A stiffness probe for soft tissue abnormality identification during laparoscopic surgery

this paper presents a smart, novel stiffness probe capable of detecting the abnormality within soft tissue during minimally invasive surgery. The proposed probe is based on force-contact area feedback of target soft tissue. A prototype for validating the concept was developed. The prototype comprises a force/torque sensor, a probe with a transparent round head and a digital camera capturing contact area of probe-tissue interaction during indentation test. By measuring the change of contact area, the indentation depth can be estimated. The stiffness then can be evaluated by measuring indentation force and depth simultaneously. The probe can also generalize a mechanical image to help a surgeon identify embedded tumors when sliding over soft tissue. The performance of the developed probe was validated by tests of uniaxial tissue indentation and sliding tissue indentation on silicone phantoms and pork organs. A comparative study of the proposed probe with manual palpation was conducted. The results show that the robe can perform stiffness measurement effectively when the probe indents and slides on the tissue surface. Due to the small size of the probe it can be employed during minimally invasive surgery to reach tissue surfaces where the manual palpation is prevented by the restricted access.