Cochlear implant outcomes in patients with superior canal dehiscence

Impact of superior semicircular canal dehiscence on cochlear implant audiologic outcomes

PURPOSE

Determine whether adult cochlear implant users with radiographic superior semicircular canal dehiscence experience clinically significant differences in audiological outcomes when compared to cochlear implant users with normal temporal bone anatomy.

MATERIALS AND METHODS

Retrospective, single institution review. Adult, post-lingual deaf patients implanted between 2010 and 2020. Inclusion criteria included age 18 years or older, available preoperative computed tomography imaging, and preoperative and postoperative AzBio audiological data for at least 6 months of cochlear implant use. Preoperative and postoperative AzBio Sentence Test scores were compared between patients with normal temporal bone anatomy and those with radiographic superior semicircular canal dehiscence or near dehiscence.

RESULTS

110 patients met inclusion criteria. Mean AzBio score for normal temporal bone anatomy group improved from 35.2 % (SD 28.2) preoperatively to 70.3 % (SD 25.7) postoperatively, an improvement of 35.1 % (SD 28.6). Mean AzBio score for near dehiscent temporal bone anatomy group improved from 26.6 % (SD 28.9) preoperatively to 64.5 % (SD 30.6) postoperatively, an improvement of 37.9 % (SD 27.9). Mean AzBio score for dehiscent temporal bone anatomy group improved from 26.3 % (SD 20.4) preoperatively to 65.1 % (SD 27.6) postoperatively, an improvement of 38.7 % (SD 26.9). Utilizing the one-way analysis of variance test, there was no significant difference in audiologic outcomes between the three groups.

CONCLUSIONS

Patients with complete or near complete radiographic superior canal dehiscence at the time of cochlear implantation achieve similar improvements in speech perception scores compared to normal anatomy adult cochlear implant users.

Nanocatalysts as fast and powerful medical intervention: Bridging cochlear implant therapies and advanced modelling using Hidden Markov Models (HMMs) for effective treatment of infections

As human population growth and waste from technologically advanced industries threaten to destabilise our delicate ecological equilibrium, the global spotlight intensifies on environmental contamination and climate-related changes. These challenges extend beyond our external environment and have significant effects on our internal ecosystems. The inner ear, which is responsible for balance and auditory perception, is a prime example. When these sensory mechanisms are impaired, disorders such as deafness can develop. Traditional treatment methods, including systemic antibiotics, are frequently ineffective due to inadequate inner ear penetration. Conventional techniques for administering substances to the inner ear fail to obtain adequate concentrations as well. In this context, cochlear implants laden with nanocatalysts emerge as a promising strategy for the targeted treatment of inner ear infections. Coated with biocompatible nanoparticles containing specific nanocatalysts, these implants can degrade or neutralise contaminants linked to inner ear infections. This method enables the controlled release of nanocatalysts directly at the infection site, thereby maximising therapeutic efficacy and minimising adverse effects. In vivo and in vitro studies have demonstrated that these implants are effective at eliminating infections, reducing inflammation, and fostering tissue regeneration in the ear. This study investigates the application of hidden Markov models (HMMs) to nanocatalyst-loaded cochlear implants. The HMM is trained on surgical phases in order to accurately identify the various phases associated with implant utilisation. This facilitates the precision placement of surgical instruments within the ear, with a location accuracy between 91% and 95% and a standard deviation between 1% and 5% for both sites. In conclusion, nanocatalysts serve as potent medicinal instruments, bridging cochlear implant therapies and advanced modelling utilising hidden Markov models for the effective treatment of inner ear infections. Cochlear implants loaded with nanocatalysts offer a promising method to combat inner ear infections and enhance patient outcomes by addressing the limitations of conventional treatments.

Effects of Age on Delayed Facial Palsy After Otologic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

To report 4 cases of delayed facial palsy (DFP) after pediatric middle ear (ME) surgery and systematically review and analyze the associated literature to evaluate the effects of age on DFP etiology, management, and prognosis.

METHODS

Systematic review of PubMed, Cochrane Library, and Embase for articles related to DFP after cochlear implantation (CI) was performed. These articles were assessed for level of evidence, methodological limitations, and number of cases. Meta-analysis was performed to assess the effects of age on DFP incidence. Furthermore, a comprehensive list of all pediatric DFP cases after otologic surgery was assembled through a multi-institutional retrospective review and systematic review of the literature.

