Objective:

The effect of malnutrition on outcomes following posterior lumbar fusion (PLF) remains understudied. This study analyzes the effect of malnutrition across a comprehensive range of BMI on complications following PLF.

Methods:

The Pearldiver Mariner database was queried between 2010-2020 using ICD-9 and ICD-10 codes for malnutrition and CPT codes for PLF. Patients were identified with preoperative BMI diagnosis codes and partitioned into one of the following BMI cohorts: underweight (BMI <20), normal BMI (19-30), obese (BMI 30-40), and morbidly obese (BMI>40). An additional all-BMI cohort was created using patients with any BMI code. All cohorts were matched 1:3 to control patients within the same BMI group without malnutrition based on age, gender, and Charlson Comorbidity Index (CCI). Complication rates were calculated using the Pearson Chi-square method with statistical significance set to p < 0.05.

Results:

The number of patients in each cohort were: 1,106 (all-BMI), 227 (underweight), 808 (normal), 667 (obese), and 449 (morbidly obese). Statistical analysis showed the all-BMI cohort had greater odds of complications related to instrumentation (Odds Ratio [OR]; 2.28; p < 0.001), need for revision (OR: 2.04; p < 0.001), pulmonary (OR: 1.45; p < 0.001), sepsis (OR: 2.89; p < 0.001), surgical site (OR: 1.87; p < 0.001), and urinary (OR: 1.41; p < 0.001) (figure 1). No difference was noted between the BMI-specific cohorts for complication risk (figure 2).

Conclusion:

Our analysis indicates that malnutrition may independently increase PLF complication risk. Surgeons may consider preoperative optimization for malnutrition patients to reduce complication risk.