Radiologic investigation of low back pain.

Low back pain is one of the commonest disorders, yet is the most confusing. The cost in work-time lost and in the search for and treatment of its many causes amounts to billions of dollars annually. The traditional techniques for anatomic visualization have been plain-film radiography and myelography, but they have limitations. The development of computed tomography and magnetic resonance imaging have substantially improved anatomic imaging. However, invasive procedures, such as discography, percutaneous nerve-root blocking and percutaneous facet injection, may be helpful in patients with disabling pain in whom noninvasive methods give negative findings, show abnormalities that do not correlate with the symptoms or identify multiple sites of disease. The invasive procedures are believed by some to be associated with too many complications. We have attempted to clarify the strengths and weaknesses of the currently available methods of investigating low back pain and the indications for their use.