Three-Dimensional Analysis of Scoliosis Surgery Using Stereophotogrammetry

Scoliosis is a deformity characterized by coronal, sagittal and axial rotation of the spine. Surgical instrumentation (metal pins and rods) and eventual fusion of the spine are required in severe cases. Assessment of the deformity requires enough accuracy to allow proactive planning of individual interventions or implant designs. Conventional 2-D radiography and even 3-D CT scanning do not provide this, but our new stereophotogrammetric analysis and 3-D visualization tools do. Stereophoto pairs taken at each stage of the operation and robust statistical techniques can be used to determine rotation, translation, goodness of fit, and overall spinal contour before, during and after the surgical instrumentation. Novel features of our software include 3-D digitizing software that improves existing stereophotogrammetry methods, robust statistical methods for measuring 3-D deformity and estimating errors, full 3-D visualization of spinal deformities with optional head-coupled stereo ("fish tank virtual reality"), full integration with commercial animation software, use of consumer PhotoCD technology that significantly lowers costs for data collection and storage while increasing accuracy, and simultaneous 3-D viewing and control at remote locations over high-speed ATM networks.