WASP: a Wasp-inspired Surgery needle for Prostate cancer procedures

Design and prototyping of a low-friction actuation mechanism

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Abstract

Prostate cancer is the second most frequently diagnosed cancer in men. A minimal invasive treatment for prostate cancer is transperineal laser ablation (TPLA), which involves inserting a needle containing a laser fibre into the prostate to induce local cell death. The ovipositor of the parasitoid wasp offers a solution to challenges in TPLA, as the wasp can penetrate substrates with zero net external force, minimising the buckling risk and tissue damage. This paper presents the WASP, a design and prototype of a manually actuated needle for TPLA. The actuation mechanism of the WASP transfers a torque while allowing a low-friction translation in the positive y-direction, enabling the needle to travel through stationary tissue. An integrated cam mechanism allows repetitive motion of the needle rods actuated by a single rotation of the urologist. Evaluation of the WASP showed successful travelling through gelatin concentrations up to 15 wt%, a stiffness comparable to human tissue. The WASP generated a small net push force (Fpush = 0.18 N) and cannot be considered fully self-propelling. Nonetheless, the net push force is notably reduced compared to manual needle insertion and effectively prevents buckling. A performance experiment showed a lower average slip ratio compared to previous studies, which may suggest that a small net push force is beneficial if buckling is prevented. Future steps contain implementing user research and a steering mechanism, to continue innovating minimally invasive surgery for prostate cancer.