Endoscopically guided placement of prefabricated cochlear implant electrodes in a common cavity malformation

Cochlear base length as predictor for angular insertion depth in incomplete partition type 2 malformations

INTRODUCTION

The preoperative determination of suitable electrode array lengths for cochlear implantation in inner ear malformations is a matter of debate. The choice is usually based on individual experience and the use of intraoperative probe electrodes. The purpose of this case series was to evaluate the applicability and precision of an angular insertion depth (AID) prediction method, based on a single measurement of the cochlear base length (CBL).

METHODS

We retrospectively measured the CBL in preoperative computed tomography (CT) images in 10 ears (8 patients) with incomplete partition type 2 malformation. With the known electrode length (linear insertion depth, LID) the AID at full insertion was retrospectively predicted for each ear with a heuristic equation derived from non-malformed cochleae. Using the intra- or post-implantation cone beam CT images, the actual AID was assessed and compared. The deviations of the predicted from the actual insertion angles were quantified (clinical prediction error) to assess the precision of this single-measure estimation.

RESULTS

Electrode arrays with 15 mm (n = 3), 19 mm (n = 2), 24 mm (n = 3), and 26 mm (n = 2) length were implanted. Postoperative AIDs ranged from 211° to 625°. Clinical AID prediction errors from -64° to 62° were observed with a mean of 0° (SD of 44°). In two ears with partial insertion of the electrode, the predicted AID was overestimated. The probe electrode was intraoperatively used in 9/10 cases.

CONCLUSION

The analyzed method provides good predictions of the AID based on LID and CBL. It does not account for incomplete insertions, which lead to an overestimation of the AID. The probe electrode is useful and well established in clinical practice. The investigated method could be used for patient-specific electrode length selection in future patients.

Hybrid Deep Feature Fusion of 2D CNN and 3D CNN for Vestibule Segmentation from CT Images

The accurate vestibule segmentation from CT images is essential to the quantitative analysis of the anatomical structure of the ear. However, it is a challenging task due to the tiny size, blur boundary, and drastic variations in shape and size. In this paper, according to the specific characteristics and segmentation requirements of the vestibule, a vestibule segmentation network with a hybrid deep feature fusion of 2D CNN and 3D CNN is proposed. First, a 2D CNN is designed to extract the intraslice features through multiple deep feature fusion strategies, including a convolutional feature fusion strategy for different receptive fields, a feature channel fusion strategy based on channel attention mechanism, and an encoder-decoder feature fusion strategy. Next, a 3D DenseUNet is designed to extract the interslice features. Finally, a hybrid feature fusion module is proposed to fuse the intraslice and interslice features to effectively exploit the context information, thus achieving the accurate segmentation of the vestibule structure. At present, there is no publicly available dataset for vestibule segmentation. Therefore, the proposed segmentation method is validated on two self-established datasets, namely, VestibuleDataSet and IEBL-DataSet. It has been compared with several state-of-the-art methods on the datasets, including the general DeeplabV3+ method and specific 3D DSD vestibule segmentation method. The experimental results show that our proposed method can achieve superior segmentation accuracy.

Electrically evoked ABR during cochlear implantation and postoperative development of speech and hearing abilities in infants with common cavity deformity as a type of inner ear malformation

Background: The electrically evoked auditory brainstem response (eABR) during cochlear implantation in common cavity (CC) deformity has not been clinically well studied.Aim/Objective: To investigate the eABR wave configuration during cochlear implantation, the postoperative development of hearing, and educational settings in infants with CC deformity.Materials and Methods: Nine infants who were congenitally deaf and found to have CC deformity and suspected cochlear nerve deficiency by temporal bone CT and MRI were studied. All of them underwent sequential and unilateral cochlear implantation and their eABRs were recorded during the surgery. The postoperative development was followed up.Results: eABRs of all the nine infants with CC deformity showed that the mean peak of the evoked wave V (eV) was the same as that in controls at latencies but was twofold higher than that in controls at thresholds and their postoperative hearing thresholds improved markedly.Conclusion and Significance: The brainstem auditory pathways of the infants were considered intact on the basis of the eV peak latencies in the eABRs. The postoperative development of their speech and hearing abilities and their educational settings varied, probably because of the twofold higher thresholds of their eABRs and limited number of auditory neural units.

Development of vestibular ocular reflex and gross motor function in infants with common cavity deformity as a type of inner ear malformation

Background： The function of common cavity deformity demonstrated by temporal bone CT and MRI has been unknown.

AIM/OBJECTIVE

To investigate the developmental changes of vestibular ocular reflex and acquisition of postural control in infants with common cavity deformity.

MATERIAL AND METHODS

Eight infants who were congenitally deaf complicated by common cavity deformity were studied. The damped rotational chair test was carried out to evaluate vestibular ocular reflex. Acquisition of head control and independent walking in these infants was compared with that in normal infant's milestones of gross motor development.

RESULTS

All of the eight infants with common cavity deformity did not show per-rotatory nystagmus in the damped rotational chair test around the first year of life. However, a normal number of beats and a longer duration of per-rotatory nystagmus for their age were recorded at around three or four years of age.

CONCLUSIONS AND SIGNIFICANCE

In the eight infants with common cavity deformity, vestibular ocular reflex was not present around the first year of life, but appeared after three or four years probably because of some vestibular sensory cells. Head control and independent walking were delayed but eventually acquired by the central vestibular compensation.

Application of "banana cochleostomy" and looped electrode insertion for cochlear implantation in children with common cavity malformation and cystic forms of cochlear hypoplasia

OBJECTIVES

Patients with profound hearing loss due to inner ear malformations may benefit from cochlear implantation; however, the surgery may present a substantial problem for the cochlear implant surgeon due to anatomical variations. The authors describe a new surgical and technical advancement for implantation in patients with small inner ear cavities that make the surgery easier and safer. On the basis of experience involving five consecutive surgeries performed in four patients with inner ear malformations, we present the advantages and application possibilities of the technique.

