Method and apparatus for comparative analysis of videofluoroscopic joint motion

Claims

What is claimed is:

1. Apparatus for generating successive video images of a moving bone of a spine of a subject comprising:

a fluoroscope including

means, including a fluoroscopic x-ray tube, for radiating x-rays toward the moving bone;

means, including a control, for controlling the operation of the fluoroscope and the radiation of x-rays by the fluoroscopic x-ray tube; and

means, including an image intensifier, for generating a fluoroscopic image of the moving bone from x-rays radiated by the fluoroscopic x-ray tube toward the image intensifier, the moving bone being located between the fluoroscopic x-ray tube and the image intensifier in the path of the x-rays radiated by the fluoroscopic x-ray tube toward the image intensifier, said image intensifier spaced from the fluoroscopic x-ray tube to permit movement of the bone therebetween;

means for detecting the fluoroscopic image of the moving bone generated by the image intensifier and converting the detected image of the moving bone into successive video images of the moving bone in various positions;

means for recording the successive video images; and

means for displaying the recorded successive video images of the moving bone as the images are being generated by the image intensifier, said displaying means being located adjacent the fluoroscope adapted to be viewed by an operator permitting the operator to selectively observe and position the bone between the fluoroscopic x-ray tube and the image intensifier in response to images displayed on the displaying means; and

means for immobilizing the lower body of the subject whereby only the spine is substantially moved during the generation of succession video images thereof.

2. Apparatus of claim 1 further comprising a crisscrossed grid adapted to be located adjacent the image intensifier between the bone and the image intensifier and adapted to enhance the image of the bone generated by the image intensifier as the bone moves by absorbing radiation directed toward the image intensifier which is not substantially perpendicular to the image intensifier.

3. Apparatus of claim 2 further comprising a table and means for supporting the fluoroscopic x-ray tube on the table such that the fluoroscopic x-ray tube is selectively tiltable with respect to the table so that the angle of the x-rays radiated by the fluoroscopic x-ray tube and impinging on the bone and the image intensifier is selectable.

4. Apparatus of claim 3 further comprising a first display connected to the control and located adjacent the means for monitoring for indicating the intensity of the exposure of the bone to x-rays generated by the fluoroscopic x-ray tube and a second display connected to the control and located adjacent the monitor for indicating the duration of the exposure of the bone to x-rays generated by the fluoroscopic x-ray tube.

5. Apparatus of claim 4 further comprising a remote monitor connected to the recording means for displaying the recorded successive video images as the images are being generated by the image intensifier, said remote monitor being located adjacent the control adapted to be viewed by a technician so that the technician is able to adjust the control in response to image displayed on the remote monitor.

6. Apparatus of claim 1 wherein the detecting means includes means for detecting a still image and for converting the still image into successive still images and wherein the recording means includes means for recording the successive still images.

7. Apparatus of claim 6 wherein the recording means includes means for recording the successive video images interlaced with the successive still images.

8. The apparatus of claim 1 wherein the detecting means comprises a video camera and the recording means comprises a video recorder.

9. Method for generating successive video images on a monitor of a bone comprising the steps of:

providing a fluoroscope;

positioning a bone within the fluoroscope;

moving the bone;

generating fluoroscopic images of he moving bone;

detecting the generated fluoroscopic images of the moving bone;

converting the detected images of the moving bone into successive video images of the moving bone;

recording the successive video images of the moving bone;

displaying the recorded successive video images of the moving bone as the fluoroscopic images are being generated;

positioning the bone within the fluoroscope in response to images displayed on the monitor;

moving the fluoroscope to track movement of the bone thereby producing successive video images of the bone as it moves; and

interlacing still images with the recorded successive video images.

10. Apparatus for analyzing the flexure of a joint between firs and second bones resulting from movement of the bones comprising:

means for creating at least two successive video images representative of the relative movement of the bones and the resulting flexure of the joint, said means for creating comprising a fluoroscopic system adapted to produce successive images of the joint and the bones as the joint is flexed and the bones are correspondingly moved, means for detecting the fluoroscopic images and means for recording the detected sequence of fluoroscopic images; and

means for comparing the successive video images to a reference representation corresponding to a reference movement of the first bone with respect to the second bone and the resulting flexure of the joint.

11. Apparatus of claim 10 wherein said fluoroscopic system comprises:

mean for providing radiation toward the joint to be analyzed;

means, located adjacent a side of the joint opposite the means for providing, for intensifying the provided radiation and for generating the image of the joint therefrom;

a crisscrossed grid located between the means for intensifying and the joint adapted to enhance the image of the joint generated by the means for intensifying.

12. The apparatus of claim 10 wherein the detecting means comprises a video camera and the recording means comprises a video recorder.

13. The apparatus of claim 10 wherein the fluoroscopic system has an x-ray tube and further comprising a table and means for supporting the tube on the table such that the tube is tiltable with respect to the table so that the angle of the x-rays radiated by the tube and impinging on the bones is selectable.

14. Apparatus for analyzing the flexure of a joint between first and second bones resulting from movement of the bones comprising:

means for immobilizing in at least one plane the first bone whereby only the second bone is substantially moved during flexure of the joint;

means for creating at least two successive video images of the relative movement of the bones and the corresponding flexing of the joint;

means for designating a reference point on the first bone on each video image and a monitoring point on the second bone in each video image; and

means for generating a representation corresponding to the pattern of movement of the monitoring point with respect to the reference point whereby only the second bone is substantially moved during flexure of he joint.

