Evaluation of liver anatomical structure and volume of living donor liver transplantation candidates by way of prototipe that manufactured with 3 dimensional printer via utilizing computed tomography data before living donor liver transplantation

In human body, liver is a unique organ with important functions in protein synthesis, regulation of sugar and fat metabolism, detoxification, regulation of immune system, and many other important metabolic processes, as well as its outstanding regeneration ability. Today, liver transplantation is the only treatment option for both acute and chronic liver failure. Grafts for liver transplantation are supplied from cadavers via organ donation or from volunteer living donors. Unfortunately, a progressively increasing number of patients are, and will be, in need of liver transplantation and the available number of organ donations are far from meeting this growing need. Therefore, living donor liver transplantation (LDLT) has become increasingly widespread, both worldwide and particularly in our country. In living donor liver transplantation, the safety of donor candidate is crucial at every stage of the procedure. First of all, it should be clearly determined in the donor candidate selection stage whether residual liver volume would suffice to meet the needs of a living donor candidate, or whether hepatic vascular bed is suitable for transplantation. Computerized tomographic angiography and volumetric calculation method are currently used for this purpose. This method allows measurement of total and residual hepatic volumes and assesses vascular bed. It would be of great value if such information could be used by member physicians of a transplant team, particularly surgeons, on a 3-D model so that they would be able to better conceptualize the operation by examining a 3-D model of a material they will operate on. In our pre-interviews, trasnplant surgeons stated that they would like to work on such a model, and added that such an opportunity would be motivating and significantly contribute to decision making. Hence, we carry out a study to obtain liver models of living donor liver transplant candidates using a 3-D printer. The 3-D printing procedure consists of 3-D image reconstruction, digital preparation, and three dimensional printing. We used to a Stratasys J750 3D printer. Firstly, we visualize liver and perform a volumetric calculation using angiographic computerized tomography. Next, by used special computer programs , we converted 2-D computerized tomography images to stereolithographic (STL) files, which processed by the Stratasy J 750 3D printer. In the printing process, blood vessels were marked by a colored ink and liver tissue by a transparent polymer. The volume of the 3-D printing liver model is 1.5 times more, which allows for a better examination of vascular structures. Worldwide studies also show that 3D printers will be an important tool for planning liver transplantation and complex liver surgeries in the future. This model is considered to be superior than conventional two dimensional imaging for liver imaging. As a physical model,it will also provide a more accurate navigation of critical areas during surgical operations.In conclusion, liver model obtained by three dimensional printing technology is expected to be one of the significant advances for the preoperative planning of living donor liver transplantation operations.