Diameter and pressure of the water-jet for liver resection

The aim of this study was to evaluate the effect of various nozzle diameter and different liquid delivery pressure on efficacy of water-jet in experimen- tal liver resection. Method: Depending on the used nozzle diameter, the animals were divided into two groups. In the first group of animals, the nozzle diameter was 0.1 mm and this group was divided into 3 subgroups depending on the liquid pressure applied: 8 ATM, 12 ATM and 16 ATM, with 5 water-jet liver dissection is in each subgroup. Water-jet dissection with nozzle diameter of 0.2 mm was used in the second group of animals, which was divided into three subgroups with 5 water-jet liver dis- section in each, depending on liquid pressure: 4 ATM, 8 ATM and 12 ATM. The criteria such as blood loss, operation time, parenchymal necrosis, expired liquid volume, and postoperative complications were used for comparison. Results: Water-jet with a diameter of 0.1mm and pres- sure of 12 ATM showed faster cutting with reasonable blood loss when compared to the low pressure sub- group (8 ATM) and result in lesser parenchymal necro- sis, smaller expired liquid volume and acceptable speed of resection when compared to the high pres- sure subgroup (16 ATM). Increase of the pressure from 4 to 12 ATM of water-jet with diameter of 0.2 mm re- sulted in increase of blood loss and necrosis, but did not effect the speed of resection significantly. Despite lesser blood loss and smaller necrosis, the water-jet at 4 ATM had slower speed of resection. Water-jet with diameter of 0.2 mm and pressure of 8 ATM cut liver more faster without significantly effecting blood loss and necrosis in comparison to that at a pressure of 4 ATM. Conclusion: Our study showed that, increasing the nozzle diameter and liquid delivery pressure resulted in an increase of blood loss and tissue necrosis. Wa- ter-jets with diameter of 0.1 mm and pressure of 12 ATM is more acceptable for resection of normal liv- ers.