Predictors of massive blood loss in pedicle subtraction osteotomy for ankylosing spondylitis kyphosis

GUO Hong-fei; ZHANG Yong-gang; YAO Zi-ming; FU Jun; WANG Jing-ming; DU Jian-wei; TANG Xiang-yu; WANG Yan

doi:10.3969/j.issn.2095-252X.2014.10.007

Abstract：Objective To investigate the predictors of massive blood loss ( MBL ) in pedicle subtraction osteotomy ( PSO ) in the treatment of spinal kyphosis caused by ankylosing spondylitis ( AS ).Methods A total of 147 patients with spinal kyphosis caused by AS underwent PSO, whose clinical data were collected. Among them, the data of 106 patients were complete, who were divided into 2 groups. In group A (n=69 ) the intraoperative blood loss was more than or equal to 30% of the estimated blood volume, and in group B (n=37 ) the intraoperative blood loss was less than 30% of the estimated blood volume. The preoperative data were compared between the 2 groups, and univariate analysis was undertaken to distinguish all the possible predictors of MBL. And a binary logistic regression analysis was used to determine the independent risk factors of MBL. The relationship between the incidence of MBL in all the 106 cases and the cumulative amount of PSO by spine surgeons was analyzed with the Pearson correlation test.Results There were more cases of double-segment osteotomy in group A ( 65% ) than in group B ( 35% ), with the global kyphosis ( GK )≥70o and the number of ifxation segments≥9. Logistic regression analysis showed that more than or equal to 9 ifxation segments and double-segment osteotomy were independent risk factors for MBL. The Pearson correlation test showed that the incidence of MBL was decreased with the increase of the cumulative amount of PSO by spine surgeons in a certain range and a linear correlation was found between them.Conclusions When PSO is performed in the treatment of spinal kyphosis caused by AS, the incidence of MBL is 65%. The predictors of MBL included the preoperative Cobb’s angle≥70o, double-segment PSO and number of ifxation segments≥9, and the last 2 predictors are independent. In a certain range, with the increase of the cumulative amount of PSO by spine surgeons, the incidence of MBL will be decreased.