ObjectiveTo investigate the correlation of radiographic parameters and health-related quality of life(HRQOL) instruments before and after thoracolumbar kyphosis correction in ankylosing spondylitis (AS) kyphosis.MethodsThirty-eight AS patients with fixed thoracolumbar kyphosis were treated with pedicle subtraction osteotomies(PSO) in our hospital from January 2004 to March 2010.Pre- and post-operative radiological parameters,Cobb T1-S1,pelvic incidence(PI),pelvic tilt (PT),sacral slope (SS),and sagittal vertical axis(SVA) were measured.The Oswestry disability index(ODI) and scoliosis research society-22(SRS-22) questionnaire were used to evaluate the clinical results.Statistical correlation analysis was made to determine correlation between radiographic parameters and overall or partial specific scores of HRQOL instruments.ResultsThe life quality and related radiological spino-pelvic parameters were improved significantly after operation.Preoperatively,Cobb T1-S1,PT,SS,and SVA had partial correlation with ODI walking score and ODI standing score; postoperatively,only PT and SS had partial correlation with ODI.ConclusionPelvic positional parameters are the key parameters for upright activities,and making pelvis in a neutral position is the ultimate goal of surgery.