrower round window niches tended to house smaller crests. The presence of the crista fenestra is an important obstacle to adequate access to the scala tympani. Nevertheless, a high-resolution CT scan provides no additional preoperative information with regard to its presence for the purpose of surgical access to the scala tympani via the round window niche.

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.

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.

Morphological classification of crista fenestra of round window corridor during pediatric cochlear implantation

2021 ◽  
pp. 110816
Author(s):  
Saad Elzayat ◽  
Hitham H. Elfarargy ◽  
Islam Soltan ◽  
Mona A. Abdel-Kareem ◽  
Maurizio Barbara ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Round Window ◽  
Morphological Classification

scholarly journals Vascular Supply of the Human Spiral Ganglion: Novel Three-Dimensional Analysis Using Synchrotron Phase-Contrast Imaging and Histology

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xueshuang Mei ◽  
Rudolf Glueckert ◽  
Annelies Schrott-Fischer ◽  
Hao Li ◽  
Hanif M. Ladak ◽  
...  
Keyword(s):  
Blood Supply ◽  
Phase Contrast ◽  
Spiral Ganglion ◽  
Three Dimensional ◽  
Vascular Anatomy ◽  
Helical Structure ◽  
Vascular Supply ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Temporal Bones

AbstractHuman spiral ganglion (HSG) cell bodies located in the bony cochlea depend on a rich vascular supply to maintain excitability. These neurons are targeted by cochlear implantation (CI) to treat deafness, and their viability is critical to ensure successful clinical outcomes. The blood supply of the HSG is difficult to study due to its helical structure and encasement in hard bone. The objective of this study was to present the first three-dimensional (3D) reconstruction and analysis of the HSG blood supply using synchrotron radiation phase-contrast imaging (SR-PCI) in combination with histological analyses of archival human cochlear sections. Twenty-six human temporal bones underwent SR-PCI. Data were processed using volume-rendering software, and a representative three-dimensional (3D) model was created to allow visualization of the vascular anatomy. Histologic analysis was used to verify the segmentations. Results revealed that the HSG is supplied by radial vascular twigs which are separate from the rest of the inner ear and encased in bone. Unlike with most organs, the arteries and veins in the human cochlea do not follow the same conduits. There is a dual venous outflow and a modiolar arterial supply. This organization may explain why the HSG may endure even in cases of advanced cochlear pathology.

Methylprednisolone Applied Directly to the Round Window Reduces Dizziness after Cochlear Implantation: A Randomized Clinical Trial

2011 ◽  
Vol 16 (5) ◽  
pp. 289-303 ◽  
Author(s):  
J.C. Enticott ◽  
H.T. Eastwood ◽  
R.J. Briggs ◽  
R.C. Dowell ◽  
S.J. O’Leary
Keyword(s):  
Clinical Trial ◽  
Randomized Clinical Trial ◽  
Cochlear Implantation ◽  
Round Window

Anatomical Characteristics of Facial Nerve and Cochlea Interaction

2017 ◽  
Vol 22 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Nadine Schart-Morén ◽  
Sune Larsson ◽  
Helge Rask-Andersen ◽  
Hao Li
Keyword(s):  
Facial Nerve ◽  
Semicircular Canal ◽  
Otic Capsule ◽  
Micro Ct ◽  
Superior Semicircular Canal Dehiscence ◽  
Topographic Anatomy ◽  
3D Rendering ◽  
Superior Semicircular Canal ◽  
Archival Collection ◽  
Temporal Bones

Objective: The aim was to study the relationship between the labyrinthine portion (LP) of the facial canal and the cochlea in human inner ear molds and temporal bones using micro-CT and 3D rendering. A reduced cochlea-facial distance may spread electric currents from the cochlear implant to the LP and cause facial nerve stimulation. Influencing factors may be the topographic anatomy and otic capsule properties. Methods: An archival collection of human temporal bones underwent micro-CT and 3D reconstruction. In addition, cochlea-facial distance was assessed in silicone and polyester resin molds, and the association between the LP and upper basal turn of the cochlea was analyzed. Results: Local thinning of the otic capsule and local anatomy may explain the development of cochlea-facial dehiscence, which was found in 1.4%. A reduced cochlea-facial distance was noted in 1 bone with a superior semicircular canal dehiscence but not in bones with superior semicircular canal “blue line.” The otic capsule often impinged upon the LP and caused narrowing. Conclusion: Micro-CT with 3D rendering offers new possibilities to study the topographic anatomy of the human temporal bone. The varied shape of the cross-section of the LP could often be explained by an “intruding” cochlea.

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