BONE SPET OF SYMPTOMATIC LUMBAR SPONDYLOLYSIS

The aim of this study was to clarify the clinical role of bone single photon emission tomography (SPET) of the lumbar spine in young persons with persistent lumbar pain which might be due to spondylolysis. Thir ty-one bone SPET studies were performed on 25 patients (19 males, 6 fe males) aged 7-26 years (average 15.6 years) who had suffered lumbar pa in associated with physical activity, and who were suspected of having spondylolysis. Planar and SPET images of the lumbar spine were obtain ed 2-3 h following the injection of Tc-99(m)-methylene diphosphonate u sing a single-head rotating gamma camera. The findings on the bone sci ntigram were compared with those on the radiograph. Bone scintigraphy at presentation was positive in only 7 of 15 sites of the pars interar ticularis defects demonstrated on plain radiographs. On the other hand , seven sites of the pars interarticularis which were normal on the ra diograph were positive on bone SPET. As clinical symptoms improved aft er immobilization using a lumbar corset, bone SPET tended to revert to wards normal. The planar image was abnormal in only 8 (42%) of the 19 abnormal sites on the SPET image. A bone SPET study is indicated in pa tients who are negative on radiological tests and who are still suspec ted of having spondylolysis. If SPET is positive in these patients, th e increased bone uptake is most likely suggestive of a state of 'stres s reaction', and may be a good indicator for patient management. If ne gative, further radiological examinations will be required for proper assessment of the origin of lumbar pain.