Robert Mlynski

Interaction of spiral ganglion neuron processes with alloplastic materials in vitro

The cochlear implant (CI) involves the introduction of alloplastic materials into the cochlea. While current implants interact with cochlear neurons at a distance, direct interactions between spiral ganglion (SG) neurites and implants could be fostered by appropriate treatment with neurotrophic factors. The interactions of fibroblasts and osteoblasts with alloplastic materials have been well studied in vitro and in vivo. However, interactions of inner ear neurons with such alloplastic materials have yet to be described. To investigate survival and growth behavior of SG neurons on different materials, SG explants from post-natal day 5 rat SG were cultured for 72 h in the presence of neurotrophin-3 (10 ng/ml) on titanium, gold, stainless steel, platinum, silicone and plastic surfaces that had been coated with laminin and poly-L-lysine. Neurite outgrowth was investigated after immunohistological staining for neurofilament, by image analysis to determine neurite extension and directional changes. Neurite morphology and adhesion to the alloplastic material were also evaluated by scanning electron microscopy (SEM). On titanium, SG neurites reached the highest extent of outgrowth, with an average length of 662 microm and a mean of 31 neurites per explant, compared to 568 microm and 21 neurites on gold, 574 microm and 24 neurites on stainless steel, 509 microm and 16 neurites on platinum, 281 microm and 12 neurites on silicone and 483 microm and 31 neurites on plastic. SEM revealed details of adhesion of neurites and interaction with non-neuronal cells. The results of this study indicate that the growth of SG neurons in vitro is strongly influenced by alloplastic materials, with titanium exhibiting the highest degree of biocompatibility with respect to neurite extension. The knowledge of neurite interaction with different alloplastic materials is of clinical interest, as development in CI technology leads to closer contact of implanted electrodes with surviving inner ear neurons.

Round window vibroplasty: Long-term results

Abstract Conclusions: The round window (RW) approach in the use of the Vibrant Soundbridge® (VSB) is a safe and effective treatment of conductive and mixed hearing losses for a period of more than 3 years of device use. Objective: To investigate the long-term safety and efficacy as well as user satisfaction of patients with conductive and mixed hearing losses implanted with the VSB using RW vibroplasty. Methods: Twelve patients with conductive and mixed hearing losses were evaluated after 40 months of daily VSB use. Safety was assessed by evaluating reports of postoperative medical and surgical complications as well as by changes in bone conduction hearing thresholds. Efficacy outcome measures included aided and unaided hearing thresholds, speech recognition in quiet and in noise and subjective benefit questionnaires. Results: The safety results revealed no significant medical complications. One subject experienced sudden hearing loss after 18–24 months of device use, but still continues to wear the device to her satisfaction. With regard to efficacy, there were no significant changes from short- to long-term results in aided word understanding, functional gain or speech recognition threshold, suggesting that the outcomes are stable over time. Subjective questionnaires revealed either the same or better results compared with the short-term data.

First European Multicenter Results With a New Transcutaneous Bone Conduction Hearing Implant System: Short-Term Safety and Efficacy

Objective To investigate safety and efficacy of a new transcutaneous bone conduction hearing implant, over a 3-month follow-up period. Study Design Prospective, single-subject repeated-measures design in which each subject serves as his/her own control. Setting Departments of Otolaryngology at 4 hospitals in Germany and Austria. Patients Subjects were 12 German-speaking adults who suffered from conductive or mixed hearing loss. The upper bone conduction threshold limit was set to 45 dB HL at frequencies between 500 Hz and 4 kHz. Intervention Implantation of a transcutaneous bone conduction hearing implant. Main Outcome Measures Subjects’ speech perception (word recognition scores and SRT50%) and audiometric thresholds (air conduction, bone conduction and sound field at frequencies 500 Hz to 8 kHz) were assessed preoperatively, 1 month postoperatively and 3 months postoperatively. The subjects were monitored for adverse events and given a questionnaire to assess their satisfaction levels. Results Speech perception as measured by word recognition scores and SRT50% improved on average about 78.8% and 25 dB HL, respectively, 3 months after implantation. Aided thresholds also improved postoperatively at all tested frequencies and continued to improve from 1 to 3 months postoperatively. Air conduction and bone conduction thresholds showed no significant changes, confirming that subjects’ residual unaided hearing was not deteriorated by the treatment. Only minor adverse events were reported and resolved by the end of the study. Conclusion The new transcutaneous bone conduction implant was demonstrated to be safe and effective in adults up to 3 months of device use.

