Transnasal endoscopy: Technical considerations, advantages and limitations

Abstract

Transnasal endoscopy (TNE) is an upper endoscopy method which is performed by the nasal route using a thin endoscope less than 6 mm in diameter. The primary goal of this method is to improve patient tolerance and convenience of the procedure. TNE can be performed without sedation and thus eliminates the risks associated with general anesthesia. In this way, TNE decreases the cost and total duration of endoscopic procedures, while maintaining the image quality of standard caliber endoscopes, providing good results for diagnostic purposes. However, the small working channel of the ultra-thin endoscope used for TNE makes it difficult to use for therapeutic procedures except in certain conditions which require a thinner endoscope. Biopsy is possible with special forceps less than 2 mm in diameter. Recently, TNE has been used for screening endoscopy in Far East Asia, including Japan. In most controlled studies, TNE was found to have better patient tolerance when compared to unsedated endoscopy. Nasal pain is the most significant symptom associated with endoscopic procedures but can be reduced with nasal pretreatment. Despite the potential advantage of TNE, it is not common in Western countries, usually due to a lack of training in the technique and a lack of awareness of its potential advantages. This paper briefly reviews the technical considerations as well as the potential advantages and limitations of TNE with ultra-thin scopes.

Keywords: Sedated endoscopy; Transnasal endoscopy; Transoral endoscopy; Ultra-thin endoscopy; Unsedated endoscopy.

Figure 1

Pretreatment delivery catheter for transnasal endoscopy (Fujinon, Fujilm, Japan).

Figure 2

Relative diameters of an ultra-thin endoscope (left, 5.9 mm) and a standard gastroscope (right, 8.8 mm).

Figure 3

Endoscopic images of transnasal endoscopy during insertion from nose (A) and oropharynx (B).