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Abstract

Hypothesis: The presence of bony inner ear malformations may associate with a number of anatomical abnormalities affecting the middle ear structures. Those malformations may create pitfalls and complications for cochlear implantation. Background: Inner ear malformations associate with varying degrees of hearing loss, and frequently require cochlear implantation for hearing rehabilitation. Therefore, the abnormalities affecting the middle- and inner-ear structures may increase the risk of surgical complications. Methods: We examined 38 human temporal bones from donors with bony inner ear malformations. Using light microscopy, we analyzed the presence of abnormalities in the structures of the middle- and inner-ear. Results: Our collection comprises of 38 specimens with inner-ear malformations (cochlear aplasia, n = 3; cochlear hypoplasia, n = 30; incomplete partition, n = 3; isolated vestibular malformation, n = 2). The anatomy of the middle ear was abnormal in most temporal bones with cochlear aplasia, cochlear hypoplasia, and incomplete partition type I (40%–100%). Some of those abnormalities (hypoplastic or obliterated mastoid, 55.2%; aplastic or obliterated round window, 71.0%; aberrant course of the facial nerve, 36.8%) may hinder the access to the round window using the conventional facial recess approach for cochlear implantation. The cochlear nerve and associated bony structures (internal auditory canal and bony canal for cochlear nerve) were normal in 71.0% of all temporal bones with inner ear malformations. Conclusion: Each different type of malformation may create specific surgical challenges to surgeons. Comprehensive preoperative imaging is fundamental toward the surgical success of cochlear implants in patients with malformations. Alternatives to circumvent those middle- and inner-ear abnormalities and potential complications are further discussed.

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... Given the numerous disabilities associated with CHARGE syndrome, understanding the characteristics of structural and cellular TB abnormalities is critical for defining the best hearing and vestibular rehabilitation strategies. 5,23 This study comprises the largest case series of TBs with CHARGE syndrome to date. ...
... The narrowing of the facial recess observed in some specimens could hinder access to the RW through a traditional posterior tympanotomy approach for CI; therefore, a comprehensive preoperative imaging routine is warranted to identify and prepare the surgeon for this potential adversity. 4,5,23 Additionally, other anatomic abnormalities may constitute drawbacks for CI surgery: the sclerotic and small mastoids, RW niche obliteration, and hypoplastic cochlea and semicircular canals. These challenges could be circumvented by using an alternative route (eg, middle fosse, suprameatal, or Rambo transcanal approach) or a subtotal petrosectomy. ...
... These challenges could be circumvented by using an alternative route (eg, middle fosse, suprameatal, or Rambo transcanal approach) or a subtotal petrosectomy. 23,29 Another interesting finding was that the FN was hypoplastic in 18% of the TBs. It was not possible to correlate these findings with the clinical presentation due to a lack of clinical data. ...
Article
Objective To perform an otopathologic analysis of temporal bones (TBs) with CHARGE syndrome. Study Design Otopathologic study of human TB specimens. Setting Otopathology laboratories. Methods From the otopathology laboratories at the University of Minnesota and Massachusetts Eye and Ear Infirmary, we selected TBs from donors with CHARGE syndrome. These TBs were serially sectioned at a thickness of 20 µm, and every 10th section was stained with hematoxylin and eosin. We performed otopathologic analyses of the external ear, middle ear (middle ear cleft, mucosal lining, ossicles, mastoid, and facial nerve), and inner ear (cochlea, vestibule, internal auditory canal, and cochlear and vestibular nerves). The gathered data were statistically analyzed. Results Our study included 12 TBs from 6 donors. We found a high prevalence of abnormalities affecting the ears. The most frequent findings were stapes malformation (100%), aberrant course of the facial nerve (100%) with narrow facial recess (50%), sclerotic and hypodeveloped mastoids (50%), cochlear (100%) and vestibular (83.3%) hypoplasia with aplasia of the semicircular canals, hypoplasia and aplasia of the cochlear (66.6%) and vestibular (91.6%) nerves, and narrowing of the bony canal of the cochlear nerve (66.6%). The number of spiral ganglion and Scarpa’s ganglion neurons were decreased in all specimens (versus normative data). Conclusions In our study, CHARGE syndrome was associated with multiple TB abnormalities that may severely affect audiovestibular function and rehabilitation.
... Anatomical malformations of the middle ear can cause complexity in cochlear implant surgeries. These abnormalities could be inner ear malformations which include cochlear aplasia, hypoplasia of the cochlea, incomplete partition with a prevalence of 40%-100%, hypoplastic mastoid with 55.2% prevalence, aberrant facial nerve course with 36% prevalence rate, aplastic round window with 71% prevalence and malformation of the vestibuli [33]. These abnormalities may resist the approach to the round window using the conventional method to reach the facial recess for putting in the implant [33]. ...
... These abnormalities could be inner ear malformations which include cochlear aplasia, hypoplasia of the cochlea, incomplete partition with a prevalence of 40%-100%, hypoplastic mastoid with 55.2% prevalence, aberrant facial nerve course with 36% prevalence rate, aplastic round window with 71% prevalence and malformation of the vestibuli [33]. These abnormalities may resist the approach to the round window using the conventional method to reach the facial recess for putting in the implant [33]. ...
Article
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A cochlear implant is a neuroprosthetic, electrical device that is developed for the treatment of patients who have sensory hearing loss. It directly stimulates the hearing nerve by bypassing the injured or damaged sensory receptors, the hair cells. This implant is directly placed in the inner ear. It is an electronic device which is proved to be very useful in patients with sensorineural hearing loss. This implant consists of a speech processor (externally present), which takes up the sound; transforms it into digital signals, and then internal components take it to convert it into electrical energy, which stimulates auditory nerves, and the brain perceives it and hears it as a sound. This is one of the most successful surgeries, which happens very frequently nowadays. Although, many complications are mostly associated with this implant. This paper deals with the preoperative, operative, and postoperative complications associated with cochlear implant surgery. That includes tinnitus, Meniere's disease, unilateral hearing loss, musical ear syndrome, infections; flap necrosis, facial nerve palsy, improper electrode placement, magnet displacement; failure and re-implantation, cholesteatoma, and pneumocephalus. These are just a few of the complications; there are much more complications which are associated with cochlear implants.
... This might be related to aberrations in the normal anatomy course associated with more frequent nerve abnormalities such as hypoplastic or aplastic cochlear nerve and deformed bony structures such as narrow IAC and stenotic bony cochlear nerve canal. 17,22,23 Various ECAP metrics (e.g., thresholds, amplitudes, the slope of amplitude growth function, etc.) have been explored to evaluate the relationship between ECAP responses and auditory performance. 9,10,28,29 Due to the retrospective nature of this study, ECAP thresholds via intraoperative NRT testing were allowed to access. ...
... Reduced incidence of measurable ECAP responses in individuals with ear anomalies is presumably due to pathological changes in the peripheral auditory system that may affect ECAP responses representing a synchronized response generated by a group of electrically activated auditory nerve fibers. The presence of IEMs is known to be associated with decreased neural survival, various degrees of modiolar defects, the likelihood of fewer spiral ganglion cells, and hypoplastic or aplastic vestibulocochlear nerve.3,7,22,23 ...
