[Correlation between lumbar vertebral instability and severe degenerative spondylolisthesis]

Severe spondylolisthesis is related to high degenerative changes in vertebral spine. Degenerative spondylolisthesis often is seen with high-sacral slope. This study was conducted to investigate the relationship between high degenerative spondylolisthesis and sacral slope. A cross-sectional prospective study was done in patients with low back pain in Shafa Yahyaian and Sina University Hospitals in Tehran, in 18 months [April 2010-October 2011]. Intermittent or continuous low back pain for three months and history of two disable low back pain attacks since one year ago were inclusion criteria. Pregnant patients were excluded. Lumbar vertebra displacement to vertebra body size ratio was calculated in dynamic mode. The ratio higher than 8% was considered as a lumbar instability. Rotation angle more than 11 Degree was considered abnormal. In this study, 52 patients [30 men, 22 women] with 38.35 +/- 9.49 years old were enrolled. Mean body mass index was 23.01 +/- 4.59 kg/m[2]. Thirty cases had abnormal vertebral displacement. Angulation of the disc space more than 11 degrees was seen in 20 patients. No statistically significant difference in pelvic index between normal and abnormal lumbar vertebra displacement [P=0.443]. The mean pelvic index in normal and abnormal angulation groups were 55.97 Degree and 53.58 Degree, respectively; the difference was not statistically significant [P=0.556]. The results of the study showed disc degeneration had no association with sacral slope. High sacral slope can intensify spondylolisthesis but does not affect the incidence of degenerative spondylolisthesis. Additional research is required to find the other causes of degenerative spondylolisthesis

Pelvic incidence and lumbar spine instability correlations in patients with chronic low back pain

Many factors such as lumbar instability and spinopelvic alignment are associated with low back pain. Our purpose was to analyze the pelvic incidence - one of spinopelvic alignment parameters- and spine instability correlations in patients with chronic low back pain. Fifty-two patients suffering from chronic low back pain entered this case control study. Lateral spine radiography was taken from patients. pelvic incidence and L3, L4 and L5's vertebral body width were measured for all patients, and lumbar instability was evaluated in 3 different levels: L5-S1, L4-L5 and L3-L4. Thirty-two patients having lumbar instability formed group A and 20 patients without lumbar spine instability allocated to group B. Average age, mean weight, height, body mass index and mean vertebral width of both groups did not differ meaningfully. Pelvic incidence's mean amounts set to 53.9 in group B and 57.7 in group A without any significant difference; but pelvic incidence was significantly lower in patients with lumbar instability of L5-S1 origin [P=0.01]. Overall, pelvic incidence did not differ between two groups. However, separate evaluation of each level revealed lumbar instability of L5-S1 segment to be associated with lower pelvic incidence