Middle Ear Implants Research Articles

Mastoid cavity obliteration in treatment of middle ear cholesteatoma

Objective: The primary goal in the surgical management of chronic otitis media with cholesteatoma is the creation of a dry and safe ear. The method of choice for management of cholesteatoma is the inside out or reverse mastoidectomy. If external auditory canal reconstruction after complete cholesteatoma removal is not possible, mastoid cavity obliteration techniques are recommended to reduce the size of the open mastoid cavity. The goal of our study is to evaluate the frequency of postoperative ear secretion and hearing situation in patients with mastoid cavity obliteration in treatment of middle ear cholesteatoma. Methods: Retrospective study of 155 patients with middle ear cholesteatoma were surgically treatment during 52 months from 01.06.2014 to 30.09.2018 in Hospital Trakia Park, Stara Zagora (Bulgaria) with canal wall reconstruction or mastoid cavity obliteration with cartilage, bone pate or bone replacement alloplastic materials. Results: After complete cholesteatoma removal we perform ear canal reconstruction in 51.61% of cases (80; n=155), and in others 41.94% of cases (65; n=155) we perform mastoid cavity obliteration. In our patient group we perform type I tympanoplasty in 36.77% (57; n=155), type III tympanoplasty in 46.45% (72; n=155), Secondlook operations in 14% (21, n = 155) and only in 5 cases we left the operating cavity open (3.23%; n=155). After mean follow-up period from 11.34 months (1÷48 months; SD 13.10 months) our frequency of postoperative ear secretion is 6.45% (10; n=155) and our cholesteatoma residual rate is 9.03% (14; n=155). Conclusion: Mastoid cavity obliteration procedures can prevent the development of postoperative retraction pockets by isolation the tympanic cavity from the attic and mastoid. This is a safe and effective technique for rehabilitation of mastoid cavities. Hearing results of this technique is variable according to the involvement of the middle ear ossicles, but with the possibility of fitting a hearing aids or middle ear implants.

Beyond Tympanomastoidectomy: A Review of Less Common Postoperative Temporal Bone CT Findings.

Postoperative temporal bone imaging after surgical procedures such as ossiculoplasty, tympanomastoidectomy, cochlear implantation, and vestibular schwannoma resection is often encountered in clinical neuroradiology practice. Less common otologic procedures can present diagnostic dilemmas, particularly if access to prior operative reports is not possible. Lack of familiarity with the less common surgical procedures and expected postoperative changes may render radiologic interpretation challenging. This review illustrates key imaging findings after surgery for Ménière disease, superior semicircular canal dehiscence, temporal encephalocele repairs, internal auditory canal decompression, active middle ear implants, jugular bulb and sigmoid sinus dehiscence repair, and petrous apicectomy.

Impact of occlusive material and cochlea-carotid artery relation on eustachian tube occlusion in subtotal petrosectomy.

ObjectiveTo evaluate the success rate of eustachian tube (ET) occlusion in subtotal petrosectomy relative to the occlusive material used and to the varying protympanum anatomy, by means of standardized alignment of the cochlea‐carotid artery relation on computed tomography images.Patients and methodsAll cases of subtotal petrosectomy carried out by the same surgeon at a tertiary care referral center were retrospectively evaluated. Only cases with available computed tomography prior to second stage cochlear or middle ear implantation were included. The occlusive material was either muscle tissue or oxidized regenerated cellulose in combination with bone wax. On 3D multiplanar image reconstruction, the varying topographic interrelation of the cochlea and the petrous carotid artery was measured and categorized into two groups: detachment or overlapping.ResultsIn 9 (31%) of the 29 included cases there was insufficient occlusion of the ET. In none of these cases was an infection of the fat filling in the obliterated cavity observed during the implantation procedure on second stage (average 10 months interval). The failure rate of both occlusion materials was almost the same (using muscle tissue, in 4 (33.3%) of 12 or oxidized regenerated cellulose, in 5 (29.4%) of 17 cases). It was also similar for both materials in each of the anatomic variation groups.ConclusionsAn incomplete occlusion of the ET alone does not appear to lead to an infection of the obliterated cavity. Autologous muscle tissue and oxidized regenerated cellulose had similar rates of ET occlusion failure. The topographical variance of the protympanum appears to have no direct influence on the success of the ET occlusion.

