Validity and reliability of measures obtained from the OSI CA-6000 Spine Motion Analyzer for lumbar spinal motion

SUMMARY. The aims of this investigation were firstly to determine the level of agreement between angular measures of lumbar spinal motion recorded by the OSI CA 6000 Spine Motion Analyzer (OSI SMA) and measures obtained from X-rays of subjects without lumbar symptoms, and secondly to determine the intra-rater reliability of measures of lumbar spinal range of motion using the OSI SMA on individuals with lumbar symptoms. To fulfill the first aim 13 asymptomatic subjects (mean age = 28.6 years; SD = 7.1) performed the motions of lumbar flexion, extension, side bending to the right, and side bending to the left twice while wearing the OSI SMA, and once for the exposure of the X-ray. The difference between the measures obtained by the two methods was plotted against the average of those measures for each subject to illustrate the level of agreement of the two methods. Differences between measures that were within one standard deviation of the mean were as follows: for flexion, 7 out of 10 showed less than 8 degrees difference; for extension, 7 out of 10 showed less than 7 degrees difference; for side bending to the right, 11 out of 13 showed less than 6 degrees difference; and for side bending to the left, 10 out of 13 showed less than 5 degrees difference. For asymptomatic subjects, measures obtained from the OSI SMA appear to provide good agreement with measures of lumbar spinal motion in the sagittal and frontal planes as determined by X-rays. To fulfil the second aim of the investigation thirty subjects with lumbar symptoms (mean age = 35.9 years; SD = 14.2) performed four trials of lumbar motion to their maximum for flexion, extension, side bending to the right and left, and rotation to the right and left. The OSI SMA hardware was then completely removed and replaced by the same examiner, and the trials were repeated. ICC values were 0.903 or higher for all motions. These results suggest that active range of motion measures obtained with the OSI SMA in subjects with lumbar symptoms are consistent over repeated trials. Copyright 1997 Harcourt Publishers Ltd.