Preventing Tissue Damage

Abstract:

Robot-assisted minimally invasive surgery (RMIS) has many benefits for patients. Compared to open surgery during which surgeons to feel the tissues directly by hands, all the instruments used in RMIS are long and narrow, inserted through narrow cannulae placed at the abdominal wall, eliminating touch sensation of tissue. Loss of haptic feedback in RMIS is a major limitation to surgeons since extensive applied force due to the lack of haptic feedback may cause unrecognized tissue damage, which could be more complicated in consideration of the various interface pattern between tissue and instrument. The research seeks to develop an approach with which 1) the forces applied to the soft tissue would be predicted without using force sensors; and 2) tissue damage magnitude and grasp quality could be estimated for a wide range of grasper-tissue interaction.

Affiliated Students and Faculty: Levi Cheng, Blake Hannaford

Figures:

Figure 1. Tissue damage due to extensive grasping force [2].
Figure 1. Tissue damage due to extensive grasping force [2].
Figure 2. Illustration of center cut plane (blue area) in full 3D model. Red areas illustrate the tissue while grey solid illustrates the grasper. [1].
Figure 2. Illustration of center cut plane (blue area) in full 3D model. Red areas illustrate the tissue while grey solid illustrates the grasper. [1].
Figure 3. Hepatic necrosis (percent) in liver versus applied stress (kPa) [2,3].
Figure 3. Hepatic necrosis (percent) in liver versus applied stress (kPa) [2,3].
Figure 4. Geometries for different graspers we studied. R refers to radius of curvature and refers to pitch size. Grasper width= 5mm, height=2mm, tooth angle α=60 degree [1].
Figure 4. Geometries for different graspers we studied. R refers to radius of curvature and refers to pitch size. Grasper width= 5mm, height=2mm, tooth angle α=60 degree [1].
Figure 5. Zoomed contour of computed necrosis distribution. Deformation is not shown. Scale is in percent. Areas with percentage of necrosis more than 10% are shown in wine red [1]
Figure 5. Zoomed contour of computed necrosis distribution. Deformation is not shown. Scale is in percent. Areas with percentage of necrosis more than 10% are shown in wine red [1]

Publications:

[1] L Cheng, B Hannaford. Evaluation of Liver Tissue Damage and Grasp Stability Using Finite Element Analysis. Computer Methods in Biomechanics and Biomedical Engineering. In press, 2014.

[2] S De, J Rosen, A Dagan, B Hannaford, P Swanson, M Sinanan. Assessment of tissue damage due to mechanical stresses. International Journal of Robotic Research, 26:1159–1171, 2007.

[3] S De. The Grasper-Tissue Interface in Minimally Invasive Surgery: Stress and Acute Indicators of Injury. Ph.D. Thesis, University of Washington, 2008.

[4] J Rosen, JD Brown, S De, M Sinanan, B Hannaford. Biomechanical properties of abdominal organs in vivo and postmortem under compression loads. Journal of Biomedical Engineering, 130(2): 021020, 2008.