Article
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Objectives This study sought to characterize the influence of inner ear malformations (IEMs) on intraoperative electrically evoked compound action potential (ECAP) and auditory performance to better understand the underlying pathophysiology related to variabilities in cochlear implant (CI) outcomes that individuals with malformed cochlea may present. Methods The medical records of 222 ears implanted with Cochlear Nucleus CI were reviewed. Of the total, 64 ears had radiologic evidence of IEMs, and 158 ears were normal. Individuals with IEMs were grouped based on the severity of anomalies; 38 had mild IEMs (e.g., enlarged vestibular aqueduct, incomplete partition type II, etc.) and 26 had severe IEMs (e.g., cochlear nerve hypoplasia, common cavity, etc.). Intraoperative ECAP thresholds obtained via neural response telemetry (NRT) and the categories of auditory performance (CAP) scores measured at 12 months postoperative were compared and correlated. Results Absent ECAP responses were more apparent in the IEM group. ECAP thresholds were significantly elevated in the severe IEM group, while the mild IEM group had ECAP thresholds comparable to the normal group. The mild IEM group achieved CAP scores similar to the normal control. Patients in the severe IEM group showed significantly lower CAP scores at 12 months postoperative. Significant negative relationships existed between ECAP thresholds and CAP scores obtained from all subjects. Conclusion Measurable ECAP responses and NRT thresholds varied across groups. The inverse relationship between NRT thresholds and CAP scores may suggest that electrophysiological responses measured during surgery may potentially be indicative of postoperative performance in our CI population. Level of Evidence 2b.
... 12,23 Batuk et al. report a case series of 12 children who received auditory brainstem implant after poor hearing outcomes with CI alone. They found a common CVN in cases of CC and report one case of CA with a hypoplastic CN. 24 Monsanto et al. found a hypoplastic CN in 66% of their cases with CA. 23 Furthermore, Adunka et al. emphasize that, even in cases with a radiologically present CN, cochlear stimulation may reveal functional CN deficiency, 25 and Birman et al. report children with functional hearing after cochlear implantation even when preoperative MRI did not reveal a nerve inside the IAC. 22 Consequently, the preoperative distinction between CA and CC and a prediction of the hearing outcome by the nerve status alone is not reliable. ...
... This issue is supported by findings from Yamazaki et al, in which the electrically evoked auditory brainstem response as tested via the CI electrode suggested that the auditory neural elements are mainly distributed to the anteroinferior part of the single cavity, that is, the cochlear portion, 27 whereas in cases of CA only vestibular parts are histologically present. 23 Structured reports on hearing outcomes after cochlear implantation in CC cases are rare, and varying results are reported. Compared to other malformations, CC cases tend to have poorer hearing outcomes. ...
Article
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Objectives The aim of this study is to compare the common cavity (CC) with the normal anatomy inner ear in order to evaluate whether the cavity is representing both the cochlear and the vestibular parts of the inner ear and to revisit CC deformity from a three‐dimensional (3D) perspective. Methods High‐resolution computed tomography image datasets of 17 temporal bones initially identified as CC were evaluated with 3D reconstruction and multiplanar image analysis using a free available software for 3D segmentation of the inner ear. All 3D images of CC were compared to a normal inner ear. Maximum and minimum diameter of the CC were correlated with the circumference of the CC in an axial plane. Results In 13 cases (76%), CC represented only the vestibular part of the inner ear and did not represent CC as defined here and by Sennaroglu, Kontorinis, and Khan. True CC was correctly diagnosed in only one case (6%). In three cases (18%), a rudimentary part of the cochlear portion could be identified. The axes' length of the elliptical cavity showed a strong positive linear relation to the circumference of the cavity (long axis: r = 0.94; P < .0001; short axis: r = 0.68; P = .0029). Conclusion This study supports the assumption that many reported CC cases only represent the vestibular part of the inner ear and are therefore cases of cochlear aplasia. 3D segmentation and systematic analysis of CT‐imaging add clinical value to the comprehension of the morphology of the anatomical structures of the inner ear. Level of Evidence 2C Laryngoscope, 2020
... Histopathological findings reveal the difficulties in demonstrating hypoplastic CN (Monsanto et al., 2019). According to the histopathological evaluation of temporal bone specimens with IEMs, a hypoplastic CN may be present but if it is located adjacent to the wall of the internal auditory canal (IAC) it may be difficult to demonstrate on magnetic resonance imaging (MRI) because of the absence of fluid signal around the nerve. ...
Article
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Objectives: This study aims to synthesize current knowledge and outcomes related to pediatric auditory brainstem implantation (ABI) in children with severe inner ear malformations (IEMs). It highlights the clinical management practices, challenges, and potential future directions for consensus development in this field. Methods: A systematic review of findings presented at the Third International Pediatric ABI Symposium organized by the Hacettepe Cochlear Implant team between 3 and 5 September 2020 was conducted, incorporating data from 41 departments across 19 countries. Relevant clinical outcomes, imaging techniques, surgical approaches, and rehabilitation strategies were analyzed to identify key trends and variability in practices. Results: The review indicates that children receiving ABIs exhibit diverse auditory outcomes influenced by individual anatomical variations and developmental factors. Early implantation, particularly before the age of three, positively correlates with better auditory and language development. Multicenter experiences underscore the necessity of tailored decision-making, which considers both surgical candidacy and comprehensive rehabilitation resources. Discussion: The variability in outcomes emphasizes the need for improved consensus and guidelines regarding eligibility, surgical techniques, and multidisciplinary rehabilitation approaches. Notable complications and the necessity for thorough imaging assessments were also identified as critical components affecting clinical decisions. Conclusion: A formal consensus statement is warranted to standardize best practices in ABI management. This will not only enhance patient outcomes but also guide future research efforts to address the remaining challenges in the treatment of children with severe IEMs. Enhanced collaboration among team members will be pivotal in achieving these objectives.
... Histopathological evaluation of temporal bones with IEMs by Monsanto et al. revealed that IP type I, characterized by an ovoid-shaped cochlear portion, had spiral ganglion cells along the posterior-inferior wall of the cochlear portion. In IP type II, severe loss of nerve fibers and spiral ganglion cells in Rosenthal's canal was observed even though the IAC and bony cochlear nerve canal were normal 26 . All these variations in the presence of nerve fibers and neuronal cell bodies could contribute to variations in hearing outcomes with CI among malformation types. ...
Article
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Estimation of cochlear length is gaining attention in the field of cochlear implants (CIs), mainly for selecting of CI electrode lengths. The currently available tools to estimate the cochlear duct length (CDL) are only valid for normal inner anatomy. However, inner ear malformation (IEM) types are associated with different degrees of cystic apices, limiting the application of CDL equations of normal anatomy inner ear. Therefore, this study aimed to understand the degree to which the outer wall (OW) is observed in different malformation types and to formulate mathematical equations to estimate the OW length (OWL) from cochlear parameters, namely the basal turn diameter (A-value) and width (B-value). Three-dimensional (3D) segmentation of promontory and fluid parts of the inner ear was performed to understand the extent to which the OW is visible to measure the OWL manually. Enlarged vestibular aqueduct syndrome (EVAS) was diagnosed in 37 ears, which consistently showed the extent of the OW to an angular depth of 540°, beyond which the cystic apex starts. Incomplete partition (IP) type I was observed in 30 ears, with the OW extending to only 360° of angular depth. IP type II was observed in 35 ears, with the OW extending to 450° of angular depth. IP type III was identified in 24 ears, with the OW observed for 540° of angular depth. Cavity-type malformations were observed in 36 ears, and circumference was measured in the axial view. A strong positive linear correlation was observed between the manually measured OWL and cochlear parameters for all malformation types analyzed. A multiple linear regression model was applied to formulate mathematical equations, which was further used to create a software application for estimating OWLs in IEM types, using cochlear parameters as inputs.
... Reduced incidence of measurable ECAP responses or poorer waveform morphology in subjects with IEMs could be due to pathological changes in the peripheral auditory system that may affect synchronization of electrically activated auditory nerve fibers and consequently affect ECAP recordings. IEMs are known to be associated with decreased neural survival, various degrees of modiolar defects, the likelihood of fewer spiral ganglion cells, and hypoplastic or aplastic vestibulocochlear nerve [20][21][22][23]. ...
