Patrick Dubach

Characteristics and dimensions of the Schneiderian membrane: a radiographic analysis using cone beam computed tomography in patients referred for dental implant surgery in the posterior maxilla.

OBJECTIVES To determine the dimensions of the Schneiderian membrane using limited cone beam computed tomography (CBCT) in individuals referred for dental implant surgery, and to determine factors influencing the mucosal thickness. MATERIAL AND METHODS The study included 143 consecutive patients referred for dental implant placement in the posterior maxilla. A total of 168 CBCT images were taken using a limited field of view of 4 × 4 cm, 6 × 6 cm, or 8 × 8 cm. Reformatted coronal CBCT slices were analyzed with regard to the thickness and characteristics of the Schneiderian membrane in nine standardized points of reference. Factors such as age, gender, or status of the remaining dentition that could influence the dimensions of the Schneiderian membrane were evaluated using univariate and multivariate linear regression models. RESULTS The thickness of the Schneiderian membrane exhibited a wide range, with a minimum value of 0.16 mm and a maximum value of 34.61 mm. The highest mean values, ranging from 2.16 to 3.11 mm, were found for the mucosa located in the mid-sagittal regions of the maxillary sinus. The most frequent mucosal findings diagnosed were flat thickenings of the Schneiderian membrane (62 positive findings, 37%). For the multivariate linear regression model, only gender had a statistically significant influence on the mean overall and mid-sagittal thickness of the sinus mucosa. CONCLUSION There is great interindividual variability in the thickness of the Schneiderian membrane. Gender seems to be the most important parameter influencing mucosal thickness in asymptomatic patients. Future studies are needed to assess the therapeutic and prognostic consequences of mucosal alterations in the maxillary sinus.

External auditory canal cholesteatoma: reassessment of and amendments to its categorization, pathogenesis, and treatment in 34 patients.

Objective: External auditory canal cholesteatoma (EACC) is a rarity. Although there have been numerous case reports, there are only few systematic analyses of case series, and the pathogenesis of idiopathic EACC remains enigmatic. Study Design: In a tertiary referral center for a population of 1.5 million inhabitants, 34 patients with 35 EACC (13 idiopathic [1 bilateral] and 22 secondary) who were treated between 1994 and 2006 were included in the study. Results: EACC cardinal symptoms were longstanding otorrhea (65%) and dull otalgia (12%). Focal bone destruction in the external auditory canal with retained squamous debris and an intact tympanic membrane were characteristic. Only 27% of the patients showed conductive hearing loss exceeding 20 dB. Patients with idiopathic EACC had lesions typically located on the floor of the external auditory canal and were older, and the mean smoking intensity was also greater (p < 0.05) compared with patients with secondary EACC. The secondary lesions were assigned to categories (poststenotic [n = 6], postoperative [n = 6], and posttraumatic EACC [n = 4]) and rare categories (radiogenic [n = 2], postinflammatory [n = 1], and postobstructive EACC [n = 1]). In addition, we describe 2 patients with EACC secondary to the complete remission of a Langerhans cell histiocytosis of the external auditory canal. Thirty of 34 patients were treated surgically and became all free of recurrence, even after extensive disease. Discussion: For the development of idiopathic EACC, repeated microtrauma (e.g., microtrauma resulting from cotton-tipped applicator abuse or from hearing aids) and diminished microcirculation (e.g., from smoking) might be risk factors. A location other than in the inferior portion of the external auditory canal indicates a secondary form of the disease, as in the case of 2 patients with atypically located EACC after years of complete remission of Langerhans cell histiocytosis, which we consider as a new posttumorous category and specific late complication of this rare disease.

Ear canal cholesteatoma: meta-analysis of clinical characteristics with update on classification, staging and treatment.

