Surgical simulation is one of interactive techniques such as a flight simulation or a CAD (Computer Aided Design) in terms of using the same computer graphics. However, different from above techniques, one big characteristic of surgical simulation is to handle unfixed forms of three-dimensional human body in which conventional computer graphics techniques are weak. Thus surgical simulation can be done with giving changes of ones anatomical three-dimensional forms in details. Changing with the times, the function and quality of the surgical simulaition transited depend on an ability of the computer itself. Simulated operations became simple to complex, and simple model of the affected part changed to model with more complex structures according the transition of its functions. By rapid improvement of the computer system in these 10 years, we can now handle the detailed affected model with the huge data in real time and natural operation. In addition, as a result of an external force during the operation, transformation of soft objects such as internal organs can be shown in real time. Moreover, by combining with virtual reality technique, it let simulation come near to real movements of fingers in the surgical simulation. It can give us not only visual feedback of the simulation, but the sense of touch of the operation comparing to three-dimensional images. Thus, we are approaching to real operation under the virtual space. Based on results by a team of the authors institute, the present circumstances of development with simulation system of the operation will be discussed. In addition, we focused on trends of the works and development of researches for future simulation systems of the operation which is close to advanced medical techniques, for instance, supporting system during the operation such as Data fusion and tele-medicine etc.

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On author's investigation, 76% of neonates are born with auricular deformity. This paper describes the spline approximation method of auricular shape that characterizes those deformities and it's application to the treatment. Contours of external auricular shape and inside fringe of helix are approximated by B-spline function of order four based on the ear base line. The position of control points that is coefficients of B-spline function is used as an indicator of auricular shape. Deformities are classified into 6 groups including normal ear and discriminant analysis is performed using the Mahalanobis generalized distance calculated by the distribution of control points. Also normal and abnormal rates are calculated by the component ratio of probability of belonging to the classified group. The success ratio of discriminant analysis and average of normal and abnormal rates are increased by using not only control points of external shape but also those of inside fringe of helix.
The system to generate the orthosis shape for the treatment of deformities that utilizes spline approximated auricular shape is developed. Orthoses manufactured by the system were applied to patients and improved deformities within a year. The transitions of auricular shape of patients are analyzed by the position of control points and normal and abnormal rates. The result of analyses also shows that using both control points of external auricular shape and inside fringe of helix well chcracterizes the improvement of those deformities.

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A method to use pre-surgical T2-weighted magnetic resonance images (MRI) with intra-surgical T 1-weighted MRI to guide prostate biopsy is presented. The method uses Tl-weighted MRI to guide the needle through the perineum, whilst T2-weighted MRI presented by a surgical navigation software was used to visualize a tumor foci and sextant targets. Two feasibility studies in an open-configuration MRI scanner indicated it is feasible to perform sextant and targeted prostate biopsies under MRI guidance.

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The kinds of interface in the automation of clinical surgery were analyzed in this study. The kinds of interface were classified into 3 kinds, that is Vehicle-Type, Process-Type and Computer-Type according to the Kawano's classification of man-machine interface. Vehicle type interface is defined as the interface that is mainly controlled under the body feeling cue and physical law such as automobile and motorcycle. Computer type interface is defined as the interface that is mainly controlled under computer interface in which only logical cue is used. Process type interface is defined as the interface in which primary parameters is main cue such as chemical plants. ME devices in the operating room has mainl vehicle type and process type interface, most of the surgical instruments such as electro-cautery, suturing and anastmotic devices and ultrasonic cavitation devices were commanded by vehicle type interface, directly controlled by body feeling cues. ME devices of patient monitoring system and clinical laboratory consist of mixture of process, vehicle and computer type interface. However most of the interface of ordering and reservation system for prescription, meal service, clinical laboratory and radiology were commanded by computer type interface. Caution must be paid that miss-ordering into the computer type interface can cause disadvantage directly to the patients as well as other kinds of ME devices, so adequate protection for human error must be equipped to the computer type interface.

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