Article
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Purpose The study was designed to assess the electrically evoked compound action potential (ECAP) responses in children with inner ear malformations compared to children with normal inner ear anatomy. Methods The study included 235 prelingual deaf children who were implanted in cochlear implant unit in King Fahad University hospital—Imam Abdulrahman Bin Faisel University. Subjects were using either Cochlear Nucleus or Medel cochlear implant devices. We had 171 (64.5%) subjects with normal inner ear anatomy and 94 (35.5%) subjects with inner ear malformations (IEMs) and they were classified into 6 groups according to inner ear anatomy. Fourteen subjects (14.9%) subjects had enlarged vestibular aqueduct (EVA), 30 (32%) subjects had Mondini deformity, 25 (26.6%) subjects had incomplete partition type two (IPII), 9 (9.6%) subjects had incomplete partition type one (IPI) and 16 (17%) subjects had hypoplastic cochlea type III or IV. Intraoperative electrically evoked compound action potential (ECAP) responses were analyzed and compared in all subjects. Results and conclusions Measurable ECAP responses can be elicited in patients with IEMs in most of the channels. Severe malformations can affect the prevalence of measuring ECAP and getting identifiable waveform morphology. Additionally, increased thresholds and lower slope of AGF was observed in IEMs specially in more severe malformations (e.g. IPI). IPI patients with better word recognition scores tended to show more identifiable ECAP measurements. This could suggest the presence of some correlation between ECAP responses and patients’ performance after cochlear implantation.
... It is a mentally challenging task to compile this series; to bring the sequence of the images to mind, to understand the anatomical structures, and to identify the IEM types. Another issue is that every IEM type is associated with certain surgical or CI electrode insertion complications, which makes knowing the type of IEM essential prior to CI surgery 3 . ...
Article
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Identification of the inner ear malformation types from radiographs is a complex process. We hypothesize that each inner ear anatomical type has a uniqueness in its appearance in radiographs. The outer contour of the inner ear was captured from the mid-modiolar section, perpendicular to the oblique-coronal plane, from which the A-value was determined from CT scans with different inner ear anatomical types. The mean A-value of normal anatomy (NA) and enlarged vestibular aqueduct syndrome (EVAS) anatomical types was greater than for Incomplete Partition (IP) type I, II, III and cochlear hypoplasia. The outer contour of the cochlear portion within the mid-modiolar section of NA and EVAS resembles the side view of Aladdin’s lamp; IP type I resembles the side-view of the Sphinx pyramid and type II a Pomeranian dog’s face. The steep spiraling cochlear turns of IP type III resemble an Auger screw tip. Drawing a line parallel to the posterior margin of internal auditory canal (IAC) in axial-view, bisecting the cavity into cochlear and vestibular portions, identifies common-cavity; whereas a cavity that falls under the straight-line leaving no cochlear portion identifies cochlear aplasia. An atlas of the outer contour of seventy-eight inner ears was created for the identification of the inner malformation types precisely.
Article
b> Introduction: Congenital inner ear malformations resulting from embryogenesis may be visualized in radiological scans. Many attempts have been made to describe and classify the defects of the inner ear based on anatomical and radiological findings. Aim: The aim was to propose and discuss computed tomography multi-planar and 3D image assessment protocols for detailed analysis of inner ear malformations in patients undergoing cochlear implantation counseling. Material and methods: A retrospective analysis of 22 malformed inner ears. CT scans were analyzed using the Multi-Planar Reconstruction (MPR) option and 3D reconstruction. Results: The protocol of image interpretation was developed to allow reproducibility for evaluating each set of images. The following malformations were identified: common cavity, cochlear hypoplasia type II, III, and IV, incomplete partition type II and III, and various combinations of vestibule labyrinth malformations. All anomalies have been presented and highlighted in figures with appropriate descriptions for easier identification. Figures of normal inner ears were also included for comparison. 3D reconstructions for each malformation were presented, adding clinical value to the detailed analysis. Conclusions: Properly analyzing CT scans in cochlear implantation counseling is a necessary and beneficial tool for appropriate candidate selection and preparation for surgery. As proposed in this study, the unified scans evaluation scheme simplifies the identification of malformations and reduces the risk of omitting particular anomalies. Multi-planar assessment of scans provides most of the necessary details. The 3D reconstruction technique is valuable in addition to diagnostics influencing the decision-making process. It can minimize the risk of misdiagnosis. Disclosure of the inner ear defect and its precise imaging provides detailed anatomical knowledge of each ear, enabling the selection of the appropriate cochlear implant electrode and the optimal surgical technique.</br
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Introduction:Incomplete partition (IP) type and accompanying cochlear nerve (CN) anomalies affect the patient’s management. We revealed the cochlear nerve area (CNA), cochlear nerve canal width (CNCW), and inner auditory canal width (IACW) of IP types.Methods:We retrospectively scanned patients with IP. There were 88 IP ears (26 IP type 1, 54 IP type 2, 8 IP type 3) and 54 controls. The CNCW and IACW were measured in axial temporal computed tomography sections. The CNA and facial nerve area (FNA) were measured in the distal IAC on the sagittal-oblique plane of 3D constructive interference steady-state T2-weighted magnetic resonance images.Results:CNA and CNA/FNA values for each IP type differed significantly compared with the control group. However, the CNCW and IACW values did not differ significantly. The CNA was the least in IP 1 cases. Five CN aplasia were detected, and all were associated with IP type 1 anomaly (3.5% of all, 5.6% of IP types, and 19.2% of IP type 1 cases). CN hypoplasia was observed in 10 IP type 1 (38.5% of IP 1), 6 IP type 2 (6.8% of IP type 2), and 1 IP type 3 (12.5% of IP type 3) ears. None of the CN hypoplasia had a CNC hypoplasia.Conclusion:CN aplasia and hypoplasia most frequently accompanied with IP type 1 in our study. Therefore, they need an extra interest in CN evaluation. CNCW and IACW are not very useful in predicting CN dysplasia in IP cases.
Chapter
For years, the term “Mondini dysplasia” was used to describe virtually every type of congenital inner ear malformation detected in imaging tests. More recently, histopathologic and imaging studies led to the description of several novel morphologic features, which were categorized into new groups according to morphologic patterns of the inner ear abnormalities. In addition, those new findings made possible to hypothesize potential pathophysiologic and embryogenic mechanisms involved in the genesis of each specific type of malformation. However, there are still obscure areas that still need to be better understood, such as quantitative and qualitative pathologic changes in the cellular, sensorial, and neural elements in the inner ear of patients with inner ear abnormalities. Therefore, histologic analysis of human temporal bones from patients who had inner ear malformations constitutes a tool of invaluable value. The clinical impact of past studies involving inner ear malformations is clear: today, cochlear implants or auditory brainstem implants are well indicated to treat hearing loss in patients with inner ear malformations, who were previously excluded from candidacy criteria. In the future, a broader understanding of yet obscure aspects of those malformations may increase even further the candidacy for those implants and create strategies for improved functional results. Thus, the objective of this chapter is to report, based on a review of the literature, otopathologic findings in human temporal bones from donors with inner ear malformations and to correlate the findings with embryogenic factors and their clinical implications.KeywordsHistopathologyEarInner earHumanCochleaVestibuleCochlear implant
Chapter
Preoperative imaging of the inner ear anomalies is central to proper treatment planning and patient management. For the imaging assessment of these patients high-resolution CT and MR imaging usually provide complementary information. The imaging of a CI or ABI candidate should not only help to fulfill the indication criteria but should also help to assess the integrity of the auditory pathway from the brainstem up to the temporal cortex.KeywordsInner ear anomaliesTemporal boneCochlear implantsComputed tomographyMagnetic resonance imaging
Article
Inner ear malformations are associated with different degrees of hearing loss. Some of these anomalies require cochlear implantation because of the occurrence of profound hearing loss. The radiological imaging necessary for the evaluation of the congenital hearing loss might also reveal the concomitant presence of important collateral findings such as the central nervous system and cranial nerves malformations. These neurological features might be extremely important in the surgical planning of the cochlear implantation and also have a role in the hearing and speech development of the affected children. In addition, anomalies affecting specific structures of the inner ear should be considered predisposing factors for otogenic meningitis and they should be identified as early as possible. The present review aims to summarize the available literature about this specific topic crucial for the patients’ neuropsychological and auditory development.
