•The Modified Frailty Index-5 (mFI-5) is a validated frailty index used to quantify surgical risk, but its role in guiding prophylactic muscle flap use in spine surgery is unclear

Methods:

•Data source: ACS NSQIP (2005–2020)

•Population: Patients ≥50 years undergoing primary posterior spinal surgery who are frail (mFI-5 ≥ 2)

•Groups: Standard closure vs. prophylactic muscle flap

•4:1 propensity matching

•Excluded: prior spinal surgery, concurrent non-spine procedures

•Outcomes: 30-day postoperative complications

•Statistics:

•Chi-square / Fisher’s exact tests

•Multivariate logistic regression

•Significance: p < 0.05

Results:

•850 patients (170 flap vs 680 no flap)

•No significant differences in: Age, sex, BMI, smoking status, comorbidities

•Univariate outcomes:

•↓ Superficial surgical site infection with flap closure [0.6% vs 3.4%, p = 0.049]

•↑ Transfusion with flap closure [35.3% vs 5.1%, p < 0.0001]

•No differences in: deep/organ space infection, wound dehiscence, reoperation, medical complications

•Multivariate outcomes:

•Flap closure→ ↓ odds of superficial surgical site infection [OR 0.06 (94% reduction), p = 0.022]

•BMI → ↑ infection risk [OR 1.09 per unit, p = 0.003]

•Remaining outcomes, including transfusion need, not statistically significant

Conclusions:

Key Findings:

•Prophylactic muscle flap coverage in high-risk (mFI-5 ≥2) patients à decrease in superficial surgical site infections (94% reduction in odds), without increase in overall complications or reoperation rates

Takeaways:

•Supports prophylactic flap use during index spinal surgery in high-risk patients

•Provides a standardized method (mFI-5) to identify candidates

•Reduces reliance on subjective surgeon judgment