Floating Mass Transducer Research Articles

Alternative Fixation of an Active Middle Ear Implant at the Short Incus Process

Introduction: Since 1996, the preferred approach for positioning the active middle-ear implant Vibrant Soundbridge© is a mastoidectomy and a posterior tympanotomy. With this device, placement of the floating mass transducer (FMT) on the long incus process is the standard method for treatment of mild-to-severe sensorineural hearing loss in the case of normal middle-ear anatomy. The aim of this study was to determine the vibrational effectiveness of FMT placement at the short incus process. Materials and Methods: An extended antrotomy and a posterior tympanotomy were performed in 5 fresh human temporal bones. As a control for normal middle-ear function, the tympanic membrane was stimulated acoustically and the vibration of the stapes footplate and the round-window (RW) membrane were (sequentially) measured by laser Doppler vibrometry. Vibration responses for coupling of an FMT to the long incus process (standard coupling) were compared to those for coupling to the short incus process. Results: Apart from narrow frequency bands near 3 and 9 kHz for the stapes footplate and RW membrane, respectively, the velocity responses presented no significant differences between standard coupling of the FMT and coupling to the short incus process. Conclusion: Coupling the FMT to the short incus process may be a viable alternative in cases where the surgical approach is limited to an extended antrotomy. A reliable technique for attachment to the short incus process has yet to be developed.

Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer.

The transfer characteristic of the human middle ear with an applied middle ear implant (floating mass transducer) is examined computationally with a Multi-body System approach and compared with experimental results. For this purpose, the geometry of the middle ear was reconstructed from μ-computer tomography slice data and prepared for a Multi-body System simulation. The transfer function of the floating mass transducer, which is the ratio of the input voltage and the generated force, is derived based on a physical context. The numerical results obtained with the Multi-body System approach are compared with experimental results by Laser Doppler measurements of the stapes footplate velocities of five different specimens. Although slightly differing anatomical structures were used for the calculation and the measurement, a high correspondence with respect to the course of stapes footplate displacement along the frequency was found. Notably, a notch at frequencies just below 1 kHz occurred. Additionally, phase courses of stapes footplate displacements were determined computationally if possible and compared with experimental results. The examinations were undertaken to quantify stapes footplate displacements in the clinical practice of middle ear implants and, also, to develop fitting strategies on a physical basis for hearing impaired patients aided with middle ear implants.

Do We Really Need a Coupler for the Round Window Application of an AMEI?

Implanting active middle ear implants (AMEI) at the round window has become a standard procedure to restore hearing for patients with moderate inner ear or mixed hearing loss. The round window (RW)-Coupler was developed as an alternative coupling aid to fit smaller RW diameters and require less drilling in the RW niche. The question arises whether using the RW-Coupler is useful and a safe procedure compared with the nonuse of the RW-Coupler Forty-nine German-speaking patients were implanted with either a RW-Coupler attached to an AMEI floating mass transducer (FMT) or without coupler. They were evaluated preoperatively and postoperatively for bone and air conduction thresholds with and without the implant, as well as speech perception tests. Bone conduction thresholds remained stable preoperatively and postoperatively. The patient's functional gain was slightly better with the RW-Coupler. Focusing on the average speech perception performances, both groups presented an improvement of speech perception above 80% at 65 dB HL. RW-Coupler-Vibroplasty was found to be a safe procedure, which produced good results in this group of patients with mixed hearing loss.

