[Multimodal training concept for temporal bone surgery]. / Multimodales Weiterbildungskonzept Schläfenbeinchirurgie.

BACKGROUND: Surgical training is increasingly supported by the use of simulators. For temporal bone surgery, shown here by means of mastoidectomy, there are other training models besides cadaver specimens, such as artificial temporal bones or computer-based simulators. OBJECTIVES: A structured training concept was created which integrates different training methods of mastoidectomy with regard to effectiveness and current learning theory in education. METHOD: A selective literature research was conducted to compare learning-theoretical findings and the availability and effectiveness of currently existing training models. RESULTS: To acquire surgical skills, a stepwise approach is suggested. Depending on the progress with computer-based simulation, plastic or native temporal bones should be used. To achieve a plateau of the learning curve, approximately 25 semi-autonomous preparations are recommended. Different 'Objective Structured Assessments of Technical Skills' (OSATS) are implemented to assess the learning progress at different levels. DISCUSSION: Simulation-based training is recommended until an adequate learning curve plateau is achieved. This is reasonable for patient safety, based on limited accessibility of human cadaveric temporal bones but also by findings of the learning theory. CONCLUSION: The curriculum integrates different training models of mastoidectomy and OSATS into an overall concept. The training plan has to be continuously adapted to new findings and technical developments.

Long-Term Outcomes of Vibroplasty Coupler Implantations to Treat Mixed/Conductive Hearing Loss.

OBJECTIVE: To evaluate the long-term safety and performance of four different vibroplasty couplers (round window, oval window, CliP and Bell coupler) in combination with an active middle ear implant. METHODS: This was a multicentre, prospective, long-term study including 5 German hospitals. Thirty adult subjects suffering from conductive or mixed hearing loss were initially enrolled for the study, 24 of these were included in the final analysis with up to 36 months of postsurgical follow-up data. Bone conduction and air conduction were measured pre- and postoperatively to evalu ate safety. Postoperative aided sound field thresholds and Freiburger monosyllable word recognition scores were compared to unaided pre-implantation results to confirm performance. Additional speech tests compared postoperative unaided with aided results. To determine patient satisfaction, an established quality-of-life questionnaire developed for conventional hearing aid usage was administered to all subjects. RESULTS: Mean postoperative bone conduction thresholds remained stable throughout the whole study period. Mean functional gain for all couplers investigated was 38.5 ± 11.4 dB HL (12 months) and 38.8 ± 12.5 dB HL (36 months). Mean word recognition scores at 65 dB SPL increased from 2.9% in the unaided by 64.2% to 67.1% in the aided situation. The mean postoperative speech reception in quiet (or 50% understanding of words in sentences) shows a speech intelligibility improvement at 36 months of 17.8 ± 12.4 dB SPL over the unaided condition. The signal-to-noise ratio (SNR) improved by 5.9 ± 7.2 dB SNR over the unaided condition. High subjective device satisfaction was reflected by the International Inventory for Hearing Aids scored very positively. CONCLUSION: A significant improvement was seen with all couplers, and audiological performance did not significantly differ between 12 and 36 months after surgery.

Multicenter Clinical Trial of Vibroplasty Couplers to Treat Mixed/Conductive Hearing Loss: First Results.

