[Study on virtual liver surgery planning applied to hepatic resection]

To evaluate the impact of preoperative three-dimensional visualization and virtual liver surgery planning on hepatic resection.

All relevant structures (livers, portal vein, hepatic veins, and tumors) were extracted from multislice CT scans of 142 cases treated from May 2007 to May 2009. By the liver surgery planning system software Liv 1.0, reconstruction and image analysis of the relevant structures was performed and virtual resections of liver were carried out. Data were correlated to intraoperative findings.

(1) Three-dimensional visualization revealed the spatial relationship of tumors to the intrahepatic vascular system, thus giving impressions how the neoplasms were situated. Virtual tumor resections corresponded to the intraoperative findings. (2) With the planning, an intended resection could be performed virtually and optimal identification of resection margins could be achieved. The ischemia and congestion territory within the remaining liver parenchyma could be calculated. Simulation resections could avoid liver parenchyma over resection and maintain a sufficient amount of liver tissue to sustain hepatic function. Virtual simulations of tumor resection were used successfully to plan of surgical procedures in the hepatic tumors. Hepatectomy was performed in 29 cases after virtual tumor resections but seemed impossible with conventional CT scan. Resection plans of 92 cases were optimized after virtual resections. (3) The mean liver volume of patients with primary hepatocellular carcinoma measured by the software and the real resected was (477 +/- 223) ml and (451 +/- 209) ml respectively. Comparison by means of linear regression analysis between volume measurement on the software and the real resected showed a nearly ideal correlation coefficient (R = 0.922, P < 0.01). The mean error was 6.1%.

The three-dimensional tumor visualization and virtual simulation of tumor resections of the software Liv 1.0 provide an important reference for a valuable planning of complex hepatic resections. It is not only benefit to improve the predictability and security of hepatectomy but also helpful to improve the success rate of complex hepatic resections.