Recent web-based technologies have brought a variety of new possibilities to the field of medical information. Nevertheless, transferring 3D patient models through usual low-band-width networks is difficult because of the large size of data file. XVL (eXtensive VRML with Lattice), a new framework for 3D Data representation with high quality surface shape, has solved this problem. In cooperation with Lattice Technology Inc., we have created XVL-formatted patient 3D models. The XVL model takes less than 100 kilobytes, whereas the same quality model in Virtual Reality Modeling Language(VRML) format requires more than 5 megabytes. Because of the many advantages of XVL, we have created a 3D web-based educational tool for repair of cleft lip-plastic surgery for congenital defects of the lips that requires complex incisions and reconstruction. Our system can interact with the model and 3D.vi sualization of the incision lines, displacement of skin flaps, and suturing. Our educational tool for cleft lip repair has demonstrated that the XVL model and its web-based application can open up new possibilities for 3D medical information systems. We are currently refining the XVL model and developing XVL-based applications to simulate the actual surgery on the World Wide Web.