Ottensmeyer M P, Ben-Ur E, Salisbury J K
Haptics Group, Artificial Intelligence Laboratory, MIT, Cambridge, MA 02139, USA.
Stud Health Technol Inform. 2000;70:236-42.
Current efforts in surgical simulation very often focus on creating realistic graphical feedback, but neglect some or all tactile and force (haptic) feedback that a surgeon would normally receive. Simulations that do include haptic feedback do not typically use real tissue compliance properties, favoring estimates and user feedback to determine realism. When tissue compliance data are used, there are virtually no in vivo property measurements to draw upon. Together with the Center for Innovative Minimally Invasive Therapy at the Massachusetts General Hospital, the Haptics Group is developing tools to introduce more comprehensive haptic feedback in laparoscopy simulators and to provide biological tissue material property data for our software simulation. The platform for providing haptic feedback is a PHANToM Haptic Interface, produced by SensAble Technologies, Inc. Our devices supplement the PHANToM to provide for grasping and optionally, for the roll axis of the tool. Together with feedback from the PHANToM, which provides the pitch, yaw and thrust axes of a typical laparoscopy tool, we can recreate all of the haptic sensations experienced during laparoscopy. The devices integrate real laparoscopy toolhandles and a compliant torso model to complete the set of visual and tactile sensations. Biological tissues are known to exhibit non-linear mechanical properties, and change their properties dramatically when removed from a living organism. To measure the properties in vivo, two devices are being developed. The first is a small displacement, 1-D indenter. It will measure the linear tissue compliance (stiffness and damping) over a wide range of frequencies. These data will be used as inputs to a finite element or other model. The second device will be able to deflect tissues in 3-D over a larger range, so that the non-linearities due to changes in the tissue geometry will be measured. This will allow us to validate the performance of the model on large tissue deformations. Both devices are designed to pass through standard 12 mm laparoscopy trocars, and will be suitable for use during open or minimally invasive procedures. We plan to acquire data from pigs used by surgeons for training purposes, but conceivably, the tools could be refined for use on humans undergoing surgery. Our work will provide the necessary data input for surgical simulations to accurately model the force interactions that a surgeon would have with tissue, and will provide the force output to create a truly realistic simulation of minimally invasive surgery.
当前手术模拟的研究工作常常聚焦于创建逼真的图形反馈，却忽视了外科医生通常会感受到的部分或全部触觉和力（触觉）反馈。包含触觉反馈的模拟通常不使用真实组织的顺应性特性，而是倾向于依靠估计和用户反馈来确定真实感。当使用组织顺应性数据时，实际上没有体内特性测量数据可供借鉴。触觉小组与麻省总医院创新微创治疗中心合作，正在开发工具，以便在腹腔镜模拟器中引入更全面的触觉反馈，并为我们的软件模拟提供生物组织材料特性数据。提供触觉反馈的平台是由 SensAble Technologies 公司生产的 PHANToM 触觉接口。我们的设备对 PHANToM 进行补充，以实现抓握功能，并可选择提供工具的滚转轴功能。结合 PHANToM 提供的典型腹腔镜工具的俯仰、偏航和推力轴反馈，我们能够重现腹腔镜手术过程中体验到的所有触觉感受。这些设备集成了真实的腹腔镜工具手柄和一个顺应性躯干模型，以完善视觉和触觉感受。已知生物组织具有非线性力学特性，并且从活体移除后其特性会发生显著变化。为了测量体内特性，正在开发两种设备。第一种是小位移一维压头。它将在很宽的频率范围内测量线性组织顺应性（刚度和阻尼）。这些数据将用作有限元模型或其他模型的输入。第二种设备将能够在更大范围内使组织进行三维偏转，从而测量由于组织几何形状变化引起的非线性。这将使我们能够验证模型在大组织变形情况下的性能。这两种设备都设计为可通过标准的 12 毫米腹腔镜套管针，并且适用于开放手术或微创手术。我们计划从外科医生用于训练目的的猪身上获取数据，但可以想象，这些工具经过改进后可用于接受手术的人类患者。我们的工作将为手术模拟提供必要的数据输入，以便准确模拟外科医生与组织之间的力相互作用，并将提供力输出，以创建真正逼真的微创手术模拟。