Status of early hearing detection and intervention in South Korea: a nationwide population-based study of national infant health checkup

The aim of this study was to evaluate the status of early hearing detection and intervention after newborn hearing screening (NHS) in South Korea. A retrospective review of Korean national health insurance service data of all infants receiving the 4-month old national infant health checkup between 2010 and 2016 from a nationwide population-based database was conducted. Based on the results of the NHS-administered hearing questionnaires as part of the national infant health checkup, individuals were classified into “pass” (1,730,615 infants) or “refer” (10,941 infants) groups. Next, an analysis was conducted of age and the frequencies of tracking audiologic tests and surgeries of the middle ear (ME) and cochlear implants (CI). Diagnostic auditory brainstem response and audiometry, and surgeries of ME and CI were significantly performed more and earlier in the refer group compared with the pass group. For infants in the pass group who were presumed to have delayed or acquired hearing loss, the time of the first audiology tests and CI surgery was significantly delayed compared to those in the refer group; the average ages for first CI were 37 and 52 months in the refer group and pass group, respectively. Therefore, for early detection of delayed-onset hearing loss, regular hearing screening programs should be considered throughout the preschool ages.

Editorial introductions

Editorial introductions

Intraoperative quantification of floating mass transducer coupling quality in active middle ear implants: a multicenter study

PurposeEvaluating the effectiveness of intraoperative auditory brainstem responses (ABRs) to stimulation by the Vibrant Soundbridge (VSB) active middle ear implant for quantifying the implant’s floating mass transducer (FMT) coupling quality.MethodsIn a diagnostic multicentric study, patients (> 18 years) who received a VSB with different coupling modalities were included. Pre- and postoperative bone conduction thresholds, intraoperative VSB-evoked ABR thresholds (VSB-ABR) using a modified audio processor programmed to preoperative bone conduction thresholds, postoperative vibrogram thresholds, and postoperative VSB-ABR thresholds were measured. Coupling quality was calculated from the difference between the pure tone average at 1000, 2000, and 4000 Hz (3PTA) vibrogram and postoperative 3PTA bone conduction thresholds.ResultsTwenty-three patients (13 males, 10 females, mean age 56.6 (± 12.5) years) were included in the study. Intraoperative VSB-ABR response thresholds could be obtained in all except one patient where the threshold was > 30 dB nHL. Postoperatively, an insufficient coupling of 36.7 dB was confirmed in this patient. In a Bland–Altman analysis of the intraoperative VSB-ABRs and coupling quality, the limits of agreement exceeded ± 10 dB, i.e., the maximum allowed difference considered as not clinically important but the variation was within the general precision of auditory brainstem responses to predict behavioral thresholds. Five outliers were identified. In two patients, the postoperative VSB-ABR thresholds were in agreement with the coupling quality, indicating a change of coupling before the postoperative testing.ConclusionThe response thresholds recorded in this set-up have the potential to predict the VSB coupling quality and optimize postoperative audiological results.

Biomechanics of the Human Middle Ear with Viscoelasticity of the Maxwell and the Kelvin-Voigt Type and Relaxation Effect.

The middle ear is one of the smallest biomechanical systems in the human body and is responsible for the hearing process. Hearing is modelled in different ways and by various methods. In this paper, three-degree-of-freedom models of the human middle ear with different viscoelastic properties are proposed. Model 1 uses the Maxwell type viscoelasticity, Model 2 is based on the Kelvin–Voigt viscoelasticity, and Model 3 uses the Kelvin–Voigt viscoelasticity with relaxation effect. The primary aim of the study is to compare the models and their dynamic responses to a voice excitation. The novelty of this study lies in using different models of viscoelasticity and relaxation effect that has been previously unstudied. First, mathematical models of the middle ear were built, then they were solved numerically by the Runge–Kutta procedure and finally, numerical results were compared with those obtained from experiments carried out on the temporal bone with the Laser Doppler Vibrometer. The models exhibit differences in the natural frequency and amplitudes near the second resonance. All analysed models can be used for modelling the rapidly changing processes that occur in the ear and to control active middle ear implants.

Binaural hearing restoration with a bilateral fully implantable middle ear implant.

