Research and development of a new RF-assisted device for bloodless rapid transection of the liver: computational modeling and in vivo experiments.

BACKGROUND: Efficient and safe transection of biological tissue in liver surgery is strongly dependent on the ability to address both parenchymal division and hemostasis simultaneously. In addition to the conventional clamp crushing or finger fracture methods other techniques based on radiofrequency (RF) currents have been extensively employed to reduce intraoperative blood loss. In this paper we present our broad research plan for a new RF-assisted device for bloodless, rapid resection of the liver. METHODS: Our research plan includes computer modeling and in vivo studies. Computer modeling was based on the Finite Element Method (FEM) and allowed us to estimate the distribution of electrical power deposited in the tissue, along with assessing the effect of the characteristics of the device on the temperature profiles. Studies based on in vivo pig liver models provided a comparison of the performance of the new device with other techniques (saline-linked technology) currently employed in clinical practice. Finally, the plan includes a pilot clinical trial, in which both the new device and the accessory equipment are seen to comply with all safety requirements. RESULTS: The FEM results showed a high electrical gradient around the tip of the blade, responsible for the maximal increase of temperature at that point, where temperature reached 100 degrees C in only 3.85 s. Other hot points with lower temperatures were located at the proximal edge of the device. Additional simulations with an electrically insulated blade produced more uniform and larger lesions (assessed as the 55 degrees C isotherm) than the electrically conducting blade. The in vivo study, in turn, showed greater transection speed (3 +/- 0 and 3 +/- 1 cm2/min for the new device in the open and laparoscopic approaches respectively) and also lower blood loss (70 +/- 74 and 26 +/- 34 mL) during transection of the liver, as compared to saline-linked technology (2 +/- 1 cm2/min with P = 0.002, and 527 +/- 273 mL with P = 0.001). CONCLUSION: A new RF-assisted device for bloodless, rapid liver resection was designed, built and tested. The results demonstrate the potential advantages of this device over others currently employed.

Laparoscopic blood-saving liver resection using a new radiofrequency-assisted device: preliminary report of an in vivo study with pig liver.

BACKGROUND: The aim of any device designed for liver resection is to allow blood saving and quick resections. This may be optimized using a minimally invasive approach. A radiofrequency-assisted device is described that combines a cooled blunt-tip electrode with a sharp blade on one side in an in vivo preliminary study using hand-assisted laparoscopy to perform partial hepatectomies. METHODS: Eight partial hepatectomies were performed on pigs with hand-assisted laparoscopy using the radiofrequency-assisted device as the only method for transection and hemostasis. The main outcome measures were transection time, blood loss, transection area, transection speed, blood loss per transection area, and tissue coagulation depth. The risk for biliary leak also was assessed using the methylene blue test. RESULTS: The transection time was 13 +/- 7 min for a mean transected area of 34 +/- 11 cm(2). The mean total blood loss was 26 +/- 34 ml. The mean transection speed was 3 +/- 1 cm(2)/min, and the blood loss per transection area was 1 +/- 1 ml/cm(2). Abdominal examination showed no complications in nearby organs. One biliary leak was identified in one case using the methylene blue test. The transection surface was 34 +/- 11 cm(2), and the mean tissue coagulation depth was 9 +/- 2 mm. The inviability of the coagulated surface was assessed by adenine dinucleotide (NADH) staining. CONCLUSIONS: The radiofrequency-assisted device has shown with a laparoscopic approach that it can perform liver resections faster and with less blood loss using a single device in a minimally invasive manner without vascular control than other commercial devices. The results show no significant differences with the same device used in an open procedure.