Biomechanical Characteristics of Internal Organs' Soft Tissues - In-Vivo measurements in minimally Invasive Surgery

 

Accurate knowledge of biomechanical characteristics of tissues is essential for developing realistic computer-based surgical simulators incorporating haptic feedback, as well as for the design of surgical robots and tools. As simulation technologies continue to be capable of modeling more complex behavior, an in vivo tissue property database is needed. Most past and current biomechanical research is focused on soft and hard anatomical structures that are subject to physiological loading, testing the organs in situ. Internal organs are different in that respect since they are not subject to extensive loads as part of their regular physiological function. However, during surgery, a different set of loading conditions are imposed on these organs as a result of the interaction with the surgical tools.

Following previous research studying the kinematics and dynamics of tool/tissue interaction in real surgical procedures, the focus of the current study was to obtain the structural biomechanical properties (engineering stress-strain and stress relaxation) of seven abdominal organs, including bladder, gallbladder, large and small intestines, liver, spleen, and stomach, using a porcine animal model. The organs were tested in vivo, in situ, and ex corpus (the latter two conditions being postmortem) under cyclical and step strain compressions using a motorized endoscopic grasper and a universal-testing machine. The tissues were tested with the same loading conditions commonly applied by surgeons during minimally invasive surgical procedures. Phenomenological models were developed for the various organs, testing conditions, and experimental devices.

A property database—unique to the literature—has been created that contains the average elastic and relaxation model parameters measured for these tissues in vivo and postmortem. The results quantitatively indicate the significant differences between tissue properties measured in vivo and postmortem. A quantitative understanding of how the unconditioned tissue properties and model parameters are influenced by time postmortem and loading condition has been obtained. The results provide the material property foundations for developing science-based haptic surgical simulators, as well as surgical tools for manual and robotic systems.

Ex-corpus testing of the stress/strain of a liver (pig) under compression loads (MTS Machine)

InVivo testing of the stress/strain of a spleen (pig) under compression loads using an endoscopic grasper (Babcock grasper) by Stortz attached to the MEG (Motorized Endoscopic Grasper) - The graphical user interface of the MEG is depicts at the background

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Device

Force Reflecting Endoscopic Grasper (FREG)
Motorized Endoscopic Grasper (MEG)
MTS Machine

| Status: Completed |

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PUblications

(*) Note: Most of the Bionics Lab publications are available on-line in a PDF format. You may used the publication's reference number as a link to the individual manuscript.

[ JP18] Rosen Jacob, Jeffrey D. Brown, Smita De, Mika N. Sinanan Blake Hannaford, Biomechanical Properties of Abdominal Organs In Vivo and Postmortem Under Compression Loads, ASME Journal of Biomedical Engineering, Vol. 130, Issue 2, April 2008

[ JP1] MacFarlane Mark, Jacob Rosen, Blake Hannaford, Carlos Pellegrini, Mika N. Sinanan, Force Feedback Grasper Helps Restore the Sense of Touch in Minimally Invasive Surgery, Journal of Gastrointestinal Surgery, Vol. 3, No. 3, pp. 278-285, May/June 1999.

[ JP2] Rosen Jacob, Blake Hannaford, Mark MacFarlane, Mika N. Sinanan, Force Controlled and Teleoperated Endoscopic Grasper for Minimally Invasive Surgery - Experimental Performance Evaluation, IEEE Transactions on Biomedical Engineering, Vol. 46, No. 10, pp. 1212-1221, October 1999.

[ CP2] Hannaford B., J. Trujillo, Mika N. Sinanan, M. Moreyra, Jacob Rosen, J. Brown, R. Lueschke, Mark MacFarlane, Computerized Endoscopic Surgical Grasper, Studies in Health Technology and Informatics - Medicine Meets Virtual Reality, Vol. 50, pp. 265-271, IOS Press, January 1998.

[ CP9] Brown Jeffrey D., Jacob Rosen, Manuel Moreyra, Mika N. Sinanan, Blake Hannaford, 'Computer-Controlled Motorized Endoscopic Grasper for In Vivo Measurements of Soft Tissue Biomechanical Characteristics,' Studies in Health Technology and Informatics - Medicine Meets Virtual Reality, vol. 85, pp. 71-73, IOS Press, January 2002.

[ CP12] Brown Jeffrey D., Jacob Rosen, Yoon Sang Kim, Lily Chang, Mika N. Sinanan, Blake Hannaford, In-Vivo and In-Situ Compressive Properties of Porcine Abdominal Soft Tissues, Studies in Health Technology and Informatics - Medicine Meets Virtual Reality, vol. 94, pp. 26-32, IOS Press, January 2003.

[ CP13] Brown Jeffrey D., Jacob Rosen, M. N. Sinanan, Blake Hannaford, In-Vivo and Postmortem Compressive Properties of Porcine Abdominal Organs, Lecture Notes in Computer Science, Volume 2878 / 2003, pp. 238 –245, Medical Image Computing and Computer-Assisted Intervention - MICCAI 2003, Toronto, Canada.

[ CP15] Brown Jeffrey D., Jacob Rosen, Lily Chang, Mika N. Sinanan, Blake Hannaford, Quantifying Surgeon Grasping Mechanics in Laparoscopy Using the Blue DRAGON System, Studies in Health Technology and Informatics - Medicine Meets Virtual Reality, vol. 98, pp. 34-36, IOS Press, January 2004