OBJECTIVE: To evaluate the safety and effectiveness of round window (RW), oval window (OW), CliP and Bell couplers for use with an active middle ear implant. METHODS: This is a multicenter, long-term, prospective trial with consecutive enrollment, involving 6 university hospitals in Germany. Bone conduction, air conduction, implant-aided warble-tone thresholds and Freiburger monosyllable word recognition scores were compared with unaided preimplantation results in 28 moderate-to-profound hearing-impaired patients after 12 months of follow-up. All patients had previously undergone failed reconstruction surgeries (up to 5 or more). In a subset of patients, additional speech tests at 12 months postoperatively were used to compare the aided with the unaided condition after implantation with the processor switched off. An established quality-of-life questionnaire for hearing aids was used to determine patient satisfaction. RESULTS: Postoperative bone conduction remained stable. Mean functional gain for all couplers was 37 dB HL (RW = 42 dB, OW = 35 dB, Bell = 38 dB, CliP = 27 dB). The mean postoperative Freiburger monosyllable score was 71% at 65 dB SPL. The postimplantation mean SRT50 (speech reception in quiet for 50% understanding of words in sentences) improved on average by 23 dB over unaided testing and signal-to-noise ratios also improved in all patients. The International Outcome Inventory for Hearing Aids (IOI-HA)quality-of-life questionnaire was scored very positively by all patients. CONCLUSION: A significant improvement was seen with all couplers, and patients were satisfied with the device at 12 months postoperatively. These results demonstrate that an active implant is an advantage in achieving good hearing benefit in patients with prior failed reconstruction surgery.

The measurement of Eustachian tube function in a hyperbaric chamber using an ear canal microphone.

OBJECTIVE: The purpose of this study was to further the understanding of the opening of the Eustachian tube in relation to changes in barometric pressure. DESIGN: An ear canal microphone was used to measure the specific sounds related to tube opening and possible eardrum movements. Five subjects with normal tube function were examined in a hyperbaric chamber (up to 304 kPa). All active and passive equalization events were recorded and correlated with the subjectively perceived pressure regulation in the measured ear. RESULTS: The signals recorded were clear and reproducible. The acoustic analysis distinguished between the different kinds of equalization. Subjective impressions were confirmed by the recorded frequency of acoustic phenomena (clicks). During compression, the sequence of active equalization manoeuvres was in a more regular and steady pattern than during decompression, when the click sounds varied. CONCLUSION: The study established a simple technical method for analyzing the function of the Eustachian tube and provided new information about barometric pressure regulation of the middle ear.

Electromyographical recording of the electrically elicited stapedius reflex via a bipolar hook electrode.

OBJECTIVE: To prove the feasibility of recording stapedius reflexes by bipolar electromyography intra-operatively during cochlea implant via a bipolar hook needle electrode. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Adults receiving a MED-EL cochlear implant. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURES: Stapedius reflex responses can be recorded by electromyography. RESULTS: A double hook electrode could be inserted into the muscle tissue via the natural opening of the pyramid process along with the stapedius tendon. In 7 out of 10 patients supplied with MED-EL CIs (PULSARCI100 or SONATATI100), electrically elicited stapedius reflex potentials were recorded after eliminating stimulation artifacts caused by electromagnetic fields during electrical stimulation by low pass filtering. CONCLUSION: Intraoperative stapedius reflex recording by bipolar electromyography via a hook electrode is feasible. Further research will show whether these signals may be used for establishing a self-adjusting speech processor.

Experimental studies on a new highly porous hydroxyapatite matrix for obliterating open mastoid cavities.

OBJECTIVE: In an initial preliminary study, the applicability of a new high-porosity hydroxyapatite (HA) ceramic for obliterating large open mastoid cavities was proven and tested in an animal model (bulla of guinea pig). STUDY DESIGN: Experimental study. METHODS: NanoBone, a highly porous matrix consisting of 76% hydroxyl apatite and 24% silicone dioxide fabricated in a sol-gel technique, was administered unilaterally into the opened bullae of 30 guinea pigs. In each animal, the opposite bulla was filled with Bio-Oss, a bone substitute consisting of a portion of mineral bovine bone. Histologic evaluations were performed 1, 2, 3, 4, 5, and 12 weeks after the implantation. RESULTS: After an initial phase in which the ceramic granules were surrounded by inflammatory cells (1-2 wk), there were increasing signs of vascularization. Osteoneogenesis and-at the same time-resorption of the HA ceramic were observed after the third week. No major difference in comparison to the bovine bone material could be found. DISCUSSION: Our results confirm the favorable qualities of the new ceramic reported in association with current maxillofacial literature. Conventional HA granules used for mastoid obliteration to date often showed problems with prolonged inflammatory reactions and, finally, extrusions. In contrast to those ceramics, the new material seems to induce more osteoneogenesis and undergoes early resorption probably due to its high porosity. Overall, it is similar to the bovine bone substance tested on the opposite ear in each animal. Further clinical studies may reveal whether NanoBone can be an adequate material for obliterating open mastoid cavities in patients.

