Burkard Schwab

Multicenter Study With a Direct Acoustic Cochlear Implant

Objective To confirm the clinical efficacy and safety of a direct acoustic cochlear implant. Study Design Prospective multicenter study. Setting The study was performed at 3 university hospitals in Europe (Germany, The Netherlands, and Switzerland). Patients Fifteen patients with severe-to-profound mixed hearing loss because of otosclerosis or previous failed stapes surgery. Intervention Implantation with a Codacs direct acoustic cochlear implant investigational device (ID) combined with a stapedotomy with a conventional stapes prosthesis Main Outcome Measures Preoperative and postoperative (3 months after activation of the investigational direct acoustic cochlear implant) audiometric evaluation measuring conventional pure tone and speech audiometry, tympanometry, aided thresholds in sound field and hearing difficulty by the Abbreviated Profile of Hearing Aid Benefit questionnaire. Results The preoperative and postoperative air and bone conduction thresholds did not change significantly by the implantation with the investigational Direct Acoustic Cochlear Implant. The mean sound field thresholds (0.25–8 kHz) improved significantly by 48 dB. The word recognition scores (WRS) at 50, 65, and 80 dB SPL improved significantly by 30.4%, 75%, and 78.2%, respectively, after implantation with the investigational direct acoustic cochlear implant compared with the preoperative unaided condition. The difficulty in hearing, measured by the Abbreviated Profile of Hearing Aid Benefit, decreased by 27% after implantation with the investigational direct acoustic cochlear implant. Conclusion Patients with moderate-to-severe mixed hearing loss because of otosclerosis can benefit substantially using the Codacs investigational device.

Clinical results after stapedotomy: a comparison between the erbium: yttrium-aluminum-garnet laser and the conventional technique.

Objective: The objective of this study was to assess whether the use of the erbium: yttrium-aluminum-garnet (Er:YAG) laser has negative effects on inner ear function and to compare the short- and long-term hearing outcome of patients undergoing conventional stapedotomy versus laser stapedotomy. Study Design: Retrospective review of prospectively collected audiometric data of patients with otosclerosis operated on by one experienced surgeon. Setting: Academic tertiary referral center. Patients: A total of 266 stapes surgeries were evaluated for intraoperative findings, of which 209 patients were evaluated for preoperative and postoperative hearing thresholds after a 6- to 452-week (mean, 22 wk) audiological follow-up. Intervention: One hundred fifteen (43%) of the operations were performed conventionally, using manual perforators for stapedotomy (Group A); in 115 (43%) surgeries, the perforators were used in combination with the Er:YAG laser (Group B), and in 36 (14%) operations, the Er:YAG was used exclusively for footplate perforation (Group C). Main Outcome Measures: Pure-tone audiometry was performed before surgery, 2 days postoperatively (bone conduction only) and at 5, 26, and 57 weeks postoperatively. Results: A postoperative temporary threshold shift of the bone conduction could be found in all groups. In Group C, where the laser was used exclusively for footplate perforation, this threshold shift was not only the most significant, but also-in contrast to the other groups-not totally reversible. In all techniques, a satisfactory air-bone gap closure could be achieved. The best long-term results (96% of the patients had ≤20 dB air-bone gap after 57 wk) could be found in Group B. Conclusion: If certain rules to minimize inner ear trauma are followed, the Er:YAG laser is a safe tool in middle ear surgery. Combining both the laser and the conventional technique, instead of the separate use of either technique, leads to superior postoperative hearing results.

Oval window membrane vibroplasty for direct acoustic cochlear stimulation: treating severe mixed hearing loss in challenging middle ears.

Objective 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. Study Design Prospective cohort study. Settings Tertiary, referral center Patients Three patients with previous middle ear surgery and moderate-to-severe ipsilateral, mixed hearing loss. Interventions 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. Main Outcome Measure Audiologic assessment involving pure-tone audiometry, aided and unaided free-field audiometry, Freiburg monosyllabic word test, and registration of any complications. Results 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. Conclusion 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.

First clinical experiences with a direct acoustic cochlear stimulator in comparison to preoperative fitted conventional hearing aids.

