Preoperative factors predicting intraoperative blood loss in female patients with adolescent idiopathic scoliosis.

In this article, a retrospective analysis of 161 female patients with adolescent idiopathic scoliosis (AIS) is performed who underwent posterior correction and fusion using all-pedicle screw instrument.The aim of this article is to find out preoperative factors that influence intraoperative blood loss (IOBL) in female patients with AIS.The IOBL in posterior correction and fusion surgery for patients with idiopathic scoliosis greatly varies. The variables affecting the IOBL also greatly vary among different studies.Medical records of all female patients with AIS who underwent posterior correction and fusion operations using the all-pedicle screw system in our hospital from January 2012 to January 2014 were reviewed. Patients with irregular menstruation, who underwent osteotomy, and using coagulants were excluded. Preoperative clinical data, including patient age, height, weight, Risser sign, day after last menstruation, major curve Cobb angle, fulcrum-bending Cobb angle, curve flexibility index, sagittal thoracic Cobb angle, sagittal lumbar Cobb angle, albumin, hemoglobin, platelet, activated partial thromboplastic time (APTT), prothrombin time, thrombin time, fibrinogen, fusion level, menstrual phase, and blood type, were collected. Data were further analyzed using multiple linear regression with forward elimination.A total of 161 patients were included in this study. The mean IOBL was 933.98 ± 158.10 mL (500-2000 mL). Forward selection showed that fulcrum-bending Cobb angle, fusion level, Risser sign, APTT, fibrinogen, and menstrual phase were the preoperative factors that influenced the IOBL in female patients with AIS. Equation of IOBL was built by multiple linear regression: IOBL = -966.228 + 54.738 Risser sign + 18.910 fulcrum-bending Cobb angle + 114.737 fibrinogen + 21.386 APTT - 71.312 team 2 - 177.985 team 3 - 165.082 team 4 + 53.470 fusion level. R = 0.782.Operation for patients with AIS was featured by large IOBL. Large fulcrum-bending Cobb angle, the number of level fused, higher Risser sign, high APTT, high preoperative blood fibrinogen concentration, and premenstrual phase predicted higher IOBL.