Tandem robot technique aids in neurovascular bundle visualization in radical prostatectomy

February 1, 2010

A team from Johns Hopkins University, Baltimore has developed a robotic transrectal ultrasound probe manipulator and three-dimensional reconstruction/navigation software that appear to aid in visualizing the neurovascular bundles during robot-assisted laparoscopic radical prostatectomy.

The TRUS Robot has been used in tandem with the da Vinci surgical robot system (Intuitive Surgical, Sunnyvale, CA) in three patients with prostate cancer, none of whom suffered any associated complications. Theoretically, this "tandem robot-assisted" approach will improve neurovascular bundle visualization, which in turn should improve postoperative recovery of sexual potency.

The Johns Hopkins group also noted that the three-dimensional reconstruction images of the prostate gland by the new software provided clear and accurate surgical landmarks, affording improved visualization.

The TRUS Robot was designed and manufactured at the Johns Hopkins Urologic Robotics Laboratory, headed by senior author Dan Stoianovici, PhD, professor of urology and mechanical engineering. It is manipulated using a simple joystick controller situated next to the surgeon controlling the da Vinci robot.

"When a region of interest on the prostate is selected in the three-dimensional reconstruction, the robot can automatically orient the ultrasound probe to image the corresponding location of the gland in real time," Dr. Stoianovici said.

"Image navigation is then performed by observing the tips of the da Vinci instruments in the live ultrasound image."

Dr. Stoianovici enumerated several advantages of the TRUS Robot over human manipulation of the TRUS, including the fact that it obviates the need for a human assistant and an optical or magnetic tracker.

In many cases, said Dr. Han, periprostatic connective tissues and intraoperative hemorrhage can make it challenging to visualize the neurovascular bundles during surgery, even with surgical loupes or laparoscopic magnification. Surgeons often estimate the location of the neurovascular bundle without validation, which is one reason why the Johns Hopkins researchers view the tandem robot-assisted approach as a significant breakthrough.

Grant awarded for further research

"The eventual goal of this approach is to improve surgical resection for prostate cancer while better preserving the neurovascular bundles and reducing side effects of the surgery," Dr. Han said. "Future studies are needed to confirm its true benefits."

Toward that end, Dr. Han and Dr. Stoianovici received a 2-year "quick trial" grant from the National Cancer Institute to further study the efficacy of their technique. They said they plan to perform the procedure in 60 additional men.

Recently, Dr. Stoianovici has made a number of improvements to the TRUS Robot and reconstruction software, including adding more freedom of movement to improve the TRUS probe's manipulatory capabilities.

The Johns Hopkins researchers believe their TRUS robot is unique. They note that although robots have been previously proposed for use in ultrasound-guided prostate biopsy and brachytherapy, those devices are designed to handle only the needle and not the TRUS probe. Similarly, they said, optical and electromagnetic systems are commonly used for tracking surgical instruments, but both have significant limitations when compared with the TRUS Robot.