RESULTS

Twenty-nine articles fit the criteria for inclusion in the meta-analysis. The incidence of DFP after CI was 0.23% and 1.01% for pediatric and adult cases, respectively. This difference was statistically significant (P < .001, odds ratio 4.36). Twenty-three cases, adding to the 4 presented herein, were suitable for a comprehensive list. The mean age was 6.9 years. Average postoperative day of paresis onset was 5.4, with an average maximum House-Brackmann grade of 3.5. All patients obtained full facial recovery after an average of 23.5 days.

CONCLUSIONS

The systematic review demonstrates that DFP after pediatric CI is rare and occurs at a significantly lower rate than in adults, further supporting the viral reactivation hypothesis of DFP. The prognosis for pediatric DFP after otologic surgery is excellent, with a high rate of full recovery in a short time frame. However, steroid administration can be considered.

LEVEL OF EVIDENCE

IIa.

Utility and value of pre-operative CT and MRI for cochlear implantation in the elderly

PURPOSE

To determine the utility and value of pre-operative imaging among the elderly population ≥70 y.o. with bilateral progressive sensorineural hearing loss undergoing cochlear implantation.

MATERIALS AND METHODS

A retrospective, cross-sectional review was performed at a tertiary referral center between 2010 and 2018 including patients ≥70 y.o. with bilateral presbycusis who underwent preoperative imaging and cochlear implantation. Primary outcome was whether pre-operative imaging changed the surgeon's surgical plan such as side of implant or abort procedure entirely. Patient characteristics including age, sex, side of implant, imaging modality, whether imaging changed surgical plan, and surgical complications were reviewed. One-way analysis of variance with post-hoc tests using the Bonferroni and Fisher's exact test were used to examine differences between groups. Secondary outcome was cost of preoperative imaging.

RESULTS

One hundred thirty-three patients (mean age 79.38 [5.51 SD]) who underwent a total of 142 surgical cases and 147 total scans. There were 92, 27, and 14 patients who underwent CT, MRI, or both, respectfully (n=133). Of the 142 implants that were placed, preoperative imaging did not reveal a contraindication to placing implant on one side over another. Total cost of imaging was $29,694. Estimated cost if 20% of cochlear implant eligible patients ≥70 y.o. underwent imaging is $7,763,490.

CONCLUSION

Decreasing unnecessary preoperative imaging can potentially decrease cost in cochlear implantation. In this sample, preoperative imaging did not affect the surgeon's choice of which side to operate on. However, imaging may provide an anatomic roadmap and contribute to either surgical confidence or caution. With the increasing amount of cochlear implant eligible elderly adults, preoperative imaging needs to be more clearly defined in this unique population.

Current Trends, Controversies, and Future Directions in the Evaluation and Management of Superior Canal Dehiscence Syndrome

Patients with superior canal dehiscence syndrome (SCDS) can present with a range of auditory and/or vestibular signs and symptoms that are associated with a bony defect of the superior semicircular canal (SSC). Over the past two decades, advances in diagnostic techniques have raised the awareness of SCDS and treatment approaches have been refined to improve patient outcomes. However, a number of challenges remain. First, there is currently no standardized clinical testing algorithm for quantifying the effects of superior canal dehiscence (SCD). SCDS mimics a number of common otologic disorders and established metrics such as supranormal bone conduction thresholds and vestibular evoked myogenic potential (VEMP) measurements; although useful in certain cases, have diagnostic limitations. Second, while high-resolution computed tomography (CT) is the gold standard for the detection of SCD, a bony defect does not always result in signs and symptoms. Third, even when SCD repair is indicated, there is a lack of consensus about nomenclature to describe the SCD, ideal surgical approach, specific repair techniques, and type of materials used. Finally, there is no established algorithm in evaluation of SCDS patients who fail primary repair and may be candidates for revision surgery. Herein, we will discuss both contemporary and emerging diagnostic approaches for patients with SCDS and highlight challenges and controversies in the management of this unique patient cohort.

Influence of Semicircular Canal Dehiscence on Cochlear Implant Outcome

INTRODUCTION

Semicircular canal dehiscence (SCD) is defined as a defect of the bone overlying the semicircular canal. It has a relatively high prevalence of 3% in the general population, which makes it likely that a certain number of patients receiving a cochlear implant (CI) would have it. However, little is known about the influence of SCD on the CI outcome. Therefore, the aim of this study was to determine the influence of SCD on CI outcome with regard to short- and long-term word perception and hearing preservation.

METHODS

This study was a retrospective analysis of postoperative word perception ability in the electric-only condition after 6, 12, and ≥18 months and of hearing preservation 4 weeks after surgery in CI recipients with and without SCD. All patients received a preoperative 1.5- or 3-tesla magnetic resonance imaging.