Influence of Short-Term Glucocorticoid Therapy on Regulatory T Cells In Vivo

Background Pre- and early clinical studies on patients with autoimmune diseases suggested that induction of regulatory T(Treg) cells may contribute to the immunosuppressive effects of glucocorticoids(GCs). Objective We readdressed the influence of GC therapy on Treg cells in immunocompetent human subjects and naïve mice. Methods Mice were treated with increasing doses of intravenous dexamethasone followed by oral taper, and Treg cells in spleen and blood were analyzed by FACS. Sixteen patients with sudden hearing loss but without an inflammatory disease received high-dose intravenous prednisolone followed by stepwise dose reduction to low oral prednisolone. Peripheral blood Treg cells were analyzed prior and after a 14 day GC therapy based on different markers. Results Repeated GC administration to mice for three days dose-dependently decreased the absolute numbers of Treg cells in blood (100 mg dexamethasone/kg body weight: 2.8±1.8×104 cells/ml vs. 33±11×104 in control mice) and spleen (dexamethasone: 2.8±1.9×105/spleen vs. 95±22×105/spleen in control mice), which slowly recovered after 14 days taper in spleen but not in blood. The relative frequency of FOXP3+ Treg cells amongst the CD4+ T cells also decreased in a dose dependent manner with the effect being more pronounced in blood than in spleen. The suppressive capacity of Treg cells was unaltered by GC treatment in vitro. In immunocompetent humans, GCs induced mild T cell lymphocytosis. However, it did not change the relative frequency of circulating Treg cells in a relevant manner, although there was some variation depending on the definition of the Treg cells (FOXP3+: 4.0±1.5% vs 3.4±1.5%*; AITR+: 0.6±0.4 vs 0.5±0.3%, CD127low: 4.0±1.3 vs 5.0±3.0%* and CTLA4+: 13.8±11.5 vs 15.6±12.5%; * p<0.05). Conclusion Short-term GC therapy does not induce the hitherto supposed increase in circulating Treg cell frequency, neither in immunocompetent humans nor in mice. Thus, it is questionable that the clinical efficacy of GCs is achieved by modulating Treg cell numbers.

Long-term rhinoflowmetry: a new method for functional rhinologic diagnostics.

Background With current functional diagnostic tools in rhinology (rhinomanometry, rhinoresistometry, and acoustic rhinometry) long-term assessment of nasal function is difficult to acquire. Usually, only the situation at the time of examination is evaluated. Therefore, temporary nasal complaints of the nasal cycle are difficult to assess. It was the aim of this work to create a diagnostic tool to measure nasal flow over a long time period under physiological and everyday life conditions. We term the method long-term rhinoflowmetry (LRFM). Methods A portable device recording nasal airflow over a time period up to 72 hours was developed. Kinetic pressure fluctuations during respiration as a measure for the flow were registered over time and relative airflow was calculated. A summary of diagnostic results is given in six exemplary patients. Results Classic nasal cycles could be recorded in detail with durations ranging from 90 minutes to 10 hours. The manifestation of nighttime nasal obstruction as well as a case of paradoxical nasal obstruction were objectified. LRFM enables the assessment of time, duration, and extent of temporary nasal obstruction. Conclusion LRFM enables an assessment of temporary nasal obstruction as well as physiological and pathological fluctuations in the nasal cycle. Especially in cases in which traditional rhinological diagnostic tools are unsatisfying, the enhanced diagnostic quality of LRFM appears to be a promising supplement to the currently available rhinological monitoring methods.

A coated electrode carrier for cochlear implantation reduces insertion forces.

To assess the insertion forces and feasibility of insertion of a prototype electrode carrier coated with a flexible and biodegradable coating developed for lubrication and drug delivery.

Schwannoma of the larynx

ObjectivesNeurogenic tumors of the larynx are extremely rare. The goal of this report is to advert to this rare disease, to review and discuss diagnostics, differential diagnoses and treatment options. Study Design: Retrospective case report and review of the literature. Methods: Case report of a schwannoma of the supraglottic larynx and review of the English- and German-language literature regarding neurogenic tumors of the larynx. Results: Neurogenic laryngeal tumors typically involve the supraglottic larynx, rarely the glottis. They can course globus sensation, dysphagia, dysphonia and upper airway obstruction. Imaging does not yield a definite diagnosis. The only curative treatment option is complete surgical resection. Conclusions: A definite diagnosis can only be made histologically. Endoscopic (laser-) resection for smaller lesions and external approaches for larger lesions are recommended treatment options.

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.

Bisphosphonate-induced osteonecrosis of the external ear canal: a retrospective study

In 2003, osteonecrosis of the jaw was described as an intraoral complication of bisphosphonate therapy. More recently, cases of avascular necrosis of the hip were reported in patients with long-lasting bisphosphonate therapy. Thus, it was the aim of the present study to analyze cases of benign osteonecrosis of the external ear canal and to retrospectively identify a possible relationship to long-lasting bisphosphonate therapy. 13 patients with osteonecrosis of the external ear canal operated on between 2005 and 2009 were included. Patient histories were reviewed for possible previous or current bisphosphonate therapy. Three patients with osteonecrosis of the external ear canal and long-term bisphosphonate therapy could be identified. They had been treated either for breast cancer or multiple myeloma. Certainly, the jaw is an area of increased risk for developing osteonecrosis with its high mechanical stress and intraoral bacterial flora. However, osteonecrosis of the hips and the external ear canal in patients receiving long-term bisphosphonate therapy necessitate further investigation of a possible systemic, bisphosphonate-related phenomenon.

The Nasal Airflow in Noses with Septal Perforation: A Model Study

Background: Septal perforation is a common clinical problem in rhinology. Affected patients suffer from a dry nose, crusts as well as recurrent epistaxis and sometimes an inspiratory whistle. The aim of this study was to investigate the underlying flow dynamic mechanisms. Methods: The physical flow effects of such pathologies were examined in functional nose models (box models) and anatomically exact models of the nose. Therefore, septal perforations of different sizes and localisations were studied in straight and deviated nasal septa. Results and Conclusions: It could be seen that the localisation of the perforation has no impact on the flow pattern. In large septal perforations, the air jet collides with the posterior edge of the perforation and disintegrates turbulently. Since airflow is physiologically turbulent in the posterior part of the nose, posterior perforations do not cause clinical complaints. The inspiratory whistling sound during respiration is based on the principle of a lip whistle. Large perforations do not cause a whistling sound. The necessary high flow velocity needed in large perforations is usually not achievable.