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Biomedical subjects

C Betsch

Publications and source records attributed to C Betsch.

9 recordsLinked to original sources
PubMed2002

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy.

The aim of this study was the quantification of vapors of the ozone-depleting refrigerant R22 in the presence of its most important substitute R134a, by the use of the reflectometric interference spectroscopy and polymers as sensitive layers. First, the sorption characteristic of different types of polymers exposed to the vapors of the two analytes was investigated. Then, binary mixtures of the two refrigerants were measured with an array set-up on the basis of six polymer sensors. The measurements were evaluated by the use of neural networks, whereby low limits of detection of 0.45 percentage volume (vol. %)for R22 and 1.45 vol. % for R134a could be established. Additionally, one polar polymer and one microporous polymer were selected for the measurements with a low-cost set-up. The quantification of R22 in the presence of R134a with this low-cost set-up was possible with a limit of detection of 0.44 vol. %, which would enable a fast and economical monitoring at recycling stations.

Air Pollutants↗
PubMed2000

Tinnitus and otosclerosis.

Fifty patients with otosclerosis and tinnitus were studied for the course of the tinnitus after stapes surgery. Tinnitus disappeared in 64% of the cases, improved in 16%, was unchanged in 14%, and worsened in 6%. The reduction in tinnitus was more favorable after a small fenestra stapedotomy than after a partial stapedectomy with removal of the posterior half of the footplate. An unfavorable postoperative course of tinnitus did not appear to be linked to the postoperative audiometric result. In our study the subjective evaluation of pitch and loudness of the tinnitus did not provide significant information regarding its prognosis.

Adult↗
PubMed2000

[Revision surgery of otosclerosis: a review of 26 cases].

OBJECTIVES: The aim of this study was to identify causes of primary stapedectomy failures and to evaluate hearing results in revision stapes surgery. MATERIAL AND METHODS: We retrospectively reviewed a series of 26 revision stapedectomies. Patient characteristics, preoperative findings, causes of failure and complication of primary stapedectomy and postoperative hearing results were noted. RESULTS: Conductive hearing loss was the most common reason for revision surgery (77 %). Leading causes of stapedectomy failure included prosthesis malfunction (42 %), fibrous adhesions (37,5 %), incus erosion (12,5 %) and otosclerotic regrowth (12,5 %). When revision was indicated because of cochleo-vestibular complication, middle ear exploration revealed 3 problems: oval window granuloma or excessively long prosthesis or perilymphatic fistula. In this series, postoperative air-bone gap was closed to less than 10 dB in 57 % of cases, to less than 20 dB in 71 % of cases and we did not observed any sensorineural hearing loss. CONCLUSION: The results of this series are comparable with previously published studies. Revision stapes surgery is not as successful as primary stapedectomy, but the risk of sensorineural hearing loss does not appear to be higher than in primary surgery. Revision surgery is a challenging problem that must be performed by an experienced surgeon.

Adult↗
PubMed1999

A new technique for laser-assisted uvulopalatoplasty: decision-tree analysis and results.

OBJECTIVE: Report a new technique of laser-assisted uvulopalatoplasty (LAUP) for snoring performed as a one-stage procedure. STUDY DESIGN: A decision-tree was used in a prospective study of 89 patients from April 1994 to May 1997. It included a fiberscopy and Muller's maneuver, rhinomanometry, pH monitoring, computed tomography scan to measure the pharyngeal lumen, pulse oximetry, and polysomnography in case of sleep apnea syndrome was suspected. METHODS: The authors performed their LAUP technique on 43 patients (48.5%) whose snoring was mainly caused by the velum. This technique consists of scarifying the velum by vaporizing the mucosa and the submucosa along a rectangle extending from the palatal dimple to the uvula and having a width of 1.5 to 2 cm. Vaporization of the palatal arches follows without exceeding the junction of the anterior and posterior pillars in height. The uvula is cut if necessary, preserving a length of at least 0.5 cm. The other patients underwent different procedures according to the cause of snoring. RESULTS: There was no significant difference between LAUP and uvulopalatoplasty (UPPP) regarding pain. No permanent phonatory disorders and no regurgitation occurred. Satisfaction evaluated on a scale ranging from 0 to 10 was equivalent for the two techniques: mean value = 7.68 (+/-2.18) for LAUP and 8.60 (+/-2.27) for UPPP. The mean follow-up was 17 months (range, 1-37 mo). Satisfaction was also identical for all techniques. CONCLUSION: Our LAUP technique combined with other procedures according to a decision-tree is efficient and safe.

Adult↗
PubMed1997

Castleman's disease in the neck: MRI.

We describe a case of Castleman's disease in a 8-year-old-boy who presented with a slowly growing mass in the upper neck. MRI showed a well-defined homogeneous mass with nonspecific signal features. Unusual features were a kidney-bean shape and the deep location in the suprahyoid region, the mass originating in the left retropharyngeal space.

Biopsy↗
PubMed1997

Diagnostic techniques in chronic sinusitis: endoscopy, sinusomanometry.

The first endoscope was conceived as early as 1806. Since then successive technical advances led endoscopy of the nose and paranasal sinuses to a routine procedure. From the rediscovery of the rigid telescopes by Hopkins in the fifties, progress has stemmed essentially from the quality of the more powerful cold lights and the improvement in the light output of the fiber optics. Exam procedures of the nose and sinuses are conducted under general as well as local anesthesia, and are commonly combined with concomitant diagnostic procedures: measure of the mucociliary clearance with indicators, biopsies, smear sampling for bacterial and fungal examinations, and sinusomanometry which can help to estimate the patency of the maxillary ostium and of the nasofrontal duct. Sinus endoscopy has been widely used to correlate efficiency of other diagnostic techniques such as plain X-rays, CT scanners, A and B mode ultrasonography. A similar work should be done for MRI. Endoscopic exploration is the key to the management of chronic pathology as it brings precise information on the quality of the naso-sinus mucosa, the presence of secretions and, combined with sinusomanometry, the functional state of the ostia or ducts.

Anesthesia, General↗