Research progress on incomplete partition type 3 inner ear malformation.

PURPOSE: This review aims to provides a comprehensive overview of the latest research progress on IP-III inner ear malformation, focusing on its geneticbasis, imaging features, cochlear implantation, and outcome. METHODS: Review the literature on clinical and genetic mechanisms associated with IP-III. RESULTS: Mutations in the POU3F4 gene emerge as the principal pathogenic contributors to IP-III anomalies, primarily manifesting through inner ear potential irregularities leading to deafness. While cochlear implantation stands as the primary intervention for restoring hearing, the unique nature of the inner ear anomaly escalates the complexity of surgical procedures and postoperative results. Hence, meticulous preoperative assessment to ascertain surgical feasibility and postoperative verification of electrode placement are imperative. Additionally, gene therapy holds promise as a prospective treatment modality. CONCLUSIONS: IP-III denotes X-linked recessive hereditary deafness, with cochlear implantation currently serving as the predominant therapeutic approach. Clinicians are tasked with preoperative assement and individualized postoperative rehabilitation.

Evaluation of subarcuate canal on CT images in the perspective of clinical basis.

OBJECTIVES: The aim of our study to contribute to the field of morphometrics by including measurements of the SAC and SAF and their distances from surrounding structures, particularly for surgeons involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery. Although there is limited information in the literature regarding the role of the subarcuate fossa (SAF) and subarcuate canal (SAC), it has been suggested that the SAC may be a potential pathway for infection from the middle ear to the posterior cranial fossa, and cerebellar abscesses may have this origin. METHODS: For the images of our study, computerized tomography images of 118 individuals (59 females and 59 males) between the ages of 18-65 who applied to Bayindir Health Group. RESULTS: The width of the cranial opening of the subarcuate canal was determined as 44 ± 0.54 mm, width of the labyrinth opening of the subarcuate canal was determined as 60 ± 0.42 mm, Length of the subarcuate canal was determined as 8.79 ± 2.31 mm, width of the subarcuate canal was determined as 5.54 ± 1.75 mm, and depth of subarcuate fossa was determined as 1.67 ± 0.69 mm. The distance of the cranial opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/C) was measured as 5.33 ± 1.81 mm, The distance of the labyrinth opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/L) was measured as 3.90 ± .98 mm, length of the petrous part of the temporal bone medial to the anterior semicircular canal measured from the apex to the SSCD (PLM) was measured as 33.56 ± 0.42 mm. No statistically significant differences were found between the right and left sides. CONCLUSIONS: The morphometric measurements obtained in this study can provide useful information for neurosurgeons, neurotologist and otolaryngologists involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery, and for patients undergoing cochlear implant planning with a retrofacial approach.

Machine learning-based prediction of the outcomes of cochlear implantation in patients with inner ear malformation.

OBJECTIVE: The objectives of this study are twofold: first, to visualize the structure of malformed cochleae through image reconstruction; and second, to develop a predictive model for postoperative outcomes of cochlear implantation (CI) in patients diagnosed with cochlear hypoplasia (CH) and incomplete partition (IP) malformation. METHODS: The clinical data from patients diagnosed with cochlear hypoplasia (CH) and incomplete partition (IP) malformation who underwent cochlear implantation (CI) at Beijing Tongren Hospital between January 2016 and August 2020 were collected. Radiological features were analyzed through 3D segmentation of the cochlea. Postoperative auditory speech rehabilitation outcomes were evaluated using the Categories of Auditory Performance (CAP) and the Speech Intelligibility Rating (SIR). This study aimed to investigate the relationship between cochlear parameters and postoperative outcomes. Additionally, a predictive model for postoperative outcomes was developed using the K-nearest neighbors (KNN) algorithm. RESULTS: In our study, we conducted feature selection by using patients' imaging and audiological attributes. This process involved methods such as the removal of missing values, correlation analysis, and chi-square tests. The findings indicated that two specific features, cochlear volume (V) and cochlear canal length (CDL), significantly contributed to predicting the outcomes of hearing and speech rehabilitation for patients with inner ear malformations. In terms of hearing rehabilitation, the KNN classification achieved an accuracy of 93.3%. Likewise, for speech rehabilitation, the KNN classification demonstrated an accuracy of 86.7%. CONCLUSION: The measurements obtained from the 3D reconstruction model hold significant clinical relevance. Despite the considerable variability in cochlear morphology across individuals, radiological features remain effective in predicting cochlear implantation (CI) prognosis for patients with inner ear malformations. The utilization of 3D segmentation techniques and the developed predictive model can assist surgeons in conducting preoperative cochlear structural measurements for patients with inner ear malformations. This, in turn, can offer a more informed perspective on the anticipated outcomes of cochlear implantation.

