From the satisfactory results obtained by operative fusion of the lumbosacral region in a series of thirty-five cases, it would seem that this procedure has a definite place in the treatment of low-back pain, when conservative measures are of no avail and when the roentgenogram demonstrates pathology or structural changes consistent with the clinical findings.

Operative fusion of the spine, to be effective in abolishing back pain, must insure absolute obliteration of all motion at the lumbosacral junction. In cases where fusion of the spine has failed to give relief, the fixation has been found, both clinically and by roentgenographic examination, to be incomplete. By the use of the operative technique described by the writer, elimination of all motion is certain.

In the diagnosis of low-back pain, more attention should be directed to the bony structure in the lumbar region and particularly to the posturally defective back. In the presence of atypical structures, trauma becomes at the most only an aggravating factor in the causation of pain. The significance of defective structures is to be especially considered in the care of industrial injuries.

Our understanding of the structural abnormalities that may underlie back pain now makes it possible to single out the spine that may be a potential source of disturbance. As a result, fusion may be carried out without subjecting the patient to long-drawn-out conservative treatment. Also, from stereoscopic studies of the lumbosacral region, it is possible to classify laborers as to physical fitness for heavy work.