Robot-assisted surgery is revolutionizing the field of minimally invasive surgery, delivering a wealth of benefits to both patients and surgeons. With only visual cues provided, however, robotic surgery hinders the surgeons’ ability to perform manual palpation to identify pathological tissues, such as tumors. To address this limitation, a robotic palpation device was developed that can rapidly and non-invasively quantify the stiffness of soft tissues (i.e., elastic modulus, E), allowing surgeons to make data-driven decisions during robotic interventions.
The device comprised of three key components: i) a deployable biosensing probe that can deform local tissue for stiffness measurement, ii) a motion control module that enables multi-directional device movements, such as linear displacement, rotation, and probe deflection, and iii) a micro-optical imaging module that provides the visual information during the probe navigation. The device was tested by evaluating the stiffness of tissue phantoms and various biological tissues, such as the lung, heart, liver tissues, and tumor models.
Results show that the device can accurately determine stiffness of tissues and identify tumor mimics in tumor models. Specifically, the measured the E values were 9.1 ± 2.3, 16.8 ± 1.8, and 26.0 ± 3.6 kPa for the swine lungs under internal pressure of 2, 25, and 45 cmH2O, respectively. Moreover, the E values for swine heart, liver, abdominal skin, and muscle were measured to be 33.0 ± 5.4, 19.2 ± 2.2, 33.5 ± 8.2, and 22.6 ± 6.0 kPa, respectively, consistent with literature data. Furthermore, the device was able to locate tumor mimics (size: ~ 2 cm) embedded in subpleural regions of swine lungs with high resolution and detection accuracy. The palpation device developed in this study can be utilized as standalone or as an integrated module within existing robotic surgical systems, allowing surgeons to intraoperatively identify pathological tissues with altered stiffness.