Attenuation and Dispersion in Cancellous Bone: Implication in Developing Ultrasound-Guided Spinal Navigation

Abstract

Background: The purpose of this study was to understand the acoustic properties of vertebral cancellous bone by combining micro-CT scan data and use this as the theoretical basis for ultrasonic navigation with posterior pedicle screw fixation during spinal fusion surgery. Results: Two bovine spinal cancellous bone blocks and two human spinal allograft bone blocks simulated the condition of cancellous bone in the pedicle screw channel. Transmission experiments were performed on them, including amplitude, attenuation and sound velocity tests. Four unfocused wideband ultrasonic transducers were used for the detection, with the central frequencies of 2.2MHz, 2.5MHz, 3MHz and 12MHz respectively. The results were favorable and stable. The amplitude of the signal decreased with depth penetration (p< 0.05). With the increase of frequency, sound attenuation and sound velocity increased (p< 0.05).Conclusions: In summary, the conclusions lay a theoretical foundation for the ultrasonic navigation system. However, how ultrasound navigation will facilitate pedicle screw insertion in spine surgery remains to be determined. Therefore, ultrasonic guided pedicle screw implantation is effective and promising in theory.