Our prototype – an expandable drainage catheter that operates via a microhydraulic system – has the ability to be increased to the desired size inside the body without having to remove it resulting in a small incision size. The syringes can push/draw water which pushes/pulls the panels through a piston mechanism in the inner lumen of the catheter, which expands/reduces the catheter size. This one catheter is able to be any size between 10-24FR.
Benign biliary strictures occur when there is a narrowing of the bile duct, and when left untreated, can lead to serious issues such as sepsis and cholangitis. The current protocol involves an initial placement of a catheter in the bile duct. A series of follow-up procedures are then required to exchange the catheter for a larger size each time. This entails significant time and money. Furthermore, certain risks are associated with this procedure including losing access site to the stricture, repeated exposure to anesthesia and radiation, and potential infection due to large incision sites.
cathSPANSION aims to create a biliary catheter that expands internally to replace the current dilation process. The catheter’s expansion is localized to the site of the stricture allowing for the incision site to remain small. Using cathSPANSION consists of an initial surgery to place the catheter in the bile duct. Subsequent procedures can be performed at the patient’s doctor’s office by attaching a syringe to the percutaneous portion of the catheter and injecting a set amount of fluid to initiate a 2 FR (0.67mm) expansion per visit. Once the patient is ready for removal, the fluid in the microhydraulic piston will be removed, causing the catheter to collapse. Verification and validation testing was performed on the 9.5x scale model. When converted to the actual size, testing verified an expansion from 10FR to 24Fr and that 0.2 mL of water caused an expansion of 2 FR.
cathSPANSION simplifies the procedure for treating benign biliary strictures by requiring eight fewer surgeries, saving at least 500 minutes, and reducing the risk of infection. Future work includes expanding the application of cathSPANSION to other areas of the body and procedures.