DESIGN OF A HANDLE TO CONTROL A MULTIFUNCTIONAL FORCEPS FOR USE IN ENDOSCOPIC SURGERY

Open Access
Author:
Mansley, Ryan Edward
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Mary I Frecker, Thesis Supervisor
  • James Gordon Brasseur, Honors Advisor
Keywords:
  • Endoscope
  • Multifunctional
  • Forceps
  • Handle design
  • Natural Orifice Transluminal Endoscopic Surgery
  • NOTES
  • Minimally Invasive Surgery
  • MIS
  • Endoscopic Surgery
Abstract:
Minimally Invasive Surgery (MIS) has proven itself to be accompanied by many benefits. Natural Orifice Transluminal Endoscopic Surgery (NOTES), a new MIS technique currently under development, has the potential to further many of the benefits of MIS. NOTES procedures involve inserting an endoscope into a natural orifice, then puncturing the wall of a hollow organ to access a surgical site in the abdominal cavity. One such technique for accessing the abdominal cavity is Self-Approximating Transluminal Access Technique (STAT). STAT has been shown to improve the feasibility of many NOTES procedures. However, due to inadequacies in the available endoscopic tools, a significant amount of time is required to perform STAT. A multifunctional endoscopic forceps with improved tissue spreading capabilities was designed with the goal of decreasing the time required to perform STAT. Due to the novel design of the forceps, a handle needed to be designed which was capable of properly operating the forceps. This thesis presents the design of such a handle. Two sets of wires were attached to the forceps, and the forceps were designed to be operated by manipulating these sets of wires. The handle needed to be capable of properly manipulating these two sets of wires. Multiple design concepts were created, and the ability of each to satisfy certain design requirements was assessed, using a decision matrix, in order to choose the concept which was most appropriate for the handle. The concept chosen employed a slider-crank mechanism to transfer linear motion of the surgeon’s thumb into rotational motion of a segment which was attached to the two sets of wires. Based on this concept, a detailed design of the handle was created and a prototype was constructed. Kinematic analyses of the forceps and handle were used to determine the necessary values of key parameters when creating the detailed design. The performance of the prototype was analyzed experimentally. The prototype was shown to be capable of properly operating the forceps, but the maximum opening angle of the forceps would be slightly smaller than is desired. This was shown to be caused by inaccuracies which occurred during construction of the prototype. Using alternative fabrication methods or modifying the design could potentially reduce these inaccuracies and increase the maximum opening angle of the forceps to its desired value. Testing of the prototype also showed that the mechanical advantage of the handle is greater than one. This is an improvement over the handles of commercially available endoscopic forceps which cannot have a mechanical advantage of greater than one. Based on the performance of the prototype, prospective refinements to the design were presented.