The Analysis Of Sagittal Parameters Of Adult Idiopathic Scoliosis And The Modeling And Clinical Validation Of The Forecasting System For Spino-pelvic Sagittal Balance

Purpose:Adult Idiopathic Scoliosis(AS) is a kind of common spinal diseases, including two groups of patients, one is occurred after skeletal maturity, the other is occurred before growing up and continues until skeletal maturity without timely treatments. The treatment goals of AS are rebuilding and maintaining the spino-pelvic balance, which is the first target of the AS treatment, as well as preventing the increase of the scoliosis and correcting the cure as much as possible. More and more researches indicate that the spino-pelvic sagittal imbalance is the significant cause of pain, disability and the decline of the health related quality of life(HRQL). As the anatomy, the Pathology, the imaging and the clinical manifestation of the spino-pelvis are complex, the clinical treatment of sagittal imbalance is difficult and the realignment surgery is complex and high-risk. The way of surgery now is reconstruct certain sagittal cure by using posterior spinal osteotomy in order to rebuild the right sagittal alignment. However, in order to successfully regain the spino-pelvic sagittal balance after surgery, how much degree should the sagittal cure be reconstruct to? This is also a question which influences the surgeons making the optimize individualized treating strategies.In recent years, researches around the sagittal balance can be described as below:1) A lot of important parameters were put forward and certified their significance, however, no research has analyzed and point out the key parameters (as described in our research) which are mostly contribute to maintaining spino-pelvic sagittal balance.2) Little researches have collected and analyzed all the sagittal parameters being raised before.3) No research has clearly combined the lumbar, the sacrum and the pelvis into one research unit (lumbosacral-pelvic complex, LSPC, as described in this research). More over, no coronal-sagittal joint research in LSPC.4) Several researches have raised certain relationships or formulas used to guid the surgical strategy, however, some defects exist: poor applicability, simple results, lacking some key parameters, lack the co-ordination of the global and the partial parameters.5) As most researches focus on the black and the white races, more and in-depth studies are needed in the field of sagittal balance of the yellow race.This research is based on the questions above. Moreover, we try to establish certain models, which could combine the global and the partial sagittal balance, and could preliminary predict certain key sagittal parameters after the spinal realignment surgery. Finally, different clinical cases was retrospectively studied, trying to expand their applicabilities. These results may be helpful to guide the optimize individualized surgical strategies for the adult spinal deformity.Material and Methods:1. Study Patients:1) patients for spino-pelvic sagittal analysis:63AS patients were collected, who are diagnosed in the same spinal deformity research center and received the same posterior spinal orthopedic surgery from2009to2011.2) patients for establishing the spino-pelvic sagittal models and clinical validation:156AS patients, diagnosed in the same spinal deformity research center from2008-2012, were collected, which randomly divided into2groups:a) modeling group,131patients, used for establishing the spino-pelvic sagittal models. b) preliminary validation group,25patients, used for preliminary validation of the models. Moreover,63ASD(adult sagittal deformity) patients who have received the purely posterior spinal osteotomy, were collected for the clinical validation from2008to2012, including24AS,21adult Congenital scoliosis,18mandatory spondylitis with kyphosis deformity, respectively.2. Methods:1) images acquisition and radiographic evaluation:all patients took preoperative and postoperative long-cassette standing upright posterior-anterior(PA) and lateral X-rays radiographs of the spine and pelvis.2surgeons measures the parameters and take the average value. Sagittal parameters includes:TK, Total TK, TJK, LL, Total LL, SVA, PI, PT, SS, PA, SSA, ST, C7ratio, T1SPI, T9SPI, PR-S1, R-L1, SPT,etc.(see details in the English List of Abbreviations).2) Data processing softwares and:all data were expressed as mean±standard error (SE). Data processing softwares include: Microsoft Excel2007、Matlab software7.8.0(R2009a)、SPSS (Chinese version19.0). Statistical methods include Pearson correlation analysis, Principal component analysis, T test, Multiple linear regression analysis etc. P<0.05was considered statistically significant.Results:1. The analysis of AS spino-pelvic sagittal parameters(1) The key parameters of AS sagittal plane include Total TK、Total LL、PI、SS、PT、PA、 PR-L1、SPT、SVA.(2) There is a complex correlation network among the sagittal parameters, which is indicates as follow. Firstly, the correlations mainly focus on parameters of pelvis, which is probably due to compensatory role of pelvis. Secondly, correlations may mainly due to the anatomy adjacent relationship. Thirdly, total TK and total LL may describe the spinal sagittal curves better than conventional TK and LL.(3) The influence of spinal posterior three-dimensional orthopedic surgery to the AS sagittal balance include, decreasing the spine curves(total TK and total LL) greatly (P<0.01), increasing PT and SPT significantly (P<0.05), decreasing SS and PR-L1significantly (P<0.05). There is no significant difference between pre and postoperative Total LL or Total TK in posterior thoracic or lumbar selective fusion surgery.2. The coronal-sagittal joint analysis of LSPC(1) The lumbar coronal deformity leads to pelvic sagittal higher compensatory status(2) The lumbar coronal deformity, beginning before skeletal maturity, has no influence on pelvic sagittal morphologic parameters; but this, beginning after that, leads to increasing tendency of PR-S1and decreasing trend of SPT. Larger sample sizes are needed for further research.3. Modeling the forecasting system of spino-pelvic sagittal balance and clinical validation using different cases1) Modeling the preliminary forecasting system of spino-pelvic sagittal balance. YPT=-46.21+0.26XtotalTK-0.65XtotalLL+0.25XPI-0.59XPR-SI(R2=0.82806, Average error:3.8357°) YSVA=-27.06+2.02XtotalTK-3.39XtotalLL+3.49XPI-2.69XPTpredict(R2=0.50548, Average error:21.8166mm)The models has good predictive ability (R2>0.5)2) Through clinical validation using different kinds of cases, we find that the forecasting models are suitable for the AS or adult congenital scoliosis with kyphosis deformity, who underwent pure posterior spinal osteotomy or hemivertebra excision surgery. But the forecasting system is not suitable for the mandatory spondylitis with kyphosis deformity.Conclusion:The sagittal balance is due to the connection and interaction between anatomic units of the spino-pelvis, and there are several key parameters which contribute mostly to the sagittal balance, among multitudinous parameters. On this basis, the forecasting system of spino-pelvic sagittal balance is set up and is suitable for the AS or adult congenital scoliosis with kyphosis deformity, who underwent pure posterior spinal osteotomy or hemivertebra excision surgery, but not for the he mandatory spondylitis with kyphosis deformity.