Biomedical subjects

Gunter Mlynski

Publications and source records attributed to Gunter Mlynski.

5 recordsLinked to original sources

PubMed2005

Acoustic rhinometry and paranasal sinuses: a systematic study in models, anatomic specimens, and in vivo.

OBJECTIVE/HYPOTHESIS: Acoustic rhinometry (AR) evaluates the cross-sectional areas (CSA) of the nasal cavity through acoustic reflections. The aim of this study was to test whether the paranasal sinuses are a cause for the measurement of increased CSA in the posterior cavum of the nose. STUDY DESIGN: : Experimental study to evaluate the influence of paranasal sinus volume on AR measurements in two anatomic nose models, an anatomic specimen, and seven individuals. METHODS: The paranasal sinus volume was systematically reduced by filling of the maxillary sinus with saline. The paranasal sinus ostia were enlarged in the models and the anatomic specimen by infundibulotomy and supraturbinal fenestration, with AR repeated thereafter. RESULTS: No modification of the posterior area-distance curve was found in the models, the specimen, and the individuals after changing the volume of the maxillary sinus with unmodified anatomy of the paranasal sinus ostia. The apparent CSA measured in the posterior cavum after infundibulotomy and supraturbinate fenestration in the models and the specimen increased with the volume of the paranasal sinuses. CONCLUSION: Regular anatomy provided, AR reveals reproducible measurements that correspond with the actual CSA up to the ostia of the paranasal sinuses. Untypical large openings to the paranasal sinuses (e.g., after paranasal sinus surgery) appear to contribute to the inaccuracy of AR by overlapping paranasal sinus CSA with the posterior part of the area distance curve.

Humans↗

PubMed2003

Numerical simulation of airflow in the human nose.

Unobstructed air passageways as well as sufficient contact of the air stream with the mucous membrane are essential for the correct function of the nose. For that, local flow phenomena, which often cannot be captured by standard diagnostic methods, are important. We developed and validated a method for the numerical simulation of the nasal airflow. Two anatomically correct, transparent resin models of human nasal cavities, manufactured by a special casting technology, and the nasal cavities of two patients were reconstructed as Computer Aided Design models based on computed tomography (CT) scans. One of the nasal models and one clinical case represented a normal nasal anatomy, while the others were examples of pathological alterations. The velocity and pressure fields in these reconstructed cavities were calculated for the entire range of physiological nasal inspiration using commercially available computational fluid dynamics software. To validate the results rhinoresistometric data were measured and characteristic streamlines were videotaped for the resin models. The numerical results were in good agreement with the experimental data for the investigated cases. An example of a complex clinical case demonstrates the potential benefit of the developed simulation method for rhinosurgical planning. The results support the assumption that even under the specific conditions of the clinical practice the application of numerical simulation of nasal airflow phenomena may become realistic in the near future. However, important technical issues such as a completely automated reconstruction of the nasal cavity still need to be resolved before such simulations are efficient and cost effective enough to become a standard tool for the rhinologist.

Adult↗

PubMed2003

Investigating the nasal cycle using endoscopy, rhinoresistometry, and acoustic rhinometry.

OBJECTIVES: Cyclic congestion and decongestion in the two nasal cavities is seen in connection with the respiratory function of the nose. The turbulent behavior of nasal airflow is a prerequisite for adequate contact of inspired air particles with the mucosa. The aim of this study was to gain insight into this turbulent behavior of nasal airflow during the nasal cycle. METHODS: The nasal cycle in 10 healthy human subjects was investigated using endoscopic imaging, rhinoresistometry, and acoustic rhinometry every 20 minutes over a time period of up to 15 hours. The following parameters were recorded for each nasal cavity: airflow resistance, hydraulic diameter, friction coefficient lambda as an indicator for the wall configuration triggering turbulence, transition from laminar to turbulent flow, and the minimal cross-sectional areas. RESULTS: In addition to the known cyclic change of flow resistance and nasal width, a periodic change in the turbulence behavior was observed. In the resting phase, mainly laminar flow was found. During the working phase, the onset of turbulence occurred already at low flow velocities. The increase of turbulence during the working phase is caused by the increase in cross-sectional area in the anterior cavum due to decongestion of the mucosa of the head of the inferior turbinate and the septal tuberculum. CONCLUSIONS: Rhinoresistometry and acoustic rhinometry complement each other. The combination of the two methods provides insight into the functional changes during the nasal cycle and into nasal physiology in general. The authors therefore advocate a combination of the two methods for functional evaluation of the nasal airway.

Adult↗

PubMed2003

Acoustic rhinometry and paranasal cavities: a systematic study in box models.

OBJECTIVE/HYPOTHESIS: Acoustic rhinometry (AR) is a well-established diagnostic tool in rhinology. The aim of the study was to test the hypothesis that the paranasal sinuses are a main cause for inaccuracy of AR in the posterior part of the nose. STUDY DESIGN: Experimental study to evaluate the influence of simulated paranasal sinus volume and of the contralateral side of the nose on AR measurements in "box models." METHODS: Models were measured with paranasal sinus volume simulated between 0 and 25 mL and with the junction between the models and the paranasal sinuses varying in length and diameter. RESULTS: Moderate but distinct modification of the posterior area-distance curve was found within the models after changing size of the paranasal sinuses and its junction to the cavity. The apparent cross-sectional area (CSA) measured in the posterior cavum decreased with the volume of the paranasal sinuses. This effect was limited by the length and the diameter of the paranasal junction, as well as by the concha. No influence of the contralateral side on AR measurements was seen. CONCLUSIONS: Acoustic rhinometry reveals reproducible measurements up to 4 cm from the nostril that correspond with the actual model CSA. Simulated paranasal sinuses appear to partially contribute to the inaccuracy in the posterior part of the area-distance curve.

Humans↗

PubMedDate not supplied

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.

Circadian Rhythm↗