[Hepatic resections using an Nd YAG laser. Anatomic and biological results of an experimental study].
Experimental hepatic resections were performed with a Nd YAG laser in 32 New-Zealand rabbits. The beam was simply transmitted by a quartz fiber of 4 degrees 2 and 8 degrees in divergence for the full angle, without any focalization. Section was possible at a power output superior to 20 W requiring short cutting time. Complete hemostasis was obtained as long as the diameter of encountered vessels did not exceed 4,5 mm. Immediately after resection the parenchyma was covered by an ischemic layer varying from 2 to 8 mm. Its thickness rapidly increased to high levels whenever the power output exceeded 40 W or when hepatic pedicle was clamped. Healing process was installed at day 30. There was no hemorrhagic, biliary or septic complication. Eleven animals were alive eight months after. Histological examination revealed four layers: a first one of carbonization, a second of condensed cells, a third of edema presenting disruption of sinusoids, and a fourth one composed of progressively normal tissue. Peripherical veins presented thrombosis of their blood content and coagulative necrosis of their wall while bile canaliculi were preserved. Fibrosis appeared in the edematous layer the 10th day and was completely formed at day 30. Electron microscopic examination revealed shadowy cells embedded in the condensed layer and mitochondrial alteration in the edematous layer. The 15th day foci of cell regenerations were registered. High levels of SGOT, SGPT and LDH (fractions IV and V) were observed immediately after resection.(ABSTRACT TRUNCATED AT 250 WORDS)