V10-04: A Novel Concept for Focal Therapy for Bladder Tumors: Robot-Assisted Laparoscopic HIFU

Video

Introductions and Objectives
A novel laparoscopic probe of High Intensity Focused Ultrasound (HIFU) has been developed (SonaCare Medical, diameter-11mm) and FDA-approved. It delivers HIFU energy continuously in tissue making it more efficient to ablate 1cc of tissue in 1 minute. Hence, it is more powerful than conventional trans-rectal HIFU that runs with ON/OFF cycle. We developed a new approach with trans-peritoneal robot-assisted HIFU for the human bladder in a fresh cadaver study to target mimic tumors.

Methods
In three fresh cadavers, regular robotic and 12mm ports (total n=5) were placed with the use of a 12mm trocar for the HIFU probe. Mimic tumors, previously dissected striated muscle (25mm diameter), were intra-vesically implanted on bilateral bladder side walls (2 tumors/case; total 6 bladder tumors). The bladder was made water-tight and filled with 250ml water. Laparoscopic HIFU probe was contacted directly with the bladder surface to visualize the mimic tumor and ablate it under real-time US guidance (6.5 MHz) which is built-in function of the device. Pelvic lymph node dissection (PLND) was performed for staging and therapeutic purpose. Gross inspection and microscopic evaluations of the bladder wall, mimic tumors, and other peri-vesical pelvic organs were performed to assess the procedure.

Results
Laparoscopic extra-vesical approach of the bladder tumors through the bladder wall with PLND was feasible in all cases (100%). The real-time US clearly visualized the mimic tumor as a similar shape to real urothelial tumor in all cases (100%). Simultaneous display of both initial planning and real-time monitoring US images confirmed targeting precision and, if necessary, alignment. Average time for HIFU procedure was 6 minutes. For appropriate device coupling, there was a learning curve of approximately 5 minutes. Entire surgical time of robotic-assisted HIFU was approximately 1 hour. Comparing treated tumors (n=5) and bladder walls with an intentionally untreated tumor revealed distinct differences of the ablative zone, with microscopic confirmation of thermal coagulative necrosis and shrunk effects in the tissue volume. The microscopic margins between the treated and untreated zones were clear, with no thermal damages or mechanical injury in the peri-vesical organs and untreated bladder wall.

Conclusions
Robotic assisted trans-peritoneal laparoscopic HIFU using an extra-vesical approach for human bladder tumors is feasible. We first developed a novel concept with laparoscopic HIFU for the human bladder in fresh cadaver study.

Funding: None