Patent ID: 9579161
Date: 2017-02-28
CPC Classifications: A61B

Claim:
1. A system for tracking a patient comprising: a display; a first reference frame adapted to be coupled to a first portion of an anatomical structure; a second reference frame adapted to be coupled to a second portion of the anatomical structure, the second reference frame positioned substantially vertically opposite the first reference frame during the tracking of the patient; a first tracking device coupled to the first reference frame; a second tracking device coupled to the second reference frame; a tracking system configured to track respective positions of the first tracking device and the second tracking device to ensure that a position of the first reference frame relative to the anatomical structure is substantially the same during a surgical procedure, and a navigation system configured to determine respective positions of the first reference frame and the second reference frame during the surgical procedure based on the respective tracked positions of the first tracking device and the second tracking device, wherein the navigation system determines if the position of the first reference frame has changed more than a predetermined amount relative to the first portion of the anatomical structure by determining a change in a difference in relative location of the first reference frame and the location of the second reference frame during the surgical procedure, and wherein the navigation system determines that the difference has changed if a location of a user-defined point on a vector drawn between the respective positions of the first reference frame and the second reference frame superimposed on a displayed image of the anatomical structure on the display is outside of a user-selected boundary volume defined on the image.