Intraoperative Biomechanical Registration of the Liver: Does the Heterogeneity of the Liver Matter?

Background: Preoperative images such as computed tomography scans or magnetic resonance imaging contain lots of valuable information that are not easily available for surgeons during an operation. To help the clinicians better target the structures of interest during an intervention, many registration methods that align preoperative images onto the intraoperative view of the organs have been developed. For important organ deformation, biomechanically-based registration has proven to be a method of choice.Method: Using an existing biomechanically-based registration algorithm for laparoscopic liver surgery we investigate in this paper the influence of the heterogeneity of the liver on the registration result.Results: No statistical difference in the results was found between the registration performed with the homogeneous model and the one carried out with the heterogeneous model.Conclusion: As the use of an heterogeneous model does not improve significantly the registration result and increase the computation time we recommend to perform the type of registration task described in the paper with a simplified homogeneous model.     

Artificial Liver Support System Combined with Liver Transplantation in the Treatment of Patients with Acute-on-Chronic Liver Failure

Background

The search for a strategy to provide temporary liver support and salvage the patients with acute-on-chronic liver failure (ACLF) remains an important issue. This study was designed to evaluate the experience in artificial liver support system (ALSS) combined with liver transplantation (LT) in the treatment of ACLF.

Methodology/Principal Findings

One hundred and seventy one patients with HBV related ACLF undergoing LT between January 2001 and December 2009 were included. Of the 171 patients, 115 received 247 sessions of plasma exchange-centered ALSS treatment prior to LT (ALSS-LT group) and the other 56 received emergency LT (LT group). The MELD score were 31±6 and 30±7 in ALSS-LT group and LT group. ALSS treatment resulted in improvement of liver function and better tolerance to LT. The average level of serum total bilirubin before LT was lower than that before the first time of ALSS treatment. The median waiting time for a donor liver was 12 days (2–226 days) from the first run of ALSS treatment to LT. Compared to LT group, the beneficial influences of ALSS on intraoperative blood loss and endotracheal intubation time were also observed in ALSS-LT group. The 1-year and 5-year survival rates in the ALSS-LT group and LT group were 79.2% and 83%, 69.7% and 78.6%.

Conclusions/Significance

Plasma exchange-centered ALSS is beneficial in salvaging patients with ACLF when a donor liver is not available. The consequential LT is the fundamental treatment modality to rescue these patients and lead to a similar survival rate as those patients receiving emergency transplantation.