METHODS

The technique does not change the surgical approach in general; however, modification of the cochleostomy shape and looping of the cochlear implant electrode enables safe advancement of the electrode with optimal positioning in the cavity. Additionally, these modifications protect against the insertion of the electrode into the internal auditory canal minimizing the risk of gushing and extracochlear stimulation.

RESULTS

The present technique has been used in five cases of cystic implantable inner ear spaces in three independent institutions by different surgeons. It has proven to be a reliable, relatively easy and safe procedure performed with very good anatomic and initially functional effects (positive intraoperative neural response telemetry measurements).

CONCLUSIONS

We hope that utilization of the "banana cochleostomy" and insertion of the looped cochlear implant electrode in the implantable cystic spaces of children with malformed inner ears will facilitate and simplify the surgical technique in this difficult procedure and additionally, in revision surgical cases. To our knowledge, the looped insertion and banana-shaped cochleostomy have not been reported previously.

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 in Inner Ear Malformations: Systematic Review of Speech Perception Outcomes and Intraoperative Findings

Objective

(1) To analyze reported speech perception outcomes in patients with inner ear malformations who undergo cochlear implantation, (2) to review the surgical complications and findings, and (3) to compare the 2 classification systems of Jackler and Sennaroglu.

Data Sources

PubMed, Scopus (including Embase), Medline, and CINAHL Plus.

Review Methods

Fifty-nine articles were included that contained speech perception and/or intraoperative data. Cases were differentiated depending on whether the Jackler or Sennaroglu malformation classification was used. A meta-analysis of proportions examined incidences of complete insertion, gusher, and facial nerve aberrancy. For speech perception data, weighted means and standard deviations were calculated for all malformations for short-, medium-, and long-term follow-up. Speech tests were grouped into 3 categories—closed-set words, open-set words, and open-set sentences—and then compared through a comparison-of-means t test.

Results

Complete insertion was seen in 81.8% of all inner ear malformations (95% CI: 72.6-89.5); gusher was reported in 39.1% of cases (95% CI: 30.3-48.2); and facial nerve anomalies were encountered in 34.4% (95% CI: 20.1-50.3). Significant improvements in average performance were seen for closed- and open-set tests across all malformation types at 12 months postoperatively.

Conclusions

Cochlear implantation outcomes are favorable for those with inner ear malformations from a surgical and speech outcome standpoint. Accurate classification of anatomic malformations, as well as standardization of postimplantation speech outcomes, is necessary to improve understanding of the impact of implantation in this difficult patient population.

Long term outcome of cochlear implantation in five children with common cavity deformity

INTRODUCTION

A common cavity (CC) deformity is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity. The outcome of cochlear implantation (CI) in this deformity is not expected as good as in other cochlear deformity. Categories of Auditory Performance (CAP) score, Speech Intelligibility Rating (SIR) scale, Meaningful Auditory-Integration Scale (MAIS) and Meaningful Use of Speech Scale (MUSS) are scales designed to assess benefit of functional device (hearing aid, Cochlear implant, ABI) in young children. The aim of the study was to observe and report the long-term audiological progress and speech development of children with CC deformity after CI by means of CAP, SIR, MAIS, MUSS scores and CI aided threshold.

METHODS AND MATERIALS

The retrospective and prospective study was carried out in five Indian children with CC deformity who underwent CI from 2004 to 2010. Demographic data of onset and/or duration of deafness, age at implantation, time with hearing aids before implantation, duration with CI and co-morbidity were retrieved from a local data base. Their outcome score in audition and speech development on the basis of their CAP and SIR score at the end of 1 year of habilitation were collected. All the patients were called to follow up to obtain latest CI aided audiogram, CAP, SIR, MAIS and MUSS scores.

RESULTS

One male and four female children were detected with common cavity deformity among 258 deaf children of age below 6 years operated during study period. The CAP and SIR Scores increased from average of 0.4 and 1 to 3.4 and 2.4, respectively, over one year of habilitation. The CAP score improved in subsequent follow up to average of 5.0 after more than 3 years of follow up but the SIR score hardly improved. We assessed the MAIS and MUSS at last visit after 3 years. The mean of MAIS and MUSS was 32.4 and 26.4, respectively.

CONCLUSION

Though the habilitation outcome was not up to the mark in children with CC deformity, CI provides excellent awareness of environment sound and development of few words.

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).

Vestibular evoked myogenic potentials of children with inner ear malformations before and after cochlear implantation

CONCLUSIONS

Our results show that among the patients with inner ear malformations, there were two patients with sensory cells of sacculus and inferior vestibular neurons and at least five patients with inferior vestibular neurons only, but no patients without sensory cells and vestibular neurons, as determined on the basis of vestibular evoked myogenic potentials (VEMPs).

OBJECTIVE

The aim of this study was to investigate whether sensory cells of sacculus or inferior vestibular neurons or both are present in cochlear implant patients with inner ear malformations, particularly common cavity (CC) deformity, using VEMPs.

PATIENTS AND METHODS

Seven children with inner ear malformation who underwent cochlear implantation (CI) participated in this study. The patients had CC deformity (n=2), incomplete partition type I (n=2), incomplete partition type II (n=1), or a narrow internal auditory canal (IAC) (n=2). It was possible to record VEMPs before and after CI in three patients and not before but after CI in four patients. After surgery, VEMPs were recorded with the cochlear implant device switched both off and on.

RESULTS

Before the CI, two patients showed VEMPs and one patient showed no VEMPs, whereas in four patients no VEMPs could be recorded. All the patients showed VEMPs with the cochlear implant on.