V6-07: A Novel Approach: Trans-peritoneal robot-assisted laparoscopic high intensity focused ultrasound for focal therapy of prostate

Video

Introductions and Objectives
A novel laparoscopic probe of High Intensity Focused Ultrasound (HIFU) has been developed (SonaCare Medical, 11 mm in diameter, with power to ablate 1cc of tissue in 1 minute), and FDA-approved. We first developed a new approach with trans-peritoneal robot-assisted HIFU for targeted focal therapy of the prostate in fresh cadaver.

Methods
In 3 fresh cadavers, gold fiducials (0.9mm in diameter x 3mm in length, CIVCO Medical Solution), which served as a center of virtual target tumor, were implanted by TRUS guidance prior to the surgery in the left-posterior peripheral zone (PZ) (n=3) and right-anterior transition zone (TZ) (n=3). Standard robotic and 12 mm ports (total n=5) were placed with use of a 12 mm trocar for the HIFU probe. Posterior approach in the Denonvillier space was applied for targeting of the posterior PZ tumor, and anterior approach in the Retzius space for targeting of the anterior TZ tumor. Laparoscopic HIFU probe was directly contacted with the surface of the targeted zone to visualize the virtual tumor and to ablate it under real-time US guidance (6.5 MHz) which is built-in function of the device. Pelvic lymph node dissection was performed for staging and therapeutic purpose. For assess the precision, efficacy and safety, gross inspection and microscopic evaluations of the prostate and peri-prostatic pelvic organs were performed.

Results
Both posterior approach to the PZ tumor and anterior approach to the TZ tumor with combination with pelvic lymph node dissection were feasible in all cases (100%). The real-time US could clearly visualize the fiducial-tumor as typical hyper-echoic spot in all cases (100%). Simultaneous display of both initial planning and real-time monitoring US images provided confirmation of targeting precision and, if necessary, alignment of the targeting. Average time for HIFU procedure was 18 minutes. For appropriate coupling of the device, there was learning curve to take about 11 minutes. Entire surgical time of robot-assisted HIFU required approximately one hour. In the step-sectional analysis of the prostate revealed clear gross anatomical change in the ablative zone, with thermal coagulative necrosis. The microscopic HIFU margins were clear, with no thermal damages and no mechanical injury in the peri-prostatic organs and untreated prostatic areas.

Conclusions
We first developed novel techniques with newly developed laparoscopic HIFU probe in the human prostate. Robot-assisted trans-peritoneal approach of laparoscopic HIFU for targeted focal therapy of the human prostate is safe and feasible.

Funding: none