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Morphologically congenital sensorineural hearing loss can be investigated under two categories. Majority of the congenital hearing loss (80%) are membranous malformations. Here the pathology involves inner ear hair cells. There is no gross bony abnormality and therefore, in these cases, high resolution computerized tomography and MRI of the temporal bone reveal normal findings. Remaining 20% have various malformations involving the bony labyrinth and therefore, can be radiologically demonstrated by CT and MRI. The latter group involves surgical challenges as well as problems in decision making. Some cases may be managed by hearing aid, some need cochlear implantation while some cases are candidates for an auditory brainstem implantation. During cochlear implantation, there may be facial nerve abnormalities, cerebrospinal fluid leakage, electrode misplacement or difficulty in finding the cochlea itself. During the surgery for inner ear malformations, surgeon must be ready to modify the surgical approach or choose special electrodes for surgery. In the present review article inner ear malformations are classified according to the differences observed in the cochlea. Hearing and language outcome after various implantation methods is closely related to the status of cochlear nerve and a practical classification of the cochlear nerve deficiency is also provided.
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Our study aimed to evaluate pathologic changes in the cochlear (inner and outer hair cells and stria vascularis) and vestibular (vestibular hair cells, dark, and transitional cells) sensorial elements in temporal bones from donors who had otitis media. We studied 40 temporal bones from donors who had otitis media. These bones were categorized in serous otitis media (SOM), serous-purulent otitis media (SPOM), mucoid/mucoid-purulent otitis media (MOM/MPOM), and chronic otitis media (COM); control group comprised 10 nondiseased temporal bones. We found significant loss of inner and outer cochlear hair cells in the basal turn of the SPOM, MOM/MPOM and COM groups; significant loss of vestibular hair cells was observed in the MOM/MPOM and COM groups. All otitis media groups had smaller mean area of the stria vascularis in the basal turn of the cochlea when compared to controls. In conclusion, our study demonstrated more severe pathologic changes in the later stages of the continuum of otitis media (MOM/MPOM and COM). Those changes seem to progress from the basal turn of the cochlea (stria vascularis, then inner and outer hair cells) to the middle turn of the cochlea and to the saccule and utricle in the MOM/MPOM and COM stages.
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Objective: To compare the audiological and radiological findings of patients with incomplete partition malformations (IPs) and analyze the relationship between the audiological and radiological findings. Materials and methods: The study included 84 patients (168 ears) with IPs as follows: 26 patients with Type I;IP-I (41 ears), 54 patients with Type II;IP-II (108 ears), and 4 patients with Type III;IP-III (8 ears). Remaining 11 ears were diagnosed with other inner ear malformations. Air and bone conduction thresholds were determined with pure tone audiometry, and the air bone gap was recorded in all patients with IPs. Magnetic resonance imaging studies and computerized tomography scans of the temporal bones were analyzed using the PACS system of our university. Results: It was found that all the ears with IP-I were diagnosed with severe to profound hearing loss. The degree of the hearing loss varied from mild to severe/profound in patients with IP-II. Severe to profound mixed hearing loss (MHL) was determined in all ears with IP-III. The air bone gap was larger in the lower frequencies in the IP-II cases diagnosed with MHL. There was not a significant difference between the air bone gap and the size of the vestibular aqueduct in ears with IP-II (p>0.05). Conclusion: Each type of IP has different audiological findings. Depending on the type and degree of the hearing loss, it is possible to choose the appropriate audiological intervention. Patients with IP should be evaluated according to the type of malformation.
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Objectives/hypothesis: In this study, our objective was to histopathologically analyze the peripheral vestibular system in patients with Mondini dysplasia. Study design: Comparative human temporal bone study. Methods: We assessed the sensory epithelium of the human vestibular system with a focus on the number of type I and type II hair cells, as well as the total number of hair cells. We compared those numbers in our Mondini dysplasia group versus our control group. Results: The loss of type I and type II hair cells in the cristae of the superior, lateral, and posterior semicircular canals, as well as in the saccular and utricular macula, was significantly higher in our Mondini dysplasia group than in our control group. The total number of hair cells significantly decreased in the cristae of the superior, lateral, and posterior semicircular canals, as well as in the saccular and utricular macula, in our Mondini dysplasia group. Conclusion: Loss of vestibular hair cells can lead to vestibular dysfunction in patients with Mondini dysplasia. Level of evidence: N/A. Laryngoscope, 2016.
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The objective of this study is to review the literature regarding Auditory Brainstem Implant (ABI) indications, surgical techniques, activation methods, and post-surgery follow-up in children. A search was performed in the LILACS, MEDLINE, SciELO, and PubMed databases in June 2014, and the key words used in the search were (("auditory brain stem implant" OR "auditory brainstem implants") OR ("auditory" AND "brainstem" AND ("implants" OR "implant")). Forty-two studies that met the criteria described in "Study Selection" were read in full; 24 studies referred to the ABI fitting process in children, and were selected for appraisal. The studies showed 120 children (younger than 18 years old) fitted with ABIs. Evaluation after surgery showed that 112 (93.3%) of the patients improved in their ability to recognize environmental sounds and speech perception. Patients with tumors or those with cochlear or cochlear nerve malformations had good outcomes as well. Two of the children did not achieve any sound perception upon ABI activation. The results obtained in 120 children fitted with an ABI showed that the patients globally improved in their ability to detect sounds and communication skills. The phenomenon could be seen both in patients with tumoral diseases of the inner ear and those with malformations of the cochlea or cochlear nerve, although patients with non-tumoral issues achieved better results than patients with schwannomas. We propose that the Food and Drug Administration (FDA) ABI indications should be extended to patients younger than 12 years old with NT diseases of the cochlea and cochlear nerve.
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To compare the outcomes between 2 age-matched cohorts of children with cochlear nerve deficiency: those receiving auditory brainstem implants (group A) or cochlear implants (group B). Retrospective cohort study. Tertiary referral center. Subjects were selected from a pool of 537 children fitted with cochlear implants (n = 443) or auditory brainstem implants (n = 94) over the past 14 years. Performance, examined with the Category of Auditory Performance scale, and complications were compared with a mean follow-up of 5 years. All children had bilateral profound sensorineural hearing loss and cochlear nerve deficiency. Magnetic resonance imaging documented an absent cochlear nerve (n = 12) and a small cochlear nerve (n = 8) in group A and an absent cochlear nerve (n = 11) and a small cochlear nerve (n = 9) in group B (P = 1.000). Children with cochlear implants had Category of Auditory Performance scores spanning from 0 to 3 levels of performance, and all required manual communication mode and visual supplementation. Children with auditory brainstem implants had Category of Auditory Performance scores spanning from 2 to 7, and most patients demonstrated behavioral responses irrespective of inner ear malformations and an absent cochlear nerve or small cochlear nerve (P < .001). In children with cochlear nerve deficiency, patients fitted with cochlear implants did not develop speech understanding and production. Those fitted with auditory brainstem implants had the opportunity to develop open-set speech perception, acquiring verbal language competence using oral communication exclusively and participating in mainstream education. The overall complication rate of auditory brainstem implants was not greater than that of cochlear implants.
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Recurrent bacterial meningitis (RBM) in many instances is associated with identifiable anatomical defects. Presence of congenital deafness with recurrent meningitis should alert clinician for presence of middle and inner ear malformation. These defects can be demonstrated by various neuro imaging techniques and can be surgically corrected. In this case report we describe a child seen at our institute with congenital deafness and recurrent meningitis, discuss the approach to RBM and briefly describe inner ear malformation associated with the same and how to differentiate them.