Cochlear Implantation: Systematic Approach to Preoperative Radiologic Evaluation.

Sensorineural hearing loss results from abnormalities that affect the hair cells of the membranous labyrinth, inner ear malformations, and conditions affecting the auditory pathway from the cochlear nerve to the processing centers of the brain. Cochlear implantation is increasingly being performed for hearing rehabilitation owing to expanding indications and a growing number of children and adults with sensorineural hearing loss. An adequate understanding of the temporal bone anatomy and diseases that affect the inner ear is paramount for alerting the operating surgeon about variants and imaging findings that can influence the surgical technique, affect the choice of cochlear implant and electrode type, and help avoid inadvertent complications. In this article, imaging protocols for sensorineural hearing loss and the normal inner ear anatomy are reviewed, with a brief description of cochlear implant devices and surgical techniques. In addition, congenital inner ear malformations and acquired causes of sensorineural hearing loss are discussed, with a focus on imaging findings that may affect surgical planning and outcomes. The anatomic factors and variations that are associated with surgical challenges and may predispose patients to periprocedural complications also are highlighted. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

The spectrum of cochlear malformations in CHARGE syndrome and insights into the role of the CHD7 gene during embryogenesis of the inner ear.

PURPOSE: We reviewed the genotypes and the imaging appearances of cochleae in CHARGE patients from two large tertiary centres and analysed the observed cochlear anomalies, providing detailed anatomical description and a grading system. The goal was to gain insight into the spectrum of cochlear anomalies in CHARGE syndrome, and thus, in the role of the CHD7 gene in otic vesicle development. METHODS: We retrospectively reviewed CT and/or MR imaging of CHARGE patients referred to our institutions between 2005 and 2022. Cochlear morphology was analysed and, when abnormal, divided into 3 groups in order of progressive severity. Other radiological findings in the temporal bone were also recorded. Comparison with the existing classification system of cochlear malformation was also attempted. RESULTS: Cochlear morphology in our CHARGE cohort ranged from normal to extreme hypoplasia. The most common phenotype was cochlear hypoplasia in which the basal turn was relatively preserved, and the upper turns were underdeveloped. All patients in the cohort had absent or markedly hypoplastic semicircular canals and small, misshapen vestibules. Aside from a stenotic cochlear aperture (fossette) being associated with a hypoplastic or absent cochlear nerve, there was no consistent relationship between cochlear nerve status (normal, hypoplasia, or aplasia) and cochlear morphology. CONCLUSION: Cochlear morphology in CHARGE syndrome is variable. Whenever the cochlea was abnormal, it was almost invariably hypoplastic. This may shed light on the role of CHD7 in cochlear development. Accurate morphological description of the cochlea contributes to proper clinical diagnosis and is important for planning surgical treatment options.

Internal auditory canal volume in normal and malformed inner ears.

PURPOSE: A narrow bony internal auditory canal (IAC) may be associated with a hypoplastic cochlear nerve and poorer hearing performances after cochlear implantation. However, definitions for a narrow IAC vary widely and commonly, qualitative grading or two-dimensional measures are used to characterize a narrow IAC. We aimed to refine the definition of a narrow IAC by determining IAC volume in both control patients and patients with inner ear malformations (IEMs). METHODS: In this multicentric study, we included high-resolution CT (HRCT) scans of 128 temporal bones (85 with IEMs: cochlear aplasia, n = 11; common cavity, n = 2; cochlear hypoplasia type, n = 19; incomplete partition type I/III, n = 8/8; Mondini malformation, n = 16; enlarged vestibular aqueduct syndrome, n = 19; 45 controls). The IAC diameter was measured in the axial plane and the IAC volume was measured by semi-automatic segmentation and three-dimensional reconstruction. RESULTS: In controls, the mean IAC diameter was 5.5 mm (SD 1.1 mm) and the mean IAC volume was 175.3 mm3 (SD 52.6 mm3). Statistically significant differences in IAC volumes were found in cochlear aplasia (68.3 mm3, p < 0.0001), IPI (107.4 mm3, p = 0.04), and IPIII (277.5 mm3, p = 0.0004 mm3). Inter-rater reliability was higher in IAC volume than in IAC diameter (intraclass correlation coefficient 0.92 vs. 0.77). CONCLUSIONS: Volumetric measurement of IAC in cases of IEMs reduces measurement variability and may add to classifying IEMs. Since a hypoplastic IAC can be associated with a hypoplastic cochlear nerve and sensorineural hearing loss, radiologic assessment of the IAC is crucial in patients with severe sensorineural hearing loss undergoing cochlear implantation.