Round Window Vibroplasty in Infants and Children with Atretic Ear

Objectives: Evaluate long-term safety and outcome of round window vibroplasty (RWVPL) by the placement of the floating mass transducer (FMT) on the round window membrane in infants and children with congenital aural atresia (CAA). Methods: External auditory canal and middle ear malformation, accompanied by more or less severe conductive or mixed hearing impairment characterize children and infants with CAA. Several atresiaplasty procedures have been proposed without evidence of long-term air-bone gap closure despite initial satisfactory outcome. Prospective study at atertiary referral center. Seven infants and 10 children with CAAwere judged not to be candidates for air and bone conductive hearing aids and their parents declined bone-anchored hearing aids. Intervention: RW implantation with the Med-El VSB. Main outcome measures: Pure tone audiogram and free-field speech testing, free-field Auditory Brainstem Response (ABR). Results: Significant improvements were observed in pure-tone threshold and speech perception immediately after surgery and at follow-up intervals (12 to 60 months) in older children ( P <0.01). In infants and younger children free-field ABRs showed a significant shift of the mean air conduction threshold from 110 dB sound pressure level (SPL) preoperatively to 40 dB SPL ( P < 0.05) and 30 dB SPL ( P < 0.01), respectively postoperatively and at the last follow-up. No complications or instances of device extrusion were observed in this series of patients. Conclusions: RWVPL offers a safe, viable and improved treatment option for infants and children with CAA.

Vibroplasty for Mixed and Conductive Hearing Loss

To summarize new application methods of an active middle ear implant (Vibrant Soundbridge) in patients with conductive or mixed hearing loss. Publications listed in the Medline/PubMed database. All publications published in English language; search term Vibrant Soundbridge AND floating mass transducer in all fields. Structured analysis of all publications. Extraction of significant findings and conclusions and audiometric data. Modern application methods of an active middle ear implant (VSB) open new therapeutic options for patients with various outer and middle ear diseases resulting in conductive or mixed hearing loss. Titanium couplers can help to couple the active middle ear implant in a standardized way to remnants of the ossicular chain or to the round window. Thus, the active middle ear implant has been established as an alternative treatment option for patients with mixed and conductive hearing. However, the heterogeneity of the studies published so far complicates the analysis of the audiometric results, and thus, the functional hearing gain after VSB implantation varies a lot.

Effekt der Promontorialfensterung auf die Schwingung der Rundfenstermembran - experimentelle Studie

Drilling a promontory window and coupling an FMT into the scala tympani may be a surgical alternative to stapes surgery in obliterative tympanosclerosis. Aim of this experimental study on human temporal bones was to measure changes of the acoustic transfer function from the tympanic membrane to the round window membrane after drilling a promontory window and insertion of a floating mass transducer.Laser vibrometry and acoustic measurements were performed on 11 temporal bone preparations equipped with a microphone attached to the round window. Calibrations were carried out to allow determination of SPLs affecting the cochlea after drilling a promontory window leaving the membranous inner ear intact and after insertion of an FMT into the cavity (with or without slight pressure).Drilling a promontory window does influence the transfer function. Insertion of the FMT with additional slight pressure further changes the transfer function.The presence of a promontory window changes the acoustic transfer function to the round window. Further investigations are needed to correlate the qualitative results with the audiological results after "third window vibroplasty" (inserted floating mass transducer without stimulation).

Round window vibroplasty in chronic ear surgery: comparison with conventional hearing rehabilitation

Conclusion: Functional hearing results with round window vibroplasty in chronically disabled middle ears were comparable and, at high frequencies, superior to the results achieved with previously used conventional hearing aids even after extended surgery. Soft tissue transfer appears to be more important than floating mass transducer (FMT) alignment with the round window membrane (RWM) for efficient coupling or sonoinversion. Objectives: To evaluate the functional hearing results of an active middle ear implant (AMEI) to the round window niche (RWN). The results were compared with previously used conventional hearing aids. The position of the FMT was determined by cone-beam computed tomography (CBCT). Methods: This was a prospective cohort study carried out in a tertiary referral center. Seven patients with severe middle ear disease were implanted with an AMEI with round window application. The postoperative hearing outcome was compared with preoperative hearing using unaided and conventionally aided conditions. The results were correlated with the physical/geometric relation of the FMT to the RWM as determined with CBCT. Results: Dislocation of the FMT was not observed. One patient was re-implanted due to accidental damage to the electrode. In all patients, the pertinent functional hearing results were achieved and were comparable to previous rehabilitation results.

