The BlueDRAGON

The UWEE BioRobotics Laboratory colaborating with the Center of Video Endoscopic Surgery at the Department of Surgery are developing tools to help teach Minimally Invasive Surgery (MIS) techniques and objectively evaluate surgical skill while using these techniques.

MIS has been practiced on a large scale for about 10 years in the United States. MIS replaces traditionally more invasive procedures for common operations such as gall bladder removal, and provides tremendous benefits for patients. Unlike traditional surgery, which involves making large incisions in the patient to accommodate the surgeons hands, MIS incisions consist of small ports, through which long tools and a camera are inserted. Because of these smaller incisions, patient recovery times are much shorter: 1-2 days instead of 1-2 weeks with traditional surgery. The shorter recovery times and decreased incidence of complications result in reduced healthcare costs.

The differences between MIS and more traditional invasive techniques present a unique set of challenges for training surgeons. In MIS procedures, surgeons lack direct physical contact with patients, making it difficult to gauge the appropriate amount of force and torque to apply during the operation. Surgeons also lack a direct line of sight, watching their progress through images projected onto a television from a tiny camera inserted into the patient. Consequently, teaching by expert surgeons necessarily becomes more abstract, and evaluations of student progress more subjective. Currently expert surgeons evaluate progress by commenting on videotapes of procedures done by young surgeons. Still another challenge is distinguishing between technical skills and cognitive development of young surgeons. For example, if a procedure has 6 steps in it, and an inexperienced surgeon is having problems completing the operation effectively, is it due to a lack of surgical skill, or is it because they have a hard time remembering the precise sequence of steps 3? Current training techniques make it difficult to evaluate these kinds of questions.

The sensors incorporated into the Blue DRAGON collect large amounts of data on the mechanical forces and torues exerted by the surgeons and the position and oriantataion of the surgical tools in space. The data is evaluated using statistical techniques, including Hidden Markov modeling. Data collected data from expert and inexperienced surgeons, who operated on an animal model system created a quantitative basis for comparing their respective skill levels. Comparing data generated by surgeons of different levels of expertise provides a more objective method of evaluating skill level and progress.

The BlueDRAGON system integration into a minimally invasive surgery setup

Preliminary data revealed some interesting facts about development of surgical skills. Most improvement in technique was achieved during the first 2-3 years of the 5-year surgical residency. After that point, technical progress increases less dramatically and cognitive skills develop more fully. The EE researchers and their collaborators in the department of surgery are currently planning a longitudinal study of surgical residents in the department of surgery.

MIS may be viewed as a language spoken by surgeons. Decomposing surgery into its fundamental elements is the key issue in understanding its meaning and developing tools to assess surgical skill level. Using the human language as an analogy the basic 'words' of MIS are the different tool-tissue interactions (e.g. grasping or cutting, grasping and pulling, sweeping and spreading etc.). Analyzing hours of MIS videotapes frame-by-frame revealed 15 different ways of interactions between the surgical tool and the tissue that can be defined as the fundamental 'words' in the surgical 'dictionary'.

Moreover, since two surgical tools are being used surgery can view as a dialogue between the two tools rather than a monologue. In the same way as a single word is pronounced differently by different people, the same tool-tissue interaction is performed differently by different surgeons, yet they all share the same meaning, or outcome, as in the realm of surgery. Utilizing the
'dictionary' of surgery, the models are then used to define the process of each step of the surgical procedure, or in other words, 'dictating chapters' of the surgical 'story'. Expert surgeons and novice surgeons are telling us a story as they perform a MIS. Selecting the appropriate words and the various pronunciations can quantitatively differentiate the skill level of an expert surgeon from a novice one. This methodology for objectively evaluate surgical skills in MIS can be implemented in various modalities such as surgical robots, simulators and real MIS in a training setup.

Blake Hannaford, Jacob Rosen, and Mika Sinanan recently received a 4-year, $1.4 million grant to develop minirobots that perform telesurgery on the
battlefield.

EEK 2002 - Electrical Engineering Kaleidoscope - Annual research review. [PDF - 1.3MB]