Objective Patients with moderate-to-severe mixed hearing losses (MHLs) are hard to provide sufficient benefit with currently available conventional hearing aids. Here, the long-term safety of a direct acoustic cochlear stimulator (DACS) and the effectiveness compared with conventional “high-performance” hearing aids were investigated. Study Design Prospective, within patient reference, nonrandomized, interventional multicenter clinical study performed at these 3 centers: Medical University Hannover, University of Heidelberg, and Helios Hospital Krefeld. Patients and Intervention Ten otosclerosis patients with severe-to-profound MHL were preoperatively fitted with state-of-the-art conventional hearing aids (HA). After 2 months of testing conventional HA, 9 of the patients decided to be implanted with a DACS. Main Outcome Measures Air conduction (AC) and bone conduction (BC) aided and unaided thresholds, speech discrimination before and after implantation and at 3, 6, and 12 months after activation. The subjective benefit was assessed by the Abbreviated Profile of Hearing Aid Benefit (APHAB). Results Preoperative hearing thresholds were preserved over the 12 month observation time after activation. Average functional gain (0.5–4 kHz) achieved with conventional HA was 47 dB compared with 56 dB with the DACS. Speech-in-noise tests revealed a lower SNR for DACS (3.1 dB) than for the HA (6.6 dB) and patients were more satisfied with the DACS. Conclusion The DACS significantly improved hearing, speech intelligibility, and satisfaction in patients with a severe-to-profound mixed hearing loss and can be considered a safe and useful alternative to conventional hearing aids.

Power stapes: an alternative method for treating hearing loss in osteogenesis imperfecta?

Objective: To present power stapes, stapedotomy, and middle ear implantation with Vibrant SoundBridge (VSB) performed in a one-step surgery as an alternative option for hearing rehabilitation in patients with osteogenesis imperfecta (OI). Study Design: Retrospective case series. Setting: Tertiary referral ear center. Patients: A family with genetically proven OI Type I. Interventions: Two patients, mother and son, with severe to profound mixed hearing loss underwent 3 power stapes, 1 unilateral and 1 bilateral sequential. Main Outcome Measures: Thorough audiological diagnostic batteries including aided and unaided pure-tone and free-field audiometry and Freiburg monosyllabic word test were used to assess the preoperative status and the postoperative hearing outcome. High-resolution computed tomography of the temporal bones was performed as well. Surgical procedure and any special considerations were analyzed in detail. Results: The hearing outcome was favorable in all cases, showing in comparison to the preoperative values an average improvement of 36.8 dB. Severe intraoperative bleeding of the middle ear mucosa was the only complication and could be easily controlled by allowing short time intervals. Inner ear trauma did not occur in any case. Conclusion: Power stapes represents a safe and promising procedure for treating hearing loss in selected patients with OI. Furthermore, it introduces a new, advantageous VSB application in cases of mixed hearing loss with severe otosclerosis and increased bone-conduction thresholds.

Round window stimulation with the floating mass transducer at constant pretension

OBJECTIVE Mechanical stimulation of the round window (RW) of the cochlea is successfully done with the Vibrant Soundbridge (Med-El), but clinical outcomes show a substantial degree of variability. One source of variability is variation in the static force applied by the stimulator to the round window (Maier et al., 2013). In this study we investigated other sources of variability by maintaining a constant pre-load testing the effect of a coupler device and the interposition of soft tissue between the stimulator and the RW. STUDY DESIGN Experimental. METHODS The stapes footplate displacement produced by stimulation of the round window was determined in fresh human temporal bones. The response to sound and actuator stimulation was measured with a Laser Doppler Velocimeter at the stapes footplate. The RW was stimulated by a Floating Mass Transducer (FMT) with/without (1) an additional RW coupler (supplied by the manufacturer), and (2) the interposition of TUTOPATCH between the stimulator and the RW, while maintaining a pre-load of ∼1.96 mN. RESULTS In 8 temporal bones with normal stapes footplate response to sound, we found an average 11.9 dB increase (500 Hz-2 kHz) under controlled conditions by using the coupler together with the interposition. The increase was statistically significant at 500 Hz (p < 0.01). Additionally, the coupler/interposition combination reduced the variability between experiments (FMT alone SD = 10.9 dB; FMT with TUTOPATCH & coupler: SD = 3.4 dB @ 500 Hz) and increased the repeatability. CONCLUSION At controlled static force an improved output level, inter-subject variability and repeatability were found by using a coupler/TUTOPATCH combination in RW stimulation with the FMT. The high variability found in clinical experience is not solely due to inter-subject variability, but to coupling conditions and can be optimized further.