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The Veria operation is a non-mastoidectomy technique for cochlear implantation. It uses the transcanal approach to the middle ear and the cochlea. The steps of the procedure are: (1) endaural approach, that offers a wide accessibility to the middle ear structures; (2) inspection of the middle ear anatomy; (3) straightening of the postero-superior bony canal wall, which is usually concave; (4) performing the cochleostomy through the outer ear canal; (5) drilling of the suprameatal hollow, which is used for the accommodation of the electrode excess; (6) drilling of the trans-wall direct tunnel, which is the pathway for the active electrode; (7) alignment of the direct tunnel to the cochleostomy; (8) extension of the incision and preparing of the flaps; (9) creating of the bed and fixing the device; (10) insertion of the electrodes; (11) manipulating the excess of the active electrode, and (12) closing. For this technique, two special instruments have been developed: a special perforator used for the drilling of the direct tunnel for the active electrode, making it completely safe, and a safety electrode forceps used to manipulate the active electrode during insertion. The direct tunnel can be enlarged superiorly permitting insertion of two electrodes, in cases where a double electrode array implant has to be used. The method is an efficient tool for handling all cochlear implant cases, including difficult ones such as revision cases, malformations, cochlear ossifications and poor mastoid development. It is safe without complications in over a hundred cases and easy to learn.
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Unlabelled: The classic approach for cochlear implant surgery includes mastoidectomy and posterior tympanotomy. The middle cranial fossa approach is a proven alternative, but it has been used only sporadically and inconsistently in cochlear implantation. Objective: To describe a new approach to expose the basal turn of the cochlea in cochlear implant surgery through the middle cranial fossa. Method: Fifty temporal bones were dissected in this anatomic study of the temporal bone. Cochleostomies were performed through the middle cranial fossa approach in the most superficial portion of the basal turn of the cochlea, using the meatal plane and the superior petrous sinus as landmarks. The lateral wall of the internal acoustic canal was dissected after the petrous apex had been drilled and stripped. The dissected wall of the inner acoustic canal was followed longitudinally to the cochleostomy. Results: Only the superficial portion of the basal turn of the cochlea was opened in the fifty temporal bones included in this study. The exposure of the basal turn of the cochlea allowed the visualization of the scala tympani and the scala vestibuli, which enabled the array to be easily inserted through the scala tympani. Conclusion: The proposed approach is simple to use and provides sufficient exposure of the basal turn of the cochlea.
Article
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Approximately 20% of patients with congenital sensorineural hearing loss have radiographic abnormalities of the inner ear. A broad spectrum of anomalous patterns have been described, most of which have been lumped together under the term “Mondini's dysplasia.” We feel that this grouping of many dissimilar entities under a single umbrella term is unwarranted. Based on a review of 63 patients with 98 congenitally malformed ears, we have been able to recognize a number of distinct anatomic patterns from their radiographic appearance. A remarkable similarity between these morphologies and the appearance of the inner ear at various stages of embryogenesis was found. This led us to propose a classification system based upon the theory that these deformities result from an arrest of development during varying stages of inner ear organogenesis.
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In the ENT region 50% of the malformations affect the ear. Malformations of the outer and middle ear are predominantly unilateral (ca. 70-90%) and mostly involve the right ear. Inner ear malformations can be unilateral or bilateral. The incidence of ear malformations is approximately 1 in 3800 newborns. Ear malformations may be genetic (associated with syndromes or not, with family history, spontaneous mutations) or acquired in nature. Malformations can affect the outer ear (pinna and external auditory canal, EAC), middle ear and inner ear, not infrequently in combination. Formal classification is advisable in order to be able to predict the prognosis and compare treatment schedules. Various classifications have been proposed: pinna and EAC malformations according to Weerda [1], middle ear malformations according to Kösling [2], and inner ear malformations according to Jackler [3], [4], to Marangos [5] and to Sennaroglu [6]. Additionally, we describe Altmann's classification of atresia auris congenita [7] and the Siegert-Mayer-Weerda score [8] for EAC and middle ear malformations, systems of great practicability that are in widespread clinical use. The diagnostic steps include clinical examination, audiological testing, genetic analysis and, especially, CT and MRI. These imaging methods are most usefully employed in combination. Precise description of the malformations by means of CT and MRI is indispensable for the planning and successful outcome of operative ear reconstruction and rehabilitation procedures, including cochlear implantation.
Chapter
Approximately 2% of congenital profound deafness cases are due to cochlear nerve (CN) deficiency. MRI is essential to confirm if the nerve is deficient, but because of limitations with resolution, especially when the internal auditory canal is narrowed, it is often unable to distinguish between hypoplasia and aplasia. A full audiometric test battery should always be performed, even if the MRI suggests CN aplasia, as there will sometimes be evidence of audition. Electrically evoked auditory brainstem response testing can be carried out transtympanically via the round window or using an intracochlear test electrode to help determine the status of the CN. If any test suggests the presence of a CN, then cochlear implantation (CI) should be considered. Children should be followed up closely with audiometric, electrophysiological and language assessments to determine the benefits. They may initially show benefit but fail to progress. CI results are variable and often result in poor outcomes with Categories of Auditory Perception scores of <5. Auditory brainstem implantation (ABI) can be considered when CI is contraindicated or fails to provide adequate benefit. This may provide better outcomes, but this form of surgery has greater risks and future device replacement (in case of device failure) may be complicated. Careful patient selection is required when considering ABI as significant learning difficulties make programming extremely challenging. Patients should be given the option of CI first and then ABI. A small minority of patients presenting late (around 2-3 years of age) may be candidates for simultaneous CI and ABI.
Article
Objective and importance: Reports of patients with concurrent middle and inner ear anomalies are rare. These patients present a surgical challenge for cochlear implantation. The surgical risk must be weighed against the predicted benefit of the patient’s hearing outcome and subsequent development of speech and language as well as their quality of life. Clinical presentation: Thirteen-year-old boy presented to the Otology clinic for auditory rehabilitation options. He has mild developmental delay, is non-verbal and communicates via American Sign Language. He was born with bilateral aural atresia and never wore amplification. On exam he has grade 1 microtia and complete ear canal atresia bilaterally. His behavioural hearing test shows profound sensorineural hearing loss of both ears. The computed tomography scan shows bilateral underdeveloped and completely opacified mastoid and middle ear, complete bony atresia of the ear canals, and an under-partitioned cochlea with poorly defined modiolus, among other abnormalities. The patient and his family were counselled on the available options as well as the need for any further studies. Intervention: Counselling of patient and family. Conclusion: While there have been reports in the literature of performing cochlear implantations in patients with a concurrent atresia and cochlear dysplasia, these were patients whose degree of inner ear anomalies was relatively minor and their prognosis of a good audiological outcome was favourable. The presented case is that of a patient for whom the surgical approach to the cochlea alone would be difficult. More importantly, his quality of life would not significantly improve in light of the predicted limited hearing and language development outcomes, given the severity of his inner ear abnormalities, limited communication abilities, prolonged period of deafness and developmental delays.
