Device for evaluating a position of balance for the human body

• US 20030004438A1
• Filed: 07/03/2002
• Published: 01/02/2003
• Est. Priority Date: 01/10/2000
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Roussouly, Pierre, Berthonnaud, Eric, Dimnet, Joannes
• Granted Patent: US 7,955,279 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 5/4023 Evaluating sense of balance
• CPC Class Codes: A61B 6/04 Positioning of patients; Tiltable beds or the like operating tables A61G13/00; operating chairs A61G15/00
• CPC Class Codes: A61B 6/0487 Motor-assisted positioning
• CPC Class Codes: A61B 6/505 for diagnosis of bone

Abstract

According to the invention, the patient (4) is placed upon a patient support (3) between an X-ray source (1) and a support for the target plate (2) sensitive to the X-rays. The patient support (3) is connected to a device for detecting the horizontal position of the global axis of gravity (5) of the patient when the X-ray source (1) is in operation. The patient (4) can, for example, remain standing. The inventive device can superimpose an image (Hg) of the global axis of gravity (5) on the digital radiographic image of the patient (4).

Claims

1. A system for evaluating an equilibrium position of the human body, including a source (1) of X-rays, means for supporting a target plate (2) sensitive to X-rays to produce on the target plate (2) a radiographic image of the patient, and patient support means (3) for supporting a patient (4) in a fixed position between the source (1) of X-rays and the support means for the target plate (2) and for generating position signals imaging the horizontal position of the global axis of gravity (5) of the patient (4) relative to the source (1) of X-rays and the target plate (2),

characterized in that it includes:

scanning means (20) for digitizing the radiographic image of the patient produced on the target plate (2), and thereby generating a digitized radiographic image,

means (21) for generating, as a function of said position signals, a digitized image of the cast shadow (Hg) of the global axis of gravity (5) in the plane of the target plate (2),

means (21) for combining with said digitized radiographic image of the patient the digitized image (Hg) of the cast shadow of the global axis of gravity (5), and thereby generating a combined digitized image,

and means (23) for viewing said combined digitized image.

2. A system according to claim 1, characterized in that the means for generating a digitized image of the cast shadow of the global axis of gravity include:

a calculation unit (21) and an associated memory (24) in which geometrical data are stored corresponding to the relative positions of the source (1) of X-rays, the plane of the sensitive plate (2), and the patient support means (3) in a fixed system of axes (XbObYb),

a program stored in a program memory area (26) of the memory (24), adapted for storing said position signals at the time of taking the radiographic image, calculating, as a function of said position signals, the straight line segment (Hg) intersecting the plane of the sensitive plate (2) and the vertical plane passing through the source (1) of X-rays and the horizontal position (Og) of the global axis of gravity (5), and storing the result of this calculation, which constitutes the image of the global axis of gravity.

3. A system according to claim 2, characterized in that:

it includes a scanner (20) for scanning the radiographic image produced on the target plate (2) sensitive to X-rays and producing a series of digital signals constituting the digitized radiographic image,

the program is adapted to receive said digital signals and stores them in the memory (24),

the program is adapted to modify the stored digitized radiographic image by substituting the image of the global axis of gravity (Hg), thereby generating said combined digitized image,

and the program is adapted to display said combined digitized image on a monitor (23), or prints it out on a support.

4. A system according to either claim 2 or claim 3, characterized in that the program includes a calibration sequence, adapted for scanning the radiographic image of a calibration object (40) with radio-opaque markers (A, B, C, D, E, F, G, H), and for calculating said geometrical data from known positions and dimensions of the radio-opaque markers of said calibration object (40), and storing the data in the memory (24).

5. A system according to any of claims 2 to 4, characterized in that it includes:

patient support means (3) having a modified weighing machine force plate (15) carried by a plurality of sensors (C1, C2, C3) arranged at marked positions relative to the system of axes (XbObYb) and producing force signals used by the calculation unit and the program as position signals,

a removable calibration weight which can be positioned on the patient support means (3), has a particular shape, has position marker means which can be made to coincide with complementary marker means on the patient support means (3), and has a center of gravity whose position relative to the position marker means is known,

the stored program including a calibration sequence calculates correction parameters for force signals produced by each sensor (C1, C2, C3) to make the calculated center of gravity coincide with the known geometrical position of the real center of gravity of the calibration weight, which correction parameters are then stored in memory for subsequent reliable calculation of the position of the global axis of gravity of patients.

6. A system according to any of claims 2 to 5, characterized in that said fixed system of axes (XbObYb) has its center (Ob) in the vertical plane (XOZ) passing through the source (1) of X-rays and perpendicular to the support means for the target plate (2) sensitive to X-rays.

7. A system according to any of claims 2 to 6, characterized in that it is adapted to take a radiographic image of the thoracic area, the lumbar area, the pelvic area and the upper femoral area of the patient (4).

8. A system according to any of claims 2 to 7, characterized in that the patient support means (3) are rotatable about a median vertical axis (10) to orient the patient (4) angularly relative to the direction of propagation of rays between the source (1) of X-rays and the support means for the target plate (2).

9. A system according to claim 8, characterized in that the patient support means (3) include armrests (8, 9) on which the patient (4) can rest his arms (6, 7) in a defined advanced position.

10. The system according to claim 9, characterized in that the armrests (8, 9) are attached to a turntable (13) which carries a modified weighing machine force plate (15) on a plurality of force sensors (C1, C2, C3) distributed at marked positions relative to the system of axes (XbObYb) and producing force signals used as position signals by the calculation unit and the program.

11. A system according to any of claims 8 to 10, characterized in that it includes means for indexing the angular position of the patient support means (3) at least every 45°

.