The Widely Patent Cochleovestibular Communication of Edward Cock is a Distinct Inner Ear Malformation: Implications for Cochlear Implantation

Otic Capsule Dehiscences Simulating Other Inner Ear Diseases: Characterization, Clinical Profile, and Follow-Up-Is Ménière's Disease the Sole Cause of Vertigo and Fluctuating Hearing Loss?

INTRODUCTION

We present a series of six cases whose clinical presentations exhibited audiovestibular manifestations of a third mobile window mechanism, bearing a reasonable resemblance to Ménière's disease and otosclerosis. The occurrence of these cases in such a short period has prompted a review of the underlying causes of its development. Understanding the pathophysiology of third mobile window syndrome and considering these entities in the differential diagnosis of conditions presenting with vertigo and hearing loss with slight air-bone gaps is essential for comprehending this group of pathologies.

MATERIALS AND METHODS

A descriptive retrospective cohort study of six cases diagnosed at a tertiary center. All of them went through auditive and vestibular examinations before and after a therapeutic strategy was performed.

RESULTS

Out of 84 cases of dehiscences described in our center during the period from 2014 to 2024, 78 belonged to superior semicircular canal dehiscence, while 6 were other otic capsule dehiscences. Among these six patients with a mean age of 47.17 years (range: 18-73), all had some form of otic capsule dehiscence with auditory and/or vestibular repercussions, measured through hearing and vestibular tests, with abnormalities in the results in five out of six patients. Two of them were diagnosed with Ménière's disease (MD). Another two had cochleo-vestibular hydrops without meeting the diagnostic criteria for MD. In two cases, the otic capsule dehiscence diagnosis resulted from an intraoperative complication due to a gusher phenomenon, while in one case, it was an accidental radiological finding. All responded well to the proposed treatment, whether medical or surgical, if needed.

CONCLUSIONS

Otic capsule dehiscences are relatively new and unfamiliar entities that should be considered when faced with cases clinically suggestive of Ménière's disease, with discrepancies in complementary tests or a poor response to treatment. While high-sensitivity and specificity audiovestibular tests exist, completing the study with imaging, especially petrous bone CT scans, is necessary to locate and characterize the otic capsule defect responsible for the clinical presentation.

A case of cochlear-facial dehiscence revealed after bilateral cochlear implants

The cochlear implant is an implanted auditory prosthesis that can restore severe and profound hearing loss. About 20% of patients with congenital sensorineural hearing loss have a malformation of the inner ear. These abnormalities must be investigated before a cochlear implant because they can lead to intra and postoperative complications and/or anomalies. Most labyrinthine malformations are well known; some are less frequent and can be underdiagnosed at the preoperative computed tomography. This report presents the case of bilateral cochlear-facial dehiscence, bony dehiscence between the facial nerve labyrinthine segment, and cochlear basal turn. In our 56-year-old patient, this malformation was misdiagnosed before the cochlear implant and revealed afterward because of abnormal facial nerve stimulation during intraoperative electrophysiological checking.

Cryptococcus neoformans in a child with CSF rhinorrhoea: A cytopathological diagnosis

Cryptococcosis is caused by Cryptococcus neoformans and is fatal in children. The fungus is known to enter respiratory tract by inhalation and localizes in lungs in immunocompetent host. Patients with immunocompromised state facilitate dissemination of disease. However, disseminated cases have been described in immunocompetent HIV-negative individuals. CSF rhinorrhoea as a predisposing cause of cryptococcal meningitis has been rarely reported. We hereby describe C. neoformans directly spreading to the meninges in 1 year child due to CSF rhinorrhoea and the fungus was detected on fluid cytology.

Evaluating Common Cavity Cochlear Deformities Using CT Images and 3D Reconstruction

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, 131:386-391, 2021.

