EUS-guided Choledocho-duodenostomy (ECD) for immediate and long-term treatment of biliary obstruction using prototype PathCreator™ compression coil and twin-headed needle

Background: We previously reported our initial feasibility canine study for ECD using a novel EUS-guided coil technique (PathCreator™). While placement of the coil through the duodenum into the dilated common bile duct (CBD) with subsequent biliary drainage using a short stent for immediate drainage, and formation of a choledocho-duodenostomy fistula was shown to be possible (successful in 1/6), substantial design modifications were necessary to maximize safety and efficacy. Parameters to be addressed included: 1) consistent fistula formation, 2) avoid bile leak, 3) prevent coil extrusion into CBD, 4) immediate biliary drainage without need for stenting. To this end, several reiterations resulted in the current “fin-coil” configuration and specifications. In addition, a prototype “twin-headed” needle was developed for immediate biliary drainage. The aim of this animal study was to determine the efficacy and safety of the modified PathCreator™ coil and the twin-headed needle for ECD.

Methods: Four male dogs (Beagle) 9–15kg were used in this survival protocol; ligation of CBD was performed 10 days prior to ECD. ECD was accomplished as follows: The prototype coil delivery device (19g needle pre-loaded with stretched coil in the lumen, Olympus Medical Systems Corp) was advanced through a duodenostomy and the dilated CBD was visualized by EUS. EUS-guided needle puncture into the dilated CBD was followed by deployment of 50% of the coil into CBD, and remaining 50% stayed within the duodenal bulb to hold CBD and duodenum walls tightly with its compressive force. A 15g twin-headed needle was used to create a transmural hole through the center of the compressed coil for immediate biliary drainage. Survival assessment included serial clinical assessment, WBC, and LFT's. Two dogs were sacrificed at 4 weeks with termination autopsy/histology. The other two dogs continue to be in the survival assessment (currently at week 13 of 26).

Results: All animals survived per protocol without complications. Immediate drainage was successful in 3/4 (determined by immediate decrease and subsequent normalization of serum bilirubin), with over-all drainage (normalization of bilirubin) successful in 4/4. Creation of a chronic fistula between CBD and duodenum was achieved in all 4 dogs. There was no evidence of bile leak or perforation. All coils dislodged successfully into the duodenum. The two on-going dogs remain stable at 13 weeks.

Conclusions: This canine study showed that further refinements in the prototype PathCreator™ coil and twin-headed needle resulted in successful ECD (biliary drainage and fistula formation) in all 4 animals. Final pre-clinical trials will follow.