Preoperative Hemoglobin is Associated with increased Length of Stay and Intensive Care Unit Length of Stay in Multilevel Thoracolumbosacral Posterior Spinal Fusion for Adult Spinal Deformity

Introduction: Preoperative hemoglobin level is an important factor in complex multilevel posterior spinal fusion (PSF) for adult spinal deformity (ASD). This study evaluates the association between preoperative hemoglobin levels and postoperative hospital and intensive care unit (ICU) length of stay (LOS) in multi-level thoracolumbosacral PSF for ASD.

Methods: Patients undergoing PSF were identified in our institutional database. Inclusion criteria were patients with PSF of 6 or more vertebrae, thoracolumbosacral region, and ASD. Patients with PSF of less than 6 levels, a cervical component in the fusion construct, and non-deformity indication were excluded. Demographics, baseline, preoperative, surgical, and postoperative characteristics were extracted. Unadjusted and adjusted (age, gender, smoking status, Charlson Comorbidity Index, operative time, levels of PSF, 3-column osteotomy use, posterior column osteotomy use) generalized linear models with cubic splines were used to elucidate relationships.

Results: 598 patients were included in the analysis. In our cohort mean preoperative hemoglobin was 13.06 ± 1.86 g/dL, mean age was 59.91 ± 14.93 years, 389 (65.05%) were female, 56 (9.36%) were smokers, mean BMI was 27.98 ± 6.29, , mean number of PSF levels was 10.74 ± 2.96, 59 (9.87%) had 3-column osteotomy, 379 (63.38%) had posterior column osteotomy, mean LOS was 7.95 ± 6.76 days, and mean ICU LOS was 2.59 ± 3.7 days. Unadjusted and adjusted regression models demonstrated significant nonlinear relationships (p < 0.001). The expected LOS significantly decreased as preoperative hemoglobin increased until 13.54 g/dL adjusted while the expected LOS remained relatively constant thereafter. The expected ICU LOS significantly decreased as preoperative hemoglobin increased until 13.18 g/dL adjusted while the expected ICU LOS remained relatively constant thereafter.

Conclusion : Preoperative hemoglobin demonstrated significant nonlinear associations with LOS and ICU LOS in multilevel PSF for ASD. Optimal preoperative hemoglobin levels appear to be approximately 13.5-13.6 g/dL for minimizing expected postoperative hospital and ICU duration.