The effect of symptom distribution on the motion characteristics of the lumbar spine

This study investigated the influence of presenting low back pain symptoms on objective measures of spinal motion. A total of 115 low back pain patients presenting at the hospital's outpatient clinic underwent a detailed motion analysis of their lumbar spine movement. Subjects were then divided into one of three groups based on the distribution of their presenting symptoms using a modification of the Quebec Task Force Classification System. The motion characteristics of these three groups were then compared with an existing database of 203 normal subjects. Prior to analysis, all subjects were age- and sex-standardized to facilitate interpretation of the results. The low back pain subjects were further sub-divided according to their underlying pathology which was ascertained from radiological investigations and clinical examination. Further analysis was performed to investigate if greater clarification in motion characteristics could be identified when patients were classified according to their symptom distribution and their underlying pathology. Analysis revealed that the severity of presenting symptoms did influence the motion characteristics of low back pain subjects. A trend of decreasing flexibility with increasing symptom severity was noted. However, there was considerable variability in the data. Accounting for the subject's underlying pathology as well as the severity of their presenting symptoms did not clarify this variability in motion characteristics any further. In conclusion, although motion is influenced by the severity of the presenting symptoms, the effects are not substantial enough to distinguish between these subjects clinically. Greater clarification is not gained by the inclusion of underlying pathology, suggesting that the Quebec Task Force Classification System using symptoms to categorize patients is adequate.