Vessel-sealing devices safe for nerve-sparing radical prostatectomy

Vessel-sealing devices offer the advantages of less hemorrhage and shorter operating times, but questions have been raised about the high temperatures they generate.

"There's always a discussion at every meeting about harming nerves, but nobody actually knew how far the temperature spread would go," said Daniel Eberli, MD, PhD, a member of the University of Zurich urologic faculty.

"Instead of placing ligations or clips, one can use these new, modern-style vessel sealing devi-ces. They heat up the tissue between two forceps pieces and they coagulate it so there's no longer blood flow, and then you just go ahead and cut it," Dr. Eberli said during his presentation at the AUA annual meeting in Chicago.

To evaluate the precise lateral temperature spread along the musculofascial tissues, Dr. Eberli and colleagues used an infrared camera, continuous temperature measurement, and histology in an in vitro model involving one of two vessel-sealing devices: LigaSure Axs and LigaSure Impact, both from Covidien, Boulder, CO, which partially funded the study.

Infrared imaging and continuous temperature measurement showed elevated temperatures onlyn an area within 2 mm from the sealing device.

"There's only 2 mm to the side where the nerve can be hurt. If you know that, and you expect the 2 mm, you're safe and you can use the vessel-sealing devices for radical prostatectomy," Dr. Eberli told Urology Times.

Tissue directly adjacent to the sealing device reached mean temperatures of 77.2°C for the LigaSure Axs and 87.3°C for the LigaSure Impact. The temperatures were below the critical value for neural tissue damage (ie, <45°C) at distances of 1.7 mm and 2.5 mm for the Axs and Impact devices, respectively.

In addition, placement of a rectangular dissecting clamp next to the sealing device further decreased the temperature spread.

"You cross-position the dissecting clamp next to the device while coagulating, and it actually works like a heat sink," said Dr. Eberli. "It will reduce the temperature significantly, about 10° to 15°."