| 摘要 |
A method of determining the size and placement of screws in pedicles during surgery in a selected spinal area, comprising using a computer to generate a dimensionally true three-dimensional image of the bony spine in the selected spinal area; using a computer to hollow out the vertebra in the three-dimensional image with cortical wall thicknesses selected by a surgeon performing the surgery; using a computer to determine the narrowest cross section (isthmus) within each pedicle; using a computer to generate a straight line starting at the center of the isthmus and extending in opposite directions so that it is positioned concentrically within the pedicle without touching the walls thereof, the line terminating inside the vertebral body a predeteimined distance from the anterior inner cortical wall and extending outwardly in the opposite direction to penetrate the posterior pedicle cortex; using a computer to expand the line concentrically and radially to a cross sectional size that is less than that of the isthmus, the line being expanded into a cylinder that stops growing when any portion thereof contacts the inner cortical wall of the hollowed out vertebral body, with the exception of the posterior pedicle cortex; and using a computer to calculate the ideal pedicle screw diameter, length and trajectory based on the dimensions and trajectory of the cylinder generated for each pedicle. ® KIPO & WIPO 2007 |
