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During the process of percutaneous puncture vascular intervention operation in endoscopic liver surgery, high precision needle manipulation requires the accurate needle tissue interaction model where the tissue fracture toughness is an important parameter to describe the tissue crack propagation, as well as to estimate tissue deformation and target displacement. However, the existing studies on fracture toughness estimation did not consider Young's modulus and the organ capsule structure. In this paper, a novel computational fracture toughness model is proposed considering insertion velocity, needle diameter and Young's modulus in insertion process, where the fracture toughness is determined by the tissue surface deformation, which was estimated through energy modeling using integrated shell element and three-dimensional solid element. The testbed is built to study the effect of different insertion velocities, needle diameters and Young's modulus on fracture toughness. The experiment result shows that the estimated result of computational fracture toughness model agrees well with the physical experimental data. In addition, the sensitivity analysis of different factors is conducted. Meanwhile, the model robustness analysis is investigated with different observation noises of Young's modulus and puncture displacement. [Display omitted] • The computational fracture toughness model is proposed based on modified insertion energy function. • The force sensor-less fracture toughness modeling approach is proposed by utilizing deformation information. • Both numerical experiments and physical phantom experiments verified the accuracy of the model. [ABSTRACT FROM AUTHOR]

Liver resectional surgery has become increasingly popular and patient outcomes continue to improve. In order to optimize postoperative outcomes several key principles of liver surgery require careful consideration. Major resection of the liver requires assessment of the future liver remnant to ensure adequate postoperative functioning, particularly when underlying liver disease is present. Appropriate extent of resection is mandated in order to achieve optimum long-term outcome, and the underlying pathology and liver parenchyma must be considered when trying to achieve this. Surgical technique can be adjusted to reduce perioperative morbidity. Techniques focused on reduction of intra-operative blood loss are low central venous pressure (CVP) resection and inflow occlusion via intermittent portal triad clamping and these can contribute to help minimize blood loss and improve outcome. Recently, laparoscopic liver resection is increasing in popularity and has achieved good short-term results and is likely to be used more widely in the future. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Radiofrequency ablation (RFA) is effective in treating hepatocellular carcinoma (HCC) and less invasive than surgical resection. However, ‘one-off’ complete tumor ablation on liver function has not been reported. Methods: We retrospectively reviewed 36 HCCs which met the criteria of ‘one-off’ complete tumor ablation: (1) tumor was completed covered by the ablated zone (confirmed by postoperative enhanced CT) with a single RFA and, (2) no sign of recurrence for at least 6 months. We categorized tumors into two groups: near vascular tumor (NVT) if the distance was less than 5 mm, and far vascular tumor (FVT) otherwise. Results: Thirteen HCCs met the criteria of NVTs, and 23 HCCs met that of FVTs. The Average tumor size was 2.6 ± 0.3 cm in FVTs and 2.5 ± 0.3 cm in NVTs. Although restored to normal range by postoperative day (POD) 7, ALT, AST, total bilirubin (TB), albumin and prothrombin time showed more significant fluctuation in NVTs compared to those in FVTs on POD1 through POD5. Moreover, 53.9% (7/13) patients in NVT group and 26.1% (6/23) in FVT group developed post-RFA transient ascites (OR = 5.1, 95% CI = 1.1–24.4). Incidence of post-RFA pleural effusion were 61.5% (8/13) in NVT but only 17.4% (4/23) in FVTs (OR = 7.6, 95% CI = 1.6–35.9). Conclusion: ‘One-off’ complete tumor ablation may impair liver function and led to more postoperative complication if a tumor is within 5 mm away from a large blood vessel (≥3 mm). Particular caution should be made in preoperative assessment on the anatomic relation between tumor and large blood vessel for patients. [Copyright &y& Elsevier]

Abstract: Abdominal organs are the most vulnerable body parts during vehicle trauma, leading to high mortality rate due to acute injuries of liver, kidney, spleen and other abdominal organs. Accurate mechanical properties and FE models of these organs are required for simulating the traumas, so that better designing of the accident environment can be done and the organs can be protected from severe damage. Also from biomedical aspect, accurate mechanical properties of organs are required for better designing of surgical tools and virtual surgery environments. In this study porcine liver, kidney and spleen tissues are studied in vitro and hyper-elastic material laws are provided for each. 12 porcine kidneys are used to perform 40 elongation tests on renal capsule and 60 compression tests on renal cortex, 5 porcine livers are used to perform 45 static compression tests on liver parenchyma and 5 porcine spleens are used to carry out 20 compression tests. All the tests are carried out at a static speed of 0.05mm/s. A comparative analysis of all the results is done with the literature and though the results are of same order of magnitude, a slight dissonance is observed for the renal capsule. It is also observed that the spleen is the least stiff organ in the abdomen whereas the kidney is the stiffest. The results of this study would be essential to develop the FE models of liver, kidney and spleen which can be further used for impact biomechanical and biomedical applications. [Copyright &y& Elsevier]