Portal de Periódicos da CAPES

THREE-DIMENSIONAL ANALYSIS OF LUMBAR-SPINE MOTION BASED ON BI-PLANE X-RAY STUDY

1988; Volume: 9; Linguagem: Inglês

10.3951/biomechanisms.9.139

1349-497X

Masaya Mimura,

Optical Systems and Laser Technology

In order to investigate lumbar physical motion or the pathogenesis of various lumbar spinal diseases, it is important to measure the lumbar coupling motion precisely in vivo. The authors developed an analysis system of the spine using bi-plane X-ray photogrammetry, that was of great benefit to these subjects. In this study, the calculating methods and composition of this system were shown precisely, and using this system the lumbar coupling motions were evaluated quantitatively in normal subjects. The system is composed of a reference frame, a measuring table with X-Y axis magnescales, and a personal computer, the PC-8801 made by NEC, Japan. Three-dimensional reference coordinates are introduced in the frame. Coordinates of any point can be reconstructed from the bi-plane X-ray films. By the use of anatomically characteristic bony landmarks of vertebrae, the vertebral coordinates are determined. The rotational angles of vertebrae are calculated as the corrective rotational angles of their own coordinates. Lumbar coupling motions were studied using this system. Fifteen normal males were used in this study. Their ages were from 24 to 36 years, with an average of 27 years. The subject was first placed in the reference frame in a neutral standing position, and then was asked to twist his trunk maximally to the right and to the left. The resulting three sets of biplanar roentgenograms were analyzed. Measured coupling motions were primary axial rotation, accompanying lateral bending and accompanying flexion/extension. The following results were obtained. (1) The axial-rotation angle, when the trunk was maximally twisted, was about 7 degrees in the whole lumbar spine. There was no significant difference at each intervertebral level. (2) When the trunk was twisted, the lumbar lordotic angle was generally decreased, and the lumbar spine showed scoliotic curvature convex to the twisted direction. The apex was generally located at the L_ intervertebral level. (3) This analyzing system was of great benefit in motion studies of the lumbar spine. And it would be expected to have further applications in various fields.