Influencing Factors on the Vestibular Function of Deaf Children and Adolescents - Evaluation by Means of Dynamic Posturography

Objectives: Previous studies have shown that both motor exercises and vestibuloocular tests reveal a difference in the balance function of deaf and normal-hearing children and adolescents. The purpose is to evaluate the influence on balance function of the hearing status. Material and Methods: A total of 80 children and adolescents between the ages of 4 and 20 years were studied. Of these, 40 children were either deaf or severely hearing impaired. The remaining 40 were control subjects of equivalent age without hearing or balance impairment. The EquiTest ® , a device used in computerized dynamic posturography, was employed for the investigations. Mean equilibrium and latency scores from both groups were compared using t-tests for unrelated random samples. Results: The deaf children achieved significantly lower equilibrium scores and latency scores than the control group. A positive linear relationship exists between the age of the subjects and the equilibrium scores obtained. Gender, extent of hearing loss and cause of deafness have no significant effect on the balance function of the deaf children. Deaf subjects with normal caloric excitability achieved significantly higher equilibrium scores than those with vestibular deficits. Conclusions: The results support the hypothesis that damage to the cochlea, whatever its cause, may also detrimentally affect the vestibular organ. They do not, however, exclude the possibility that the poorer balance proficiency shown by deaf children may have other possible causes, such as CNS damage. The fact that equilibrium scores increase with increasing age can be seen as indicating the maturation of central nervous mechanisms involved in integrating the various sensory qualities in the sense of balance. An improvement in vestibular function through special training appears plausible, although this would necessitate diagnosis at a very early stage.

Investigation of Balance Function Using Dynamic Posturography under Electrical-Acoustic Stimulation in Cochlear Implant Recipients

Introduction. The purpose of the present study is to investigate the effect of electrical-acoustic stimulation on vestibular function in CI patients by using the EquiTest and to help answer the question of whether electrically stimulating the inner ear using a cochlear implant influences the balance system in any way. Material and Methods. A test population (n = 50) was selected at random from among the cochlear implant recipients. Dynamic posturography (using the EquiTest) was performed with the device switched off an switched on. Results. In summary, it can be said that an activated cochlear implant affects the function of the vestibular system and may, to an extent, even lead to a stabilization of balance function under the static conditions of dynamic posturography, but nevertheless also to a significant destabilization. Significant improvements in vestibular function were seen mainly in equilibrium scores under conditions 4 and 5, the composite equilibrium score, and the vestibular components as revealed by sensory analysis. Conclusions. Only under the static conditions are significantly poorer scores achieved when stimulation is applied. It may be that the explanation for any symptoms of dizziness lies precisely in the fact that they occur in supposedly noncritical situations, since, when the cochlear implant makes increased demands on the balance system, induced disturbances can be centrally suppressed.

Do we really need a Coupler for the round window application of an AMEI

Objective 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 Materials and Methods 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. Results 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. Conclusion RW-Coupler-Vibroplasty was found to be a safe procedure, which produced good results in this group of patients with mixed hearing loss.

Ultrafast laser pulses for medical applications

Ultrafast lasers have become a promising tool for micromachining and extremely precise ablation of all kinds of materials. Due to the low energy threshold, thermal and mechanical side effects are limited to the bu micrometers range. The neglection of side effects enables the use of ultrashort laser pulses in a broad field of medical applications. Moreover, the interaction process based on nonlinear absorption offers the opportunity to process transparent tissue three dimensionally inside the bulk. We demonstrate the feasibility of surgical procedures in different fields of medical interest: in ophthalmology intrastromal cutting and preparing of cornael flaps for refractive surgery in living animals is presented. Besides, the very low mechanical side effects enables the use of fs- laser in otoralyngology to treat ocecular bones. Moreover, the precise cutting quality can be used in fields of cardiovascular surgery for the treatment of arteriosklerosis as well as in dentistry to remove caries from dental hard tissue.