MRI findings of lumbar spine instability in degenerative spondylolisthesis

Purpose:To find out the factors suggesting lumbar segmental instability in patients with degenerative spondylolisthesis (DS) on conventional magnetic resonance imaging (MRI).Methods:Ninety-four patients with DS who underwent decompression surgery with or without fusion were selected. Patient demographics and findings on simple radiographs and MRI were analyzed. We divided patients into two groups by the presence of lumbar instability on simple standing plain radiographs and measured degeneration status of intervertebral discs and facet joints and distance of facet fluid signal on T2 axial MRI on each groups. The data were analyzed to find out the correlation between facet fluid signal and lumbar instability.Results:Sixty-three patients were confirmed to have lumbar instability (unstable group (UG), 67%), while 31 patients (stable group (SG), 33%) did not have instability on simple radiographs. The mean age was slightly older in SG (p < 0.05) and SG patients’ degeneration status of intervertebral discs and...