Integration of optical applicator with balloon catheter for photothermal treatment of biliary stricture.

Abstract

Bile duct stricture is an uncommon disease in gastroenterology resulting from postoperative trauma. In spite of non-surgical treatments, clinical outcomes for the biliary strictures still encounter high restenosis and stent migration. The objective of the current study was to investigate the feasible application of a balloon catheter-integrated diffing applicator to thermally treat the bile duct stricture. 400-μm optical fibers were micro-machined and then integrated with an inflatable balloon catheter. The fabricated applicator was tested on porcine bile ducts with 20-W 980 nm laser light for 60 s, and a thermal camera was used to measure thermal response of the tissue. Due to mechanical pressure, the inflated balloon was able to expand the tissue lumen up to 6 mm in diameter. Compared to control, the inner area of the treated tissue was increased by four fold (i.e., 2.74±0.05 mm2 for treated vs. 0.73±0.14 mm2 for control) during the balloon catheter-assisted laser irradiation. The laser-induced tissue temperature reached up to 80.1±6.4 °C (thermal gradient = 1.2 °C/s). A thin layer of coagulation necrosis (0.5±0.1 mm) consistently formed around the lumen. The proposed balloon catheter-integrated diffusing applicator can be a feasible minimally invasive device to photothermally treat the obstructive bile ducts. Lasers Surg. Med. 49:781-786, 2017. © 2017 Wiley Periodicals, Inc.