Long‐term Outcome of Round Window Vibrant SoundBridge Implantation in Extensive Ossicular Chain Defects

To evaluate retrospectively the long-term safety and efficacy of the first 50 patients, all suffering from severe ossicular chain defects and with moderate to severe mixed hearing loss, who received the Vibrant SoundBridge with the floating mass transducer located on the round window membrane. To evaluate differences in outcome versus etiology and age of the patient population. Case series with planned data collection. Tertiary referral medical center. Patients eligible for implantation of the floating mass transducer on the round window membrane ranged in age from 2 months to 74 years with a moderate to severe conductive or mixed hearing loss from different etiologies. For each adult patient, preoperative versus postoperative bone and air conduction thresholds, air-bone gaps, and speech understanding scores were evaluated at 24-month follow-up. At 60-month follow-up, data were available from 33 patients. Preoperative and postoperative free-field auditory brainstem responses were studied in infants and children. Intraoperative and short- and long-term postoperative complications are presented. There were significant improvements in speech perception and pure-tone audiometry in adults and auditory brainstem response thresholds in infants immediately after surgery and at follow-up examinations (12 to 71 months). No significant complications or device extrusions were observed in the present series. Infants, children, and adults with moderate to severe conductive or mixed hearing loss obtained substantial benefit from implantation of the floating mass transducer on the round window membrane regardless of the etiology of hearing loss and previous surgery.

Presentation of floating mass transducer and Vibroplasty Couplers on CT and Cone Beam CT

Various titanium coupling elements, Vibroplasty Couplers, maintaining the attachment of the Floating Mass Transducer (FMT) of the active middle ear implant Vibrant Soundbridge (VSB) to the round window, the stapes suprastructure or the stapes footplate are in use to optimally transfer energy from the FMT to the inner ear fluids. In certain cases it is of interest to radiologically verify the correct position of the FMT coupler assembly. The imaging appearance of FMT connected to these couplers, however, is not well known. The aim of this study was to present the radiological appearance of correctly positioned Vibroplasty Couplers together with the FMT using two different imaging techniques. Vibroplasty Couplers were attached to the FMT of a Vibrant Soundbridge and implanted in formalin fixed human temporal bones. Five FMT coupler assemblies were implanted in different positions: conventionally to the incus, a Bell-Coupler, a CliP-Coupler, a Round Window-Coupler and an Oval Window-Coupler. High spatial resolution imaging with Multi-Detector CT (MDCT) and Cone Beam CT (CBCT) was performed in each specimen. Images were blind evaluated by two radiologists on a visual basis. Middle ear details, identification of FMT and coupler, position of FMT coupler assembly and artefacts were assessed. CBCT showed a better spatial resolution and a higher visual image quality than MDCT, but there was no significant advantage over MDCT in delineating the structures or the temporal bone of the FMT Coupler assemblies. The FMT with its coupler element could be clearly identified in the two imaging techniques. The correct positioning of the FMT and all types of couplers could be demonstrated. Both methods, MDCT and CBCT, are appropriate methods for postoperative localization of FMT in combination with Vibroplasty Couplers and for verifying their correct position. If CBCT is available, this method is recommended due to the better spatial resolution and less metal artifacts.

Direct round window stimulation with the Med-El Vibrant Soundbridge: 5 years of experience using a technique without interposed fascia

The objective of this study was to present 5 years of surgical experience, and the extended results of hearing preservation (based on 3-year follow-up), with the Med-El Vibrant Soundbridge (VSB) in which the floating mass transducer (FMT) is placed directly against the round window membrane, and the fascia is used only as covering tissue to keep it in position. A retrospective survey of surgical and audiological data was conducted to evaluate the performance and stability of patient hearing, with audiometric measurements performed over fixed time intervals up to 36 months. 21 patients, aged 19–62 years (mean 48.4), with mixed or conductive, bilateral or unilateral hearing loss were included in this study. Surgical intervention involved monaural implantation of the Med-El VSB between 2006 and 2009. The results were assessed using pure tone audiometry. In 5 years of experience with the technique, no significant complications or device extrusion were observed except for two revision surgeries requiring FMT repositioning. In the 3-year follow-up, we observed stable hearing in the implanted ear. It is concluded that direct round window stimulation without interposed fascia is an alternative for patients with hearing impairment caused by chronic otitis media and/or lack of ossicles, especially after modified radical mastoidectomy. It allows good results in a selected group of patients, although further observation on a larger population is needed to confirm long-term validity and effectiveness.

