The Study On The Selection Of Lower Instrumented Vertebra In Posterior Spinal Fusion Treatment For Degenerative Lumbar Scoliosis

Objective:To evaluate the influence on the outcomes of posterior spinal fusion in degenerative lumbar scoliosis by choosing different lower instrumented vertebra.Material and methods:25degenerative lumbar scoliosis patients who underwent posterior spinal fusion from2010to2013in our hospital were selected for this retrospective study. All of them were classified by choosing different lower instrumented vertebra:L5(group A) and S1(group B). Radiographic measurement included Coronal scoliosis cobb angle, trunk shift (TS), Coronal Vertical Axis (CVA), lumbar lordosis (LL), Thoracolumbar kyphosiss (TK) and the amount of the fusion levels on the standing anterior-posterior radiographs before and after surgery. The statistical differences of preoperative and postoperative data of two groups were compared.Results:The means of Coronal scoliosis cobb angle in group A and B were respectively23.04±8.99°and23.08±8.46°before the surgery, both of which had no significant differences (P>0.05). And the cobb angles turned to12.52±9.34°and12.90±6.08°, but the correcting rate did not differ statistically (P>0.05) while did within either group (P<0.01).The pre-surgery trunk shift value were respectively28.25±19.13mm and31.15±12.84mm in two groups, which showed no significant differences, respectively compared with the post surgery value14.17±11.26mm and14.46±9.68mm.(P>0.05).However the pre-and post TS did differ significantly in either group (P<0.001).Similarly, the LL and TK values had no significant differences between two groups both pre-and post-surgery.(pre-LL:-21.21±22.72°and-18.41±23.48°, post-LL:-43.01±5.33°and-38.56±8.00°; pre-TK:17.37±11.68°and10.15±9.29°, post-LL:10.54±5.16°and9.61±5.64°(P>0.05), but had statistical significance when compared within group (P<0.01).For the CVA and SVA, they had statistical significance when compared within group (P<0.05) when choosing L5, however choosing S1had no statistical significance (P>0.05). For the amount of fusion levels, there are no significant differences were displayed between groups.Conclusion:In the posterior spinal fusion treatment for DLS, choosing L5or S1as LIV can achieve similar and satisfactory correcting effects. Choosing L5as LIV can achieve better effects in coronal and sagittal vertical axis..