Current criteria for selecting cochlear implant in deaf patients: a review

Cochlear implantation is indicated in patients with severe to profound hearing loss that cannot be adequately treated by other auditory rehabilitation measures. The definitive indication of cochlear implantation is made on the basis of an extensive interdisciplinary clinical, audiological, radiological, and psychological diagnostic work-up. There are numerous changes are happening in cochlear implant candidacy. These have been associated with concomitant changes in surgical techniques, which enhanced the utility and safety of cochlear implantation. Currently, cochlear implants are approved for individuals with severe to profound unilateral hearing loss rather than previously needed for bilateral profound hearing loss. Studies have begun using the short electrode arrays for shallow insertion in patients with low-frequency residual hearing loss. The advancement in designs of the cochlear implant along with improvements in surgical techniques reduce the complications and result in the safety and efficacy of the cochlear implant which further encourages the use of these devices. This review article aims to discuss the new concepts in the candidacy of the cochlear implant, cochlear implant in younger children and hearing preservation, a cochlear implant for unilateral deafness, bilateral cochlear implant, and cochlear implant with neural plasticity and selection of patients for the cochlear implant.

Evaluating cochlear insertion trauma and hearing preservation after cochlear implantation (CIPRES): a study protocol for a randomized single-blind controlled trial

Background In order to preserve residual hearing in patients with sensorineural hearing loss (SNHL) who receive a cochlear implant (CI), insertion trauma to the delicate structures of the cochlea needs to be minimized. The surgical approach comprises the conventional mastoidectomy-posterior tympanotomy (MPT) to arrive at the middle ear, followed by either a cochleostomy (CO) or the round window (RW) approach. Both techniques have their benefits and disadvantages. Another important aspect in structure preservation is the design of the electrode array. Two different designs are used: a “straight” lateral wall lying electrode array (LW) or a “pre-curved” perimodiolar lying electrode array (PM). Interestingly, until now, the best surgical approach and design of the implant is uncertain. Our hypothesis is that there is a difference in hearing preservation outcomes between the four possible treatment options. Methods We designed a monocenter, multi-arm, randomized controlled trial to compare insertion trauma between four groups of patients, with each group having a unique combination of an electrode array type (LW or PM) and surgical approach (RW or CO). In total, 48 patients will be randomized into one of these four intervention groups. Our primary objective is the comparison of postoperative hearing preservation between these four groups. Secondly, we aim to assess structure preservation (i.e., scalar translocation, with basilar membrane disruption or tip fold-over of array) for each group. Thirdly, we will compare objective outcomes of hearing and structure preservation by way of electrocochleography (ECochG). Discussion Cochlear implantation by way of a cochleostomy or round window approach, using different electrode array types, is the standard medical care for patients with severe to profound bilateral sensorineural hearing loss, as it is a relatively simple and low-risk procedure that greatly benefits patients. However, loss of residual hearing remains a problem. This trial is the first randomized controlled trial that evaluates the effect of cochlear insertion trauma of several CI treatment options on hearing preservation. Trial registration Netherlands Trial Register (NTR) NL8586. Registered on 4 May 2020. Retrospectively registered; 3/48 participants were included before registration.

One Year Assessment of the Hearing Preservation Potential of the EVO Electrode Array

Background: A prospective longitudinal multicentre study was conducted to assess the one-year postsurgical hearing preservation profile of the EVOTM electrode array. Methods: Fifteen adults presenting indications of electro-acoustic stimulation (pure-tone audiometry (PTA) thresholds ≤70 dB below 750 Hz) were implanted with the EVO™ electrode array. Hearing thresholds were collected at five time-points from CI activation to twelve months (12M) after activation. Hearing thresholds and hearing preservation profiles (HEARRING group classification) were assessed. Results: All subjects had measurable hearing thresholds at follow-up. No case of complete loss of hearing or minimal hearing preservation was reported at any time point. At activation (Nact = 15), five participants had complete hearing preservation, and ten participants had partial hearing preservation. At the 12M time point (N12m = 6), three participants had complete hearing preservation, and three participants had partial hearing preservation. Mean hearing loss at activation was 11 dB for full range PTA and 25 dB for PTAs low-frequency (125–500 Hz). Conclusions: This study provides the first longitudinal follow-up on associated hearing profiles to the EVO™ electrode array, which are comparable to the literature. However, other studies on larger populations should be performed.

