Preliminary Study of the Deposition of Aerosol in the Maxillary Sinuses Using a Plastinated Model

Abstract

In spite of the widespread use of aerosols in respiratory diseases, very few studies have been performed in the field of ear, nose, and throat (ENT) disorders. The conditions for penetration of aerosols inside the sinus cavities are thus still not understood fully. The aim of this study was to investigate the penetration of aerosols inside maxillary sinuses in vitro, using plastinated models. Three plastinated specimens of the nose and sinuses were made from three different corpses. These specimens were validated by CT scans and were used to study deposition of aerosol in the maxillary sinuses. We performed scintigraphic images of the models in above, face, and profile views using a technetium (99mTc)-labelled solution to show aerosol deposition. We also counted the radioactivity deposited on gauze compresses placed inside the maxillary sinuses. In addition, we constructed a measuring unit with miniature humidity sensors placed inside the sinuses. We recorded the changes in relative humidity observed during nebulization. Results from these studies showed that scintigraphic images of the specimen, whatever the incidence of the views, were not accurate enough to differentiate the aerosol deposition in the maxillary sinuses from that in the nasal cavity. Using indirect counting on gauze compresses made possible the quantification of local aerosol deposition, and we found that aerosols entered into the sinuses. This confirmed that aerosols could reach the middle meatus, which is the main area for sinusitis disorders. The increased activity compared to background varied from 17 to 127%. The humidity sensors recorded changes in relative humidity during the nebulization. These humidity changes fitted a nonlinear model represented by the equation: y = b0 (1 - e(-b1t)), where b0 is the plateau and b1 is the speed to reach the plateau. These techniques may be useful in the future for in vitro characterization of aerosol penetration into the maxillary sinuses.

In Vitro Experiments and Numerical Simulations of Airflow in Realistic Nasal Airway Geometry

“…2) because it constitutes the most realistic model. 3,4 The anatomical specimen was obtained from a cadaver donated to the "Laboratoire d'Anatomie de la Faculté de Médecine Jacques Lisfranc (Saint-Etienne, France)." This type of donation is anonymous.…”

“…This type of donation is anonymous. Our plastinated model is the same as "model 2" used in the study by Durand et al 4 Plastination is a well-known technique for anatomical conservation. It consists of extracting water and lipids from biological tissues and then replacing them with curable polymers.…”

“…The physical model of nasal airways is obtained from a human plastinated head (i.e., after substituting polymers for water and lipids 3,4 ). The numerical model is obtained from the same physical model after scanning the plastinated head and a specific three-dimensional reconstruction procedure performed using the stack of CT images.…”

Influence of Dosage Form, Formulation, and Delivery Device on Olfactory Deposition and Clearance: Enhancement of Nose-to-CNS Uptake

“…The boxed region delineates the olfactory region, which is shown in Fig. 2 drugs are best targeted to the middle meatus [33], while the turbinates and septum wall are best for systemic delivery owing to efficient drug absorption [1]. For direct nose-to-CNS transport, the olfactory region is the best target [34].…”

Nebulization of antibiotics in management of sinusitis

“…Comparison of the deposition patterns of nebulizers versus nasal sprays has been done [14]. Such studies have shown nebulizers to be capable of covering a greater surface area than nasal sprays cover in normal human volunteers [15].…”