When using simulations to determine electrode geometry and energy deposition patterns for TURP devices, a dominating factor for consideration is the tissue resection rate of the proposed system. While it is well understood that the vaporization of biological tissue is the mechanism of tissue division, previous models have been unable to match experimental results for a given applied power. Whether modeled as direct tissue/electrode contact or through the spatial transform of arcing, the predicted division rate was significantly lower than that observed though experiment. For the present study, heating rate was again used to determine the vaporization rate during the resection. This model assumes that in order for the wire loop to advance not all of the tissue in front of the electrode must be vaporized but the centerline of the advance must have sufficient energy deposited to divide the tissue. Integrating the volumetric energy deposition rate along this centerline in front of the advancing electrode provides a comparison to the required vaporization energy density resulting in a predicted time necessary for reaching the tissue division threshold. Using the simulation results for a standard TURP electrode and various power settings, five cases were compared to experimental results using in vitro bovine prostate tissue. Each tested at three cutting rates, evaluating the ability to advance through the tissue. The simulation predicted tissue division rates in good agreement with those seen via experiment, although the predicted values biased slightly higher suggesting that further mathematical model refinements are necessary.

Date Published: 26 February 2013
PDF: 7 pages
Proc. SPIE 8584, Energy-based Treatment of Tissue and Assessment VII, 85840A (26 February 2013); doi: 10.1117/12.2006426

Published in SPIE Proceedings Vol. 8584:
Energy-based Treatment of Tissue and Assessment VII
Thomas P. Ryan, Editor(s)