Influence of curve magnitude and other variables on operative time, blood loss and transfusion requirements in adolescent idiopathic scoliosis.

BACKGROUND: Posterior spinal instrumentation and fusion for correction of adolescent idiopathic scoliosis (AIS) typically requires lengthy operating time and may be associated with significant blood loss and subsequent transfusion. This study aimed to identify factors predictive of duration of surgery, intraoperative blood loss and transfusion requirements in an Irish AIS cohort.

METHODS: A retrospective review of 77 consecutive patients with AIS who underwent single-stage posterior spinal instrumentation and fusion over a two-year period at two Dublin tertiary hospitals was performed. Data were collected prospectively and parameters under analysis included pre- and postoperative radiographic measurements, intraoperative blood loss, surgical duration, blood products required, laboratory blood values and perioperative complications.

RESULTS: Mean preoperative primary curve Cobb angle was 62.3°; mean surgical duration was 5.6 h. The perioperative allogeneic red blood cell transfusion rate was 42.8 % with a median requirement of 1 unit. Larger curve magnitudes were positively correlated with longer fusion segments, increased operative time and greater estimated intraoperative blood loss. Preoperative Cobb angles greater than 70° [Relative Risk (RR) 4.42, p = 0.003] and estimated intraoperative blood loss greater than 1400 ml (RR 3.01, p = 0.037) were independent predictors of red blood cell transfusion risk.

CONCLUSION: Larger preoperative curve magnitudes in AIS increase operative time and intraoperative blood loss; preoperative Cobb angles greater than 70(o) and intraoperative blood loss greater than 1400 ml are predictive of red blood cell transfusion requirement in this patient group.