Development of a Novel Fistula Occlusion Device

Abstract

Fistulas are a pathological tunnel between two hollow organs or an organ and the skin. There is currently no gold-standard for treatment as invasive surgical procedures carry significant morbidity, and potential for failure; many patients are also not surgical candidates due to comorbid conditions. Patients’ with fistulas have high mortality rates and a poor quality of life. The goal of this thesis was to develop a prototype and computational model of a minimally invasive fistula occlusion device. The prototype was designed to be an electromagnetic catheter that could deliver a glue plug to a precise location. It used a solenoid to control the magnetic field and plug delivery. The design of the prototypes went through several stages before arriving at the final construction. Various materials were attempted for the solenoid core and a range of wire sizes for the copper coil. The final manufacturing process involves alternating coats of iron paint and iron wire for the core with a copper wire coil. Horizontal and vertical magnetic force experiments were conducted to analyze the effects of core size. Three different sized cores were built to determine how much iron was needed to achieve a clinically relevant magnetic force. It was demonstrated that it is possible to achieve the necessary force using hollow solenoids. A computational model was built in MATLAB so that the researchers could analyze a greater range of design parameters moving forward. Validation and verification of the model has shown magnetic field shapes consistent with solenoid theory. The results of this study indicate that the ideas presented in the preliminary patent filed in July of 2015 are feasible. Further refinement is necessary to create the final device to be used in patients but it is possible to develop an electromagnetic catheter to control small plugs for fistula repair.