Development of Microsurgery Support System with Micro-manipulator

本研究以角膜手术和脑外科手术为重点，开发一种微创、接触少、定位准确、重复性高的显微手术支撑系统。角膜周边组织的损伤比其他手术更为严重，准分子激光非接触切口更适合于角膜手术，可获得轮廓清晰的角膜。目前，准分子激光在临床基础上被测试用于角膜手术，但是角膜的定位及其曲率的三维表面测量的问题仍然没有解决。因此，我们已经开发了一个原型的激光扫描系统，使我们能够得到任意的切口线或椭圆和高精度的定位光束（小于100微米）后，三维表面测量的角膜。切口的指定很容易在监视器屏幕上完成，监视器屏幕将测量表面叠加在角膜的视频图像上。通过对新鲜猪角膜去核的多次实验，获得了准分子激光用于切口的照射条件。对于脑外科手术，我们已经开发了一个原型的机械手系统的主动导航套管。该系统连接到一个系统的CT图像的三维重建，这是在东京大学开发的。机械手具有6个自由度;其中两个组成一个万向节机构，其中三个是三个正交轴，最后一个用于插管。利用三维重建系统定位肿瘤和水肿等目标，并将坐标送入控制操纵器的PC。为了使CT模型坐标与患者上的坐标相对应，在CT切片中成像至少三个标记，其由操纵器指向以用于校准。

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.