How Much Blood Loss Is Appropriate for a 2- to 3-Level Posterior Lumbar Fusion?

backgroundDespite the known association between higher estimated blood loss (EBL) and suboptimal outcomes, the threshold of EBL that negatively impacts outcomes following elective spine surgery remains unknown. In an open 2- and 3-level posterolateral lumbar fusion, we sought to find a threshold of surgeon-reported EBL associated with length of stay (LOS), 30-day complications, and patient-reported outcomes (PROs).

methodsA single-center, retrospective cohort study was performed for 2- and 3-level open posterolateral lumbar fusions between October 2010 and April 2021. Surgeon-reported EBL (milliliters) was the primary independent variable for predicting LOS (days). Secondary outcomes included 30-day complications and PROs as the minimal clinically important difference (MCID). Multivariable regression and receiver operating characteristic curve with Youden's Index were calculated.

results

conclusionsIn patients undergoing open, posterolateral lumbar fusions, surgeon-reported EBL thresholds at 375 mL for 2-level fusions and 675 mL for 3-level fusions were moderately associated with LOS beyond POD2. In 3-level lumbar fusions, EBL above 538 mL showed a potential association with an increased odds of 30-day complications. CLINICAL RELEVANCE: Surgeons should improve their ability to manage blood loss and implement methods to keep EBL below the provided thresholds to decrease LOS and minimize the risk of complications. LEVEL OF EVIDENCE: 3: