Lumbosacral fractional curve effected on the postoperative coronal imbalance in adult spinal deformity

English Keywords:Lumbosacral fractional curve  Adult spinal deformity  Coronal balance  Scoliosis correction  Complication

English Abstract:

  【Abstract】 Objectives: To investigate the risk factors for postoperative coronal imbalance after adult thoracolumbar/lumbar spinal deformity surgery, and evaluate the impact of lumbosacral fractional curve(L4-S1, LFC) on the postoperative coronal imbalance. Methods: Patients with adult spinal deformity who received correction treatment from January 2008 to September 2018 were retrospectively reviewed. Inclusion criteria included age older than twenty years, major thoracolumbar/lumbar curve(Cobb angle≥30°) with apex located between T12-L4, and compensatory lumbosacral fractional curve. All the patients underwent long segment fusion(more than 5 levels), and had at least six months follow-up. Demographic and radiographic data, surgical parameters, health-related quality of life(HRQOL) outcomes, as well as the relationship between lumbosacral fractional curve and postoperative coronal imbalance were analyzed. Results: A total of 157 adult spinal deformity patients were included in this study, 52 males and 105 females, with an average age of 56.4 years old(range, 26-77 years). There were 39 cases of congenital deformity, 35 cases of idiopathic scoliosis and 83 cases of de novo scoliosis. Twenty-four patients(15.3%) occurred coronal imbalanced after surgery, in whose postoperative ODI and SF-12 PCS outcomes had no significantly changed when compared with the preoperative level. In radiographic analysis, there was no significant difference(P＞0.05) of the following parameters between balance group and imbalance group, including major curve angle and flexibility, LFC angle and flexibility, preoperative L4, L5 vertebral tilt, osteotomy method, upper and lower instrumentation level, correction rate and remnant angle of the major curve. There was significant difference of the following parameters between balance and imbalance group, including remnant angle of LFC curve(6.3° vs 12.2°, P=0.000), postoperative L4 tilt(8.2° vs 17.3°, P=0.000), and postoperative L5 tilt(6.4° vs 15.2°, P=0.000). The incidence of postoperative coronal imbalance significantly increased in patients with coronal C7 plumb line at convexity side of the major thoracolumbar/lumbar curve(23.2%). Conclusions: The health-related quality of life (HQOL) is significantly affected in patient with postoperative coronal imbalance. Preexist C7 plumb line at convexity side of the major thoracolumbar/lumbar curve, large remnant angle of LFC, large postoperative L4 and L5 tilt are risk factors of postoperative coronal imbalance.