Low back pain: a radiographic enigma

Ninety-nine anteroposterior and lateral lumbar radiographs taken of males ages 18-55 were independently analyzed by three chiropractors who assessed 56 variables, including determinations of disc space height, vertebral malalignments and subluxations, spondylosis, postural disturbances, relationships between pelvis and spine, and other congenital or acquired abnormalities. The distribution of low back complaints in this study included 31% with no low back pain, 44% with previous or present mild low back pain and 24% with previous or current severe, and often disabling, low back pain. Determinations were made of interobserver reliability between the three chiropractors and a medical radiologist. Of the 56 radiographic variables assessed by the chiropractors, six demonstrated a high interobserver reliability. In general, the best reliability was for variables that were actual measurements, rather than subjective observations. Sixteen additional variables demonstrated a fair interobserver reliability. Comparison of the observations between a radiologist and the chiropractors showed correlations in their assessments of disc space height at L3-4 and L4-5; otherwise, there was poor interobserver reliability. Few of the radiographic variables were found to be reliable predictors of present or prior history of low back and leg complaints. A few variables (most notably disc space narrowing) were statistically associated with back or leg complaints (P = 0.025). We conclude that spinal radiographs, whether analyzed by measurements, by a radiologist or by chiropractors, have minimal value in predicting the presence or absence of low back complaints and, in particular, have no value in epidemiological studies.