The combined effect of nutritional status and body mass index on 90-day adverse events following long-segments fusion for adult spinal deformity: a propensity score-matched analysis.

OBJECTIVE

The aim of this study was to investigate the individual and combined effects of PNI (prognostic nutritional index) and BMI (body mass index) on 90-day adverse events (AEs) following adult spinal deformity (ASD) surgery.

METHODS

A retrospective analysis was conducted on prospectively collected data from patients who underwent open long-segment fusion surgery for ASD. Patients were stratified into four groups based on BMI and PNI: low BMI with low PNI (LBLP), high BMI with low PNI (HBLP), low BMI with high PNI (LBHP), and high BMI with high PNI (HBHP). The primary outcome was the incidence of postoperative AEs within 90 days of ASD surgery.

RESULTS

The LBLP group had a significantly higher risk of overall AEs (58.7% vs. 33.3%, p = 0.004) and infectious complications (20.6% vs. 7.9%, p = 0.042) compared to the LBHP group. The HBHP group exhibited a higher rate of major AEs (28.1% vs. 12.3%, p = 0.036) and infectious complications (15.6% vs. 3.5%, p = 0.026) within 90 days postoperatively than the LBHP group. Multivariate logistic regression analysis identified male, higher American Society of Anesthesiologists class, increased intraoperative blood loss, and HBHP status (compared to LBHP) as independent predictors of 90-day major AEs.

CONCLUSION

In patients with low PNI, those with low BMI had a significantly higher risk of overall adverse events and infectious complications. Conversely, among patients with high PNI, those with high BMI were more prone to major adverse events and infectious complications within 90 days postoperatively.