An Instrumented Surgical Tool for Local Ischemia Detection.

摘要

Minimally invasive surgical procedures have improved the standard of patient care by reducing recovery time, chance of infection, and scarring. A recent review estimates that leaks occur in 3% to 6% of bowel anastomoses, resulting in "increased morbidity and mortality and adversely [affecting] length of stay, cost, and cancer recurrence"[53]. Many of these leaks are caused by ischemic tissue.;This dissertation covers the development of a surgical tool for reliable ischemia detection during routine manipulation of the tissue. The design of the tool and choice of the sensors leverages existing work in physiological measurements and surgical tool design. Detecting a change in temperature can indicate ischemic tissue. The optical absorption spectrum of a tissue can be used to detect tissue oxygen concentration and tissue ischemia. Electrical impedance of ischemic tissue changes over time due to cell swelling, closing intercellular gap junctions, and the accumulation of metabolic products [38]. Additionally, collecting simultaneous data from multiple sensors allows the computer to make a stronger decision than on just one sensor at a time. The tool includes sensors for measuring the temperature, local optical absorption spectrum, and electrical impedance of the grasped tissue, while controlling the grasp force and jaw position, thereby controlling the tool-tissue interface.;Data was collected from 9 animals and analyzed using artificial neural networks (ANN) and support vector machines (SVM). Classification results for the entire data set reached 67% for the best SVM implementation and 73% for the ANN. Classification results on each animal individually averaged 85% for the SVM and 89% for the ANN.