The change and clinical significance of sagittal spino-pelvic parameters of adult isthmic spondylolisthesis

English Keywords:Spondylolisthesis  Spinopelvic sagittal parameters  L5 incidence

English Abstract:

  【Abstract】 Objectives: To investigate the differences of spino-pelvic parameters in patients with isthmic spondylolisthesis of different grades, and the correlation between L5 incidence angle(L5I) and the percentage of spondylolisthesis. Methods: 60 patients with L5-S1 isthmic spondylolisthesis(mean age, 47.0 years; range, 28 to 69 years) and age-matched control group of 77 normal adults(mean age, 43.5 years; range, 25 to 63 years) were recruited in this retrospective study. Parameters including slip distance(SD), slipping percentage(SP), pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), L5 incidence(L5I), lumbar-sacral angle(LSA), lumbar lordosis(LL), sagittal vertical axis(SVA) were measured on the long-cassette standing upright lateral radiographs of the spine and pelvis. Patients with spondylolisthesis were divided into two groups based on slipping percentage: group A(low grade) with SP≤30%(30 cases of 60) and group B(high grade) with SP>30%(30 cases of 60). Differences in sagittal parameters among groups were analyzed by using independent samples t-test, and Pearsons′ correlation coefficients were used to investigate the relationship between spino-pelvic parameters and SP. Results: PI, PT, SS, and LL were higher(P<0.05) in subjects with isthmic spondylolisthesis than those in the control group, while LSA decreased significantly. L5I in group B was significantly higher than that in control group, while there was no significant difference between group A and control group. Strong positive correlation between SP and PI, PT, SS, SVA and negative correlation between SP and LSA were confirmed in all the patients with spondylolisthesis. SP showed a positive correlation with L5I in group B(P<0.05), which was the other case in group A. L5I demonstrated a positive correlation with PI and showed a negative relation to LSA in the total isthmic spondylolisthesis group. Conclusions: Spino-pelvic parameters including PI, PT, SS and LL are significantly greater in adult patients with isthmic spondylolisthesis. L5I significantly increases in patients with severer spondylolisthesis and shows positive correlation with slipping percentage which indicates that more attention should be paid to the improvement of L5I.