The factors analyzed included gender, body mass index (BMI), duration of surgery, type of surgery, aspiration, and number of fusion levels. Estimated blood loss (EBL) was obtained from the clinical records of patients as the blood collected from suctioning and the cumulative weight of the saturated sponges. Actual blood loss (ABL) was calculated from the estimated blood volume and hemoglobin level of patients. Hidden blood loss was calculated as the difference between ABL and EBL.
Seventy-eight consecutive patients who underwent ALIF were reviewed. The average values (mean ± SD) for EBL and ABL were 700.1 ± 562.3 mL and 1150.6 ± 770.0 mL, respectively (P = 0.001, Student's t-test). The hidden blood loss averaged 39.2% of the ABL. According to linear regression analysis, surgical duration, type of surgery, and the inclusion of the L4/5 level were independent factors contributing to the ABL (P < 0.05), whereas BMI and gender did not correlate with ABL or EBL.
ALIF is associated with substantial perioperative hidden blood loss. Length of surgery, type of surgery, and the inclusion of L4/5 in the procedure are significant risk factors for increased blood loss.
Level IV: retrospective or historical series.