Computer-gestützte Operationsplanung bei Leberlebendspenden

Comparing a virtual reality head-mounted display to on-screen three-dimensional visualization and two-dimensional computed tomography data for training in decision making in hepatic surgery: a randomized controlled study

OBJECTIVE

Evaluation of the benefits of a virtual reality (VR) environment with a head-mounted display (HMD) for decision-making in liver surgery.

BACKGROUND

Training in liver surgery involves appraising radiologic images and considering the patient's clinical information. Accurate assessment of 2D-tomography images is complex and requires considerable experience, and often the images are divorced from the clinical information. We present a comprehensive and interactive tool for visualizing operation planning data in a VR environment using a head-mounted-display and compare it to 3D visualization and 2D-tomography.

METHODS

Ninety medical students were randomized into three groups (1:1:1 ratio). All participants analyzed three liver surgery patient cases with increasing difficulty. The cases were analyzed using 2D-tomography data (group "2D"), a 3D visualization on a 2D display (group "3D") or within a VR environment (group "VR"). The VR environment was displayed using the "Oculus Rift ™" HMD technology. Participants answered 11 questions on anatomy, tumor involvement and surgical decision-making and 18 evaluative questions (Likert scale).

RESULTS

Sum of correct answers were significantly higher in the 3D (7.1 ± 1.4, p < 0.001) and VR (7.1 ± 1.4, p < 0.001) groups than the 2D group (5.4 ± 1.4) while there was no difference between 3D and VR (p = 0.987). Times to answer in the 3D (6:44 ± 02:22 min, p < 0.001) and VR (6:24 ± 02:43 min, p < 0.001) groups were significantly faster than the 2D group (09:13 ± 03:10 min) while there was no difference between 3D and VR (p = 0.419). The VR environment was evaluated as most useful for identification of anatomic anomalies, risk and target structures and for the transfer of anatomical and pathological information to the intraoperative situation in the questionnaire.

CONCLUSIONS

A VR environment with 3D visualization using a HMD is useful as a surgical training tool to accurately and quickly determine liver anatomy and tumor involvement in surgery.

IMHOTEP: cross-professional evaluation of a three-dimensional virtual reality system for interactive surgical operation planning, tumor board discussion and immersive training for complex liver surgery in a head-mounted display

BACKGROUND

Virtual reality (VR) with head-mounted displays (HMD) may improve medical training and patient care by improving display and integration of different types of information. The aim of this study was to evaluate among different healthcare professions the potential of an interactive and immersive VR environment for liver surgery that integrates all relevant patient data from different sources needed for planning and training of procedures.

METHODS

3D-models of the liver, other abdominal organs, vessels, and tumors of a sample patient with multiple hepatic masses were created. 3D-models, clinical patient data, and other imaging data were visualized in a dedicated VR environment with an HMD (IMHOTEP). Users could interact with the data using head movements and a computer mouse. Structures of interest could be selected and viewed individually or grouped. IMHOTEP was evaluated in the context of preoperative planning and training of liver surgery and for the potential of broader surgical application. A standardized questionnaire was voluntarily answered by four groups (students, nurses, resident and attending surgeons).

RESULTS

In the evaluation by 158 participants (57 medical students, 35 resident surgeons, 13 attending surgeons and 53 nurses), 89.9% found the VR system agreeable to work with. Participants generally agreed that complex cases in particular could be assessed better (94.3%) and faster (84.8%) with VR than with traditional 2D display methods. The highest potential was seen in student training (87.3%), resident training (84.6%), and clinical routine use (80.3%). Least potential was seen in nursing training (54.8%).

CONCLUSIONS

The present study demonstrates that using VR with HMD to integrate all available patient data for the preoperative planning of hepatic resections is a viable concept. VR with HMD promises great potential to improve medical training and operation planning and thereby to achieve improvement in patient care.

[Living liver donor: indications and technical aspects]

Living donor liver transplantation (LDLT) nowadays represents an important and safe alternative to conventional deceased donor liver transplantation (DDLT). A major concern related to the LDLT procedure is still represented by donor safety because a serious operation not without risks must be carried out on a healthy individual. In the present review of the indications for LDLT the technical concepts of donor surgery, criteria for donor selection and evaluation and morbidity and mortality results related to the procedure are presented. In general, the indications for LDLT are almost the same as for DDLT. The donor hepatectomy (right, left or left lateral) is presented in five main phases. The reported morbidity rates vary between 10 % and 60 % and are strongly related to the experience of the transplant center. The currently reported postoperative mortality rates for left and right hepatectomy are 0.1 % and 0.5 %, respectively. The results of LDLT are similar if not even better than those for DDLT depending on the specific indications.

Current trends in live liver donation

The introduction of living donor liver transplantation (LDLT) has been one of the most remarkable steps in the field of liver transplantation (LT), able to significantly expand the scarce donor pool in countries in which the growing demands of organs are not met by the shortage of available cadaveric grafts. Although the benefits of this procedure are enormous, the physical and psychological sacrifice of the donors is immense, and the expectations for a good outcome for themselves, as well as for the recipients, are high. We report a current overview of the latest trends in live liver donation in its different aspects (i.e. donor's selection, evaluation, operation, morbidity, mortality, ethics and psychology). This review is based on our center's personal experience with almost 200 LDLTs and a detailed analysis of the international literature of the last 7 years about this topic. Knowing in detail how to approach to the different aspects of living liver donation may be helpful in further improve donor's safety and even recipient's outcome.