15. Apparatus of claim 14 further comprising:

means for storing a reference representation corresponding to a reference movement of the first bone with respect to the second bone and the resulting flexure of the joint; and

means for comparing the reference representation to a present representation.

16. Apparatus of claim 15 further comprising means for providing an alarm when the difference between the reference representation and the present representation is greater than a predetermined limit.

17. Apparatus of claim 15 wherein the reference representation and the present representation comprise equations of the patterns of movement of the monitoring point with respect to the reference point and wherein the means for comparing includes means for determining the difference between coefficients of the equations.

18. Apparatus of claim 15 wherein the reference representation and the present representation comprise graphs of the movement of the monitoring point with respect to the reference point and wherein the means for comparing determines the difference between slopes of the graphs.

19. Apparatus of claim 15 further comprising an image memory and an analog-to-digital converter adapted to convert the video images into corresponding digital information and adapted to store the corresponding digital information in the image memory; a reference memory having digital information corresponding to the reference representation; and a central processing unit adapted to compare the corresponding digital information stored in the image memory to the reference representation stored in the reference memory.

20. Apparatus of claim 15 wherein said means for generating includes means for calculating, from the video images, the minimum and maximum angles between the first and second bones and said means for comparing includes means for determining differences between the minimum and maximum angles as compared to minimum and maximum reference angles, respectively, stored in the means for storing.

21. Apparatus of claim 14 wherein said means for creating comprises a fluoroscopic system adapted to produce images of the joint and the bones as the bones are moved resulting in flexure of the joint, a video camera adapted to detect the fluoroscopic images and a video recorder adapted to record the detected fluoroscopic images.

22. Apparatus of claim 21 wherein said fluoroscopic system comprises:

means for providing radiation toward the joint to be evaluated;

means, located adjacent a side of the joint opposite the means for providing, for intensifying the provided radiation and for generating said images of the joint therefrom;

a crisscrossed grid located between the means for intensifying and the joint adapted to enhance the image of the joint generated by the means for intensifying.

23. Apparatus of claim 21 wherein said means for designating comprises a video monitor adapted to display the detected fluoroscopic images recorded in the video recorder and a light pen connected to the video monitor adapted to indicate the reference point on the first bone and monitoring point on the second bone.

24. Apparatus of claim 14 for use with a human subject wherein said means for immobilizing comprises means for engaging the legs of the subject to prevent movement thereof and for permitting lumbar spine flexing and means for rotating the subject and said engaging means about an axis coaxial with the subject's spine when the subject is substantially erect.

25. Apparatus for analyzing the flexure of a joint between first and second bones resulting from movement of the bones comprising:

means for generating, from at least two successive video reference images of the movement of the bones and the resulting flexure of the joint, a reference representation corresponding thereto;

means for generating from at least two successive video present images of the movement of the bones and the resulting flexure of the joint, a present representation corresponding thereto;

means for comparing the reference representation to the present representation; and

wherein each of said means for generating comprises a fluoroscopic system adapted to produce images of the joint and the bones as the joint is flexed and the bones are correspondingly moved, a video camera adapted to detect the fluoroscopic images and a video recorder adapted to record the detected fluoroscopic images.

26. A fluoroscopic system comprising:

means for providing radiation toward a joint between first and second bones to be evaluated;

means, located adjacent a side of the joint opposite the means for providing, for intensifying the provided radiation and for generating an image of the object therefrom;

a crisscrossed grid adapted to be located between the means for intensifying and the object adapted to enhance the image of the object generated by the means for intensifying;

means for recording at least two successive images generated by said intensifying means, said images representing the movement of the bones and the resulting flexure of the joint; and

means for comparing the successive images to a reference representation corresponding to a desired or previous movement of the first bone with respect to the second bone and the resulting flexure of the joint.

27. The system of claim 26 wherein said means for providing comprises an x-ray tube and said means for intensifying comprises an image intensifier.

28. The system of claim 26 further comprising means for immobilizing the first bone whereby only the second bone is substantially moved.

29. In a video fluoroscopic system including means for providing radiation toward an object to be evaluated during movement ad means adapted to be located adjacent a side of the object opposite the means for providing, for intensifying the provided radiation and for generating an image of the object therefrom, the improvement comprising:

a crisscrossed grid of radiopaque material adapted to enhance the image of the object generated by the means for intensifying; and

means for supporting said grid on the means for intensifying between the means for intensifying and the object wherein said means for supporting comprises a pair of opposing tracks mounted externally on the means for intensifying, said grid positioned within the opposing tracks for selective, slidable movement.

30. Method for analyzing the movement of a joint between first and second bones comprising the steps of:

creating at least two successive video images of the movement of the bones by producing fluoroscopic images of the joint and the bones as the bones are moved, and detecting the fluoroscopic images and recording the detected fluoroscopic images;

determining differences between the successive video images as compared to a reference representation corresponding to a reference movement of the first bone with respect to the second bone.

31. Method of claim 30 wherein said step of creating comprises the step of using a fluoroscopic system comprising:

means for providing radiation toward the joint to be evaluated;

means, located adjacent a side of the joint opposite the providing, for intensifying the provided radiation and for generating said images of the joint therefrom;

a crisscrossed grid located between the intensifying means and the joint adapted to enhance the image of the joint g