Alja'afreh T
Department of Electrical Engineering, Mutah University, Karak, Jordan.
Proc Inst Mech Eng H. 2010;224(4):531-40. doi: 10.1243/09544119JEIM698.
This paper investigates the effect of the needle velocity on soft-tissue motion ex vivo and in vivo. In many needle-based intervention procedures, which are common minimally invasive surgical techniques, the needle can be assumed to be rigid and the tissue deforms and displaces considerably as the needle moves forwards to its target. This paper presents an energy-based fracture mechanics approach to show that the increasing needle velocity can reduce tissue motion during the insertion process. The main feature of this paper is that it extends the proposed approach to model the insertion dynamics, whereas most of the literature treats needle insertion as a quasi-static process. Ex-vivo test results on lamb heart samples show that the force required to initiate penetration decreases with increasing needle velocity up to a critical velocity, above which the rate-independent penetration force of the underlying tissue becomes the limiting factor. In-vivo tests show that increased needle velocity results in reduced force and displacement for needle insertion into the heart. Results indicate that automated insertion could substantially improve performance in some applications.
本文研究了针速度对离体和体内软组织运动的影响。在许多基于针的介入手术中，这些都是常见的微创手术技术，可以假定针是刚性的，并且当针向前移动到其目标时，组织会发生相当大的变形和位移。本文提出了一种基于能量的断裂力学方法，以表明增加针速度可以减少插入过程中的组织运动。本文的主要特点是扩展了所提出的方法来模拟插入动力学，而大多数文献将针插入视为准静态过程。对羊心脏样本的离体测试结果表明，开始穿刺所需的力随着针速度的增加而减小，直至达到临界速度，超过该速度后，下层组织的与速率无关的穿刺力成为限制因素。体内测试表明，增加针速度会导致针插入心脏时所需的力和位移减小。结果表明，在某些应用中，自动插入可以显著提高性能。
