22 Characterization of Ceramic Electrosurgical Tools

Faculty Mentor: Taylor Sparks (Materials Science & Engineering, University of Utah)

Electrosurgery enables many possibilities in today’s surgical fields. The devices being tested dissect and separate tissues through minimally invasive incisions while intending to minimize bleeding and trauma. Developed by Excelsior-SST, the proposed device family, named Bead-Enhanced Electrosurgical Dissectors (BEED), connects to an electrosurgical generator (ESG) through a monopolar connector cable. Each device consists of an electrified metal electrode encased and recessed within a ceramic tip. The ceramic materials in the device tip, made of Yttria Stabilized Zirconia (YSZ), are herein characterized and reported to meet medical safety standards. The manufactured ceramics produce a metastable tetragonal phase (YTSZ) when it is sintered at 1450°C. Metastable YTSZ is known in the industry to have a beneficial protective feature whereupon, if a microcrack forms, the YTSZ converts from the tetragonal phase into a stable monoclinic phase thereby strengthening the ceramic. The transformation enforces a slight volume expansion which adds closing stress on the crack and toughens the material. Many material properties contribute to the standards, including density, residual porosity, strength, hardness, thermal shock resistance, and chemical stability in solvents. In this report, we summarize the performance of the BEED family of devices with respect to these properties and study in comparison, as well, one of the longest, preexisting, internationally available, electrosurgical ceramic, FDA cleared, products, the Utah Medical Epitome®. Specifically, we examine each ceramic’s microstructure using X-Ray Diffraction, Scanning Electron Microscopy, Nano-indentation, Chemical Testing, Differential Scanning Calorimetry, and Archimedes Density. These tests confirm the device’s chemical stability, structural strength, and adequate thermal properties. We include a comparative analysis of BEED tips fabricated with two different manufacturing/synthetic approaches: injection molding (IM) and additive manufacturing (AM).