Development of a liquid drug delivery payload for modular, wireless, incorporeal robots for laparoscopic surgery

Abstract

Minimally invasive abdominal surgery (laparoscopy) is performed using long, slender instruments inserted through multiple small incisions in the patient's abdominal wall. This results in less post--operative pain, shorter hospital stays, and a quicker return to normal activities for the patient compared to conventional open surgery; however, the use of small entry incisions provides only limited access to the surgical site compared to conventional open surgery. Robotic systems have been developed that overcome some limitations with laparoscopic surgery. The systems, however, are very high cost, provide limited benefit to the patient, and do not completely address limited access issues and the need for multiple incisions. New techniques, such as single--port laparoscopic and natural orifice surgery, reduce the number of entry incisions but still provide only limited access to the surgical site. An innovative solution that potentially overcomes both limitations is to insert miniature robotic assistants entirely inside the abdominal cavity through a single incision where they can be readily relocated as needed. Previous work has demonstrated that a family of fixed--base and modular, wireless, intracorporeal, mobile robots can successfully monitor physiological conditions, perform biopsies, staple and clamp tissue, and provide visual feedback within the abdominal cavity. Current robots do not have the ability to store or dispense liquids such as hemostatic agents. The use of hemostatic agents, such as fibrin sealants, instead of mechanical or electrical means of hemostasis alleviates the extensive training required for laparoscopic suturing, the nerve damage accompanying staples or tacks, and the need for a relatively large energy source for electrocautery tools and harmonic scalpels. An incorporeal robot capable of carrying and delivering liquids would combine the advantages of incorporeal mobile robots and liquid hemostatic agents. The main focus of this thesis is the development of a liquid delivery payload for a family of incorporeal robotic assistants. Included in this development is a method for mixing two liquids stored inside the robot as they are dispensed, which is needed for dual compound liquids such as fibrin sealants. Finally, two improvements to the design of the control electronics are presented that allow for more rapid robot deployment and provide the ability for point of use changes to the embedded control software