Entity

Time filter

Source Type


Umale S.,University of Strasbourg | Deck C.,University of Strasbourg | Bourdet N.,University of Strasbourg | Diana M.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | And 2 more authors.
Journal of Biomechanics | Year: 2015

Kidneys are third most injured organs in abdominal trauma after liver and spleen; this study therefore is an attempt to understand the behaviour of kidneys under blunt trauma. Dynamic impact tests were performed on 20 fresh porcine kidneys to study the injury propagation in the organ, and the acceleration of the impactor was measured. A kidney model was developed with structural details like capsule and cortex. The kidney cortex was modelled with solid hexahedral elements and the capsule was modelled with quadratic shell elements. The material models for the capsule and cortex were used from the experimental data reported in our previous study. The developed model was calibrated using previous and current experimental results to reproduce the injuries of the organ in terms of acceleration of the impactor, and the injuries sustained by the organ during the experiments. The developed kidney model is observed to be robust and can be integrated with the available human body finite element models to simulate accidents and to predict or simulate injuries. © 2015 Elsevier Ltd. Source


Umale S.,University of Strasbourg | Deck C.,University of Strasbourg | Bourdet N.,University of Strasbourg | Diana M.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | And 2 more authors.
2013 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury | Year: 2013

The objective of this study is to develop robust finite element models of the liver and kidney. The organs are modeled for the first time as hyper viscoelastic materials and with individual constituents of each (viz. the capsule and veins). To characterize the tissues, static and dynamic experiments were performed on individual parts of the porcine abdominal organs, such as capsule, vessels and parenchyma and hyper elastic, visco elastic and hyper viscoelastic materials in the form of Ogden, Mooney Rivlin and Maxwell materials were developed for each. These material models were further used to develop the finite element model of human organs. To validate these models in vitro dynamic tests on porcine kidneys were performed, whereas dynamic impact test data from the literature on human liver were used. Experiments were reproduced with the numerical approach in the LS Dyna explicit solver. The developed models are observed to reproduce the injuries of the organ to a great extent in terms of acceleration and peak force of the impactor as well as lacerations sustained by the organ during the experiments. The developed models are robust and can be integrated with the available human body finite element models to simulate accidents and to predict or simulate injuries. Source


Umale S.,French National Center for Scientific Research | Deck C.,French National Center for Scientific Research | Bourdet N.,French National Center for Scientific Research | Dhumane P.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | And 3 more authors.
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2012

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 0.05 mm/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. © 2012 Elsevier Ltd. Source


Akladios C.,University of Strasbourg | Ronzino V.,University of Strasbourg | Schrot-Sanyan S.,University of Strasbourg | Afors K.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | And 4 more authors.
Journal of Minimally Invasive Gynecology | Year: 2015

Study Objective: Two validated laparoscopic approaches for para-aortic lymphadenectomy (PAL) exist: the transperitoneal and the extraperitoneal. The aim of this study was to compare the surgical outcomes of both approaches. Design: A retrospective review of all patients who underwent laparoscopic PAL for a gynecologic malignancy between January 2008 and October2013. Setting: University Hospital. Patients: Two patients groups were compared: transperitoneal (n=51) and extraperitoneal (n=21). Interventions: Paraaortic lymphadenectomy. Measurements and Main Results: The χ2 test, Fisher's exact test, or Student's t-test were used for univariate analysis and a stepwise logistic regression for multivariate analysis. The threshold of statistical significance was set at 0.05. All patient characteristics were similar between the 2 groups (p>.05 for all variables). There was only 1 (1.3%) conversion to laparotomy encountered in the transperitoneal PAL group and 3 conversions from extraperitoneal to transperitoneal PAL (14.2%). In 1 case of extraperitoneal PAL, the procedure was abandoned because of inadequate equipment (body mass index 48kg/m2). The mean duration of surgery was longer in the transperitoneal group: 200min (35-360) versus 125.6min (45-180) in the extraperitoneal group (p=.001). The mean number of harvested lymph nodes was higher in the transperitoneal group: 17 (4-37) versus 13 (3-25) in the extraperitoneal group (p=.029). There was no difference in postoperative course and complications between both groups in multivariate analysis. Conclusions: In nonobese patients, the extraperitoneal PAL is associated with shorter surgical duration, whereas the transperitoneal approach was associated with a higher number of harvested lymph nodes. As a result of improved ergonomy, the transperitoneal approach enables laparoscopic management of operative complications. © 2015 AAGL. Source


Mahmoud N.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | Mahmoud N.,CNRS Computer Science and Engineering Laboratory | Grasa O.G.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | Nicolau S.A.,Ircad Institute Of Recherche Contre Les Cancers Of Lappareil Digestif | And 4 more authors.
International Journal of Computer Assisted Radiology and Surgery | Year: 2016

Purpose: An augmented reality system to visualize a 3D preoperative anatomical model on intra-operative patient is proposed. The hardware requirement is commercial tablet-PC equipped with a camera. Thus, no external tracking device nor artificial landmarks on the patient are required. Methods: We resort to visual SLAM to provide markerless real-time tablet-PC camera location with respect to the patient. The preoperative model is registered with respect to the patient through 4–6 anchor points. The anchors correspond to anatomical references selected on the tablet-PC screen at the beginning of the procedure. Results: Accurate and real-time preoperative model alignment (approximately 5-mm mean FRE and TRE) was achieved, even when anchors were not visible in the current field of view. The system has been experimentally validated on human volunteers, in vivo pigs and a phantom. Conclusions: The proposed system can be smoothly integrated into the surgical workflow because it: (1) operates in real time, (2) requires minimal additional hardware only a tablet-PC with camera, (3) is robust to occlusion, (4) requires minimal interaction from the medical staff. © 2016 CARS Source

Discover hidden collaborations