Diagnostic Nasal Endoscopy
Synonyms: DNE, Nasal endoscopy, Diagnostic nasal endoscopy.
Introduction: Examination of nose has been revolutionised by the advent of nasal endoscopes. These endoscopes are nothing but miniature telescope. It comes in the following sizes 2.7mm, and 4mm. It comes in various angulations namely 0 degrees, 30 degrees, 45 degrees, and 70 degrees. The 2.7 mm endoscope is used for diagnostic nasal endoscopy and in children. For diagnostic nasal endoscopy it is better to use a 2.7 mm 30 degree nasal endoscope if available. A 4mm 30 degree nasal endoscope can also be used for diagnostic nasal endoscopy in adults.
Indications of diagnostic nasal endoscopy:
1. To evaluate why a patient is not responding to medication.
2. To determine whether surgical management is necessary.
3. To examine the results of sinus surgery
4. To determine the effects of conditions such as severe allergies, immune deficiencies and mucociliary disorders (disorders that affect mucous membranes and cilia)
5. To determine whether a nasal obstruction (e.g., polyps, tumor) is present in the nasal cavity
6. To determine whether any foreign bodies (e.g., small object inserted by a child) are lodged in the nasal cavity
7. To remove a nasal obstruction or foreign material from the nasal cavity
8. To determine whether an infection has moved beyond the sinuses
9. To diagnose chronic recurrent sinusitis in children with asthma
10. To diagnose reason for anosmia (loss of smell).
11. To evaluate any discharges from the nasal cavities like CSF.
12. To diagnose reason for facial pain / headaches.
Procedure: Topical anesthetic 4% xylocaine is used to anesthetise the nasal cavity before the procedure. About 7 ml of 4% xylocaine is mixed with 10 drops of xylometazoline. Cotton pledgets are dipped in the solution, squeezed dry and used to pack the nasal cavity. Pledgets are packed in the inferior, middle and superior meati. Packs are left in place for full 5 minutes. Diagnostic endoscopy is performed using a 30 degree nasal endoscope. If 2.7 mm scope is available it is preferred because it can reach the smallest crevices of the nose. 4mm endoscope is sufficient to examine adult nasal cavities.
The process of examination can be divided into three passes:
1. First pass / inferior pass
2. Second pass
3. Third pass.
First pass: In this the endoscope is introduced along the floor of the nasal cavity. Middle turbinate is the first structure to come into view. Its superior attachment is studied. Inferior surface of the middle turbinate is studied. As the endoscope is slid posteriorly the adenoid tissue comes into view. On the lateral surface of the nasopharynx the pharyngeal end of eustachean tube can be identified. Its function can be assessed by asking the patient to swallow. The endoscope is now turned 90 degrees in the opposite direction, the uvula and soft palate comes into view. The endoscope is again rotated by 90 degrees in the same direction, the opposite side pharyngeal end of eustachean tube is visualised. In this field both eustachean tubes become visible.
Image showing inferior surface of middle turbinate
Second pass: After the first pass is over, the scope is gently withdrawn out and slide medial to the middle turbinate. The relation ship between the middle turbinate and nasal septum is studied. This relationship is classified as TS1, TS2, and TS3. It depends on whether, after application of decongestant both the medial and lateral surfaces of the middle turbinate is visible (TS1), part of the middle turbinate is obscured by septal deviation (TS2), or the septal deviation is completely obscures the middle turbinate (TS3). The scope is gently slipped medial to the middle turbinate. The sphenoid ostium comes into view. Secretions if any from the ostium is noted.
Endoscopic image of sphenoid ostium
Third pass: Is the most important of all the three passes. This pass studies the crucial middle turbinate area. The middle turbinate is evaluated for its shape and size as well as its relationship to the lateral nasal wall and septum. A bulge just above and anterior to the attachment of the middle turbinate suggests an enlarged agge nasi cells. Sometimes the anterior tip of the middle turbinate may be triangular. This shape has no significane unless it causes obstruction to the middle meatus. A middle turbinate that is concave medially rather than laterally is considered paradoxical. But paradoxical turbinate which is symptomatic needs to be treated. If the middle turbinate is enlarged due to the presence of a large air cell inside the middle turbinate it is known as concha bullosa. The middle turbinate is gently medialised using its plasticity. The middle meatus comes into view. The attachment of the uncinate process is carefully noted. Discharge if any from this area is also recorded. If accessory ostium is present it comes into view now. Accessory ostium is present more posteriorly. Normal ostium is actually not visible during diagnostic nasal endoscopy. Accessory ostium is spherical in shape and oriented anteroposteriorly, while the natural ostium of maxillary sinus is oval in shape and oriented transversely.
Endoscopic view of middle meatus
Endoscopic image of maxillary sinus ostium