The clinical significance of rapid prototyping technique in complex spinal deformity surgery—Case sharing and literature review

Treatment of complex severe spinal deformities, such as scoliosis with a Cobb angle greater than 90°, critical spinal kyphosis, or vertebral and rib deformity with impaired lung capacity, remains a great challenge. Preoperative image studies including plain film radiography, computed tomography, and magnetic resonance imaging provide only two-dimensional (2D) images and limited information about these severe deformities. In addition, these studies cannot directly offer visual or tactile feedback for surgeons and patients. On the contrary, the rapid prototyping (RP) technique provides surgeons with full-scale, 3D models, which make more accurate and more direct morphometric information of the complex spinal deformity obtainable. In this study, we intend to share our experience with the RP technique in pediatric spine deformity cases and to provide a literature review. In our study, two patients with severe spinal deformity were included. A real-size spinal model was produced for each patient on the basis of contiguous computer tomography with a slice thickness of 1 mm. All models were used to plan the resection and to identify the anatomic landmarks during the operation. With the aid of these full-scale spinal models, all surgical procedures were performed exactly according to the preoperative plan. A 16-year-old girl with congenital scoliosis with a Cobb angle greater than 90° received staged surgery, including vertebral column resection, correction, and posteriolateral spinal fusion. The other patient was a 3-year-old boy with 80° of Gibbus spine deformity. By means of an anteriolateral approach after thoracotomy, the paraspinal abscess debridement, vertebral column resection, and vertical expandable prosthetic titanium rib application were performed. No postoperative complications such as spinal cord, nerve root, or major vascular injuries were found. The 3D RP models are really helpful in providing direct visual and tactile feedback, improving preoperative planning, identifying the important anatomic landmarks during the surgery, and communicating with patients. If the RP technique can be improved in the future, it is likely to become more acceptable and practical.