A CFD approach to understand nasoseptal perforations.

Nasoseptal perforations (NSP) are becoming common in the modern world, and can cause a wide variety of symptoms, including a sensation of nasal obstruction, epistaxis, crusting, dryness, headache, nasal pain and a whistling sound. There is an extensive range of surgical treatment techniques, but reported results were rarely statistically significant. The lack of consistent surgical results may be related to the lack of knowledge about the pathophysiology of NSP and how they affect the nasal flow. Computational fluid dynamics (CFD) has proved to be a very useful tool to study nasal function. We have used CFD software (the program MECOMLAND® and the Digbody® tool for virtual surgery) to investigate the behaviour of the parameters R-[Formula: see text] based on CFD results, when four subjects underwent virtual surgery to induce a septal perforation: two subjects with healthy noses and two patients suffering from nasal airway obstruction. For each case a CFD study was performed, before and after creating an anterior (close to nostrils) or a posterior (close to choanae) NSP. In all cases analyzed, a posterior septal perforation did not result in a significant volumetric flow rate [Formula: see text] through the perforation between nasal passages. However, for anterior defects only in those nasal cavities considered diseased or unhealthy, high values of [Formula: see text] were found. The induced NSP only rendered significant flow alterations in noses with preexisting nasal airway obstruction alterations, whereas in nasal cavities considered as normal the creation of a NSP did not produce significant differences between both sides. We strongly suggest that this finding can explain the variety of symptoms and the number of asymptomatic patients bearing NSP.