A variety of tests are currently used in an attempt to predict pain relief following arthrodesis of the lumbar and lumbosacral spine. External spinal skeletal fixation provides a means by which specific spinal motion units can be rigidly immobilized. A trial of temporary external fixation was investigated for its value in predicting the outcome of surgical fusion. Thirty-five patients with chronic low-back pain have been prospectively studied. The results show a statistically significant superiority of temporary external spinal fixation in predicting surgical result as compared with plain radiographs, discograms and facet blocks.