Adding image guidance to robotic surgery is feasible, beneficial

Robotic image-guided surgery (RIGS) with the daVinci-S surgical system (Intuitive Surgical, Sunnyvale, CA) demonstratedfeasibility and enhanced tumor resection in a series of mock surgeries, investigators reported at the AUA annualmeeting.

Incorporation of image guidance into the surgical system led to a threefold decrease in the mean resection ratio compared withconventional resection, reported S. Duke Harrell, MD, of Vanderbilt University in Nashville. Image guidance also reduced thesurgical task time by more than one-third compared with conventional surgery.

"As it turns out, even in early experience with the robot, augmenting that with image guidance is beneficial," Dr. Harrelltold Urology Times.

Although accurate and precise, the daVinci system remains limited by the requirement for direct visual navigation and the operator's inabilityto visualize subsurface structures. In an effort to minimize those limitations, Vanderbilt investigators developed a RIGSsystem for use with the daVinci robotic platform.

Dr. Harrell reported results from a study of 13 cylindrical polyvinyl alcohol gel phantoms, which were injected with dilutediodinated contrast medium visible to a laparoscopic camera. The phantoms were divided into image-guided and nonimage-guidedgroups.

For the nonimage control group, the surgeon was given a preoperative CT scan and was asked to resect a contrast-enhanced tumor.During image-guided surgery, the preoperative CT scan was co-registered with the daVinci RIGS system and displayed on thesurgeon's console. By means of an optical tracking system, instrument tips could be tracked in real time and correlated with thepreoperative CT.

Investigators used a postoperative CT scan to examine resection cavity size and tumor remnant, and computer resection ratioswere plotted against tumor radii.

The mean tumor radius was 0.48 cm, which was associated with a mean ideal resection volume of 1.75 cm³. The mean resectionratio was 9.01 for the control group and 3.26 for image-guided surgery (p

The results suggest that the image-guided platform has potential application in urology and in other surgical fields, Dr.Harrell and colleagues concluded.