Nasal Endoscopy

Nasal endoscopy has become the most important and rewarding clinical examination method in rhinologic diagnosis.
Prerequisites: Nasal endoscopy requires practice because, unlike anterior rhinoscopy, it provides only close-up views of small intranasal areas. Besides rigid endoscopes, which are available in 4-mm and 2.8mm diameters and assorted viewing angles (e.g., 0, 30, 120), flexible endoscopes are also available for inspecting the nose and nasopharynx and exploring all of the pharynx and larynx in one sitting. Their main disadvantages compared with rigid scopes are their weaker light intensity and poorer image resolution. Also, it takes two hands to operate a flexible endoscope, while a rigid scope leaves one hand free for manipulating instruments. The patient is seated for the examination. As in anterior rhinoscopy, the preparations include decongestion of the nasal mucosa. A topical anesthetic
should also be applied. Diagnostic nasal endoscopy is performed with a 4-mm 30  telescope. The 2.8-mm scope is used only in a very narrow nasal cavity or in children.
Technique: First the examiner advances the endoscope into the nasopharynx and inspects the eustachian tube orifice, torus tubarius, posterior pharyngeal wall, and roof of the nasopharynx.
While the transnasal nasopharyngeal inspection can provide very detailed views (e.g., for early detection of nasopharyngeal cancer), it should still be supplemented by transoral postrhinoscopic endoscopy. Nasal endoscopy is particularly useful for evaluating the ostiomeatal unit, as this pathophysiologically important region generally cannot be adequately evaluated by anterior rhinoscopy alone. To inspect the middle meatus, the endoscope is first advanced toward the head of the middle turbinate. This should provide a good overview of the middle meatus. To advance farther into the ostiomeatal unit, the scope must negotiate the narrow passage between the uncinate process and the middle turbinate. Normally, this can be done only with a narrow-gauge scope (2.8 mm). The 4-mm endoscope can be used at this site only in patients who have had previous intranasal sinus surgery with resection of the uncinate process. Direct endoscopic inspection of the paranasal sinuses
is possible only to a limited degree. In some cases, the sphenoid sinus can be examined with a thin telescope passed through the natural ostium in the anterior sinus wall. If endoscopic exploration of the maxillary sinus is required (e.g., for a suspected tumor), it can be done either through the inferior meatus after perforating the lateral nasal wall or by a transfacial approach with incision of the maxillary sinus mucosa and perforation of its anterior wall.