Paradoxical motion in L5-S1 adult spondylolytic spondylolisthesis

Abstract

Introduction In patients with spondylolisthesis, it is assumed that flexion accentuates anterior displacement, whereas extension causes some reduction. Paradoxical movement-where flexion causes reduction of spondylolisthesis and extension increases the anterior translation, is rarely described. In this study, we investigate the prevalence of paradoxical motion in patients with L5-S1 spondylolytic spondylolisthesis and why this abnormal motion occurs. Materials and methods Flexion and extension radiographs of 41 patients with grade I and II spondylolytic spondylolisthesis of the L5-S1 segment were analysed. Patients who had previous lumbar spine surgery, recent lumbar spine trauma, those more than 50 years of age and those with poor quality radiographs were excluded. Results There were 24 male and 17 female patients. The average age was 32.7 years. Of the 41 patients, 29 (70.7%) showed no significant instability. Six (15%) patients showed anterolisthesis, where flexion accentuated the forward displacement, while further six (15%) patients showed paradoxical motion. Statistical analyses found that patients with paradoxical motion had a significantly higher slip angle. Conclusion In this study, we have demonstrated that: (1) paradoxical motion in spondylolytic spondylolisthesis is more common than previously thought. (2) Patients without anterolisthesis during flexion in dynamic radiographs may still have (paradoxical) instability. (3) Paradoxical motion may be more common in patients with a low sacral slope and increased lumbosacral lordosis.

The effects of anterior vacuum disc on surgical outcomes of degenerative versus spondylolytic spondylolisthesis: at a minimum two-year follow-up

“…These findings reveal that patients in the DS group sustained more anterior instability. Indeed, we also found that some patients in the IS group (data not shown in the present study) had paradoxical motion, as Oh et al described[ 27 ]. In paradoxical movement, flexion reduces spondylolisthesis while extension increases anterior listhesis.…”

ISSLS PRIZE IN BIOENGINEERING SCIENCE 2018: dynamic imaging of degenerative spondylolisthesis reveals mid-range dynamic lumbar instability not evident on static clinical radiographs

“…However, the inverse has also been reported as early as 1944 by Knuttson et al who found 4 cases of retrolisthesis of the superior vertebral body on forward bending at the L5/S1 segment[25]. This phenomenon has more recently been described in patients with spondylolytic spondylolisthesis[26]. One study showed that nearly half of patients analyzed with spondylolytic spondylolisthesis displayed this so-called “paradoxical motion” via measurement of instantaneous center of rotation, with displacements ranging from 0.5 to 4.5 mm[27].…”

Effects of axial loaded magnetic resonance imaging of lumbar spine on dural sac and lateral recesses

“…Axial loading causes a reduction in the area and diameter of the dural sac at L3/L4 and L4/L5, and, to a lesser extent, at the level of the lumbar spine than L5/S1, which is probably due to paradoxical motion exerted at this level (17).…”