ORLANDO, FL USA (UroToday.com) - The efficacy of percutaneous interventions depends greatly on the accuracy of guidance. This is achieved most often using ultrasound, fluoroscopy, and/or computed tomography (CT). Here, Ukimura and colleagues report on the first application of a navigation system using GPS technology and preoperative CT imaging to facilitate percutaneous targeting.
Using a cadaver model, the team obtained preoperative CT scans and transferred them to the navigation system to construct a 3D model. The probe used in the system has sensors that allow its position to be represented in the 3D model. The goal of their study was to assess the accuracy of this targeting system. Gold fiducial-markers were placed within kidney and prostate parenchyma prior to performing the preoperative scans (target marker). Second gold fiducial-markers were also placed using the treatment probe (treatment marker). This was performed twice from two skin incisions greater than 2 cm apart. Postoperative CT scans were performed to measure the proximity of target and treatment markers.
They found that target and treatment markers were 16.6 mm apart in the prostate and 12 mm apart in the kidney. The paired treatment markers were 7.7 mm apart. When examining each axis, the z-axis presented the greatest degree of error, which the study authors ascribe to compression of the tissues during probe entry.
Overall, this study provides a good look into the near future percutaneous guidance. With improvement in the software’s ability to adjust for tissue compression and manipulation during the procedure, accuracy may be further improved. This holds great implications for procedure efficiency, efficacy, and safety.
Presented by Osamu Ukimura, MD at the American Urological Association (AUA) Annual Meeting - May 16 - 21, 2014 - Orlando, Florida USA
Department of Urology, University of Southern California, Los Angeles, CA USA
Written by Martin Hofmann, MD, University of California (Irvine), and medical writer for UroToday.com