Thefully implantable middle ear implant (C-FI-MEI) is designed for patients with moderate-to-severe sensorineural hearing loss or those with mixed hearing loss. To analyze the audiological post-operative results of subjects bilaterally implanted with C-FI-MEI. Retrospective study: 14 patients with bilateral, moderate-to-severe, sensorineural or mixed hearing loss were treated. This clinical sample included 14 cases bilaterally implanted (13 sequentially, 1 simultaneously). The evaluation at each follow-up after surgery included otologic examination, a structured interview, and different audiological tests composed of pure tone audiometry, speech in quiet and in noise test, and localization task. The mean follow-up was 67.2 ± 33months. There were no significant differences between pre and post-operative pure tone averages. The patients showed no significant differences between pre-operatively aided and C-FI-MEI implant-aided conditions in terms of word recognition score. Speech perception in noise under different loudspeaker arrangements and localization tests demonstrated a binaural advantage in bilaterally implanted patients. The mean daily use time was 17.4 and 16.7h, respectively, for right and left side. The results for the 14 patients, bilaterally implanted with C-FI-MEI, suggest that bilateral implantation of fully implantable middle ear hearing devices is an effective procedure. 4.

Feasibility and Efficacy of Vibrant Soundbridge Short Process Coupler in Patients With Aural Atresia.

Different options are available for hearing restoration in patients with aural atresia. Middle ear implantation with the Vibrant Soundbridge (VSB) has been used successfully in many patients with aural atresia with conductive or mixed hearing loss. The aim of the current study was to assess the safety and the efficiency of VSBs coupled to the short process of the incus in patients with aural atresia with conductive or mixed hearing loss. The study was a retrospective chart review conducted at a tertiary university hospital. Audiological and surgical data from six ears with aural atresia implanted with VSBs coupled to the short process of the incus were analyzed. The audiological results were compared with previously reported results obtained after the utilization of different coupling techniques. All six atretic ears were successfully implanted using the short process coupler, and there were no major complications. Postoperative bone conduction thresholds did not differ substantially from preoperative thresholds. The respective mean preoperative pure-tone average 4, speech reception threshold, and word recognition score values were 56.7 dB, 61.7 dB, and 44%. Postoperative pure-tone average 4 thresholds (25 ± 3.5 dB) and speech reception thresholds (20.8 ± 8 dB) were significantly improved. The maximum postoperative word recognition score achieved was 100%. The audiological outcomes obtained were similar to previously reported outcomes after classic stapes placement. Coupling of the floating mass transducer to the short process of the incus in patients with aural atresia resulted in significant audiological improvements that were comparable to previously reported improvements after placement via other methods.

Fully Implantable Active Middle Ear Implants After Subtotal Petrosectomy With Fat Obliteration: Preliminary Clinical Results.

In patients with chronic middle ear disease, especially after revision surgery for ventilation problems and mixed hearing loss, active middle ear implants may provide an alternative treatment option. The fully implantable active middle-ear implant (FI-AMEI) is designed for implantation in a ventilated mastoid with an intact posterior canal wall. Until now, there have been no reports on audiometric results after implantation of a FI-AMEI in a fat-obliterated cavity after subtotal petrosectomy (SPE). Retrospective case review. Tertiary referral center. Twelve patients were included after numerous previous tympanoplasty surgeries for severe mixed hearing loss and FI-AMEI implantation. In five patients, the FI-AMEI was implanted in a cavity, with fat obliteration, after SPE. Seven patients received FI-AMEI implantation after intact canal wall (ICW) surgery. Audiometric results (pure-tone audiometry, Freiburger monosyllables) are demonstrated for 12 patients after an observation period of 3 months. The improvement in monosyllable score was 40 to 85% for the 12 patients. Free-field-aided thresholds showed high heterogeneity. FI-AMEI implantation combined with SPE provides an alternative approach to hearing rehabilitation to non-FI-AMEI implantation. Studies with a high number of patients and long-term observation periods are necessary to statistically verify these results.

A Quantitative Approach for the Objective Assessment of Coupling Efficiency for an Active Middle Ear Implant by Recording Auditory Steady-state Responses.

