COMPUTER-ASSISTED ORTHOPEDIC-SURGERY WITH IMAGE-BASED INDIVIDUAL TEMPLATES

Recent developments in computer assisted surgery offer promising solut ions for the translation of the high accuracy of the preoperative imag ing and planning into precise intraoperative surgery. Broad clinical a pplication is hindered by high costs, additional time during intervent ion, problems of intraoperative man and machine interaction, and the s patially constrained arrangement of additional equipment within the op erating theater, An alternative technique for computerized tomographic image based preoperative three-dimensional planning and precise surge ry on bone structures using individual templates has been developed, F or the preoperative customization of these mechanical tool guides, a d esktop computer controlled milling device is used as a three-dimension al printer to mold the shape of small reference areas of the bone surf ace automatically into the body of the template. Thus, the planned pos ition and orientation of the tool guide in spatial relation to bone is stored in a structural way and can be reproduced intraoperatively by adjusting the position of the customized contact faces of the template until the location of exact fit to the bone is found, No additional c omputerized equipment or time is needed during surgery, The feasibilit y of this approach has been shown in spine, hip, and knee surgery, and it has been applied clinically for pelvic repositioning osteotomies i n acetabular dysplasia therapy.