[Risk factors associated with massive drainage after posterior spinal orthopaedic surgery for adolescent scoliosis]

Objective: To identify risk factors that influence the massive drainage after posterior spinal orthopaedic surgery for adolescent scoliosis. Methods: A total of 1 461 patients from 11 to 18 years old diagnosed with adolescent scoliosis who underwent first posterior spinal orthopaedic surgery in affiliated Drum Tower Hospital, Medical School of Nanjing University between November 2010 and October 2015 were retrospectively reviewed. Patients were categorized on the basis of massive or normal drainage, with the boundary 30(th) percentile of drainage/estimated blood volume. Preoperative factors including age, gender, body mass index(BMI), ASA physical status, diagnostic type of scoliosis, main Cobb angle, laboratory tests, intraoperative factors including the number of fusion level and screws, tranexamic acid used or not, use of osteotomy and thoracoplasty, use of cell salvage technology, duration of operation, the volume of urine output, blood loss, fluid therapy and transfusion, postoperative factors including the length of hospital stay, number of transfusion, the volume of drainage, time of drain were collected. Univariate and multivariate analyses were used to determine risk factors which were independently associated with massive drainage. Results: The average drainage was (856.3±333.4)ml. 479(32.8%) patients had massive drainage(drainage≥30% of drainage/estimated blood volume). Multivariate analysis identified risk factors of massive drainage: BMI<17.63 kg/m(2), odds ratio(OR)=2.90, preoperative platelet count<190×10(9)/L (OR=1.67), preoperative main Cobb angle≥55 degrees(OR=1.66), number of fusion levels≥11(OR=2.33), number of screws≥15(OR=1.73), use of osteotomy(OR=1.54), intraoperative volume of crystalloids≥35.63 ml/kg(OR=1.40), intraoperative volume of colloids≥28.92 ml/kg(OR=1.82), intraoperative volume of transfusion≥19.55 ml/kg(OR=1.72), while the use of tranexamic acid(OR=0.26) was the only protective factor. Conclusion: BMI<17.63 kg/m(2,) preoperative platelet count<190×10(9)/L, preoperative main Cobb angle≥55 degrees, number of fusion levels≥11, number of screws≥15, use of osteotomy, intraoperative volume of crystalloids≥35.63 ml/kg, intraoperative volume of colloids≥28.92 ml/kg, intraoperative volume of transfusion≥19.55 ml/kg were risk factors associated with massive drainage after posterior spinal orthopaedic surgery for adolescent scoliosis, while the use of tranexamic acid could decrease the possibility of massive drainage.