Article
To see the radiological anatomy of inner ear malformations in hearing impaired children. This study was a prospective observational study done at a tertiary care teaching hospital in north India. The included were children of 1–7 years with first time detected severe to profound SNHL. The evaluation of hearing was done by brainstem evoked response audiometry. Those with history of chronic suppurative otitis media and conductive hearing loss were excluded. The all included were undergone high resolution computed tomography of the tympano-mastoid region. A written informed consent was taken. The institutional ethics committee approved the study protocol. We screened 130 children of 1–7 years of age with complaints of severe to profound hearing impairment (SNHL) by BERA. We excluded 38 and 14 children who had conductive hearing loss with or without CSOM and did not give consent, respectively. Among recruited 78 children, 47 (60.3%) had severe (71–90 dB) and 31 (39.7%) had profound (> 90 dB) SNHL. The majority of children (60/78, 76.9%) had a bilateral hearing impairment, only 18 (23.1%) had unilateral hearing impairment. The mean ± SD of age was 3.9 ± 1.3 years (95% CI = 3.6–4.2). The incidence of severe to profound SNHL was higher, though not statistically significant among the girls. Only 7.7% children with severe to profound SNHL were detected within first 2 years of life. Most of the children (92.3%) with severe to profound SNHL were detected after 2 years of age. Among 78 with severe to profound SNHL, 16 (20.5%) children had structural anomalies in their internal ears. Only 2 (6.9%) ears had single anomaly, others (27, 93.1%) had multiple anomalies. A maximum number of anomalies found in one ear were 5. The most common anomalies were found in the vestibule. The total number of anomalies were 115. Five children (6.4%) with severe to profound SNHL had craniofacial dysmorphism. Approximately 20% of children with severe to profound SNHL have congenital anomalies in their internal ears. It is crucial to know these anomalies before planning of CI. HRCT of tympano-mastoid is the first modality to know these anomalies. MRI should also be included to know the details of vestibulocochlear nerve. Since, the neurocognitive outcome would be the best if CI will be done as early as possible preferably around 1 year of age. Therefore, children must be screened at the appropriate age, firstly by OAE followed by BERA.
Article
Objective: To describe and discuss otologic manifestations of Larsen syndrome, based on a case report and a systematic review of the literature. Materials and methods: We performed a PubMED database search, and we selected studies reporting otolaryngologic manifestations secondary to Larsen syndrome. The selected articles were read in full, and three researchers independently extracted data from the studies. In parallel, we report the case of a 14-year-old patient who had hearing loss secondary to Larsen syndrome. Results: Fifteen studies met our selection criteria. Seven studies reported hearing loss in patients with Larsen syndrome (4 had conductive hearing loss and 3 had mixed hearing loss). The conductive hearing loss may be secondary to ossicular malformations and/or middle ear effusions. Other causes for conductive hearing loss are mesenchymal remnants in the middle ear, Eustachian tube dysfunction, and cleft palate. Surgical management of the hearing loss is possible in selected cases, although the surgical and anesthetic risks should be considered. Hearing aids seem to be safe and effective treatment options for the hearing loss secondary to Larsen syndrome. Conclusion: Although rare, patients with Larsen syndrome may have hearing loss. The most frequent type of deficit is conductive, either secondary to malformation of the ossicles or middle ear effusion. Possible surgical correction of these abnormalities should be weighed against the anesthetic risks of these patients.
Article
Objectives The bony cochlear nerve canal is the space between the fundus of the internal auditory canal and the base of the cochlear modiolus that carries cochlear nerve fibres. This study aimed to determine the distribution of bony labyrinth anomalies and cochlear nerve anomalies in patients with bony cochlear nerve canal and internal auditory canal atresia and stenosis, and then to compare the diameter of the bony cochlear nerve canal and internal auditory canal with cochlear nerve status. Methods The study included 38 sensorineural hearing loss patients (59 ears) in whom the bony cochlear nerve canal diameter at the mid-modiolus was 1.5 mm or less. Atretic and stenotic bony cochlear nerve canals were examined separately, and internal auditory canals with a mid-point diameter of less than 2 mm were considered stenotic. Temporal bone computed tomography and magnetic resonance imaging scans were reviewed to determine cochlear nerve status. Results Cochlear hypoplasia was noted in 44 out of 59 ears (75 per cent) with a bony cochlear nerve canal diameter at the mid-modiolus of 1.5 mm or less. Approximately 33 per cent of ears with bony cochlear nerve canal stenosis also had a stenotic internal auditory canal and 84 per cent had a hypoplastic or aplastic cochlear nerve. All patients with bony cochlear nerve canal atresia had cochlear nerve deficiency. The cochlear nerve was hypoplastic or aplastic when the diameter of the bony cochlear nerve canal was less than 1.5 mm and the diameter of the internal auditory canal was less than 2 mm. Conclusion The cochlear nerve may be aplastic or hypoplastic even if temporal bone computed tomography findings indicate a normal cochlea. If possible, patients scheduled to receive a cochlear implant should undergo both computed tomography and magnetic resonance imaging of the temporal bone. The bony cochlear nerve canal and internal auditory canal are complementary structures, and both should be assessed to determine cochlear nerve status.
Article
Objective: The aim of the current study is to evaluate audiologic and radiologic findings of cochlear hypoplasia which is a subgroup of inner ear malformations. Methods: This study was a prospective clinical study and based on voluntary participation from cases with cochlear hypoplasia diagnosis. The study was conducted at Hacettepe University, Department of Otolaryngology, Head and Neck Surgery and Department of Audiology. Subjects were selected from an inner ear malformations database. Inclusion criteria were having cochlear hypoplasia for at least one ear. There were 66 subjects with an age range of 12 months and 60 years 5 months. For each subject, pure tone audiometry and tympanometry were applied according to chronological and cognitive age. And also, auditory brainstem response test was applied to when it is need. Subjects' radiologic results were reevaluated to confirm cochlear hypoplasia, cochlear nerve and cochlear aperture. Results: Cochlear hypoplasia types were statistically significantly different in terms of HL degree. This difference was caused by cochlear hypoplasia type IV group being was statistically different from the other three groups. Like with degree of HL, cochlear hypoplasia groups were statistically different from other three groups in terms of type of hearing loss. Cochlear aperture and cochlear nerve status showed variation according to cochlear hypoplasia type but these differences were not statistically approved. Conclusions: In the current study, incidence of cochlear hypoplasia was 23.5% in all inner ear malformation. With this study, it was seen that subtypes of cochlear hypoplasia showed variability in terms of degree and type of hearing loss and also cochlear aperture and cochlear nerve status. Especially cochlear hypoplasia type IV differs from other three cochlear hypoplasia types.
Article
Objective: To investigate the histopathology of inner ear malformations (IEMs) in order to explain their pathophysiology. Method: Light microscopy was used to study 33 specimens exhibiting various IEMs in the collection of the Otopathology Laboratory at Harvard University's Massachusetts Eye and Ear Infirmary. Results: The investigation found 18 incidences of cochlear hypoplasia (CH) (3 CH-I, 10 CH-II, 5 CH-III), 11 incomplete partitions (IPs) (5 IP-I, 6 IP-II), 2 vestibular dilatations, and 2 cases of cochlear nerve aplasia. The IP-I cases had characteristic defective endosteums, while the IP-II cases showed hydropic changes in the scala vestibuli. The CH cases were small in size externally, with normal or defective internal architecture. Conclusion: In combination with embryological data, these findings suggest that cases of CH-III and CH-IV are most probably genetically predetermined to be small in size, and that development of the membranous labyrinth stops at a point earlier than normal, so that it is shorter. At the time of complete ossification, this results in a cochlea with small external dimensions and normal internal architecture. In CH-I and CH-II cases, there is arrested development of the internal architecture, in addition to a small cochlea; it is most likely that in these cases, there is a severely defective vascular supply from the internal auditory canal (IAC). IP-I may be the result of a defective vascular supply from the blood vessels of the IAC. In IP-II, an enlarged endolymphatic sac (EES) appears to be the genetic abnormality that causes the other abnormalities, as it allows high pressure to be transmitted into the cochlea and vestibule. In IP-III, the pathophysiology appears to be an abnormal vascular supply from the middle ear mucosa, caused by a genetic abnormality and resulting in a thinner otic capsule and the absence of the modiolus.
