Robot‐assisted laparoscopic high‐intensity focused ultrasound for focal therapy of prostate: Novel approach

Abstract

Focal therapy for prostate cancer is an experimental approach, and the best candidate for the focal targeted therapy continues to evolve along with the development of therapeutic modalities. HIFU delivers ultrasonic energy to a focal area of tissue with resultant local heat and complete coagulative necrosis. [1][2][3][4] Transrectal HIFU has been proven to be capable of providing long-term local control of prostate cancer.5-7 A novel FDA (510k)-cleared laparoscopic HIFU probe for soft tissue ablation has been developed (Sonatherm laparoscopic probe; SonaCare Medical LLC, Indianapolis, IN, USA; Fig. 1a,b). This device has an 11-mm shaft that delivers continuous HIFU-energy in direct contact with the target tissues to ablate 1 cc of tissue per minute (extremely powerful compared with the conventional transrectal HIFU), and could provide a new opportunity for focal HIFU with a laparoscopic approach in conjunction with pelvic lymphadenectomy for precise staging and additional therapeutic benefit in non-low-risk prostate cancer.The aims of the present study were to show the technical feasibility and precision of the laparoscopic HIFU approach for targeted focal ablation to the predetermined image-visible lesion, using a posterior approach from the Denonvilliers' space for the PZ tumor and an anterior approach from the Retzius space for the TZ tumor.Three fresh male cadavers were used for the present study in accordance with all institutional review board ethical requirements. Under transrectal US guidance, gold fiducials (0.9 mmdiameter × 3 mm-length; CIVCO Medical Solutions, Kalona, IA, USA) were implanted in the left posterior (PZ; n = 3) and right anterior (TZ; n = 3) of the cadaver prostates to serve as the center of a virtual tumor. Transperitoneal laparoscopic access was obtained using a da Vinci (Intuitive Surgical, Sunnyvale, CA, USA) robot-assisted approach. Through a posterior approach by the incision of the posterior vesical peritoneum, Denonvilliers' fascia was incised and the prostate was released from the anterior surface of the rectum towards the apex. The HIFU probe was placed between the rectum and prostate to target PZ tumors (Fig. 1c). An anterior approach through the Retzius space was used to target TZ tumors (Fig. 1d). During the anterior approach, a 4 × 4-inch dry gauze was tamponed posterior to the prostate to protect the rectal wall from any risk of accidental injury caused by HIFU energy penetrating through the prostate.The HIFU probe was placed in direct contact with the surface of the targeted zone with coupling assistance between the device and the prostate surface by US jelly, and the virtual tumor was set as the center of the ablation zone. The virtual tumor was identified as a hyperechoic lesion on real-time US. Robotic bilateral pelvic lymph node dissection was carried out with an extended pattern template. Gross inspection and histological evaluation of the prostate and the periprostate anatomy were carried out. A 3-mm step-sectional analysis of the prostate was carried out to measure...

Robotic transmural ablation of bladder tumors using high‐intensity focused ultrasound: Experimental study

“…HIFU has been used for ablating several different types of cancer, including pancreas, bone, breast, liver, soft tissue and others. Within urological oncology, transrectal HIFU ablation of prostate cancer has been used extensively in Europe; in addition, a few studies have shown proof‐of‐concept for lap‐HIFU ablation of small renal masses . Herein, we explore the concept, and determine the technical feasibility of targeted ablation of the intact bladder wall and tumor using a lap‐HIFU approach in the human cadaver and live large animal model.…”

“…However, the laparoscopic HIFU probe destroys all the tissue from its point of contact on the tissue outward, therefore it does not spare any intervening tissue. When compared with the traditional transrectal HIFU probe, the lap‐HIFU probe is thinner, longer, contains a larger ablation zone, delivers energy continuously and causes complete tissue necrosis . Finally, the laparoscopic probe is more powerful and efficient than the transrectal probe, thus enabling treatment of larger tissue volumes in a shorter amount of time.…”

“…The Sonatherm is an FDA‐approved laparoscopic probe (Sonatherm laparoscopic probe; SonaCare Medical LLC, Indianapolis, IN, USA) that consists of a single UE transducer (11 mm diameter) that is capable of carrying out both diagnostic gray‐scale imaging (6.5 MHz) and therapeutic delivery of HIFU energy (4.0 MHz). It can carry out targeted soft tissue ablation with sharply‐delineated demarcation zones and without collateral damage to the surrounding untargeted tissue . The therapeutic transducer, with the probe placed in direct contact with the target tissue and appropriately coupled, delivers continuous HIFU (no intervening tissue is spared) to ablate 1 cc of tissue per min with an adjustable ablation zone of up to a maximal depth of 35 mm.…”

“…It can carry out targeted soft tissue ablation with sharply-delineated demarcation zones and without collateral damage to the surrounding untargeted tissue. [3][4][5] The therapeutic transducer, with the probe placed in direct contact with the target tissue and appropriately coupled, delivers continuous HIFU (no intervening tissue is spared) to ablate 1 cc of tissue per min with an adjustable ablation zone of up to a maximal depth of 35 mm. Axial and sagittal US images for both preoperative planning and realtime intraoperative imaging are shown simultaneously in the workstation.…”

“…Recently, a laparoscopic approach to ablate intra-abdominal tumors, such as kidney tumors, using a US FDAapproved HIFU, has been proposed. [3][4][5] The primary objective of the present study was to assess the feasibility of lap-HIFU for targeted ablation of the bladder wall and tumor extravesically using a robot-assisted laparoscopic approach in human cadavers and a large animal model. Additionally, we describe a novel method of creating a "mimic" bladder tumor model for research purposes.…”