Vibrant sound bridge application to middle ear windows versus conventional hearing aids: a comparative study based on international outcome inventory for hearing aids

In this study, we aimed to compare the outcomes of satisfaction of the patients who used hearing aids preceding the vibrant sound bridge (VSB) application on middle ear windows (14 oval window and 5 round window). Nineteen adult patients with conductive or mixed hearing loss were included in the study. All patients used behind the ear hearing aids on the site which was selected for VSB application. The patients used hearing aids for at least 3 months before the VSB operation. The floating mass transducer (FMT) was placed on one of the middle ear windows (oval or round) in VSB operation. The patients were evaluated with International Outcome Inventory for Hearing Aids (IOI-HA) preoperatively after at least 3 months trial of conventional hearing aid and postoperatively after 3 months use of VSB. No perioperative problem was encountered. The total score of IOI-HA was significantly higher with VSB compared with conventional hearing aids (p < 0.05). No statistically significant difference was found between the daily use, residual activity limitations, satisfaction, impact on others, quality of life between middle ear implant and hearing aid (p > 0.05). The IOI-HA scores were significantly higher with the middle ear implant than the conventional hearing aid regarding benefit and residual participation restrictions (p < 0.05). Although the scores for quality of life assessment was similar between VSB and hearing aid use, there was a superiority of VSB in terms of benefit and residual participation restrictions as well as overall IOI-HA scores as the FMT was placed on one of the middle ear windows.

Radiological Control of the Floating Mass Transducer Attached to the Round Window

The surgical rehabilitation of mixed hearing losses can be performed by coupling the floating mass transducer of the Vibrant Soundbridge to the round window. The quality of coupling the floating mass transducer to the round window is crucial for the audiological outcome. It was the aim of this study to further observe the different patterns of floating mass transducer position at the round window. We compared twenty patients with mixed hearing loss implanted with a floating mass transducer attached to the round window and 24 surgeries between 5/2007 and 6/2010. An evaluation of the chronological observation of the flat panel angiography-controlled position of the floating mass transducer at the round window with relation to the surgical report and the audiological outcome was done. We observed no changes in the mean pre- and postbone conduction thresholds. The floating mass transducer position was variable and could be radiologically classified and correlated with the audiologically outcome. A learning curve was observed from the earlier to later implantations. Postoperative, radiological evaluation of the location and angle of the floating mass transducer by means of flat panel tomography allowed us to classify the floating mass transducer position at the round window into 4 groups.

Application of the Vibrant Soundbridge middle-ear implant for aural atresia in patients with Treacher Collins syndrome

To present results for the auditory rehabilitation of patients with Treacher Collins syndrome with bilateral osseous atresia, using middle-ear implantation with a Vibrant Soundbridge. Three patients underwent vibroplasty for aural atresia with moderate to severe conductive hearing loss. The pre-operative Jahrsdoerfer radiological score was 4 for all patients. Patients underwent active middle-ear implantation of a Vibrant Soundbridge implant (coupling the floating mass transducer to the rudimentary stapes or footplate distally, and positioning it adjacent to the round window membrane proximally), with audiological analysis as follow up. After implant activation, the mean air conduction threshold ± standard deviation decreased to 22.8 ± 5.5 dB HL, representing a mean functional gain of 44.5 dB. The mean word recognition score (for bisyllabic words at 65 dB SPL) increased from 0 to 97 per cent. Vibrant Soundbridge implantation is an effective hearing rehabilitation procedure in patients with Treacher Collins syndrome with bilateral osseous atresia. This is a versatile implant which can achieve coupling even in cases of severe middle-ear malformation.