Inner Ear Anomalies in Children With Apert Syndrome: A Radiological and Audiological Analysis.

INTRODUCTION: Apert syndrome is a multisystem genetic disorder typically characterized by craniosynostosis and syndactyly. Studies also report an increased incidence of hearing loss in children with Apert syndrome in comparison to the general population. The aim of this study was to gain an understanding of the inner ear radiological anatomical variations seen in children with Apert syndrome and correlate these with audiological outcomes. MATERIALS AND METHODS: This was a retrospective review of computed tomography imaging of patients with Apert syndrome. Radiological images were examined for anatomical variations in inner ear structures. These were correlated with audiological testing. RESULTS: Nineteen patients were included in the study. The most commonly observed anomaly was an absent bony window of the lateral semi-circular canal (SCC) in 11 patients (58%), followed by an enlarged lateral SCC in 12 patients (63%). This combination of anomalies was seen collectively in 42% of patients and together these give the appearance of a 'rectangular vestibular cavity'. Audiological results were available in 11 patients and 9 of these patients had a conductive hearing loss. CONCLUSION: To the authors' knowledge, this is the first study that reports radiological findings alongside audiological testing in Apert syndrome and describes the appearance of a 'rectangular vestibular cavity'.

Noncoding Microdeletion in Mouse Hgf Disrupts Neural Crest Migration into the Stria Vascularis, Reduces the Endocochlear Potential, and Suggests the Neuropathology for Human Nonsyndromic Deafness DFNB39.

Hepatocyte growth factor (HGF) is a multifunctional protein that signals through the MET receptor. HGF stimulates cell proliferation, cell dispersion, neuronal survival, and wound healing. In the inner ear, levels of HGF must be fine-tuned for normal hearing. In mice, a deficiency of HGF expression limited to the auditory system, or an overexpression of HGF, causes neurosensory deafness. In humans, noncoding variants in HGF are associated with nonsyndromic deafness DFNB39 However, the mechanism by which these noncoding variants causes deafness was unknown. Here, we reveal the cause of this deafness using a mouse model engineered with a noncoding intronic 10 bp deletion (del10) in Hgf Male and female mice homozygous for del10 exhibit moderate-to-profound hearing loss at 4 weeks of age as measured by tone burst auditory brainstem responses. The wild type (WT) 80 mV endocochlear potential was significantly reduced in homozygous del10 mice compared with WT littermates. In normal cochlea, endocochlear potentials are dependent on ion homeostasis mediated by the stria vascularis (SV). Previous studies showed that developmental incorporation of neural crest cells into the SV depends on signaling from HGF/MET. We show by immunohistochemistry that, in del10 homozygotes, neural crest cells fail to infiltrate the developing SV intermediate layer. Phenotyping and RNAseq analyses reveal no other significant abnormalities in other tissues. We conclude that, in the inner ear, the noncoding del10 mutation in Hgf leads to developmental defects of the SV and consequently dysfunctional ion homeostasis and a reduction in the EP, recapitulating human DFNB39 nonsyndromic deafness.SIGNIFICANCE STATEMENT Hereditary deafness is a common, clinically and genetically heterogeneous neurosensory disorder. Previously, we reported that human deafness DFNB39 is associated with noncoding variants in the 3'UTR of a short isoform of HGF encoding hepatocyte growth factor. For normal hearing, HGF levels must be fine-tuned as an excess or deficiency of HGF cause deafness in mouse. Using a Hgf mutant mouse with a small 10 bp deletion recapitulating a human DFNB39 noncoding variant, we demonstrate that neural crest cells fail to migrate into the stria vascularis intermediate layer, resulting in a significantly reduced endocochlear potential, the driving force for sound transduction by inner ear hair cells. HGF-associated deafness is a neurocristopathy but, unlike many other neurocristopathies, it is not syndromic.

Nonsyndromic Congenital Causes of Sensorineural Hearing Loss in Children: An Illustrative Review.

