Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4473_Библиотеки_им_академика_М_И_Перельмана

The nose is a prominent facial feature that plays an important role aesthetically as well as physio­logically. During nasal surgery, these physiologi­cal functions must be preserved or improved if they have been compromised. Basic nasal func-

The relatively small surface area of the nasal mucosa (160cm2) and the underlying submucosa are faced with the formidable task of humidifying and warming about 14,000L of inspired air that pass through the nasal cavities of a normal active adult in 1day. The submucosa allows for energy and metabolites to be transported to the mucosa, which acts as the interface for exchange. Air is heated by conduction, convection, and radiation. The heat exchange is efcient, because the blood ow is in the opposite direction to the incoming airow, a process known as countercurrent exchange. This process is facilitated by the rich vascular network of the nasal septum and turbi­nates. In comfortable room conditions, about 280kJ of energy is required to warm the air to 32°C in the rhinopharynx. To saturate this vol­ume of inspired air with humidity, 1400kJ of energy and 600g of water are expended. On expi­ration, a considerable proportion of warmth and humidity are extracted from the air to conserve energy [13–15]. Some conditions related to impaired humidifying capacity of the nasal mucosa include nasal crusting, bleeding, rhinor­rhea, and asthma, especially in cold weather [16].

internal nasal valve collapse, may be seen upon

simple external inspection of the nose in which a pinched middle third may be visible. This usually presents as a discontinuity along the brow-tip aesthetic line where the middle third is pinched and narrowed while the upper third, which is sup­ported by bone, remains wide. This inverted V deformity has been linked to the separation of the upper lateral cartilages from the overlying nasal bones during rhinoplasty, but can actually be seen more commonly among patients with inter­nal nasal valve collapse, especially those with thin skin, who have either never undergone previ­ous rhinoplasty or who have had a standard dor­sal reduction rhinoplasty without disarticulation of the upper lateral cartilages from the nasal bones. Static internal nasal valve collapse may appear clinically as scar tissue, strictures, or web­bing in the valve angle (as might occur after sepa­ration of the upper lateral cartilage and mucosa from the septum without sparing the mucosal attachments between the two structures). Static narrowing of the middle third of the nose can also be the result of congenital or traumatic weakness or absence of the upper lateral cartilages, or other deformities, such as thickening or twisting of the upper lateral cartilages. In patients with an over­projected tension type nasal deformity, over­growth of the nasal septum causes the angle between the upper lateral cartilage and the nasal septum to be excessively narrowed. Such patients may also frequently be found to have thin and weak upper lateral cartilages, which tend to add a dynamic component to the internal nasal valve collapse.