Inflammation is highly associated with traumatic sequelae of robotic laparoscopic radical prostatectomy, but it appears that preemptive, loco-regional hypothermia to the pelvis will largely mitigate its harmful effects.
First author Thomas E. Ahlering, MD, and colleagues presented data on 104 men aged ≥70 years who underwent either hypothermic robotic prostatectomy (16 patients) or standard, non-cooled robotic prostatectomy (88 patients). Postoperative pad-free rates at 1 and 3 months were significantly higher among patients in the hypothermic group.
"Urologists have been using hypothermia as far back as the 1960s and '70s in partial nephrectomy and renal transplantation," said Dr. Ahlering, professor and vice chair of urology at UC Irvine.
Greatly simplified, hypothermia reduces metabolic demands in cells, thus making those cells more resistant to injury. Dr. Ahlering was inspired to try the technique in prostate surgery after NFL player Kevin Everett broke his C5 vertebra in 2007 and underwent hypothermia to minimize tissue damage.
"We had come to the conclusion earlier that there was no way to remove the prostate without inducing some traction injury," he said. "That led us to believe that nerve rehabilitation was the next frontier."
Dr. Ahlering's team achieves pelvic cooling through the use of cold irrigation and an endorectal cooling balloon cycled with saline at 4ºC.
Patient characteristics in the study were very similar between the hypothermia and non-hypothermia groups, including age (72.4 vs. 73.1 years, respectively), PSA (6.7 vs. 8.2 ng/mL), AUA score (11.0 vs. 9.6), bother (1.8 vs. 1.9), and body mass index (26.8 vs. 26.6).
Pad-free rates at 1 and 3 months were 37% and 73%, respectively, for the men who underwent pelvic cooling, compared with 14% and 53% for the non-cooling arm (p=.03 and .13).
"When we first began this work in February 2008, our focus was on potency," Dr. Ahlering said. "But shortly after we began, it was apparent that men were getting free of urinary pads more quickly than normal. Pad-free continence is a more objective outcome that all men undergoing radical prostatectomy share, whereas potency is an issue in only about 50% of men, is much more subjective, and takes much longer to assess."
Still, Dr. Ahlering's team is continuing the search for more pronounced results with hypothermia in sexual function. One possibility is a new balloon system that, unlike the current system, will not require shutdowns during critical parts of the surgery because of space limitations with the balloon. Postoperative cooling time may also affect potency, Dr. Ahlering noted.
Older patients benefit
It is significant that patients in the study were at least 70 years of age, he added. Older men tend to take longer to recover continence after surgery, and in 20% to 50% of cases, they never attain pad-free status.
"The older the man, the higher the risk. We just assumed it was because older men don't recover as well," said Dr. Ahlering. "But in this group, men were getting off of pads at a much higher rate, so it appears that by controlling the inflammatory aspect of the procedure, we're especially helping older patients. Specifically, it's the inflammatory component from which the older patients weren't recovering as well as the younger patients."
UC Irvine has entered into a licensing agreement with Innercool Therapies, Inc., San Diego, for the purpose of developing the endorectal cooling balloon system.