Development of Microsurgery Support System with Micro-manipulator

本研究以角膜手术和脑外科为重点，开发出比手部手术创伤小、接触少、定位准确、可重复性高的显微手术支撑系统。对周边组织的任何损伤都比其他手术更为重要，使用准分子激光的非接触式切开更适合于角膜手术，以获得清晰的轮廓。准分子激光目前正在临床上用于角膜手术，但角膜的定位及其三维表面曲率测量的问题仍未解决。为此，我们研制了一套激光扫描系统样机，该系统可以在对角膜进行三维表面测量后，获得任意的切割线或椭圆，以及高精度的光束定位(小于100微米)。指定切口很容易在监视器屏幕上完成，该屏幕将测量的表面叠加在角膜的视频图像上。通过对新鲜猪去核角膜的多次实验，获得了准分子激光用于切割的照射条件。在脑外科方面，我们开发了一种用于插管主动导航的机械手系统原型。该系统与东京大学开发的CT图像三维重建系统相连接。该机械手具有6个自由度，其中两个自由度组成万向节机构，其中三个为三个正交轴，最后一个用于插管。利用三维重建系统对肿瘤和水肿等目标进行定位，并将坐标送入控制机械手的PC。为了将CT模型坐标与患者身上的坐标相对应，至少在CT切片上成像三个标记物，机械手指向这些标记物进行校准。

In this research, corneal surgery and brain surgery are emphasized to develop microsurgery support system which are less invasive, less contact, more accurate and with higher repeatability in positioning than hand skills. Any damage to the peripheral tissues are more crucial than the other surgery.Non-contact incision using excimer laser is more suitable for the corneal surgery to obtain a clear-cut profile. Excimer laser is currently tested for corneal surgery on clinical basis, but problems of positioning of the cornea and its three dimensional surface measurement for curvature still remain unsolved. Thus, we have developed a prototype of laser scanning system which enables us to get arbitrary incision lines or ellipses and high accuracy of positioning of the beam (less than 100 micron) after three dimensional surface measurement of the cornea. Designation of an incision is easily doneon a monitor screen which superposes the measured surface on the video image of the cornea. Irradiation conditions of excimer laser for incision were obtained through a number of experiments with enucleated fresh porcine corneas. As for brain surgery, we have developed a prototype of manipulator system for active navigation of a cannula. The system is hooked up to a system for 3 dimensional reconstruction of CT images, which was developed in the University of Tokyo. The manipulator features 6 degrees of freedom ; two of which compose a gimbal mechanism, three of which are three orthogonal axes, the last one for cannulation. Targets such as tumor and edema are located with the three dimensional reconstruction system and the coordinates are fed into a PC which controls the manipulator. To correspond CT model coordinates to the coordinates on the patient, at least three markers are imaged in CT slices, which are pointed by the manipulator for the calibration.