The coupling efficiency of a semi-implantable active middle ear implant with an electromagnetically driven floating mass transducer coupled to a middle ear ossicle or the round window can only be quantified postoperatively in cooperative patients by measuring behavioral vibroplasty in situ thresholds in comparison with bone conduction thresholds. The objective of the study was to develop a method to objectively determine the vibroplasty in situ thresholds by determining calibration factors from the relation between the objective and behavioral vibroplasty in situ thresholds. Prospective experimental study. Fifteen patients, implanted with an active middle ear implant for at least 6 months. Diagnostic. Vibroplasty in situ thresholds measured objectively by auditory steady state responses (floating mass transducer [FMT]ASSR). Subjective vibroplasty in situ thresholds were measured in this experimental ASSR set-up (FMTsubj.) and behaviorally by pure-tone audiometry (vibrogram). All thresholds were obtained at 500, 1000, 2000, and 4000 Hz. Thresholds could be objectively measured by ASSR in all patients. Differences between the FMTASSR and FMTsubj. were statistically significant but small. A significant correlation was found between the FMTASSR and the vibrogram thresholds at 4000 Hz but not for the other test frequencies. The method is feasible to measure objective vibroplasty in situ thresholds in active middle ear implant users. Since calibration factors could not be determined for all frequencies, the method is only applicable to comparatively determine the coupling efficiency of the floating mass transducer.

Operative techniques in Otolaryngology: Hearing restoration options

Hearing loss in elderly patients, commonly referred to as age-related hearing loss (ARHL), is an increasingly significant cause of morbidity. ARHL noted to be the second most common illness in the elderly population, and can often be detrimental to the quality of life of patients. Presently, restorative treatment for age-related hearing loss is limited, however, multifactorial rehabilitation and management strategies exist. A pivotal aspect of management in ARHL is the use of amplifying hearing aids and implantable devices. At this time, options for amplification include external and internal hearing aids, middle ear implants, bone-anchored devices, and cochlear implants. Despite the presence of numerous management options, many patients with hearing loss are not using amplifying devices. This chapter discusses the different management options for ARHL including important considerations and operative techniques, with cochlear implants being discussed in a separate chapter.

Effect of stimulation sites on the performance of electromagnetic middle ear implant: A finite element analysis

Electromagnetic middle ear implants (MEIs), which use the mechanical vibration of their implanted transducers to treat hearing loss, have emerged to overcome the limitations of conventional hearing aids. Several reports have indicated that the electromagnetic MEI's performance changed with different stimulation sites of the transducer. The aim of this study was to analyze the influence of the transducers' stimulation sites on the electromagnetic MEIs' performance. To aid this investigation, a human ear finite-element model was developed from micro-CT images of an adult's right ear. The validity of the model was confirmed by comparing the model-derived results with experimental data. Then, stimulation forces, which simulate ideal electromagnetic transducers, were respectively applied at five typical coupling sites: the umbo, incus body, incus long process, the round window, and the stapes. The stimulation sites' influence on the electromagnetic MEI's performance was studied by analyzing their corresponding basilar membrane displacements. The results show that stimulation of the round window with a force produces more cochlear stimulation than equal force stimulation of the umbo, incus body, incus long process and the stapes, though the superiority of the round window depends on its smaller area compared to the stapes footplate. Among the forward stimulation, the stapes is the optimal stimulation site for the electromagnetic transducer regarding its hearing compensation's efficiency. The performance of the umbo stimulation is comparable to that of the incus-long-process stimulation. Driving the incus body is less efficient than stimulating the other forward driving sites. Additional, using the stapes response to evaluate the forward stimulation gives results similar to those deduced by the basilar membrane response; in contrast, for the round-window stimulation, the evaluation result based on the stapes response is prominently less than the one calculated by the basilar membrane response, especially in the mid-high frequency range.

Subjective Hearing Impression and Quality of Life in Patients With Bilateral Active Middle Ear Implants.

This study compared the quality of life in patients with bilateral active middle ear implants to their quality of life when they were unilaterally implanted. Twenty-one patients implanted sequentially with the Vibrant Soundbridge (VSB) active middle ear implant completed quality-of-life surveys. The patients were asked to rate whether and to what extent their quality of life has changed upon receiving a second VSB. Hearing-specific quality of life was assessed with the Speech, Spatial, and Qualities of Hearing Scale (SSQ12-B), and general quality of life was with the Glasgow Benefit Inventory (GBI). In addition, the patients completed a health-related quality-of-life questionnaire (AQoL-8D). Finally, the changes in hearing-related and general quality of life were correlated to the change in word recognition ability after implantation of the second VSB (Freiburg monosyllabic word test; unilateral VSB versus bilateral VSB at 65 dB SPL). On the SSQ12, subjects scored a median of + 2.73 (p < 0.001; significantly different from zero) on a scale of -5 to + 5 where 0 indicates no change. All three subscores showed significant improvement. On the GBI, patients reached a median overall score of + 23.6 (p < 0.001; significantly different from zero) on a scale of -100 to + 100 where 0 indicates no change. Here, the improvement was mainly visible in the general subscore, whereas the social support and physical health subscores did not change due to the intervention. Both subjective benefit rating scores strongly correlated with the change in word recognition scores, suggesting that both hearing and general quality of life improved with increased word recognition due to bilateral VSB use. No significant correlation was found between the subjects' general health (as measured by AQoL-8D utility scores) and SSQ12-B or GBI overall scores. Usage of a second active middle ear implant substantially improved our patients' subjective hearing and general quality of life compared with unilateral use. The increase in quality of life may be linked to improved speech understanding due to bilateral use of a middle ear implant. Furthermore, these outcomes were not influenced by our patients' general health state at the time of survey.

