Preoperative malnutrition is associated with increased postoperative complications following lumbar fusion: a...

Lumbar fusion (LF) is a common surgical intervention for degenerative spinal conditions but carries significant short- and long-term risks. Preoperative malnutrition, characterized by low serum albumin or leukocyte counts, impairs wound healing and increases susceptibility to infection, yet its influence on LF outcomes remains underexplored. This study evaluates the association between preoperative malnutrition and long-term postoperative outcomes following LF.

Adult patients undergoing LF between 2003 and 2023 were identified in the TriNetX US Collaborative Network. Malnutrition was defined as serum albumin <3.5 g/dL or leukocyte count <1,500/mm³ within 1 year preoperatively. A 1:1 propensity score match was performed for demographics, comorbidities, surgical approach, and body mass index (BMI), yielding two cohorts (n=20,693 each). Ninety-day and 5‑year postoperative outcomes were compared using hazard ratios (HRs) with 95% confidence intervals (CIs).

Malnourished patients experienced significantly higher 90‑day rates of transfusion (8.4% vs. 4.5%; HR 1.87, 95% CI: 1.73-2.02), wound complications (2.6% vs. 1.5%; HR 1.70, 95% CI: 1.48-1.95), infection (3.2% vs. 2.3%; HR 1.37, 95% CI: 1.22-1.54), and hospital readmission (17.3% vs. 13.8%; HR 1.26, 95% CI: 1.20-1.32). At 5 years, malnourished patients had higher rates of pseudoarthrosis (25.8% vs. 20.5%; HR 1.32, 95% CI: 1.26-1.38), revision surgery (16.2% vs. 11.9%; HR 1.41, 95% CI: 1.34-1.49), and compression fractures (5.8% vs. 3.7%; HR 1.60, 95% CI: 1.46-1.76). All-cause mortality was lower in the malnourished cohort (4.3% vs. 5.8%; HR 0.75, 95% CI: 0.69-0.82), likely reflecting selection bias.

Preoperative malnutrition is independently associated with increased postoperative complications, reoperations, and impaired long-term surgical success after LF. Routine nutritional assessment and optimization should be considered in preoperative planning to reduce morbidity and healthcare utilization.