Answer:
Nasal endoscopy has greatly facilitated the diagnosis and treatment of nasal airway complaints in both the office and the operative settings. It allows a more comprehensive view of the internal nasal anatomy not seen by traditional rhinoscopy, as well as allowing easy photographic documentation. Studies by Levine and Vining have shown that nasal endoscopy can find pathology often missed by other modalities. Nasal endoscopes come in two diameters (2.7 or 4.0 mm) and three angles (0, 30, 70 degrees). Most adults should be inspected with 4.0-mm endoscopes. If a significant nasal obstruction exists then the 2.7-mm scope should be used. This smaller scope is also used in smaller adults and in children. It should also be used when examining tighter anatomic spaces within the nose. The 2.7-mm scope is more fragile and requires more maintenance. The 30 degree scope is considered the most applicable since much of the nasal anatomy is positioned superiorly while the angle is not difficult for the observer to adapt to. The 70 degree scope is more difficult to use and is best used to examine isolated areas of the medial or lateral nasal walls such as the opening to the nasofrontal duct.
Endoscopy should be used in conjunction with a standard nasal speculum exam. Topical anesthesia with cocaine solution (1%, 4%, or 10%) or a 4% xylocaine & 1% phenylephrine mixture is applied by spraying it into the nasal cavity or inserting it on cotton sponges along the floor and roof of each nostril. The agent should be given 5 to 7 minutes before further examination is performed to achieve maximum effect in anesthesia and vasoconstriction. With the patient seated in an examination chair, the scope is placed in the nasal vestibule and advanced posterior along the floor of the nose beneath the inferior turbinate, allowing a view of the inferior meatus, septum, soft palate, eustachian tube, and the anterior and posterior aspects of the inferior turbinate. The scope is slowly withdrawn to allow reinspection for missed pathology. The second pass is directed between the inferior turbinate and the middle turbinate. The ethmoidal areas and nasofrontal region are inspected with this pass. Adjunctive views of the nasofrontal region can be obtained with a pass of a 70 degree scope. In general, the exam should be performed with delicacy and finesse. Even with proper anesthetic preparation, the nose remains very sensitive and prone to traumatic injury. The endocope should never be forced into a desired position.