Effect of Dexamethasone Combination with Gentamicin in Chemical Labyrinthectomy on Hearing Preservation and Vertigo Control in Patients with Unilateral Meniere’s Disease: A Randomized Controlled Clinical Trial

Chemical labyrinthectomy using gentamicin is a popular method for treating intractable vertigo attacks in Meniere’s disease. However, the risk of hearing loss remains a major concern for clinicians. We investigated the effect of simultaneous dexamethasone and gentamicin application on hearing preservation and vertigo control in patients with intractable unilateral Meniere’s disease. A single-institutional, prospective, single-blinded, randomized clinical trial was conducted. Gentamicin-soaked Gelfoam® was directly applied on the oval window following middle ear exploration. On the round window, dexamethasone-soaked Gelfoam® was applied in the gentamicin with dexamethasone group (GD group, n = 18), and saline-soaked Gelfoam® was applied in the gentamicin with sham reagent group (GO group, n = 19). The hearing change 8 weeks after the procedure and vertigo control 2–12 months after the procedure were investigated. The high-frequency hearing threshold was significantly increased in the GO group (p = 0.005 and 0.012 for 4 and 8 kHz, respectively), but not in the GD group. The short-term (2–6 months) vertigo control was more successful in the GD group (57.89% vs. 94.44%, p = 0.019), but long-term control (6–12 months) was insignificant. In conclusion, the combined application of gentamicin and dexamethasone in chemical labyrinthectomy is an effective method for protecting high-frequency hearing and vertigo control.

Long-term follow-up of applying autologous bone grafts for reconstructing tympanomastoid defects in functional cholesteatoma surgery

Objectives This study investigated the long-term surgical outcomes of functional cholesteatoma surgery with canal wall reconstruction using autologous bone grafts as the primary material in patients with acquired cholesteatoma. Subjects and Methods Medical charts were retrospectively reviewed for all patients admitted to one institution for surgical intervention between 2010 and 2018. We analyzed 66 patients (66 ears) who underwent functional tympanomastoidectomy involving the use of autologous bone grafts for canal wall defect reconstruction. Surgical outcomes were evaluated by comparing preoperative audiometric results with follow-up data (at least 36 months after surgery). Logistic regression analyses were performed to determine prognostic factors related to long-term hearing success. These factors included classification and stage of cholesteatoma, stapes condition, ossicular chain damage, active infection of the middle ear, state of the contralateral ear, preoperative hearing thresholds, gender, and age. Results The mean follow-up period was 49.2 months. The recidivism rate was 6% (four of 66 ears). The pure-tone average significantly improved from 50.78 ± 19.98 to 40.81 ± 21.22 dB hearing level (HL; p < 0.001). Air–bone gaps significantly improved from 26.26 ± 10.53 to 17.58 ± 8.21 dB HL (p < 0.001). In multivariate logistic regression analysis, early-stage disease (p = 0.021) and pars flaccida cholesteatoma (p = 0.036) exhibited statistically significant correlations with successful hearing preservation. Conclusion Functional cholesteatoma surgery with autologous bone grafts reconstruction is an effective approach to significantly improve hearing with low recidivism rates. Localized disease and pars flaccida cholesteatoma were two independent predictors of successful hearing preservation.

Petrous Bone Cholesteatoma: Facial and Hearing Preservation

Objectives: Petrous bone cholesteatoma (PBC) is a rare condition of the petrous portion of the temporal bone. Treatment of choice consists of radical surgical removal, paying attention to protect the facial nerve and inner ear as far as possible. The aim of the present study was to evaluate the efficacy of modified translabyrinthine techniques in preserving hearing function and the use of the adjuvant endoscopic techniques in a group of PBC patients. Methods: This study comprised 16 cases of PBCs surgically treated in our Department. Pre- and post-operative hearing status was assessed with pure tone audiometry and speech discrimination and graded according to the Gardner- Robertson classification system. Facial function was based on the House Brackman (HB) classification. PBCs were grouped using Sanna’s classification. The choice of surgical technique was based on the above findings together with preoperative evidence. Post-operative follow-up ranged from 1 to 10 years and also included Computed Tomography and Magnetic Resonance Imaging assessment. Results: PBCs were classified as follows: 37.5% infralabyrinthine; 43.75% supralabyrinthine; and 18.75% massive. Preservation of the bone conduction threshold was feasible in 62.5% of patients. For supralabyrinthine PBCs a subtotal petrosetomy was performed in all cases and hearing preservation was possible in 57% of them: an adjuvant endoscopic approach was performed in 43%. Infralabyrinthine PBCs were treated using a modified translabyrinthine approach with preservation of bone conduction in 83% of patients; an adjuvant endoscopic approach was performed in 50% cases. One patient with a massive cholesteatoma was treated by modified translabyrinthine approach, preserving a serviceable level of hearing. In all massive cases, an adjuvant endoscopic approach was performed. In 2 patients with preoperative palsy, facial nerve function showed an improvement. The follow-up period revealed evidence of limited recurrence at CT imaging in 2 patients. Conclusions: The introduction of modified surgical approaches, able to preserve the anatomical-functional structures, have shown an improvement of post-operative hearing outcomes.