Preoperative Imaging Evaluation Of Spinal Flexibility And Sagittal Compensatory Mechanism In Patients With Degenerative Spinal Deformities

Objective:To assess the prediction ability of bending X-ray film for the correction in degenerative scoliosis(DS).Methods:65 DS patients who underwent posterior surgery in our institution were included. Among them,37 cases received posterior surgery alone and 28 cases received posterior osteotomy surgery. For all patients, pre-operative standing X-ray film, bending X-ray films and post-operative standing X-ray film were taken. Cobb angle was measured in each film. Pearson’s correlation was used to determine the relationship between pre-operative bending Cobb angle and post-operative standing Cobb angle. Correlation between bending flexibility(BF) with correction rate(CR) was also evaluated. Prediction effect between the two groups was compared.Results:For all 65 subjects, Pre-operative bending Cobb angle was correlated with post-operative Cobb angle(r=0.652, p< 0.001) and BF was correlated with CR(r=0.451, p<0.001). For the posterior surgery alone group, the relationship between pre-operative bending Cobb angle and post-operative Cobb angle showed a significant correlation(r=0.772,p<0.001), as well as BF and CR(r=0.729,p<0.001). For the posterior osteotomy surgery group, there was correlation between pre-operative bending Cobb angle and post-operative Cobb angle(r=0.596,p=0.001), but no significant correlation between BF and CR(r=0.237,p=0.225).Conclusion:Pre-operative bending X-ray film can predict the outcome of correction in DS, and its prediction power is superior in posterior only surgery than in posterior osteotomy surgery.Objective:To investigate degenerative changes of the intervertebral disc and their impact on spinal flexibility in patients with degenerative scoliosis.Methods:Retrospective analysis of 66 patients(average age 58.4 years,10 men and 56 women) with degenerative lumbar scoliosis(DLS) was conducted from May 2008 to February 2014. For all patients, pre-operative standing X-ray film, bending X-ray films and thoracolumbar MRI were taken. Cobb’s angle was measured in each X-ray film and intervertebral angle was measured in both standing and bending X-ray films. All discs were graded according to Pfirrmann degeneration grades on T2 weighted saggital MRI imaging. Statistical analyses were performed to determine the correlation between intervertebral disc degeneration with the whole spine flexibility and segmental flexibility.Results:(1)For all 66 subjects, the average Cobb’s angle of pre-operative and bending X-ray film was 35.53°,20.54°, respectively. The average flexibility was 45.32% in our study. Totally 268 discs were graded, including grade Ⅰ 8, Ⅱ 68, Ⅲ 83, Ⅳ 91, V 18. (2) In the main curve, there was significant correlation between the average degree of disc degeneration and the whole spine flexibility(r=-0.727, p< 0.001); (3)The grade of segmental disc degeneration was negatively related to segmental flexibility(p<0.01); (4) The apical intervertebral disc had the most degeneration(p< 0.001) and worst flexibility(p<0.001), compared with other discs in the main curve.Conclusion:The degree of intervertebral disc degeneration is negatively correlated with spinal flexibility in the main curve.Objective:To compare the sagittal compensatory mode between degenerative thoracolumbar kyphosis(DTK) and post-traumatic thoracolumbar kyphosis(PTK).Methods:Retrospective analysis was conducted on 60 patients with thoracolumbar kyphosis treated at our hospital from June 2010 to February 2015 (32 DTK and 28 PTK). For comparison,30 asymptomatic volunteers were included as control group. Standing long cassette posteroanterior and lateral X-ray films were taken for each patient. Kyphosis angle(KA), thoracic kyphosis(TK), lumbar lordosis(LL), pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS) and sagittal vertical axis(SVA) were measured. Differences in these spino-pelvic parameters were compared among the three groups.Results:(1The average age of DTK, PTK and control group was 56.0±7.3,39.0± 8.5,45.5±5.5 years old, respectively.The average age of DTK group was significantly higher than the other two groups(P< 0.001). (2)The TK of DTK group was significantly higher than PTK group(26.5°±5.8° vs 23.3°±7.8°,P<0.05), but no difference was found between DTK group and control group(26.0°±6.3°). (3)The LL and SS were significantly lower in DTK group(23.1°±12.4°,20.4°± 7.7°)than hose in PTK group(43.4°±7.8°,30.4°±6.6°). Additionally, DTK group had higher SVA and PT(62.7 ± 17.5mm,26.1 °±11.9°) than PTK group(16.7 ±7.1mm,16.7°±8.6°), but the values of SVA and PT were similar in PTK group and control group(15.8±7.4mm,15.4°±6.4°). (4)There were no significantly difference in KA between DTK group and PTK group(46.7°±12.8° vs 46.0°± 13.8°); No significantly difference were found in PI among the three groups(45.5° ±9.7°,46.1°±8.8°,45.1°±8.8°).Conclusion:Patients with DTK tend to present sagittal decompensation with decreased LL, retroversion of the pelvis and anterior-shifted SVA. However, regional kyphosis and decreased TK were the common sagittal profile in PTK patients with balanced spino-pelvic alignment.