Purpose of reviewWe present an update on clinical evaluation, staging, classification and treatment of canal cholesteatoma, including a meta-analysis of clinical data of the last 30 years. Recent findingsEar canal cholesteatoma is frequently associated secondarily to other canal pathologies. The cause for the rare idiopathic form of the disease remains enigmatic. Epidemiologic and experimental studies of its pathogenesis have increased; however, the main explanatory theory of a deficient migratory capacity of the canal epithelium affected has been falsified only recently. Therefore, the debate on the pathogenesis has gained additional impetus and more data is needed. SummaryCanal cholesteatoma is a rarity in otologic pathology, often leading to misdiagnosis as external otitis or otomycosis by physicians unfamiliar with the disease. It presents typically with otorrhea, focal erosion and keratin accumulation in the osseous ear canal and has to be distinguished from keratosis obturans, which leads to otalgia and bilateral conductive hearing loss by ceruminal plugs, with circumferential distention of the ear canal. Treatment by canaloplasty is curative and highly successful. Alternative conservative treatment is feasible, however, requiring long-term follow up, with often painful cleaning of the lesion.

CT Radiation Dose for Computer-Assisted Endoscopic Sinus Surgery: Dose Survey and Determination of Dose-Reduction Limits

BACKGROUND AND PURPOSE: Computer-assisted navigation is increasingly used in functional endoscopic sinus surgery (FESS) to prevent injury to vital structures, necessitating preparative CT and, thus, radiation exposure. The purpose of our study was to investigate currently used radiation doses for CT in computer-assisted navigation in sinus surgery (CAS-CT) and to assess minimal doses required. MATERIALS AND METHODS: A questionnaire inquiring about dose parameters used for CAS-CT was sent to 30 radiologic institutions. The feasibility of low-dose registration was tested with a phantom. The influence of CAS-CT dose on technical accuracy and on the practical performance of 5 ear, nose, and throat (ENT) surgeons was evaluated with cadaver heads. RESULTS: The questionnaire response rate was 63%. Variation between minimal and maximal dose used for CAS-CT was 18-fold. Phantom registration was possible with doses as low as 1.1 mGy. No dose dependence on technical accuracy was found. ENT surgeons were able to identify anatomic landmarks on scans with a dose as low as 3.1 mGy. CONCLUSIONS: The vast dose difference between institutions mirrors different attitudes toward image quality and radiation-protection issues rather than being technically founded, and many patients undergo CAS-CT at higher doses than necessary. The only limit for dose reduction in CT for computer-assisted endoscopic sinus surgery is the ENT surgeons ability to cope with impaired image quality, whereas there is no technically justified lower dose limit. We recommend, generally, doses used for the typical diagnostic low-dose sinus CT (120 kV/20–50 mAs). When no diagnostic image quality is needed, even a reduction down to a third is possible.

Diagnostic value of biopsies in identifying cytoplasmic antineutrophil cytoplasmic antibody-negative localized Wegener's granulomatosis presenting primarily with sinonasal disease.

Background A substantial proportion of Wegeners disease (WG) patients present with localized disease of the upper airways, i.e., sinonasal and other ear/nose/throat (ENT) symptoms. Because of the oligosymptomatic presentation a timely diagnosis of this potentially fatal disease is challenging. This study evaluates diagnostic peculiarities between WG in its localized and generalized form of the disease. Methods Retrospective analysis was performed of 82 patients with suspected WG manifesting in the ENT region between 1989 and 2009. Comparison was performed of the clinical and laboratory results between patients with localized (n = 15) and generalized stage (n = 16) as well as non-WG patients (n = 50). Results ENT signs and symptoms were subtle, especially in the population presenting with localized disease. Therapy refractory rhinosinusitis or serous otitis media were the most frequent presentations of WG. In testing for localized WG, mucosal biopsy had the highest sensitivity (53%) compared with cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCAs) with a lower sensitivity (47%) but highest specificity (96%) and highest positive predictive value (PPV; 78% versus 73%). Patients with generalized WG typically revealed a pathological urine sediment, hemoptysis, or rheumatological symptoms. In the generalized stage, c-ANCA had the highest sensitivity (81%), specificity (96% versus 95%), and highest PPV (87%). Conclusion Timely diagnosis and treatment of localized WG limited to the ENT region remains problematic. Even with adequate therapy, nearly one-half of patients with sinonasal localization suffer from relapse, at least 1 in 10 will progress to generalized disease, and up to two-thirds may develop permanent tissue damage. Unfortunately, the diagnostic usefulness of c-ANCA is significantly reduced at this early stage compared with cases with generalized disease (p = 0.04). Hence, the relative diagnostic value of mucosal biopsy increases especially for the significant proportion of c-ANCA– localized WG patients (47%). Sinonasal tissue sampling represents a cornerstone for diagnosis, which unlike c-ANCA testing can be repeated in short intervals and is associated with low morbidity.

