Transnasal pharyngoscopy to assist nasobiliary tube placement: a simple technique to avoid injury to the patient, endoscopist, and endoscope

We read with interest the article by Dr Baron [1] on his “safe” transnasoral endoscopic technique to facilitate nasobiliary catheter placement while avoiding injury to the endoscopist. Oral-nasal transfer of a nasal transfer tube (NTT) is the final step of endoscopic nasobiliary drainage (ENBD), which involves introduction of a NTT from the nose to the posterior oropharynx. This blind insertion process, similar to nasogastric tube placement, can cause pain and nasomucosal injury. Moreover, according to most manufacturers’ instructions, a pair of forceps is used to grasp the NTT out of the posterior oropharynx; however, this rigid instrument may also cause mucosal injury to the oral cavity and oropharynx ([Fig. 1 a]). Sometimes endoscopists risk their fingers being bitten during this procedure ([Fig. 1 b]).

Fig. 1 Nasobiliary tube placement. Potential injury to the patient or the endoscopist may occur when a pair of biopsy forceps (a) or the endoscopist’s index finger (b) enters the oropharynx to bring out a nose-to-mouth transfer tube. c Without a mouthpiece, an ultrathin endoscope is vulnerable to damage due to involuntary biting.

Transnasal insertion is a proper route for a transnasal endoscope (TNE) but the endoscope is susceptible to damage when inserted into or retrieved out through the mouth. An undersedated patient or a patient awakening from anesthesia tends to mumble, expel the mouthpiece, and shut his or her mouth tightly. Baron’s transnasoral procedure risks damage to the TNE, particularly in a patient without a suitable mouthpiece ([Fig. 1 c]; see also Baron’s [Fig. 1]). Moreover, retroflexing a TNE just above the epiglottis, passing through the soft palate and protruding its tip out of the mouth would inevitably elicit a strong gag reflex from the patient during which the TNE is vulnerable to biting damage.

There are at least two possible causes of the nasal bleeding observed by Baron. First, when coming out of the mouth, the sharply angulated bending section of the TNE would have compressed firmly on the delicate nasal mucosa. Second, use of a retrieval basket to grasp the proximal end of an ENBD catheter may have created a “crotch” causing scratch injury to the patient’s oronasal mucosa during its mouth-to-nose backward journey (Baron, [Fig. 2]).

Fig. 2 Transnasal pharyngoscopy to assist oral-nasal transfer of an endoscopic nasobiliary drainage (ENBD) tube. The proximal ENBD catheter, pre-tied with a thread (a), is partly re-circled back (b) to the lateral pharyngeal wall above the epiglottis (c). Transnasal pharyngoscopy locates the thread (arrowhead), which is then grasped by the biopsy forceps via the endoscopic channel (c). The ENBD tube is finally pulled out of the nose (d arrowhead, [Video 1]) and the mouth-to-nose transfer is finished when the external loop outside the mouth and internal loop in the oral cavity are unraveled (e, f dotted arrows, [Video 1]).

Video 1 The proximal endoscopic nasobiliary drainage (ENBD) catheter is re-inserted back into the mouth and retained in the lateral pharyngeal wall. Transnasal pharyngoscopy locates the proximal ENBD catheter pre-tied with a thread, which is then grasped by the biopsy forceps via the working channel. The ENBD tube is pulled out of the nose and the mouth-to-nose transfer is completed when the external loop outside the mouth and internal loop in the oral cavity are straightened.

To avoid the oral-nasal transfer procedure, some endoscopists choose to perform one-step transnasal endoscopic retrograde cholangiopancreatography (ERCP) and ENBD using an ultrathin scope [2] [3]. However, conventional ERCP/ENBD is still the mainstay for most endoscopists. To avoid injury not only to the endoscopist but also to the patient and to prevent damage to the endoscope, we have been using a simpler and safe transnasal endoscopic technique that does not need a NTT. A thread is pre-tied at the proximal end of an ENBD catheter. When the proximal segment emerges from the mouth, it is partly re-circled back to the lateral pharyngeal wall ([Fig. 2 a, b]). With a TNE transnasally inserted just to the posterior pharynx, the thread is grasped by a pair of biopsy forceps, and the ENBD catheter is pulled out of the nose ([Fig. 2 c, d]). Instead of using a basket or snare, a pair of small-sized transnasal biopsy forceps clutch the ENBD tube, creating a head-on ([Fig. 2 d], arrowhead) but not furcated scope-catheter assembly for safe passage through the sinonasal tract. The mouth-to-nose transfer is completed when the external loop outside the mouth and the internal loop in the oral cavity are unraveled ([Fig. 2 e, f], dotted arrows).

In conclusion, compared with the forceps-assisted or manual extraction of a NTT from the mouth, transnasal pharyngoscopy is a safe method to facilitate the mouth-to-nose transfer procedure. Although Baron’s method can avoid the endoscopist from being bitten, the improperly used ultrathin endoscope may be scarified. Thus, this endoscopic transnasoral technique should only be used in patients without teeth. To safely pass the baton, endoscopists can simply use the back door – the pharynx.

References

• 1 Baron T H. Transnasal endoscopy to facilitate nasobiliary tube placement: a simple and safe technique to avoid injury to the endoscopist.  Endoscopy. 2010;  42 (Suppl 2) 323
• 2 Mori A, Asano T, Maruyama T et al. Transnasal ERCP/ENBD using an ultrathin esophagogastroduodenoscope.  J Gastroenterol. 2006;  41 1237-1238
• 3 Itoi T, Kawai T, Sofuni A et al. Efficacy and safety of 1-step transnasal endoscopic nasobiliary drainage for the treatment of acute cholangitis in patients with previous endoscopic sphincterotomy (with videos).  Gastrointest Endosc. 2008;  68 84-90