Correlation and clinical significance between change of Cobb angle and correction of the major curve in patients undergoing posterior vertebral corpectomy

English Keywords:Spinal deformities  Posterior vertebral corpectomy  Major curve  Cobb angle

English Abstract:

  【Abstract】 Objective：To investigate the correlation and clinical significance between change of Cobb angle and correction of the major curve in patients undergoing posterior vertebral corpectomy（PVC）， and the correlation between the placement of pedicle screw in major curve and the correction effect.Method：46 patients suffering from severe rigid spinal deformities undergoing PVC were retrospectively reviewed.All patients underwent standard anteroposterior entire spine radiograph before and after operation，the major curve at coronal plane was divided into three parts：upper，middle，and lower segment.The Cobb angle of each segment was measured.The changes of the Cobb angle for major curve and each segment before and after operation were analyzed and the relationship between the placement of pedicle screws and the correction rate was investigated.Result：The Cobb angle of major curve decreased from preoperative 110.1°±18.1° to postoperative 51.0°±17.3°（P<0.05），with the average correction rate of （54.1±12.2）%（P<0.05）.The middle segment decreased 28.1°±14.7°（P<0.05），with the contribution rate to major curve correction of （49.1±27.3）%.The upper and lower segment decreased 15.7°±13.1° and 15.3°±12.4° respectively（P<0.05），which showed no significant difference between them in contribution rate（25.2±16.6% vs 26.3±22.6%）（P>0.05）.22 patients had at least one pedicle screw in each of the adjacent upper and lower vertebrae of corpectomy，which ensured a better correction rate than otherwise（P<0.05）.Our data also indicated that deformity correction was closely related to the pedicle screw placement rate（r=0.82，P<0.05）.Conclusion：The middle segment contributes most to the major curve correction，the number of placed pedicle screws plays an important role to the correction，and pedicle screw placed adjacently is more important.