Severe Cutaneous Leishmaniasis in a Human Immunodeficiency Virus Patient Coinfected with Leishmania braziliensis and Its Endosymbiotic Virus

Leishmania parasites cause a broad range of disease, with cutaneous afflictions being, by far, the most prevalent. Variations in disease severity and symptomatic spectrum are mostly associated to parasite species. One risk factor for the severity and emergence of leishmaniasis is immunosuppression, usually arising by coinfection of the patient with human immunodeficiency virus (HIV). Interestingly, several species of Leishmania have been shown to bear an endogenous cytoplasmic dsRNA virus (LRV) of the Totiviridae family, and recently we correlated the presence of LRV1 within Leishmania parasites to an exacerbation murine leishmaniasis and with an elevated frequency of drug treatment failures in humans. This raises the possibility of further exacerbation of leishmaniasis in the presence of both viruses, and here we report a case of cutaneous leishmaniasis caused by Leishmania braziliensis bearing LRV1 with aggressive pathogenesis in an HIV patient. LRV1 was isolated and partially sequenced from skin and nasal lesions. Genetic identity of both sequences reinforced the assumption that nasal parasites originate from primary skin lesions. Surprisingly, combined antiretroviral therapy did not impact the devolution of Leishmania infection. The Leishmania infection was successfully treated through administration of liposomal amphotericin B.

Internet Video Telephony Allows Speech Reading by Deaf Individuals and Improves Speech Perception by Cochlear Implant Users

Objective To analyze speech reading through Internet video calls by profoundly hearing-impaired individuals and cochlear implant (CI) users. Methods Speech reading skills of 14 deaf adults and 21 CI users were assessed using the Hochmair Schulz Moser (HSM) sentence test. We presented video simulations using different video resolutions (1280×720, 640×480, 320×240, 160×120 px), frame rates (30, 20, 10, 7, 5 frames per second (fps)), speech velocities (three different speakers), webcameras (Logitech Pro9000, C600 and C500) and image/sound delays (0–500 ms). All video simulations were presented with and without sound and in two screen sizes. Additionally, scores for live Skype™ video connection and live face-to-face communication were assessed. Results Higher frame rate (>7 fps), higher camera resolution (>640×480 px) and shorter picture/sound delay (<100 ms) were associated with increased speech perception scores. Scores were strongly dependent on the speaker but were not influenced by physical properties of the camera optics or the full screen mode. There is a significant median gain of +8.5%pts (p = 0.009) in speech perception for all 21 CI-users if visual cues are additionally shown. CI users with poor open set speech perception scores (n = 11) showed the greatest benefit under combined audio-visual presentation (median speech perception +11.8%pts, p = 0.032). Conclusion Webcameras have the potential to improve telecommunication of hearing-impaired individuals.

Speech perception benefits of internet versus conventional telephony for hearing-impaired individuals.