Functional outcomes of Vibrant Soundbridge applied on the middle ear windows in comparison with conventional hearing aids

Conclusion: Vibrant Soundbridge (VSB) application to the middle ear windows yields better functional outcomes than conventional hearing aids. However, speech discrimination scores obtained with VSB and conventional hearing aids are similar. Objective: To assess audiological outcomes of round and oval window applications of VSB in comparison with conventional hearing aids. Methods: Nineteen adult patients were included in the study. The patients had mild to moderate, moderate or moderate to profound conductive or mixed hearing loss. During surgery the floating mass transducer (FMT) was placed on the round (n = 14) or oval (n = 5) window. After the surgery, audiometric evaluation and free field audiometric evaluation of both ears was carried out. Results: The hearing thresholds in the low frequencies were not significantly different between the conventional hearing aids and VSB. The functional gains obtained with oval and round window approaches were similar except for 500 Hz. The hearing thresholds in the mid and high frequencies were significantly better with VSB than the conventional hearing aids. The functional gain in the low frequencies was not significantly different between VSB and conventional hearing aids. The functional gain in the other frequencies was significantly better with VSB than conventional hearing aids.

Middle ear implant in conductive and mixed congenital hearing loss in children

PurposeActive middle ear implant can be used in children and adolescents with congenital hearing loss. The authors report their experience with the semi implantable Medel Vibrant Soundbridge® (VSB) in the audiologic rehabilitation of such patients. MethodsIn this retrospective study, audiological and surgical data of 10 children (10.5±4 years) implanted with 12 VSB in 2 tertiary cares ENT Departments were analysed. ResultsTwo children with bilateral external auditory canal (EAC) atresia and mixed hearing loss (mean air conduction (AC) thresholds=65dB HL) were bilaterally implanted. Eight children presented with microtia associated with EAC atresia bilaterally (n=3) and unilaterally (n=5). All of them had a conductive hearing loss in the implanted ear (mean (AC) thresholds were 58.75dB HL preoperatively). The Floating Mass Transducer was crimped on the long process of the incus (n=8) or on the suprastructure of the stapes (n=4). There were no intra- or postoperative surgical complications. All the children wore their implants after 5 weeks. Postoperative mean bone conduction (BC) thresholds were unchanged. The mean aided thresholds with VSB (four frequencies warble tones at 0.5, 1, 2 and 4kHz) were 28dB HL (±10). Word discrimination threshold in quiet conditions in free field with the VSB unilaterally activated was 50% at 38dB SPL (±9). ConclusionThe results indicate that satisfaction of the children and their parents is very encouraging but surgeons should be cautious with this new approach in relation to the pinna reconstruction and to possible risks to inner ear and facial nerve.

Oval Window Membrane Vibroplasty for Direct Acoustic Cochlear Stimulation

To date, all the Vibrant Soundbridge (VSB) applications have managed to stimulate the inner ear indirectly. Our objective was to present a new VSB application for direct inner ear stimulation. Prospective cohort study. Tertiary, referral center Three patients with previous middle ear surgery and moderate-to-severe ipsilateral, mixed hearing loss. Oval window membrane vibroplasty (OWMV) for direct acoustic cochlear stimulation. A total ossicular replacement prosthesis (TORP) was attached to the floating mass transducer (FMT). Then, the stapes footplate was perforated, and the tip of the FMT-TORP assembly was advanced approximately 1 mm into the inner ear. A silicon ring was placed around the TORP's tip to prevent it from slipping deeper into the inner ear. Audiologic assessment involving pure-tone audiometry, aided and unaided free-field audiometry, Freiburg monosyllabic word test, and registration of any complications. OWMV resulted in an average functional hearing gain of 36.1 dB (range, 24.2-47.5 dB). Although the greatest amplification was observed in the higher frequencies, there also was a significant improvement in the lower frequencies. The surgery was not related to any difficulties; vertigo, inner ear trauma, or further complications did not occur. We present a new method for direct acoustic cochlear stimulation using an active middle ear implant. The preliminary results show that OWMV is a promising and safe option for treating moderate and severe hearing loss, even in challenging cases with previous middle ear operations or fixed stapes footplate.