RESULTS

Fifty-five patients were included. Forty-eight patients (87%) had no SCD, and 7 patients (13%) had SCD. Mean postoperative word perception scores were 66% in the non-SCD group versus 50% in the SCD group (p = 0.17) after 6 months, 74 versus 64% (p = 0.28) after 12 months, and 77 versus 73% (p = 0.62) after 18 or more months. The mean postoperative hearing loss in patients with functional residual hearing before surgery (n = 34) was 22 dB in the non-SCD group versus 31 dB in the SCD group (p = 0.15).

CONCLUSIONS

CI outcome is comparable between recipients without and with SCD. Specifically, hearing preservation rate and word perception ability in the electric-only condition seem not affected by SCD. The rate of progress of word perception ability in the first 12 months after cochlear implantation is not influenced by SCD.

Meta-analysis of subjective complaints of vertigo and vestibular tests after cochlear implantation

OBJECTIVE

Postoperative vertigo is a common complaint after cochlear implantation, but published incidence rates differ vastly. The aim of the present study was to investigate both subjective complaints of vertigo before and after cochlear implantation and related vestibular diagnostic tests on cochlear implant candidates.

DATA SOURCES

We performed a systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement in PubMed, Cochrane Register, and EMBASE.

REVIEW METHODS

We presented 116 eligible studies investigating subjective complaints of vertigo after cochlear implantation and/or related vestibular diagnostic tests. We conducted three meta-analyses of 46 eligible studies with matched pre- and postoperative data to calculate the odds ratio of new vertigo onset, as well as the impairment of vestibular receptors measured by nystagmography and cervical vestibular evoked myogenic potentials (cVEMP). Postoperative vertigo was calculated from 95 studies and further subdivided by mean age with pooled data.

RESULTS

We observed a significant increase in postoperative vertigo and significant impairment of nystagmography and cVEMP detection. Vertigo after cochlear implantation was reported in 9.3% of the patients with a continuous increase in patient age at surgery. In a subgroup of studies, new onset of vertigo was found in 17.4% of the patients. In addition, 7.2% of the patients had persisting vertigo complaints, whereas 11.6% described an altered vertigo quality and 7.7% had their preoperative complaints resolved. A comparison of round window approach and cochleostomy revealed significantly increased vertigo after cochleostomy. Both insertion methods showed similar effects in nystagmography and cVEMP testing.

CONCLUSION

Cochlear implantation has a significant impact on subjective vertigo and vestibular receptor function. This is affected by the patient's age at the time of surgery. The surgical technique (round window or cochleostomy) may influence the outcome, but this requires further investigation. Younger patients may compensate better following vestibular dysfunction. Perioperative testing is required to correlate vestibular impairment and subjective complaints. Laryngoscope, 2018 Laryngoscope, 128:2110-2123, 2018.

Characteristics of Wax Occlusion in the Surgical Repair of Superior Canal Dehiscence in Human Temporal Bone Specimens

HYPOTHESIS

Superior canal dehiscence (SCD) repair using surgical bone wax may result in variable outcomes if large wax volumes are applied.

BACKGROUND

SCD is a disorder characterized by a pathologic defect in the bony labyrinth of the superior semicircular canal (SSC), resulting in vestibular and/or auditory symptoms. Repair of SCD using bone wax can provide symptomatic relief, but surgical outcomes are variable. These observations may be associated with the inconsistency in the position and extension of intralabyrinthine bone wax during surgical repair.

METHODS

A pathological model of SCD was created using cadaveric human temporal bones and a microdrill. Defects in the arcuate eminence 0.5 to 3.5  mm in length were repaired by surgical occlusion with bone wax. The volume of wax used in the repair was quantified. The position of bone wax was evaluated by direct visualization and imaging (computed tomography [CT]). To visualize wax on CT, specimens were repaired using radiopaque wax.

RESULTS

Exceedingly small volumes of bone wax (3.0-5.0  mm2) reliably occluded the canal lumen. Multiple wax applications resulted in extension into the common crus and ampulla. The length of this extension was related to the number of applications.

CONCLUSIONS

Repair of SCD with bone wax occludes the bony defect completely in most patients. Wax can extend along the lumen of the superior canal beyond the limits of the dehiscence to reach the sensory neuroepithelium of the vestibular end organs. Limiting the number of wax applications is essential to avoid inadvertent injury to the delicate neurosensory systems.