Utilization of ultrasonically forced pulsating water jet decaying for bone cement removal

Abstract

Ultrasonic pulsating water jet for non-thermal and selective removal of acrylic bone cement is studied. Variation of acoustic chamber length is used for tuning of the ultrasonic system into the resonance regime to gain maximum power transmission. The study investigates the minimal technological conditions such as nozzle traverse speed and supply water pressure required to generate disintegration grooves in bone cement mantle. It also proposes the safe standoff distance range, which is essential for its potential application during the extraction of bone cement without compromising host bone. Palacos R+G bone cement was used for the experiments. Generated groove depths were measured using MicroProf FRT and analyzed using SPIP software. Depth values showed an increasing trend with an increase in acoustic chamber length, decrease in traverse speed, and increase in supply pressure values. From the entire experimental domain, a maximum depth of 615 μm was obtained at 22-mm chamber length, 0.5-mm/s traverse speed, 10-MPa pressure, and a standoff distance of 4 mm. Brittle fractured surface features like material chipping, micro-pits, cracks, and sheared material layers were observed in the SEM images. Disintegrated debris, diameter 21–37 μm, conceived from pit diameters can be used to design a suction unit. Real-time control of the disintegration process using accelerometer sensors was shown. The results support the idea of using pulsating water jet for bone cement removal in a single blind hole. Minimal technological parameters reduce reaction force of the hand tool, allowing bone cement removal without bone fracture or perforation.