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Thesis (doctoral)--Rijksuniversiteit te Utrecht.

Thesis (doctoral)--Rijksuniversiteit te Utrecht.

Objective/Hypothesis: This study aimed to determine the clinical and cost-effectiveness of endoscopes during cholesteatoma surgery. More specifically, this study hypothesized that endoscope use would reduce cholesteatoma recurrence rates and cost. Study Design: Case series involving the prospective enrollment of 110 consecutive cholesteatoma patients over a 2-year period. Methods: Patients underwent cholesteatoma surgery with microscopy. During dissection, the location of the cholesteatoma was assessed. At the end of dissection and before reconstruction, the same subunits were visualized with straight and angled endoscopes for residual cholesteatoma. Hearing was analyzed before surgery and at the last possible examination. Costs were analyzed using Medicare reimbursement rates from the Centers for Medicare and Medicaid Services. Results: Intraoperative endoscopic surveillance was able to detect residual cholesteatoma in 18 patients. With a 0° endoscope, residual cholesteatoma was noted in the epitympanum (two patients), sinus tympani (one patient), and the supratubal air cells (one patient). With a 45° endoscope, residual cholesteatoma was noted in the epitympanum (three patients), sinus tympani (nine patients), the supratubal air cells (two patients), and the mesotympanum (two patients). From a cost analysis, endoscopic surveillance ($6110.36 per patient) are less expensive than second look surgeries ($11,829.83 per patient), observation ($7097.20 per patient), and observation with annual magnetic resonance imaging studies ($9891.95 per patient). The patients hearing improved after surgery, consistent with previous studies. No complications were noted from the use of endoscopes. Conclusions: Intraoperative endoscopic surveillance reduced recurrence in our series of 110 patients. Endoscopes are particularly useful in evaluating the epitympanum, mesotympanum, sinus tympani, and supratubal air cells. Moreover, endoscopic surveillance is cost-effective. Level of Evidence: 4 Laryngoscope, 128:2867–2871, 2018.

Eine totale Mittelohr-Prothese (TORP) mit einem mit Silikon ummantelten Kugelgelenk ist in der Lage Druckveränderungen zu kompensieren und somit eine bessere Schallübertragung, im Vergleich zu starren Prothesen, zu erzielen. Die Ergebnisse können als vorläufig betrachtet werden, da diese experimentelle Studie sich auf eine von vielen verschiedenen möglichen Situationen der Tympanoplastik und eine damit verbundene kleine Stichprobengröße beschränkte. Dennoch sind die Ergebnisse mit der flexiblen TORP vielversprechend für die weitere Entwicklung. / A total ossicular replacement prosthesis (TORP) with a silicone coated ball and socket joint (BSJ) is able to compensate pressure changes and therefore provide better sound transmission compared with rigid prostheses. The findings may be considered preliminary as this experimental study was limited to just one of the many different possible situations of tympanoplasty and it involved a small sample size. Nevertheless, the results with the flexible TORP were promising and could encourage further investigations on such prostheses.

O efeito do fator de crescimento epitelial e da pentoxifilina, isolados ou em associação, foi avaliado em perfurações subagudas de membranas timpânicas de chinchilas, comparando-se ao grupo controle. O fator de crescimento epitelial auxiliou o processo de cicatrização de perfurações subagudas de membranas timpânicas, o que não se observou com a pentoxifilina. O percentual de cicatrização das perfurações foi de 30,3%, 3,6%, 16,5% e 8,7% nos grupos fator de crescimento epitelial, pentoxifilina, fator de crescimento epitelial com pentoxifilina e controle, respectivamente / The effect of epidermal growth factor and pentoxifylline, in combination or alone, was evaluated in chinchillas with subacute tympanic membrane perforations, and compared with a control group. Epidermal growth factor helped in the healing of subacute tympanic membrane perforations, but the same was not observed for pentoxifylline. The healing rate of perforations was 30.3%, 3.6%, 16.5% and 8.7% for the following groups: epidermal growth factor, pentoxifylline, epidermal growth factor with pentoxifylline and untreated controls, respectively

O efeito do fator de crescimento epitelial e da pentoxifilina, isolados ou em associação, foi avaliado em perfurações subagudas de membranas timpânicas de chinchilas, comparando-se ao grupo controle. O fator de crescimento epitelial auxiliou o processo de cicatrização de perfurações subagudas de membranas timpânicas, o que não se observou com a pentoxifilina. O percentual de cicatrização das perfurações foi de 30,3%, 3,6%, 16,5% e 8,7% nos grupos fator de crescimento epitelial, pentoxifilina, fator de crescimento epitelial com pentoxifilina e controle, respectivamente / The effect of epidermal growth factor and pentoxifylline, in combination or alone, was evaluated in chinchillas with subacute tympanic membrane perforations, and compared with a control group. Epidermal growth factor helped in the healing of subacute tympanic membrane perforations, but the same was not observed for pentoxifylline. The healing rate of perforations was 30.3%, 3.6%, 16.5% and 8.7% for the following groups: epidermal growth factor, pentoxifylline, epidermal growth factor with pentoxifylline and untreated controls, respectively

The presented thesis concerns the biomechanics of hearing. The main aim of this work is the determination of so called corrections which allow for the comparison of synthetic audiograms and measured audiograms. With these corrections we attempt to overcome the discrepancy that exists between the computational modelling and audiological measurement. The discrepancy lies in a fact that the computational modelling usually simulates the sound coming from a free eld to the external auditory canal, while audiological measurement is realized by audiological headphones, whether the auditory system is healthy or injured. Then corrections adjust the computational model so that the obtained result is comparable to audiological measurement. In this work is also addressed the influence of stapes kinematics to the excitation of basilar membrane. The movement of stapes consists of piston-like movement and rocking movement. The computational simulation shows which movement is more signicant for the excitation of basilar membrane and how this effect can be used in otosurgery, in particular, for type IV of tympanoplasty.