Prediction of blood loss during surgery on the lumbar spine with the patient supported prone on the Jackson table.

Background Context: To date, many studies have examined the effects of one or several factors on blood loss during lumbar spine surgery. The nature and extent of the operation, patient position, blood pressure, and a variety of factors related to patient size have been touted as predictors of blood loss.

Purpose: To measure multiple factors implicated as determinants of blood loss and develop a multivariable statistical model capable of predicting blood loss.