RAPID PROTOTYPING

Abstract

Surgeons frequently must perform delicate surgery without the benefit of a firsthand look at what they will be operating on. Fracture orientation can be difficult to conceptualize, especially in the acetabulum or spine. Anatomic reduction and stable fixation remain a challenge and have required long incisions with wide exposure, sometimes with increased postoperative morbidity1-9. The inadvertent penetration of screws into the hip joint, during the treatment of both complex acetabular fractures and posterior wall pelvic fractures, has been well documented10,11. Successful surgical correction of deformities of the hip joint before the onset of osteoarthritis requires accurate characterization of the anatomic deviations from normal as the first step in the planning of a corrective osteotomy. Pedicle screws inserted with a standard surgical technique have sometimes penetrated the wall or even missed the pedicle12-20. Diagnostic techniques such as radiography, computed tomography, and magnetic resonance imaging provide only two-dimensional images of fractures and may not depict subtle fractures. Advances in radiology combined with advances in computer technology have made the three-dimensional representation of anatomic structures in living subjects easily obtainable. With use of modern rapid prototyping techniques, computers can now accurately reproduce three-dimensional models of actual osseous anatomy, which can be invaluable for understanding the characteristics of the fracture, for preoperative contouring of plates, and for selection of screw trajectories. The surgical precision that is possible with use of computer image guidance for placement of screws or pins about the hip joint for the treatment of complex acetabular fractures and for insertion of pedicle screws is impressive1,2,21-27. However, this technology is not yet commonly used by surgeons because of its apparent complexity. Easy fabrication of accurate three-dimensional models of the osseous anatomy, easy …