[Early diagnosis of isthmic spondylolysis with MRI]

Early diagnosis of isthmic lumbar spondylolysis cannot always be established on plain radiographs and CT scans, only. In the case presented here, magnetic resonance imaging (MRI) showed typical bone marrow changes in T1- and T2-weighted images, even at an early stage.

A 11-year old female judoka complained of deep lumbar pain with local tenderness to pressure at L3 to S1. Clinically, there was no neurologic deficit. Conventional x-ray showed no abnormalities. In contrast, MRI revealed a locally ill-defined bone marrow oedema in both pars interarticularis of the 5th lumbar vertebra. This was interpreted as the typical MR-tomographic feature of occult stress fracture, which has to be seen as early evidence of isthmic spondylolysis. Complete restitution was achieved after conservative treatment.

In early spondylolysis--presented here in form of a case report--, changes of MR signal intensity in the pars interarticularis may be detected, even before fracture lines are to be seen on plain radiographs. Further studies are necessary to confirm MRI to be the method of choice for early diagnosis.