Method to Reduce Target Motion Through Needle–Tissue Interactions

Abstract

During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.

Minimally disruptive needle insertion: a biologically inspired solution

“…Replicating the experiments with FE models may present an efficient way of optimizing motion profile parameters. Three-dimensional findings presented here can be used to further develop FE models (as presented in [21]) that realistically capture the interactions associated with fracture, as well as friction. The anchoring effect could also be enhanced by increasing directional frictional resistance of the outer needle surface, e.g.…”

“…As one segment was pushed forward, the remaining three segments were pulled backwards (figure 1b, bottom). The amount of pullback ( p) was empirically set to 30%, as it was shown to offer a good compromise between reduced tissue motion and higher individual segment speed [21]. Each cycle began with the leading segment moving forward, followed by the segment lying opposite, and so forth.…”

“…Subsequently, FE simulations, supported by single-plane measurements obtained with the same set-up as in [20], were developed to demonstrate reduced target motion due to varied insertion parameters in a previous study [21].…”

Experimental validation of curvature tracking with a programmable bevel-tip steerable needle

“…The experimental trials demonstrate how the assumption that PBNs are able to track references of curvature that describe curves in three-dimensional space is valid. It also demonstrate that steering can be achieved without duty-cycle spinning along the insertion axis, which was previously shown to be advantageous in terms of reduced tissue deformation and target motion [5]. Furthermore, this work presents, for the first time, an experimental validation of the relationship between the curvature of the catheter and the relative offset between segments, during a 3D insertions.…”

“…With the exception of "the Programmable Bevel-Tip" Needle (PBN) design, steering is performed using a combination of pushing and rotation of the needle along the insertion axis, Conversely, PBNs exploit a biologically inspired design that reproduces the multi-segment ovispositor (or egg laying channel) of certain parasitic wasps. In its current embodiment, the needle is made of plastic and can steer in three dimensions without duty-cycle spinning along the insertion axis, which has recently been shown to significantly reduce tissue deformation as a result of the insertion process [5], [6].…”