OBJECTIVE. The purpose of this article is to provide an illustrative review of nonsyndromic congenital causes of sensorineural hearing loss (SNHL) in children. CONCLUSION. Early recognition and treatment are essential in maximizing developmental outcomes in children with congenital SNHL. Because imaging plays an integral role in identifying underlying causes of SNHL, it is imperative that radiologists be able to recognize, describe, and appropriately categorize the spectrum of congenital inner ear malformations in children.

Imaging of inner ear malformations: a primer for radiologists.

In the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagnosis and treatment of patients with inner ear disease. The most suitable technique should be selected depending on the clinical setting. However, in cases of congenital malformation of the inner ear, these techniques should be considered complementary. Since prompt intervention has a positive impact on the treatment outcomes, early diagnosis of IEMs is very important in the management of deaf patients. This article reviews the key concepts of IEMs for clinical radiologists by focusing on recent literature updates, discusses the principal imaging findings and clinical implications for every IEM subgroup, thus providing a practical diagnostic approach.

Audiological Performance in Children with Inner Ear Malformations Before and After Cochlear Implantation: A Cohort Study of 274 Patients.

BACKGROUND AND OBJECTIVE: Inner ear malformations (IEMs) are common in children with hearing loss. The different types of IEMs form a unique subgroup of cochlear implant (CI) candidates. We aimed to evaluate the auditory perception outcomes of CI in children with different types of IEMs and compare them with CI users without IEMs. METHODS: The study included 274 CI users with and without IEMs as two groups (n = 137, each). Both groups' chronological age at implantation and duration of CI usage was matched (± 8 months). All subjects were evaluated pre-operatively and post-operatively by the Ling's sound test and the auditory perception test battery, which includes the Meaningful Auditory Integration Scale (MAIS), closed-set Pattern Perception Test (PPT) and open-set Sentence Recognition Test (SRT). Besides, children with IEMs were assessed for language development. RESULTS: Progress in the IEMs' group differed according to the type of ear anomaly. CI users with enlarged vestibular aqueduct had the highest scores, while users with common cavity had the lowest. Children with IEMs performed well on the closed-set test while having difficulty with the open-set test. CONCLUSION: Cochlear implantation outcomes are favourable in IEMs' patients with a cochlear nerve visible on magnetic resonance imaging. Our results indicate that it is critical to take the anatomical differences into account during follow-up and rehabilitation programmes. Each CI user should be evaluated according to his or her individual needs.

Association Between Incomplete Partition Type III and Abnormal Hypothalamic Morphology: Further Imaging Evidence.

PURPOSE: Incomplete partition III (IP-III), characterized by congenital mixed or sensorineural hearing loss, is a rare genetic disease transmitted through X-linked mode of inheritance. Inner ear findings of IP-III have been well described and allow an immediate diagnosis to be made. Recently, an association between IP-III and distinct hypothalamic malformations has been reported in some of the patients with IP-III. The purpose of this study was to investigate the morphologic abnormalities of the hypothalamus in IP-III. MATERIALS AND METHODS: Magnetic resonance imaging studies of 8 subjects, including 1 set of brothers, who were diagnosed with IP-III based on their clinical and inner ear imaging findings, were analyzed. RESULTS: Of the 8 subjects, 7 demonstrated some degree of morphologic abnormality of the hypothalamus. Of these, 2 showed asymmetrical thickening, 1 showed symmetrical thickening, and 4 showed mass-like enlargement of the hypothalamus. Six of 7 subjects with hypothalamic abnormalities showed asymmetry in caudal extension of the abnormalities, which was more discernible on coronal oblique T2-weighted images. Clinically, none of the subjects had endocrinologic or neurologic symptoms. CONCLUSIONS: This retrospective analysis presents further magnetic resonance imaging evidence on the association between the rare IP-III malformations and the presence of hypothalamic morphologic abnormalities.

Irregular Contour of Inner Ear Structures and Hypomineralized Areas at Otic Capsule: Are They Other Additional Imaging Findings of Incomplete Partition-III?

