Discharge Hemoglobin Impacts Functional Recovery After Lumbar Fusion

STUDY DESIGN: Retrospective longitudinal observational study. OBJECTIVE: To identify the impact of anemia at discharge on surgical outcomes and functional recovery following lumbar fusion. SUMMARY OF BACKGROUND DATA: Acute blood loss anemia is common following lumbar spine surgery. Current protocols emphasise limiting transfusions, resulting in more patients being discharged with lower haemoglobin. MATERIALS AND METHODS: Records of a consecutive series of patients who underwent one-level or two-level transforaminal lumbar interbody fusion (TLIF) from 2013 to 2022 were reviewed. Standard demographics, surgical parameters, and complications within a year after discharge were recorded. Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS, 0-10) for back and leg pain were collected preoperatively and at 3 months and 1 year postoperatively. Patients were categorized into three groups based on discharge hemoglobin: moderate (8-10 g/dL), mild (10-13 g/dL for males; 10-12 g/dL for females), and no anemia (>13 g/dL for males; >12 g/dL for females). Complications and PROMs were compared. RESULTS: Of 576 patients, 253 were included in the analysis. The average hemoglobin at discharge was 11.1±1.6 mg/dL. Fifty-eight patients (23%) were discharged with moderate, 144 (57%) with mild, and 51 (20%) with no anemia. Complications rates were higher in patients discharged with lower hemoglobin, with significant differences observed in 90-day readmission (14%, 4%, 0%, P =0.002), infections (14%, 4%, 4%, P =0.022), stroke (5%, 0%, 2%, P =0.021), and gastrointestinal complications (13%, 0%, 8%, P <0.001). Patients with moderate anemia at discharge showed the highest ODI and NRS score of leg pain at all timepoints. There were significant differences in the trajectories of ODI ( P =0.021) and leg pain ( P =0.018) among the three groups. Among 180 patients with no complications, either during hospitalization or after discharge, the significant differences remained in leg pain. CONCLUSION: Anaemia at discharge was significantly associated with the complication rate and worse functional recovery following lumbar fusion surgery.