Design of Force-Sensing Sleeve for Minimal Access Surgical Instruments

Due to the nature of Minimal Access Surgery (MAS), surgeons are faced with multiple challenges including: (1) lack of direct hand-eye coordination, (2) loss of depth perception, (3) fixed access points, (4) long surgical instruments, and (5) reduced access to the surgical site. These challenges ultimately affect the surgeon's ability to sense the forces between the laparoscopic instrument and tissue. Improper force control can lead to poor clinical outcomes such as tissue necrosis, infection, and scarring. Currently, minimal literature exists on the benefit of force metrics in training and clinical environments. Moreover, existing MAS force-sensing technologies prevent researchers and surgeons from conducting extensive MAS force studies due to their limited applications in MAS training or the operating room, and/or complex manufacturing processes. This thesis work describes the design of a novel force sensor for a broad range of standard MAS instruments and procedures. The proposed Force-Sensing Sleeve (FSS) design utilizes a flexible printed circuit and multiple strain gauges to determine distal instrument forces from mechanical deformations measured in the MAS tool's exterior shaft. The FSS acts as a minimally disruptive add-on and can be applied to standard MAS instruments in a simple and low-cost assembly process. A supporting-system for the FSS was also developed to provide the full force-sensing solution capable of wirelessly measuring, logging, and displaying force data in real-time. A standard MAS needle holder was equipped with the FSS system and tested in a realistic surgical training environment of the most complex Fundamentals of Laparoscopic Surgery (FLS) task (Intracorporeal Suture Knot Task (ISKT)); this proof of concept study's preliminary findings demonstrated the potential use of ISKT mean force measurements as a first approximation of surgical expertise, however more sophisticated dynamic force metrics are likely required for the further classification of surgeon expertise. The FSS system's ability to leverage existing operating room instruments and potential to be used in both standardized MAS training programs and surgical environments creates the opportunity for extensive force investigations in standard MAS tasks to determine how force metrics can benefit the surgical community and enhance patient safety and care.Ph.D