airflow in paranasal sinuses

n/

Nose and Sinus Air Flow Model

Air flow in nose and sinuses is studied by means of a simple model based on the steady-state ideal fluid flow assumption and repeated use of Bernoulli's equation. In particular, by describing flow of air drawn in through the vestibulumnasi during inspiration, we investigate how ventilation of the maxillary sinus is affected by surgical removal of part of the lateral walls of the nasal cavity close to the ostiummeatal complex. We find that, according to the model proposed, removal of tissues from this inner part of the nasal cavity may cause a decrease of the flux rate from the maxillary sinus

Mathematical model for preoperative identification of obstructed nasal subsites

The planning of experimental studies for evaluation of nasal airflow is particularly challenging given the difficulty in obtaining objective measurements in vivo. Although standard rhinomanometry and acoustic rhinometry are the most widely used diagnostic tools for evaluation of nasal airflow, they provide only a global measurement of nasal dynamics, without temporal or spatial details. Furthermore, the numerical simulation of nasal airflow as computational fluid dynamics technology is not validated. Unfortunately, to date, there are no available diagnostic tools to objectively evaluate the geometry of the nasal cavities and to measure nasal resistance and the degree of nasal obstruction, which is of utmost importance for surgical planning. To overcame these limitations, we developed a mathematical model based on Bernoulli's equation, which allows clinicians to obtain, with the use of a particular direct digital manometry, pressure measurements over time to identify which nasal subsite is obstructed. To the best of our knowledge, this is the first study to identify two limiting curves, one below and one above an average representative curve, describing the time dependence of the gauge pressure inside a single nostril. These upper and lower curves enclosed an area into which the airflow pattern of healthy individuals falls. In our opinion, this model may be useful to study each nasal subsite and to objectively evaluate the geometry and resistances of the nasal cavities, particularly in preoperative planning and follow-up

Mathematical model for preoperative identification of obstructed nasal subsites

La realizzazione di studi sperimentali per la valutazione dei flussi aerei nasali è particolarmente indaginosa, data la difficoltà di ottenere in vivo unaccurata misurazione degli stessi. Inoltre, sebbene la rinomanometria standard e la rinometria acustica rappresentino i metodi più utilizzati nella pratica clinica, esse forniscono solo una misura globale ed approssimativa dei flussi aerei nasali, senza definirne i particolari temporali o spaziali. Allo stesso modo gli studi sulla fluidodinamica computazionale rappresentano solo una simulazione numerica, ben lontana da quelle che sono le variabili anatomiche e fisiologiche delle cavità nasali. Pertanto, ad oggi, non esistono ancora strumenti diagnostici in grado di misurare oggettivamente la geometria delle cavità nasali, le resistenze ed il grado di ostruzione nei diversi sotto-siti nasali, elemento questultimo fondamentale per una corretta programmazione chirurgica. Allo scopo di superare i limiti della diagnostica standard abbiamo elaborato un modello matematico basato sullequazione di Bernoulli applicata alle cavità nasali di soggetti sani per lo studio dei gradienti pressori di vari sotto-siti nasali, che sono stati misurati grazie ad un particolare manometro digitale. Il nostro studio, unico in letteratura, ha identificato due curve limite che racchiudono unarea rappresentativa entro cui cadono i livelli normali di flusso in corrispondenza del vestibolo nasale. Il modello descritto potrebbe essere utile per studiare tutti i sotto-siti nasali sede di ostruzione ai fini di una corretta programmazione chirurgica e di un valido follow-up postoperatorio

Airflow In Paranasal Sinuses

The function of paranasal sinuses has been investigated by considering a time-dependent gauge-pressure expression for airflow in the nose. Depending on the type of inhalation pattern by the same individual, it is shown that air flowing through the nasal cavity determines a more or less effective translation of the molecules of air coming from the paranasal sinuses. A functional manometric survey of the middle meatus was carried out on a homogeneous group of 50 Caucasian individuals

Nose air-flow-rate measurements by means of nose and sinus manometry

A time-dependent gauge-pressure expression for air flow in the nasal cavity is derived by means Bernoulli's equations and is used for comparison to digital manometry data. With the help of direct digital manometry, in fact, the airflow rate through each nasal 'key point' can be measured section by section. In particular, we investigate the time evolution of the gauge pressure in the vestibulum nasi, comparing normal and abnormal subjects data. It is shown that pulmonary respiration dynamics can be indirectly inferred from these data

THE NOSE AND SINUS MANOMETRY: A BIO-PHYSICAL MODEL APPLIED TO FUNCTIONAL ENDOSCOPIC SINUS SURGERY

The effectiveness of sinus ventilation is due to a regular anatomy of inner nose structures such as the maxillary sinus ostium. With the aid of nose and sinus manometric measurements, it is possible to show that better functional results can be achieved using a conservative surgical technique. The present study compared 30 patients subdivided in two groups. Group A underwent conservative endoscopic sinus surgery whereas group B was operated on using non-conservative endoscopic sinus surgery. Thirty days later, both groups underwent a manometric survey of the maxillary sinus ostium by means of the digital manometry system. The pressure values obtained by nasal and sinus manometry in Group A or Group B patients were referred to those obtained in a Standard Group without nasal-sinus pathologies, calculating a percentage index of functional efficacy (maxillary sinus functional efficacy). The average percentage of the maxillary sinus functional efficacy was 98,35 percent for group-A patients, and 49,73 percent for group-B patients. Student t test revealed a statistical difference only between group B patients and standard group patients (p less than 0.4). Patients submitted to a more aggressive endoscopic approach showed inadequate sinus ventilation when compared to the standard reference group

The nose and sinus manometry: a bio-physical model applied to functional endoscopic sinus surgery.

The effectiveness of sinus ventilation is due to a regular anatomy of inner nose structures such as the maxillary sinus ostium. With the aid of nose and sinus manometric measurements, it is possible to show that better functional results can be achieved using a conservative surgical technique. The present study compared 30 patients subdivided in two groups. Group A underwent conservative endoscopic sinus surgery whereas group B was operated on using non-conservative endoscopic sinus surgery. Thirty days later, both groups underwent a manometric survey of the maxillary sinus ostium by means of the digital manometry system. The pressure values obtained by nasal and sinus manometry in Group A or Group B patients were referred to those obtained in a Standard Group without nasal-sinus pathologies, calculating a percentage index of functional efficacy (maxillary sinus functional efficacy). The average percentage of the maxillary sinus functional efficacy was 98,35% for group-A patients, and 49,73% for group-B patients. Student t test revealed a statistical difference only between group B patients and standard group patients (p<0.4). Patients submitted to a more aggressive endoscopic approach showed inadequate sinus ventilation when compared to the standard reference group