Cochlear-Internal Canal and Cochlear-Facial Dehiscence: A Novel Entity

Different types of otic capsule dehiscence restricted to the cochlea have been described. Here we describe the case of a patient with a cochlear-internal auditory canal dehiscence associated with a cochlear-facial dehiscence not reported before. A 53-year-old patient with severe to profound sensorineural hearing loss due to bilateral Meniere's disease underwent a cochlear implant surgery on the right ear. Preoperative brain magnetic resonance imaging findings were reported to be normal; during surgery, a cerebrospinal fluid gusher occurred at the time of round window opening. Postoperative computed tomography imaging showed a bony dehiscence at two levels of the otic capsule.

Slotted labyrinthotomy approach with customized electrode for patients with common cavity deformity

OBJECTIVES/HYPOTHESIS

Cochlear implantation for patients with common cavity deformity (CCD) can be difficult, with a higher incidence of intra- and postoperative complications; outcomes with CCD patients are also highly variable. In this study, surgical time was compared between the traditional facial recess approach (TFRA) and the transmastoid slotted labyrinthotomy approach (TSLA). Audiological outcomes and the benefit of using customized electrode arrays for CCD patients are also discussed.

STUDY DESIGN

Retrospective review of 13 cochlear implant (CI) patients with CCD.

METHODS

Six patients were implanted with the TFRA using traditional electrodes, and seven patients were implanted with the TSLA using customized electrodes. Intra- and postoperative complications were reviewed. Audiological outcomes were measured 3 months to 2 years after CI activation.

RESULTS

The mean surgical time for TSLA group was nearly half as long as for the TRFA group (P < .05). Although mean audiological outcomes were better for the TSLA group, there was no significant difference between groups (P > .05).

CONCLUSIONS

For CCD patients, TSLA for cochlear implantation is recommended due to shortened surgical time; customized electrode arrays may be additionally advantageous in terms of audiological outcomes.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:468-472, 2018.

Cochlear implantation outcomes in children with common cavity deformity; a retrospective study

Objective

A common cavity deformity (CCD) is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity that results in profound hearing loss. There are few studies paying attention to common cavity. Our group is engrossed in observing the improvement of auditory and verbal abilities in children who have received cochlear implantation (CI), and comparing these targets between children with common cavity and normal inner ear structure.

Material and methods

A retrospective study was conducted in 12 patients with profound hearing loss that were divided into a common cavity group and a control group, six in each group matched in sex, age and time of implantation, based on inner ear structure. Categories of Auditory Performance (CAP) and speech intelligibility rating (SIR) scores and aided hearing thresholds were collected and compared between the two groups. All patients wore CI for more than 1 year at the Cochlear Center of Anhui Medical University from 2011 to 2015.

Results

Postoperative CAP and SIR scores were higher than before operation in both groups (p < 0.05), although the scores were lower in the CCD group than in the control group (p < 0.05). The aided threshold was also lower in the control group than in the CCD group (p < 0.05).

Conclusion

Even though audiological improvement in children with CCD was not as good as in those without CCD, CI provides benefits in auditory perception and communication skills in these children.

Cochlear implantation in 21 patients with common cavity malformation

CONCLUSION

The facial recess approach is preferred in common cavity (CC) malformation with an incomplete basal turn, and the transmastoid single-slit labyrinthotomy approach in classic CC malformation. Patients with CC benefit from cochlear implantation (CI) over time, but the audiological and speech development is poorer than in cases with normal cochleas.

OBJECTIVES

To discuss the surgical aspects and performance of CI in 21 patients with CC malformation.

METHODS

Twenty-one CC malformations were classified into 2 types: classic CC malformation and CC malformation with an incomplete basal turn. Twenty-one patients without inner ear malformation were set as the control group. Thus, data for 42 patients were analyzed.

RESULTS

The facial recess approach was used in 3 patients with CC malformation with an incomplete basal turn, and the transmastoid single-slit labyrinthotomy approach in 18 patients with classic CC malformation. After follow-up for 36 months, the average free-field hearing threshold was higher, and the scores for the CAP, SIR, IT-MAIS, and closed-set/open-set auditory speech perception tests were lower than in the control group (p < 0.05).

