Hydrodissection Enhances Safety of Prostate Cryoablation

By David Levy, MD

Prior to 2000, experience with prostate cryotherapy was associated with significant procedure-related morbidity. Issues stemmed from poor control of the liquid nitrogen cooling agent, as well as the lack of an effective urethral-warming device and inability to monitor target tissue temperatures.

The development of third-generation cryosurgical technology in 2000 incorporated the following: delivery of pressurized argon and helium gases through small, direct-access transperineal probes; utilization of a Food and Drug Administration-approved urethral-warming catheter; modified computer software to provide the surgeon with intraoperative treatment planning; and computer-assisted cryoprobe placement. These modifications resulted in dramatic decreases in procedure-related rectal fistula and urinary incontinence.

In a 2012 report from the national Cryo On-Line Database (COLD) Registry, the incidence of rectal fistula and urinary incontinence was 0.2 percent and 3.4 percent, respectively, in a study cohort of 1,280 patients with five-year follow-up. Despite these encouraging data, some providers remain hesitant to embrace this technology and apply it to patients for primary therapy or in the setting of localized radiation failure.

Rectal fistula is a devastating potential complication of prostate cryotherapy. Various approaches have been utilized in an effort to minimize its incidence. Posterior displacement of the ultrasound probe to physically separate the anterior rectal wall from the prostate and the ice ball is one such maneuver, but this may compromise visualization of the anterior aspect of the gland.

Hydrodissection Procedure Details

Since 2010, we at Cleveland Clinic have utilized normal saline hydrodissection of the anterior rectal wall in more than 150 primary and more than 70 salvage cryoablation cases without a single case of rectal fistula. We believe that hydrodissection has had a significant impact on the incidence of this procedure-related complication.

We perform hydrodissection of the rectum with a 6-inch 18-gauge spinal needle inserted into Denonvilliers’ fascia. We inject normal saline into the avascular plane between the prostate and rectal wall, which results in posterior migration of the anterior rectal wall (Figures 1.a. and 1.b.). A measurable space is created between the posterior aspect of the prostate and anterior rectal wall that can exceed 1.5 cm. Despite the assumption that the rectum is fused to the prostate after radiation, we find this feasible to achieve even in radiation-failure patients (Figure 2).

Figure 1.a. Introduction of spinal needle and injection of normal saline into the avascular plane.

Figure 1.b. Saline injection creates a measurable space between the posterior aspect of the prostate and the anterior rectal wall.

Figure 2. A perioperative ultrasound image shows successful hydrodissection of the anterior rectal wall.

We perform this maneuver after placement of the first two cryoprobes, which help stabilize the gland and minimize movement. Following injection of the saline, we place the Denonvilliers’ thermocouple, followed by the external sphincter thermocouple, and the procedure continues per routine. We have recorded Denonvilliers’ fascia temperatures as low as –33 degrees Celsius without any rectal dysfunction or injury. One member of our team has abandoned the use of the Denonvilliers’ thermocouple and simply irrigates fluid actively during the latter stages of the freeze cycles to visually ensure that the rectum is significantly separated from the ice ball, even when it extends well outside the prostate.

It is imperative to avoid injection of air during this maneuver as well as violation of the perirectal vasculature. The presence of air or bleeding can compromise ultrasound visualization, which is necessary for the completion of the cryoablation procedure.

Hydrodissection of the anterior rectal wall enhances the safety of prostate cryoablation, further decreasing the likelihood of procedure-related complications even in the more difficult post-radiation salvage-cryoablation setting. We continue to study our cryoablation population to further enhance the safety of this minimally invasive outpatient prostate cancer therapy.

Dr. Levy is a staff member of Cleveland Clinic Glickman Urological & Kidney Institute’s Department of Urology.