Endoscopic ultrasound-guided methylene blue injection to achieve bile duct cannulation after failed ERCP.

Endoscopic ultrasound (EUS)-guided biliary drainage is an increasingly popular technique for cases of previously unsuccessful endoscopic retrograde cholangiopancreatography (ERCP). It has good results in expert hands, but is a challenging procedure with a significant rate of adverse events [1]. EUS-guided methylene blue cholangiopancreatography is a wireless alternative to the rendezvous technique in benign pancreaticobiliary disease. This interventional EUS-guided technique has been reported anecdotally to facilitate pancreatic duct and common bile duct access [2–4]. Recently, our interventional endoscopy unit published a case series with good results [5]. The purpose of the present report is to elaborate on some important technical details and to clarify some doubts. The standard procedure includes EUS and ERCP steps, respectively. The EUS part is as follows. i) Advance of a linear array echoendoscope and identification of the duct. Both long and short scope positions are allowed. ii) Checking for interposing vessels using Doppler. iii) EUSguided duct puncture from the gastrointestinal (GI) tract with a 22-gauge needle, which has been prepared without the stylet and purged with saline serum. iv) Aspiration of fluid (bile, pancreatic) before injection. v) Obtaining ductography: slow, careful injection of dilute contrast (with physiological saline solution [SSF]; 1:1). vi) EUS-guided colorant injection: slow, meticulous injection of dilute colorant (methylene blue plus SSF; 1:9); a total amount of 5–15mL should be enough, depending on the duct diameter. After this last step, if the ductogram is less visible, due to the dilution effect, an additional amount of contrast (3–5mL) can be injected, to ensure a well-marked “road map.” The ERCP part is as follows. A duodenoscope immediately replaces the echoendoscope. Under endoscopic view, the papillary orifice is identified by methylene blue flow and bulge effect (▶Fig. 1; ▶Video1). Finally, duct cannulation is attempted using sphinctertome wire-guided cannulation, preferably small-diameter ERCP catheters (i. e. 3.9 Fr), or using pre-cut techniques (i. e. needle-knife). This part is challenging; expertise in challenging ERCP procedures is mandatory.