Radionuclide bone scanning in females with chronic low back pain.

Sixty female patients with chronic low back pain have been studied clinically, radiographically, and by radionuclide bone scanning for evidence of sacroiliac disease. Twenty-four patients had quantitative sacroiliac scintigraphy (QSS) results suggesting sacroiliitis. In only one of these patients was the radiograph abnormal. Clinical and laboratory examinations failed to reveal any possible associated aetiological factors. Six-month follow-up of 18 patients showed that subjective improvement of pain is associated with a return to normal of QSS results, often secondary to anti-inflammatory medication. It is concluded that sacroiliac disease may be a common cause for chronic low back pain in women and that its presence may be missed if radiographs are relied upon to confirm the diagnosis. Its aetiology remains obscure.