Surgical and audiological outcomes of a fully implantable middle ear implant: early results from a retrospective multicentre study

This paper reports the surgical and audiological outcomes of a large series of patients who received a fully implantable middle ear implant (MEI): carina (Cochlear, Australia). This is a multicentre retrospective study involving three tertiary referral centres. Patient data were collected for the first 42 consecutive patients who were fitted with the MEI between 2014 and 2019 (Sheffield from February 2017 to January 2019; São Paulo from April 2015 to September 2017; Porto from December 2014 to May 2017). The main outcome measures included surgical results, free field speech testing with speech recognition thresholds (SRT) and audiological gain. There was one major complication due to infection resulting in a brain abscess and explantation of the device. Three other patients had minor skin infections; no other complications were reported. Results show a functional gain of 19.5dB (p < 0.05) with the MEI versus unaided condition. SRT improved from 57.4dB to 44.6dB with the MEI (p < 0.05). This fully implanable active MEI offers a reliable option for patients with moderate-to-severe sensorineural or mixed hearing losses especially for those do not tolerate or cannot use conventional hearing aids. It provides significant improvement in hearing as shown in the audiological outcomes. The surgery is relatively straightforward but there is a steep learning curve. The devices are well tolerated by all patients.

Stability of the standard incus coupling of the Carina middle ear actuator after 1.5T MRI.

Limited data is available concerning the safety of active middle ear implants (AMEI) during Magnetic Resonance Imaging (MRI). Measurements in temporal bones are the gold standard for preclinical assessment of device safety. In this study the coupling stability of an actuator as used in a fully implantable AMEI was determined in temporal bones. Eleven temporal bones were implanted with the actuator according to the manufacturer's surgical guidelines. The actuator was coupled on the incus short process as recommended for sensorineural hearing loss. Temporal bones were exposed 10 times to the MRI magnetic field by entering the MRI suite in a clinically relevant way. Computed Tomography (CT) images were acquired before and after the experiment to investigate the risk of actuator dislocation. Based on the electrical impedance of the actuator, the loading of the actuator to the incus was confirmed. Relative actuator displacement was determined on the CT images by comparing the initial with the final actuator position in 3D space. Impedance curves were analyzed after each exposure to check the loading of the actuator to the ossicles. Analysis of CT images with a 0.30.6 mm in-plane resolution indicate no actuator displacement. The maximum detected change in impedance for all actuators was 8.43 Ω at the actuator's resonance frequency. Impedance curves measured when the actuator was retracted from the short process after the experiment still indicate the presence of a clear resonance peak. No actuator displacement or dislocation could be detected in the analysis of CT images and the measured impedance curves. Impedance curves obtained when the actuator was retracted from the incus short process still show a clear resonance peak, indicating the device is still functional after the MRI exposures.

Minimally-invasive incision using the implantable Hearing device Carina

The skin incision for cochlear implants and active middle ear implants like Vibrant Soundbridge and Bonebridge has evolved toward a minimally invasive access in recent years.For the active middle ear implant CARINA a significantly larger incision is recommended, which corresponds to that of Cochlear Implant care nearly two decades ago.As a result, increased complication rates due to extended incision can be expected. In order to minimize the complication rate for the active middle ear implant CARINA the possibility for minimally invasive incisions was reconsidered and developed. Up to now, 4 patients have been successfully treated with a CARINA system with the minimally invasive skin incision of less than 5 cm length without postoperative complications. By optimizing the fixation by using self-tapping screws, this access route can be established as a standard.

