Methods for determining pedicle base circumference, pedicle isthmus and center of the pedicle isthmus

Abstract

A method of determining the pedicle base circumference and the pedicle isthmus to facilitate screw placement in a pedicle of a vertebral body during spinal surgery, comprising providing a series of first lines tangential to the outer cortical surface of the vertebral body in and near the pedicle on a transverse section from a three-dimensional image of the vertebral body, providing a series of second lines extending through the vertebral body in and near the pedicle thereof in perpendicular relation to the series of first lines, identifying the pedicle base circumference as the areas of the outer cortical surface where adjacent second lines are at the greatest angle with respect to one another, and identifying the pedicle isthmus as the areas of the outer cortical surface where the secondlines that are opposed to each other are closest to being parallel to one another. The center of the pedicle isthmus is identified from a cross-section thereof as the intersection of two lines derived from the centers of infinitesimal orthogonal second perpendicular lines from the outer cortical surface.

Description

Methods for determining the base circumference of the pedicle, the isthmus of the pedicle, and the center of the isthmus of the pedicle This application claims the benefit of US Provisional Patent Application Serial No. 60 / 761,365, filed January 24,2006. field of invention The present invention relates generally to the field of spinal surgery and to computerized or automated methods for the precise placement of pedicle screws or instruments in spinal surgery, and in particular to determining the pedicle basecircumference, pedicle isthmus, and pedicle isthmus center Methods. Background of the invention Inserting screws into the human spine is a common surgical procedure that has enabled numerous spinal surgeries. Screws are usually placed in the pedicles of individual vertebrae in the lumbosacral spine. Because of their biomechanical advantages over other fixation methods, surgeons are expanding the area of ​​the spine where the pedicle screws are placed. However, adjac...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that it can determine anomalous paths, especially for deformed pedicle bones, resulting in a smaller optimal diameter and length for the determined screw, resulting in a biomechanically poorer construct

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