SUN-336 A NEW KIDNEY BIOPSY DEVICE PROTOTYPE WITH HAEMOSTATIC FUNCTION

Abstract

Native kidney biopsy is currently the gold standard to diagnose kidney disease. However, it is not routinely performed because of a 5% risk of severe bleeding, due to inadvertent puncture of small and micro renal vasculature. This could lead to complications such as requirement for blood transfusion, embolization, partial nephrectomy and death. We aimed to design and develop a radical new kidney biopsy device with concurrent haemostatic function to plug the biopsy tract immediately following needle withdrawal. We had investigated different engineering specifications and models of the biopsy device, such as needle dimensions and geometry, friction between needle and tissue, needle stiffness, spring constant, volume of haemostatic agent, volume of tissue collecting site and velocity of the outer needle. We developed a prototype and then evaluated it on various simulation models. We used commercially available haemostatic agent AristaTM AH (C.R. Bard, Inc. USA) for the testing for the biopsy device. We developed three conceptual biopsy device designs (A: rotatable inner needle, B: double inner needles and C: separate drug channel). The design A (Figure 1) was selected into the final prototype development. In this design, the biopsy instrument consists of an outer needle, inner needle, and a push rod. There is a semi-cylindrical opening near the distal of the outer needle, which facilitates entry of tissue after insertion into targeted position. The inner needle is coaxially placed in the outer needle. The end of the inner needle is a cavity, which is used to store the tissue sample. Relative motion of the outer needle and the inner needle form an end-cut. When sampling is completed, an opening on the inner tube can be exposed by rotating the inner needle 180 degrees, and haemostatic agents stored in the inner needle released by pushing the rod. Figure 1: Design A: The delivery mechanism of the haemostatic agent employs a rotatable inner needle. A prototype (Figure 2) had been developed, and verification tests with regards to the tensile force of the spring and testing on various simulation models had been carried out. The ability to extract sample and release haemostatic agent was 85% and 100% in ex vivo porcine liver, and 100% and 80% in ex vivo porcine kidney. Figure 2: Prototype of the biopsy device. We had designed and developed a new kidney biopsy device prototype with the ability to plug the biopsy tract immediately with haemostatic agent following biopsy. We have filled the patent (application no: 10201801487V) with the Intellectual Property Office of Singapore. Further testing in live animal would be carried out to improve the design of the biopsy device before conducting any human studies.