Stephen Chang

In Brief Objective: Report the midterm results of laparoscopic resection for hepatocellular in chronic liver disease (CLD). Summary Background Data: Surgical resection for hepatocellular carcinoma (HCC) in chronic liver disease (CLD) remains controversial because of high morbidity and recurrence rates. Laparoscopic resection of liver tumors has recently been developed and could reduce morbidity. Methods: From 1998 to 2003, patients with HCC and CLD were considered for laparoscopic liver resection. Inclusion criteria were chronic hepatitis or Child's A cirrhosis, solitary tumor ≤5 cm in size, and location in peripheral segments of the liver. Mortality, morbidity, recurrence rates, and survival were analyzed. Results: A total of 27 patients were included. Liver resections included anatomic resection in 17 cases and non anatomic resection in 10. Seven conversions to laparotomy (26%) occurred for moderate hemorrhage in 5 cases and technical difficulties in 2 cases. Mortality and morbidity rates were 0% and 33%, respectively. Postoperative ascites and encephalopathy occurred in 2 patients (7%) who both had undergone conversion to laparotomy. Mean surgical margin was 11 mm (range, 1–47 mm). After a mean follow-up of 2 years (range, 1.1–4.7), 8 patients (30%) developed intrahepatic tumor recurrence of which one died. Treatment of recurrence was possible in 4 patients (50%), including orthotopic liver transplantation, right hepatectomy, radiofrequency ablation, and chemoembolization in 1 case each. There were no adhesions in the 2 reoperated patients. Overall and disease-free 3-year survival rates were 93% and 64%, respectively. Conclusion: Our study shows that laparoscopic liver resection for HCC in selected patients is a safe procedure with very good midterm results. This approach could have an impact on the therapeutic strategy of HCC complicating CLD as a treatment with curative intent or as a bridge to liver transplantation. Laparoscopic liver resection for peripheral hepatocellular carcinoma in selected patients was associated with no mortality and minimal morbidity. Overall and disease-free 3-year survival rates were 93% and 64%, respectively. This approach could have an impact on the therapeutic strategy of hepatocellular carcinoma complicating chronic liver disease as a treatment with curative intent or as a bridge to liver transplantation.

An interactive surgical simulation system needs to meet three main requirements, speed, accuracy, and stability. In this paper, we present a stable and accurate method for animating mass-spring systems in real time. An integration scheme derived from explicit integration is used to obtain interactive realistic animation for a multiobject environment. We explore a predictor-corrector approach by correcting the estimation of the explicit integration in a poststep process. We introduce novel constraints on positions into the mass-spring model (MSM) to model the nonlinearity and preserve volume for the realistic simulation of the incompressibility. We verify the proposed MSM by comparing its deformations with the reference deformations of the nonlinear finite-element method. Moreover, experiments on porcine organs are designed for the evaluation of the multiobject deformation. Using a pair of freshly harvested porcine liver and gallbladder, the real organ deformations are acquired by computed tomography and used as the reference ground truth. Compared to the porcine model, our model achieves a 1.502 mm mean absolute error measured at landmark locations for cases with small deformation (the largest deformation is 49.109 mm) and a 3.639 mm mean absolute error for cases with large deformation (the largest deformation is 83.137 mm). The changes of volume for the two deformations are limited to 0.030% and 0.057%, respectively. Finally, an implementation in a virtual reality environment for laparoscopic cholecystectomy demonstrates that our model is capable to simulate large deformation and preserve volume in real-time calculations.

Radiofrequecy ablation is the most widely used local ablative therapy for both primary and metastatic liver tumours. However, it has limited application in the treatment of large tumours (tumours >3cm) and multicentric tumours. In recent years, many strategies have been developed to extend the application of radiofrequency ablation to large tumours. A promising approach is to take advantage of the rapid advancement in imaging and robotic technologies to construct an integrated surgical navigation and medical robotic system. This paper presents a review of existing surgical navigation methods and medical robots. We also introduce our current developed model - Transcutaneous Robot-assisted Ablation-device Insertion Navigation System (TRAINS). The clinical viability of this prototyped integrated navigation and robotic system for large and multicentric tumors is demonstrated using animal experiments.