PURPOSE: Incomplete partition III (IP-III) characterized by congenital mixed or sensorineural hearing loss is a rare genetic disease transmitted through X-linked inheritance. Incomplete partition III can be easily achieved based on pathognomonic computed tomography findings. The aims of this study were to investigate the otic capsule abnormalities in IP-III and to report irregular contour of membranous labyrinth and hypomineralized areas at otic capsule, which have not previously been described. MATERIALS AND METHODS: The otic capsule features of 10 subjects (8 affected patients, 1 of whom is a female; 2 carrier mothers), who were diagnosed on clinical and typical radiologic findings, were analyzed. RESULTS: All patients had typical IP-III as described in the literature. Seven of 10 patients had irregular contour. Seven of 10 patients demonstrated hypomineralized areas, which were very hypodense to normally develop otic capsule areas. One affected patients and 2 carrier mothers had a normal-looking membranous labyrinth contour and normal mineralization at otic capsule. CONCLUSIONS: We report for the first time the irregular contour of inner ear structures and hypodense otic capsule areas in patients with IP-III. We think that though speculative, abnormal development of the inner endosteal layer results in irregular contour of inner ear structures. Hypomineralized areas at otic capsule could be explained by abnormal development of middle enchondral layer due to reduced or absent vascular supply from middle ear mucosa during fetal life. These findings may be accepted as additional criteria of IP-III.

Bimodal stimulation in children with inner ear malformation: One side cochlear implant and contralateral auditory brainstem implant.

OBJECTIVE: To determine audiological outcomes of children who use a cochlear implant (CI) in one ear and an auditory brainstem implant (ABI) in the contralateral ear. DESIGN: Retrospective case review. SETTING: Tertiary referral hospital. PARTICIPANTS: Twelve children followed with CI and contralateral auditory brainstem implant (ABI) by Hacettepe University Department of Otorhinolaryngology and Audiology in Turkey. All children were diagnosed with different inner ear malformations with cochlear nerve aplasia/hypoplasia. CI was planned in the ear with better sound detection during behavioural testing with inserted ear phones and with better CN as seen on MRI. Due to the limited auditory and speech progress with the cochlear implant, ABI was performed on the contralateral ear in all subjects. MAIN OUTCOME MEASURES: Audiological performance and auditory perception skills of children with cochlear nerve deficiency (CND) who use bimodal electrical stimulation with CI and contralateral ABI. RESULTS: Mean age of the subjects was 84.00 ± 33.94 months. Age at CI surgery and ABI surgery was 25.00 ± 10.98 months and 41.50 ± 16.14 months, respectively. However, hearing thresholds only with CI and only with ABI did not reveal significant difference, and auditory perception scores improved with bimodal stimulation. The MAIS scores were significantly improved from unilateral CI to bimodal stimulation (P = .002). Pattern perception and word recognition scores were significantly higher with the bimodal condition when compared to CI only and ABI only conditions. CONCLUSION: Children with CND showed better performance with CI and contralateral ABI combined. Depending on the audiological and radiological results, bimodal stimulation should be advised for children with CND.

EAST/SeSAME syndrome: Review of the literature and introduction of four new Latvian patients.

EAST (Epilepsy, Ataxia, Sensorineural deafness, Tubulopathy) or SeSAME (Seizures, Sensorineural deafness, Ataxia, Mental retardation, and Electrolyte imbalance) syndrome is a rare autosomal recessive syndrome first described in 2009 independently by Bockenhauer and Scholl. It is caused by mutations in KCNJ10, which encodes Kir4.1, an inwardly rectifying K+ channel found in the brain, inner ear, kidney and eye. To date, 16 mutations and at least 28 patients have been reported. In this paper, we review mutations causing EAST/SeSAME syndrome, clinical manifestations in detail, and efficacy of treatment in previously reported patients. We also report a new Latvian kindred with 4 patients. In contrast to the majority of previous reports, we found a progressive course of the disorder in terms of hearing impairment and neurologic deficit. The treatment is based on antiepileptic drugs, electrolyte replacement, hearing aids and mobility devices. Future research should concentrate on recognizing the lesions in the central nervous system to evaluate new potential diagnostic criteria and on formally evaluating intellectual disability.

Hypothalamic malformations in patients with X-linked deafness and incomplete partition type 3.

Patients with X-linked deafness carry mutations in the POU3F4 gene and have pathognomonic inner ear malformations characterised by symmetrical incomplete partition type 3 (absent modiolus and lamina spiralis but preserved interscalar septum in a normal-sized cochlea) and large internal auditory meatus (IAM) with an increased risk of gusher during stapes surgery. We describe a range of fairly characteristic malformations in the hypothalamus of some patients with this rare condition, ranging from subtle asymmetric appearance and thickening of the tuber cinereum to more marked hypothalamic enlargement. We discuss the role of POU3F4 in the normal development of both the inner ear and hypothalamus and the proposed pathophysiology of incomplete partition type 3.