Location of the stapedius muscle with reference to the facial nerve in patients with unilateral congenital aural atresia: implication for active middle ear implants surgery

Background: Detailed investigations of the stapedial muscle (SM) in congenital aural atresia (CAA) patients have yet to be adequately conducted.Objectives: To assess image variations in the mastoid segment of the facial nerve (FN) and SM in CAA.Materials and methods: A total of nine patients comprising of 9 ears with unilateral CAA were studied. The courses of the FN and SM were evaluated from the basic point to 1 mm intervals between the mastoid portion of FN, and measured from the mean X and Y values in each group.Results: The atresia side of FN among the Y values showed significant differences compared to the contralateral side. In terms of the SM, there were no significant differences in both the X and Y values. The stapedial muscle of the CAA patients was located medially to the FN. Conversely, the distance from the PSC to the FN revealed no significant differences with regard to the X and Y values for each group.Conclusion: The current observations revealed that the SM is located more posterior to the FN in CAA patients, and this is mainly attributed to the laterally and anteriorly displaced FN.

Hearing Aid Treatment in Patients with Mixed Hearing Loss. Part I: Expected Benefit and Limitations after Stapes Surgery

Objective: The purpose of the present study was to determine the fraction of patients with mixed hearing loss who can or cannot expect benefit from power hearing aids (HAs) after stapes surgery. Design: The audiological outcome of 374 stapes surgeries was used to calculate the patients’ individual postoperative requirements in terms of gain and output of HAs. These requirements were compared to the available gain and output provided by state-of-the-art power HAs at 0.5, 1.0, 2.0, and 4.0 kHz. According to these comparisons, ears were divided into three groups. For G0, required gain and output lay within the corresponding technical limits of the HAs at all frequencies. In G1, one or both requirements could not be fulfilled at 1 frequency. G2 combined all ears where the requirements lay beyond the HA’s technical limitations at 2 or more frequencies. Results: Stapes surgery resulted in an improvement of air-bone gap (ABG) in 84.5% of the cases by 15.7 dB on average. Based on pure-tone average (0.5, 1.0, 2.0, 4.0 kHz), 40.6% of all cases showed an ABG ≤10 dB. 44.9% of all cases did no longer need a HA after stapes surgery. A power HA would fulfill both audiological criteria at all 4 frequencies in 81.6% of cases that needed a HA postoperatively. However, 18.4% would not be sufficiently treatable at 1 or more frequencies (15.0% in G1, 3.4% in G2). Conclusions: The present study identified a subset of patients with mixed hearing loss after stapes surgery that cannot be treated sufficiently with available power HAs. As the residual ABG is an important reason for this lack of treatment success, the advancement of alternative hearing devices that circumvent the middle ear, such as powerful active middle ear implants, is indicated.

Effects of Vibrant Soundbridge on tinnitus accompanied by sensorineural hearing loss.

Tinnitus is a common symptom among patients with hearing loss, and many studies have reported successful tinnitus suppression with hearing devices. Active middle ear implantation of the Vibrant Soundbridge (VSB) is a good alternative to existing hearing devices. This study evaluated the effects of VSB implantation on tinnitus and sought to identify the main audiological factor that affects tinnitus suppression. The study participants were 16 adults who had tinnitus with sensorineural hearing loss, and who underwent VSB implantations. Pure-tone audiometry; word recognition test; tinnitus handicap inventory (THI); and visual analog scale (VAS) assessment of loudness, awareness, and annoyance were performed before and 12 months after surgery. Changes in hearing threshold, word recognition scores (WRS), THI scores, and VAS scores were analyzed. VAS scores for loudness (mean difference: 1.9, 95% CI: 0.6, 3.1), awareness (mean difference: 1.6, 95% CI: 0.4, 2.8), and annoyance (mean difference: 1.7, 95% CI: 0.7, 2.8) showed significant improvements from baseline to 12 months after surgery. In addition, THI scores showed a significant decrease (mean difference: 13.8, 95% CI: 2.9, 24.9). The average hearing threshold level, WRS, and most comfortable level (MCL) also showed significant improvements at 12 months after surgery (mean difference: 17.3, 95% CI: 13.3, 21.3; mean difference: -7.6, 95% CI: -15.1, -0.1; mean difference: 26.3, 95% CI: 22.9, 29.6, respectively). Among the aforementioned factors, changes in MCL were best correlated with those in THI scores (mean difference: 2.55, 95% CI: 0.90, 4.21). A VSB implant is beneficial to subjects with tinnitus accompanied by sensorineural hearing loss. The changes in THI scores best correlated with those in MCL. This improvement may represent a masking effect that contributes to tinnitus suppression in patients with VSB implants.