The bleeding pattern in ankylosing spondylitis patients with thoracolumbar kyphosis treated with pedicle subtraction osteotomy

English Keywords:Ankylosing spondylitis  Kyphosis  Pedicle subtraction osteotomy  Bleeding

English Abstract:

  【Abstract】 Objectives: To investigate the bleeding pattern in the process of pedicle subtraction osteotomy(PSO) for treating thoracolumbar kyphosis with concomitant ankylosing spondylitis(AS). Methods: Twenty-one AS patients performed with one level PSO were included in this study. There were 19 males and 2 females, with the mean age of 35.7±12.7 years (range, 18 to 65 years).The recorded parameters included global kyphosis (GK), the number of fixation segments and PSO level. The surgical procedures were divided into the following six phases：exposure, pedicle screws placement, PSO, closure of the osteotomy site, correction rod placement and closure of the incision. The operation time and the blood loss at each stage were recorded. Results: The total blood loss was 1869.2±378.5ml. The blood loss in the phases of exposure, pedicle screws placement, PSO, closure of the osteotomy site, correction rod placement and closure of the incision were 116.6±52.5ml, 236.4±91.1ml, 832.1±223.5ml, 210.9±61.8ml, 244.7±42.0ml and 228.5±46.1ml, respectively. The percentage of blood loss at each stage was 6.2%, 12.6%, 44.5%, 11.2%, 13.0% and 12.5%, respectively. Conclusions: The largest portion of blood loss occurred in the PSO. Therefore, sufficient blood perfusion must be provided to reduce the risk of spinal cord ischemia at this phase.