Article
Intraoperative cerebrospinal fluid (CSF) leakages from the cochleostomy site - known as gushers - are a serious complication of cochlear implantation surgery in cases of congenital deafness. They occur as the result of abnormal communication between CSF in the internal auditory canal and perilymph in the cochlea. Gushers are well recognized as occurring in a proportion of cases in which there is a clearly visible congenital malformation of the cochlea. In this report, we describe two cases in which pre-operative computed tomography (CT) scanning of the cochlea was initially reported as normal but gushers occurred during cochlear implant surgery. In both cases, more detailed review of the CT scans (peroperatively in the first case, pre-operatively in the second case) showed a defect at the cochlear base, in the absence of any other cochlear malformation. The aim of this paper is to draw attention to the risk of missing this abnormality and to encourage careful inspection of the cochlear base on CT scans in all cases, even when the rest of the cochlear appears normal.
Article
Conclusion: The technique proposed is simple, reliable, and provides sufficient exposure of the basal portion of the cochlea while avoiding disabling complications. It enables visualization of the cochlear basal turn and the osseous spiral lamina, facilitating the insertion of the cochlear implant array through the scala tympani. Objectives: To describe a novel approach for exposing the cochlear basal turn for cochlear implantation through the middle cranial fossa. Methods: Fifty temporal bones were dissected and a cochleostomy was performed via a middle fossa approach on the most superficial part of the cochlear basal turn, using the superior petrosal sinus, the skeletonized petrous apex, the lateral surface of the meatal plane trailed on the petrous apex from its most proximal portion, and the great superficial petrosal nerve as landmarks. The distance between the landmarks and the distance between the cochleostomy and the round window were measured. Results: In all temporal bones, only the top portion of the cochlear basal turn was uncovered. The cochleostomy allowed both the scala tympani and the vestibule to be exposed. A computed tomography scan of the temporal bones was performed to document the electrode insertion from the cochlear basal turn until its apex. The mean ± SD minor and major distances between the cochleostomy and the meatal plane were estimated to be 2.48 ± 0.88 mm and 3.11 ± 0.86 mm, respectively. The mean distance from the cochleostomy to the round window was 8.38 ± 1.96 mm, and that to the superior petrosal sinus was 9.19 ± 1.59 mm. The mean minor and major distances between the cochleostomy and the long axis of the meatal plane from its most proximal portion were estimated to be 6.63 ± 1.38 mm and 8.29 ± 1.43 mm, respectively.
Article
Inner ear malformations constitute about 20% of congenital sensorineural hearing loss. In this review article an updated classification of cochlear malformations is provided. Incomplete partition and cochlear hypoplasia cases are each divided further into three groups. There are two main difficulties in the surgery of inner ear malformations; gusher and facial nerve abnormalities. Radiological features of malformations necessary to identify these problems preoperatively are discussed. Facial nerve abnormalities that may occur are described. Two different types of cerebrospinal fluid leakage are defined and necessary measures to prevent leakage are described. Standard and modified surgical approaches to overcome the described problems are described with literature findings. Finally meningitis which may occur with and without cochlear implantation in this special group of patients is emphasized. This is common in incomplete partition type I patients and is usually due to a fistula in one of the windows (usually oval window) which occurs as a result of cerebrospinal fluid pressure. This is a medical emergency leading to potential meningitis and measures that should be taken to stop the leak as soon as possible are described.
Article
Approximately 20% of patients with congenital sensorineural hearing loss have radiographic abnormalities of the inner ear. A broad spectrum of anomalous patterns have been described, most of which have been lumped together under the term "Mondini's dysplasia." We feel that this grouping of many dissimilar entities under a single umbrella term is unwarranted. Based on a review of 63 patients with 98 congenitally malformed ears, we have been able to recognize a number of distinct anatomic patterns from their radiographic appearance. A remarkable similarity between these morphologies and the appearance of the inner ear at various stages of embryogenesis was found. This led us to propose a classification system based upon the theory that these deformities result from an arrest of development during varying stages of inner ear organogenesis.
Article
The temporal bone findings from two patients with Mondini's genetic aplastic deafness are described. Profound sensorineural deafness was present in both cases and audiology and speech studies were available for the first patient. Cochlear changes which were similar for both, consisted of a flattened cochlear capsule, 1½ instead of 2½ cochlear turns, missing interscalar septum, between middle and apical turn forming a scala communis or cloaca, organ of Corti lesions more marked in the upper turn, spotty aplasia of the stria vascularis and spiral ligament, and reduced spiral ganglion cells and dendrites. An unusual finding in the first patient was the complete absence (aplasia) of the three semicircular canals, the utricle, and the vestibular nerve. An abnormal saccule and a markedly enlarged endolymphatic duct and sac were also present.
Article
From a histopathological survey of 12 ears (7 cases) of Mondini's deformity and deafness, the following conclusions or interpretations are drawn: 1) Mondini's bony deformity diagnosable by polytomography does not necessarily indicate Mondini's deafness or x-ray diagnosis of Mondini's deafness cannot be specifically relied upon. 2) The pars superior (semicircular canals and utricle) may be absent (aplastic) or the canals may be enlarged leading to interesting questions regarding vestibular physiology in such patients. 3) Enlarged endolymphatic duct and deficient utriculoendolymphatic valve are commonly found associated with absence of endolymphatic hydrops or collapse suggesting an operational longitudinal flow. 4) One and one-half or fewer (instead of 2 1/2) cochlear turns are characteristic; however, end-organ of Corti lesions (aplasia) may be present or absent leading to interesting speculations for further research regarding auditory function, especially in those cases with normal-appearing sensory structures. 5) Mechanisms of hearing loss in Mondini's deafness can be variably explained on the basis of inner ear or middle ear pathology including dysgenesis of the end-organs and associated neural elements sufficient to cause sensorineural hearing loss, aplasia of the oval or round windows which might explain manifest "sensorineural hearing loss" in the presence of normal-appearing organs of Corti and aplasia or infection of the middle ear causing a conductive loss which can be superimposed upon a sensorineural hearing loss.
Article
Congenital deformities of the labyrinth of the inner ear can be associated with meningitis and varying degrees of hearing loss or deafness. A recurrence of meningitis is due to the development of a fistulous communication between the subarachnoid space and the middle ear cavity, and can prove lethal. An illustrative case of a 4-year-old Japanese girl with bilateral severe hearing loss, recurrent meningitis and malformations of the inner ear and stapes footplate is presented. Removal of the stapes during tympanotomy provoked a gush of cerebrospinal fluid. The defect was repaired successfully, and there has been no further episodes of meningitis to date.
Article
The preliminary results of insertion of a cochlear implant via the middle fossa in nine patients with profound bilateral hearing loss are described. Aetiologies included a bilateral radical mastoidectomy cavity, adhesive otitis media, autoimmune inner ear disease, previous cranial trauma, genetic pre-lingual deafness, and otosclerosis. A classic middle fossa approach was adopted. A small cochleostomy measuring 1.5 mm in diameter was performed on the most superficial part of the basal turn. A Nucleus 24M cochlear implant system (Cochlear Corporation) was inserted in four patients, a Lauraflex implant (Philips Hearing Implants) was used in three patients and a Combi 40+ (Med-el) with a double electrode array in two. Single electrode arrays were inserted from the cochleostomy to the cochlear apex and occupied a portion of the basal turn, as well as the middle and apical turns. Double electrode arrays were inserted, one towards the apex and one into the basal turn of the cochlea towards the round window. The receiver stimulator was positioned in a bone well previously drilled in the temporal squama and the electrode carrier was inserted in the fenestrated cochlea. The activity of the inserted electrodes was tested by means of telemetry and intraoperative recording of electrically evoked auditory brainstem responses (EABR). Speech recognition tests, performed over a period of time ranging from one to six months after cochlear implant activation, yielded better results in these patients compared with those obtained in postlingually deaf patients operated on via the traditional transmastoid route. Cochlear implant insertion via the middle fossa approach is a technique which is suitable for the implantation of patients with bilateral radical mastoidectomy cavities, chronic middle ear disease, middle ear malformations, or with partial obliteration of the cochlea in the basal turn. However, the main advantage of inserting the implant through the middle fossa cochleostomy consists in the possibility of stimulating, with the single array, areas of the cochlea, i.e. part of the basal, middle and apical turns, where a greater survival rate of spiral ganglion cells is known to occur. In addition, with the double array total occupation of the cochlea is possible, providing the possibility of replicating the tonotopic organization of the cochlea. This new approach has led to major improvements in speech recognition in all patients compared with patients operated on via the transmastoid approach and, given the present state of the art, may be the elective approach for optimal implantation outcomes.
