Radiographic characteristics of sagittal spino-pelvic alignment in degenerative lumbar scoliosis

English Keywords:Degenerative lumbar scoliosis  Spine  Pelvis  Sagittal plane

English Abstract:

  【Abstract】 Objectives： To study the radiographic characteristics of sagittal spino-pelvic morphology in degenerative lumbar scoliosis(DLS) and its significance in the pathogenesis of DLS. Methods： This was a retrospective analysis of 103 cases(36 males and 67 females) with DLS, all cases had a mean age of 62.6±7.4 years(43-78 yr); the control group included 139 cases of asymptomatic young volunteers; another control group included 145 cases with cervical spondylosis. The coronal and sagittal parameters of DLS group and the corresponding parameters of the two control groups on anteroposterior and lateral radiograph of the whole spine were measured. L3 tilt, Cobb′s angle, coronal vertical axis(CVA), lumbar lordosis(LL), sagittal vertical axis(SVA), thoracic kyphosis(TK), pelvic incidence(PI), pelvic tilt(PT) and sacral slope(SS) were included. The sagittal parameters in DLS group were compared with those in the two control groups by using independent-sample Student′s t test, and the correlations of the parameters in DLS group were analyzed by using Pearson coefficients. Results: The average PI of DLS group was 50.4°±10.2°, which was significantly higher than that of the control group of aymptomatic young adults(45.1°±9.6°, P<0.01) and the control group of cervical spondylosis(46.9°±9.1°, P<0.01). The DLS group had lower LL and SS(P<0.01), higher PT and SVA(P<0.01) than the two control groups, and lower TK than the cervical spondylosisi group. In DLS group, there were 37 patients complicated with degenerative lumbar spondylolisthesis, accounting for 35.9%, and the average PI was 53.1°±8.8°, while the other 66 cases without degenerative spondylolisthesis had an average PI of 48.9°±10.6°. The PI of them had a significant difference and was significantly higher than that in asymptomatic young adults(P<0.05). There were significant correlations between scoliosis Cobb′s angle and PT(P<0.05), while no correlation was found between other coronal parameters and the sagittal parameters. Significant pairwise correlations were found among LL, PI, SS and PT(P<0.01), LL and PT were correlated with TK(P<0.01), SS was also correlated with TK(P<0.05), and LL was correlated with SVA(P<0.01). Conclusions: DLS patients have a higher PI than normal young adults and cervical spondylosis patients, and a higher PI may participate in the pathogenesis of DLS. Lumbar spine in DLS remains ability of regulating the sagittal spino-pelvic balance.