Wireless Tissue Palpation
In minimally invasive and robotic surgery the surgeon has minimal, or no, chance to leverage tactile and kinesthetic sensations in exploring non-visible organ features to detect hidden tumor margins or to prevent accidental tissue damage. Since registration with preoperative imaging is not effective for soft tissues, restoring tactile sensations would be crucial to guide a complete resection of tumoral masses without sacrificing excess normal tissue. One of the main barriers to adoption for laparoscopic instruments with embedded force and/or tactile sensors developed so far can be identified as the need for a dedicated surgical access port for the palpation device. We propose a wireless approach to intraoperative palpation that does not require port space.
The proposed approach takes advantage of an external magnetic field source and an intraoperative wireless palpation device (WPD). The WPD can be introduced into the peritoneal cavity through a standard trocar and positioned on the target by a laparoscopic grasper. Then, tissue indentation can be achieved by properly modulating the gradient of the external magnetic field.
The WPD is a cylindrical capsule with a diameter of 12.7 mm (compatible with access through a standard trocar for 12 mm instruments) and a length of 27.5 mm. Inside the WPD, a wireless microcontroller transmits the measurements acquired by a triaxial accelerometer and a set of magnetic field sensors. These data are used to derive tissue indentation depth and pressure, thus obtaining the elastic module of the tissue being palpated. The WPD also embeds a permanent magnet that is coupled with an external source of magnetic field that modulate the indentation force.
M. Beccani, C. Di Natali, C. E. Benjamin, C. S. Bell, N. E. Hall, P. Valdastri, “Wireless Tissue Palpation: head characterization to improve tumor detection in soft tissue”, Sensors and Actuators: A Physical, 2015, Vol. 223, pp. 180-190. [ PDF]
M. Beccani, C. Di Natali, L. Sliker, J. Schoen, M. E. Rentschler, P. Valdastri, “Wireless Tissue Palpation for Intraoperative Detection of Lumps in Soft Tissue”, IEEE Transactions on Biomedical Engineering, 2014, Vol. 61, N. 2, pp. 353-361. [PDF][ COVER ]
X. Wang, C. Di Natali, M. Beccani, M. Kern, P. Valdastri, M. Rentschler, “Novel Medical Wired Palpation Device: A Device Validation Study Of Material Properties”, Transducers 2013, Barcelona, Spain, pp. 1653-1658. [ PDF ]
M. Beccani, C. Di Natali, M. E. Rentschler, P. Valdastri, “Wireless Tissue Palpation: Proof of Concept for a Single Degree of Freedom”, IEEE International Conference on Robotics and Automation (ICRA) 2013, Karlsruhe, Germany, pp. 703-709. [ PDF ]
M. Beccani, C. Di Natali, M. Rentschler, P. Valdastri, “Uniaxial Wireless Tissue Palpation Device for Minimally Invasive Surgery”, ASME Design of Medical Devices Conference, April 2013, Minneapolis, Minnesota, ASME Journal of Medical Devices, Vol. 7, N. 2, 020919 (3 pp). [ PDF ]