Article
The objective of this review is to analyze aspects of congenital malformation of the ear in relation to cochlear implantation in children. Having briefly described the in utero development of the ear and the classification of types of external, middle and inner ear malformation, five practical aspects of these malformations are discussed. It seems likely that the combination of bilateral profound sensorineural deafness with bilateral microtia severe enough to make a surgical approach to the cochlea difficult will be extremely uncommon. No such cases have been reported, although Klippel-Feil deformity seems the syndrome most likely to produce this set of circumstances. Abnormalities in the intratympanic course of the facial nerve have been associated with cochlear malformation, emphasizing the benefit of intra-operative facial nerve monitoring, and a technique suggested for safely avoiding an abnormally placed nerve. Fistulae of cerebrospinal fluid (CSF) and perilymph can complicate surgery and are relatively common in common cavity and Mondini malformations. Strategies for facilitating surgery in the presence of ‘gushers’, for measuring the pressure of a gusher and for placement of the cochlear implant electrode array are reviewed, with reports of fluctuating levels of electric current when implants lie in dysplastic cochleas. The relationship of implant performance to VIIIth nerve tissue in malformed cochleas is discussed, with a description of the histological findings in a common cavity cochlea. Techniques for identifying the absence of the cochlear nerve are reviewed. Stimulation of the facial nerve by cochlear implants has been described in cases of congenital malformation of the labyrinth but is relatively uncommon. Case reports of the benefit received by implanted children with congenital cochlear malformation have appeared since 1988. Most cases reported have not yet been followed for long enough to establish a clear picture of the outcome following cochlear implantationin such children; no centre has yet built up a large series of cases, but there have been two multicentre postal surveys. It seems likely that in cochlear malformation the range of potential outcomes in terms of hearing threshold and the development of speech perception and production will be similar to the range found in implanted children without cochlear dysplasia. However there is, as yet, no clear picture of the mean level of performance within this range.
Article
The report proposes a new classification system for inner ear malformations, based on radiological features of inner ear malformations reviewed in 23 patients. The investigation took the form of a retrospective review of computerized tomography findings relating to the temporal bone in 23 patients (13 male and 10 female patients) with inner ear malformations. The subjects were patients with profound bilateral sensorineural hearing loss who had all had high-resolution computed tomography (CT) with contiguous 1-mm-thick images obtained through the petrous bone in axial sections. The CT results were reviewed for malformations of bony otic capsule under the following subgroups: cochlear, vestibular, semicircular canal, internal auditory canal (IAC), and vestibular and cochlear aqueduct malformations. Cochlear malformations were classified as Michel deformity, common cavity deformity, cochlear aplasia, hypoplastic cochlea, incomplete partition types I (IP-I) and II (IP-II) (Mondini deformity). Incomplete partition type I (cystic cochleovestibular malformation) is defined as a malformation in which the cochlea lacks the entire modiolus and cribriform area, resulting in a cystic appearance, and there is an accompanying large cystic vestibule. In IP-II (the Mondini deformity), there is a cochlea consisting of 1.5 turns (in which the middle and apical turns coalesce to form a cystic apex) accompanied by a dilated vestibule and enlarged vestibular aqueduct. Four patients demonstrated anomalies involving only one inner ear component. All the remaining patients had diseases or conditions affecting more than one inner ear component. Eight ears had IP-I, and 10 patients had IP-II. Ears with IP-I had large cystic vestibules, whereas the amount of dilation was minimal in patients with IP-II. The majority of the semicircular canals (67%) were normal. Semicircular canal aplasia accompanied cases of Michel deformity, cochlear hypoplasia, and common cavity. In 14 ears, the IAC had a defective fundus at the lateral end. In two ears the IAC was absent. In all seven cases of common cavity malformations, there was a bony defect at the lateral end of the IAC. In five of them the IAC was enlarged, whereas in two the IAC was narrow. All patients with IP-I had an enlarged IAC, whereas in patients with type II disease, four had a normal IAC and 10 had an enlarged IAC. All cases of IP-II had an enlarged vestibular aqueduct, whereas this finding was not present in any of the cases of IP-I. In all cases, the vestibular aqueduct findings were symmetrical on both sides (simultaneously normal or enlarged). No patient demonstrated enlargement or any other abnormalities involving the cochlear aqueduct. Radiological findings of congenital malformations in the present study suggested two different types of incomplete partition. Cystic cochleovestibular malformation (IP-I) and the classic Mondini deformity (IP-II). The type I malformation is less differentiated than the type II malformation. Classic Mondini deformity has three components (a cystic apex, dilated vestibule, and large vestibular aqueduct), whereas type I malformation has an empty, cystic cochlea and vestibule without an enlarged vestibular aqueduct. Mondini deformity represents a later malformation, so the amount of dysplasia is much less than in type II. Therefore, it is more accurate and useful for clinical purposes to classify these malformations (in descending order of severity) as follows: Michel deformity, cochlear aplasia, common cavity, IP-I (cystic cochleovestibular malformation), cochlear hypoplasia, and IP-II (Mondini deformity). Only in this way can these complex malformations be grouped precisely and the results of cochlear implantation compared.
Article
The Veria operation is a non-mastoidectomy technique for cochlear implantation. It uses the transcanal approach to the middle ear and the cochlea. The steps of the procedure are: (1) endaural approach, that offers a wide accessibility to the middle ear structures; (2) inspection of the middle ear anatomy; (3) straightening of the postero-superior bony canal wall, which is usually concave; (4) performing the cochleostomy through the outer ear canal; (5) drilling of the suprameatal hollow, which is used for the accommodation of the electrode excess; (6) drilling of the trans-wall direct tunnel, which is the pathway for the active electrode; (7) alignment of the direct tunnel to the cochleostomy; (8) extension of the incision and preparing of the flaps; (9) creating of the bed and fixing the device; (10) insertion of the electrodes; (11) manipulating the excess of the active electrode, and (12) closing. For this technique, two special instruments have been developed: a special perforator used for the drilling of the direct tunnel for the active electrode, making it completely safe, and a safety electrode forceps used to manipulate the active electrode during insertion. The direct tunnel can be enlarged superiorly permitting insertion of two electrodes, in cases where a double electrode array implant has to be used. The method is an efficient tool for handling all cochlear implant cases, including difficult ones such as revision cases, malformations, cochlear ossifications and poor mastoid development. It is safe without complications in over a hundred cases and easy to learn.
Article
The suprameatal approach is an alternative method for performing cochlear implantation developed in the Sheba Medical Center in 1999. This technique eliminates the need for mastoidectomy and posterior tympanotomy. The middle ear is entered through a retroauricular tympanotomy flap, and the electrode is introduced into the cochlea via a tunnel drilled in the suprameatal region superior to Henle's spine. The suprameatal approach is a simple and safe technique that does not endanger the facial nerve nor the chorda tympani. A wide exposure of the promontory enables exact determination of scala tympani and smooth introduction of the electrodes into the cochlea. This technique may also be used in malformed or ossified cochlea. Until now 140 patients were operated in our department and an additional 48 patients were operated on in the department of Otorhinolaryngology at the University of Vienna employing the suprameatal approach technique.
Auditory Brainstem Implants in Children: Results Based on a Review of the Literature
  • C Monsanto R Da
  • A G Bittencourt
  • Njb Neto
Monsanto R da C, Bittencourt AG, Neto NJB, et al. Auditory Brainstem Implants in Children: Results Based on a Review of the Literature. Int J Adv Otol 2014;10:284-290.