Spine
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Comparative Study
An analysis of errors in kinematic parameters associated with in vivo functional radiographs.
A pair of functional radiographs, taken at each end of the range of motion, are used to determine spinal motions. Graphic construction and computer-assisted methods are available for the radiographic analysis. The later provides many more motion parameters. ⋯ There were only minimal differences, however, between the digitizers when the radiographic films were remarked and redigitized. The error ranges (2 x SD) for the motion parameters were 1) rotation = +/- 1.25 degrees; 2) translation of the inferior posterior vertebral body corner = +/- 0.86 degrees; and 3) coordinates for the center of rotation = +/- 4.3 mm. Both the spinal level and radiographic quality affected the magnitude of errors in all motion parameters.