Transient facial palsy in two cases of benign, very rare middle ear tumors (carcinoid tumor and myxoma).

OBJECTIVE: Presentation of the clinical features of 2 very rare middle ear tumors in which the guiding symptom was facial palsy. MATERIAL AND METHODS: Illustrative case reports about a myxoma and a carcinoid tumor of the middle ear associated with peripheral facial palsy. RESULTS: The facial palsy was transient in either case, and its pathomechanism is open for discussion. In both cases, the initial symptoms were typical for an inflammatory process. Moreover, both tumor entities are typically found in organs other than the ear; if located in the middle ear, those neoplasms grow rather superficially. In those cases, a surgical exposure of the middle ear is indicated. CONCLUSION: The etiopathology of an acute peripheral facial palsy is often hard to identify. If the facial weakness starts together with symptoms suggesting an inflammatory process, the differential diagnosis may be focused first on diseases like herpes zoster oticus and a severe course of acute purulent otitis media. We report the cases of 2 rare middle ear tumors causing facial palsy. Treatment of choice should be complete surgical excision.

Intratympanic application of botulinum toxin: experiments in guinea pigs for excluding ototoxic effects.

The aim of the study was to exclude ototoxic side effects of intratympanally applied botulinum toxin. The background is that a transection of the tensor tympani tendon (tenotomy) may relieve symptoms of tinnitus due to myoclonic tensor contractions. Moreover, there are certain indications that in some cases tenotomy may influence the course of Menière's disease positively. In such cases, a temporary (probatory) inactivation of the muscle with botulinum toxin might be better than a definitive surgical solution. Although in theory botulinum toxin should not have ototoxic side effects, a study on animals (guinea pigs) should prove this assumption. On eight guinea pigs (16 ears), the middle ear spaces (bullae) were opened and botulinum toxin was introduced. Hearing thresholds were measured via ABR recordings, prior to 1 and 3 weeks, respectively, after botulinum toxin application. Histological examinations of the middle ear mucosa were performed on each animal. In our series, the hearing thresholds remained essentially unchanged. Furthermore, no middle ear pathologies could be found in histology. No negative effects of botulinum toxin on hearing could be observed in our series. This is a precondition for the further development of the concept of intratympanical applications of the drug, to inactivate the tensor tympani muscle or for other options.

Tonic contractions of the tensor tympani muscle: a key to some non-specific middle ear symptoms? Hypothesis and data from temporal bone experiments.

CONCLUSIONS: The results of this study show that in clinical practice it will not be easy to diagnose tonic contractions of the tensor tympani muscle and only a combination of findings will be helpful. Based on these experimental results a clinical study will be started which should clarify the diagnostic relevance of indicators of tonic tensor muscle contractions. OBJECTIVES: There are indications from the literature and from personal experience that tonic contractions of the tensor tympani muscle may play a role in some ear symptoms, such as fullness, certain cases of tinnitus, slight hearing loss or Ménière's disease-like findings. In order to prove this theory we looked for indicators, either visual or functional, to help clinically diagnose the functional state of the muscle, particularly its tonic contraction. MATERIAL AND METHODS: Experiments simulating tensor contractions were carried out on temporal bone specimens. Traction was applied either to the isolated muscle, to its tendon or to the malleus neck. Effects were observed either visually via an endoscope or by impedance audiometry using multiple-frequency tympanometry. RESULTS: During simulated tensor traction the aspect of the tympanic membrane changed slightly, i.e. there was some inward movement of the umbo. However, such effects were only identifiable during the pulling action or by directly comparing the "contracted" and "relaxed" states. Tympanometry revealed a decrease in the peak amplitudes and a shift in the middle ear resonance towards higher frequencies during contractions.