ABSTRACT
Objective To explore the influence factor of the stability of L5S1 fusion and the relationship between the stability of sacrum fusion and the clinical outcome for degenerative lumber scoliosis with long-segment fusion.Metheds Fifty patients with degenerative lumber scoliosis who underwent the long-segment fusion from June 2010 to January 2015 were included in this retrospective study.Based on post-operative L5S1 fusion,patients were divided into two groups.There were 15 patients(30％,9 male and 6 female patients) with a failing sacrum fusion whose average age 60±7.6 years (range from 58 to 78 years).6 patients had the situation at T12-S1,7 at L1-S1 and 2 at L2-S1.There were 35 patients (70％,26 male and 9 female patients) with a satisfying sacrum fusion whose average age 58.4±4.8 years (range from 50 to 80 years).Among them,16 were at T12-S1,12 at L1-S1 and 7 at L2-S1 levels.The interbody fusion rate and accuracy of pedicle screws were evaluated by anteroposterior and lateral spine radiographs in standing and CT scanning during the postoperative follow-up.The age,body mass index (BMI),bone mineral density,Cobb's angel,lumbar lordosis (LL),sagittal vertical axis (SVA),thoracic kyphosis (TLK),sacral slope (SS),pelvic inclination (PI) and pelvic tilt (PT) were compared between the 2 groups to analysis the relevant factor of the failing L5S1 fusion.Oswestry disability index (ODI) and visual analogue scale (VAS) were compared between the 2 groups in the postoperative follow-up.Results There were no statistically significant difference between the 2 groups preoperative in the age,BMI,lumbar Cobb angel,LL,SVA,TLK,SS,PI and PT.But there was a significant difference between the bone mineral density of 2 groups.LL were-40.5°± 8.7° vs.-41.2°±7.9°;TLK were 1.7°±7.4° vs.1.8°±6.7°;SS were 32.1°±5.6° vs.32.4°±5.5°;PT were 18.7°±10.5° vs.19.5°± 10.1°;PI were 42.3°±4.4° vs.40.1°±5.2°;SVA were 9.2±3.5 cm vs.9.5±3.1 cm;T value were-2.7±1.1 vs.-1.2±1.4.There were no statistically significant difference between the 2 groups in the ODI and VAS in the postoperative follow-up.Oswestry disability index were 8.2％±5.2％ vs.7.8％±4.5％;VAS value were 3.4±2.6 vs.3.1±2.1.Conclusion The smaller the bone mineral density of the patients with DS,the higher the incidence of the fusion failure L5S1 fusion.And when the failing L5S1 of fusion happened,the clinical outcome will not always be poor.