Retraction

Carner M, Cerini R, Colletti L, Barillari M, Spagnolli F, Cardobi N, Pozzi Mucelli R, Colletti V. Computed Tomography in 15 Congenital Aural Atresia Patients and Floating Mass Transducer on the Round Window [published online ahead of print March 12, 2012]. Otolaryngol Head Neck Surg. doi: 10.1177/0194599812437136.

A New Vibroplasty Coupling Technique as a Treatment for Conductive and Mixed Hearing Losses

The primary objective was to report on experiences regarding the safety and efficacy of the Vibrant Soundbridge (VSB) using a floating mass transducer (FMT)-partial/total ossicular replacement prosthesis (PORP/TORP) assembly as a treatment for conductive and mixed hearing losses of mild-to-moderate/severe degree. The secondary objective was to gather information regarding device fitting, as well as to refine surgical procedures. Five German-speaking adults from 2 European study sites were implanted with a VSB using an FMT-PORP/TORP assembly and evaluated before and after surgery for air-and bone-conduction thresholds and speech recognition performance. Evaluating the safety and efficacy of the VSB in combination with a PORP or TORP to treat conductive and mixed hearing loss. Residual cochlear hearing was unaffected by implantation with the device. Functional gain (measured as the difference between preoperative unaided and postoperative VSB-aided thresholds) could be calculated in 2 of 5 subjects, demonstrating that the VSB is effective in treating bone-conduction hearing losses of moderate/severe degree. Word recognition tests in quiet and noise showed good improvement in 3 of the cases. One patient experienced several other medical problems, making her audiological outcomes limited. One patient was excluded from the study owing to insufficient benefit and subsequently underwent revision surgery with FMT placement at the round window. The use of the VSB, implanted using the FMT-PORP/TORP assembly, was safe in all and efficacious in 3 of the 5 cases in this study. These are patients who may have few, if any, other options to manage their hearing loss.

Application of Active Middle Ear Implants in Patients With Severe Mixed Hearing Loss

To determine the long-term benefit of the Vibrant Soundbridge (VSB) middle ear implant in patients with severe mixed hearing loss and to compare it with other hearing devices. A retrospective analysis. University-affiliated medical center. Six patients with severe mixed hearing loss and a mean sensorineural hearing loss component between 40 and 70 dB. Patients received a VSB with the floating mass transducer (FMT) coupled to the round window or to the oval window via a residual stapes structure. Functional gain and speech recognition results. Results are compared with 2 control groups matched for mean sensorineural hearing loss: 1) patients with mixed hearing loss and a bone-anchored hearing device, and 2) patients with sensorineural hearing loss and traditional implantation of the VSB. There is large variance in functional gain between the patients suggesting high variability in the effectivity of the FMT coupling. The speech recognition results for the experimental group were not systematically better than in either control group. There is large variability in results that might be ascribed to coupling effectivity. On the average, speech recognition results were not better or worse than those found in patients with similar hearing loss fitted with bone-anchored hearing devices.

Middle ear implants: functional gain in mixed hearing loss

Osseous atresia and chronic otitis media are diseases benefit with middle ear implants. Surgery for atresia is technically complicated, has significant number of complications and functional results are often poor. The osseointegrated hearing aids are an alternative. They provide a very good functional gain, but have many problems with the skin and osseointegration. In chronic otitis media, the ossiculoplasty solved partially the hearing problem. Unfortunately in some cases of otitis media and in open cavities fitted with conventional hearing aids the gain is unsatisfactory. AimTo determine the usefulness of an active middle ear implant. Material and methodLongitudinal Study. Vibrant-Soundbrigde was implanted in 8 patients with severe mixed hearing loss. 4 patients had chronic otitis media and 4 had unilateral atresia. The placement of the stimulator (FMT or Floating Mass Transducer) was in 5 patients on round window, 2 in stapes and one in the oval window. ResultsFunctional gain was 35 dB, 40 dB, 48.7 dB and 50 dB for the frequencies 500, 1000, 2000 and 4000 Hz, respectively. ConclusionVibrant-Soundbrigde is an excellent option in hearing recovery in severe and profound mixed hearing loss. It also provides an excellent functional gain in diseases difficult to treat with conventional hearing aids.