Pelvic Incidence and Lumbar Spine Instability Correlations in Patients with Chronic Low Back Pain

PURPOSE 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. METHODS 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. RESULTS 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). CONCLUSIONS 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.