Background Telephone communication is a challenge for many hearing-impaired individuals. One important technical reason for this difficulty is the restricted frequency range (0.3–3.4 kHz) of conventional landline telephones. Internet telephony (voice over Internet protocol [VoIP]) is transmitted with a larger frequency range (0.1–8 kHz) and therefore includes more frequencies relevant to speech perception. According to a recently published, laboratory-based study, the theoretical advantage of ideal VoIP conditions over conventional telephone quality has translated into improved speech perception by hearing-impaired individuals. However, the speech perception benefits of nonideal VoIP network conditions, which may occur in daily life, have not been explored. VoIP use cannot be recommended to hearing-impaired individuals before its potential under more realistic conditions has been examined. Objective To compare realistic VoIP network conditions, under which digital data packets may be lost, with ideal conventional telephone quality with respect to their impact on speech perception by hearing-impaired individuals. Methods We assessed speech perception using standardized test material presented under simulated VoIP conditions with increasing digital data packet loss (from 0% to 20%) and compared with simulated ideal conventional telephone quality. We monaurally tested 10 adult users of cochlear implants, 10 adult users of hearing aids, and 10 normal-hearing adults in the free sound field, both in quiet and with background noise. Results Across all participant groups, mean speech perception scores using VoIP with 0%, 5%, and 10% packet loss were 15.2% (range 0%–53%), 10.6% (4%–46%), and 8.8% (7%–33%) higher, respectively, than with ideal conventional telephone quality. Speech perception did not differ between VoIP with 20% packet loss and conventional telephone quality. The maximum benefits were observed under ideal VoIP conditions without packet loss and were 36% (P = .001) for cochlear implant users, 18% (P = .002) for hearing aid users, and 53% (P = .001) for normal-hearing adults. With a packet loss of 10%, the maximum benefits were 30% (P = .002) for cochlear implant users, 6% (P = .38) for hearing aid users, and 33% (P = .002) for normal-hearing adults. Conclusions VoIP offers a speech perception benefit over conventional telephone quality, even when mild or moderate packet loss scenarios are created in the laboratory. VoIP, therefore, has the potential to significantly improve telecommunication abilities for the large community of hearing-impaired individuals.

How internet telephony could improve communication for hearing-impaired individuals

Objective: To test, whether modern Internet telephony with a broadband transmission (0.1-8 kHz) of speech improves speech perception in comparison to conventional telephony (0.3-3.5 kHz) in hearing-impaired and normal-hearing adults. Study Design: Experimental clinical study. Setting: Audiologic laboratory in a tertiary referral center in Bern, Switzerland. Patients: Twenty-one adult hearing-impaired patients consisting of 11 users of cochlear implants and 10 users of hearing aids were selected from the institutions database based on pure tone audiograms, speech perception scores, and device settings. Ten normal-hearing adults served as controls. Intervention: Superiority trial of speech perception assessed with Internet versus conventional telephone quality and noninferiority trial of Internet telephone versus frequency restricted, uncompressed audio CD quality. A modern broadband codec was chosen to simulate Internet telephone quality, and ideal network conditions without packet loss were assumed. Main Outcome Measures: Speech perception scores of a monosyllabic word test in quiet and a sentence test in background noise assessed in different audio qualities. Results: Test scores were, on average, 15% (4-33) higher in the monosyllabic word and 25% (8-51) higher in the sentence test using Internet versus conventional telephone quality across all subject groups. Speech perception was not significantly different when Internet telephone quality was compared with high-cut CD quality. Conclusion: Internet telephony offers significantly improved speech perception to hearing-impaired and normal-hearing adults under ideal laboratory conditions through doubling the frequency range and through conserving audio quality during digital sound processing.

Intensity-Modulated Radiotherapy for a Rendu-Osler-Weber Disease Patient with Recurrent Severe Epistaxis: A Case Report

We present a case of a Rendu-Osler-Weber disease patient with recurrent life threatening epistaxis demanding multiple blood transfusions despite of repetitive endoscopic laser and electrocoagulations, endovascular embolisation, septodermoplasty, and long-term intranasal dressings. As alternative treatment modalities repeatedly failed and the patient became almost permanently dependent on nasal dressing, we performed a highly conformal intensity-modulated radiotherapy of the nasal cavity; a total dose of 50 Gy in 2 Gy single fractions was applied. The therapy was very well tolerated, no acute toxicities occurred. Two weeks after the last radiation dose had been applied, the nasal dressing could be removed without problems. Endoscopical control revealed an almost avascular white mucosa without any trace of bleeding spots; previously existing hemangiomas and crusts had disappeared. After a 1-year-follow up, the patient had no significant recurrent epistaxis.