Implantation of the common cavity malformation may prevent meningitis

OBJECTIVES AND IMPORTANCE: Children with certain congenital malformations of the inner ear, including those with a common cavity defect, have a higher incidence of spontaneous cerebrospinal fluid (CSF) leak and resulting meningitis. However, they may also benefit from cochlear implantation. We suggest that surgical management may be possible that both prevents meningitis and provides hearing rehabilitation during the same procedure.

CLINICAL PRESENTATION

A 2-year-old girl with bilateral common cavity defects who had previously undergone cochlear implantation developed contralateral CSF leak resulting in meningitis.

INTERVENTION

After resolution of the infection, cochlear implantation was performed at the same time as definitive CSF leak repair. Simultaneous cochlear implantation and repair of the CSF leak successfully decreased the chance of recurrent meningitis in this case. She has been deriving hearing benefit from the bilateral implants.

CONCLUSION

This case suggests a role for cochlear implantation to be combined with simultaneous CSF leak repair in children with a cochlear malformation. Furthermore, bilateral cochlear implantation at an early age may be warranted in these patients before CSF leaks and meningitis have occurred.

Cochlear implantation in children with labyrinthine anomalies and cochlear nerve deficiency: implications for auditory brainstem implantation

OBJECTIVES/HYPOTHESIS

Compare outcomes among children with inner ear malformations and/or cochlear nerve deficiency (CND) who have received a cochlear implant (CI).

STUDY DESIGN

Individual retrospective cohort study from 1993 to 2010.

METHODS

A select cohort of 76 children was identified. Imaging characteristics, operative findings, complications, mapping parameters, and performance were assessed. Comparisons among the different groups were undertaken.

RESULTS

Surgery was mostly uncomplicated. Nearly all children demonstrated behavioral responses to CI stimulation irrespective of inner ear morphology or the presence of CND. Children with CND had higher pure tone averages (PTAs) and required greater charge for stimulation than other malformation types. Open-set speech perception was achieved in 100% of children with incomplete partition-enlarged vestibular aqueduct (IP-EVA), 50% of those with hypoplastic malformations, and 19% of CND cases. Robust responses on eighth nerve compound action potential (ECAP) testing through the implant was associated with higher levels of speech perception. Manually supplemented communication strategies were more common among children with hypoplastic malformations (69%) and CND (95%) than those with IP-EVA (18%).

CONCLUSIONS

Children with IP-EVA malformations have an excellent prognosis for developing open-set speech perception and using oral communication modes following CI. On the contrary, children with severe malformations or CND may have elevated charge requirements for attaining sound detection alone. These children's prognosis for obtaining open-set speech understanding, using exclusive oral communication, and participating in mainstream education is more limited. These findings have important implications for considering alternative forms of intervention such as auditory brainstem implantation and/or supplementation with visually based communication strategies.

From labyrinthine aplasia to otocyst deformity

INTRODUCTION

Inner ear malformations (IEMs) are rare and it is unusual to encounter the rarest of them, namely labyrinthine aplasia (LA) and otocyst deformity. They do, however, provide useful pointers as to the early embryonic development of the ear. LA is characterised as a complete absence of inner ear structures. While some common findings do emerge, a clear definition of the otocyst deformity does not exist. It is often confused with the common cavity first described by Edward Cock. Our purpose was to radiologically characterise LA and otocyst deformity.

METHODS

Retrospective analysis of CT and MRI data from four patients with LA or otocyst deformity. Middle and inner ear findings were categorised by two neuroradiologists.

RESULTS

The bony carotid canal was found to be absent in all patients. Posterior located cystic structures were found in association with LA and otocyst deformity. In the most severe cases, only soft tissue was present at the medial border of the middle ear cavity. The individuals with otocyst deformity also had hypoplasia of the petrous apex bone.

CONCLUSIONS

These cases demonstrate gradual changes in the two most severe IEMs. Clarification of terms was necessary and, based on these findings, we propose defining otocyst deformity as a cystic structure in place of the inner ear, with the cochlea, IAC and carotid canal absent. This condition needs to be differentiated from the common cavity described by Edward Cook. A clear definition of inner ear malformations is essential if outcomes following cochlear implantation are to be compared.