Cochlear implantation in incomplete partition type I.

OBJECTIVES: To share our experience in cochlear implanted patients with incomplete partition type I, to compare it with the literature results and to disclose difficulties facing cochlear implant teams dealing with these patients. MATERIALS AND METHODS: Clinical records of 1089 cochlear implant procedures in a cochlear implant center were reviewed and data of patients who had incomplete partition type I were enrolled in this study. Their auditory and speech performances were evaluated 3 years after the implantation. RESULTS: Eighteen cases (1.65%) had incomplete partition type I. Cerebrospinal fluid gusher was encountered during opening the cochlea in 15 patients (83.3%). There were no cases of persistent CSF leak or postoperative meningitis. In 61.1% of patients, some additional anomalies were found during the operation. Although in 55.6% of cases no electrically evoked compound action potential was detected even in long-term follow-up, all patients had satisfactory auditory and speech outcome. CONCLUSION: Cochlear implantation is a relatively safe and effective treatment for patients who have incomplete partition type I, even if the procedure may be somehow challenging.

Outcomes of cochlear implantation in children with inner ear malformations.

PURPOSE: To evaluate the surgical experience and auditory functions and progress of speech development of cochlear implantation in malformed ears. MATERIALS AND METHODS: Between November 1995 and July 2017, thirty-seven patients (26 females and 11 males; mean age: 138.275 ± 96.24 months) with diverse anomalies of the inner ear were retrospectively examined for surgical and audiological results. Speech Intelligibility Rating (SIR), Categories of Auditory Perception (CAP), Pure Tone Average (PTA), Speech Intelligibility Rating (SRT), and Word Discrimination Score (WDS) were the audiological tests used to evaluate the efficacy of CI in the malformed inner ears. RESULTS: CSF gusher was experienced by six patients (three with LVA (large vestibular aqueduct), one with IP (incomplete partition) I, and two with both IP II Mondini malformations and LVA). Two patients had transient facial paresis after surgery. All patients fully recovered within 6 months. The postoperative PTA, SRT, and WDS test results showed significant differences between progressive and congenital sensorineural hearing loss (p values < 0.05 for all). On the other hand, the postoperative CAP and SIR test results revealed no significant differences between the two groups. According to etiology, the PTA and SRT values were significantly lower in common cavity patients than the LVA patients (p values < 0.01); no significant differences were found among the other etiological groups. CONCLUSIONS: Cochlear implantation is safe in children with inner ear malformations. However, the success rate is low compared to patients with normal anatomy in terms of audiological results; the most successful group of patients with inner ear malformation is large vestibular aqueduct.

Cochlear implants for patients with inner ear malformation: Experience in a cohort of 877 surgeries.

OBJECTIVE: To analyse clinical information from a cohort of 877 cochlear implant (CI) surgeries performed in patients with inner ear malformations and report our experience with this procedure. METHODS: Clinical information on patients with inner ear malformation who underwent CI surgery in our department from January 2010 to April 2017 was analysed. RESULTS: Seven hundred and fifty-four CI surgeries (86.0%) were uneventful but cerebrospinal fluid gusher occurred during surgery in 118 cases (13.5%). Not including the patients lost to follow-up, postoperative Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores were collected from 13 patients with common cavity deformity, 38 with IP-I, 11 with hypoplasia, 13 with IP-III, 285 with IP-II and 43 with cochlear nerve deficiency. The mean CAP scores were 2.55, 3.39, 3.45, 3.77, 3.98, 2.95 and 2.90, and the mean SIR scores were 1.54, 3.68, 3.72, 3.54, 3.80, 2.31 and 2.32. Patients with common cavity deformity who underwent surgery using the traditional facial recess approach or transmastoid slotted labyrinthotomy approach had significantly better post-activation scores on the CAP, SIR and Meaningful Auditory Integration Scale/Infant-Toddler Meaningful Auditory Integration Scale, with no significant differences between the two approaches. CONCLUSION: The traditional facial recess approach can be successful, and several approaches may be used for electrode insertion and gusher control in patients with a severe deformity, particularly common cavity deformity and IP-III. A gusher was the most common intraoperative finding and occurred most often in patients with IP-III. Careful consideration of the type of electrode used is important.