Prophylactic muscle flap coverage in frail patients undergoing spinal surgery

Postoperative wound complications remain a significant challenge in complex spinal fusion, particularly in patients with multiple comorbidities. Prophylactic muscle flap coverage can reduce these complications, but the specific patient populations most likely to benefit have not been consistently defined. This study evaluated the utility of the five-item modified frailty index (mFI-5) scores in identifying high-risk patients who may benefit from prophylactic muscle flap closure.

The American College of Surgeons National Surgical Quality Improvement Program database (2005-2020) was queried for patients ≥50 years old undergoing posterior-approach spinal surgery with and without prophylactic muscle flap closure. Patients with mFI-5 scores ≥2 were included, while revision and non-spine procedures were excluded. A 4:1 propensity score match was performed, comparing nonflap to flap patients. Postoperative complications were assessed with chi-square and Fisher's exact tests, and outcomes were further analyzed using multivariate logistic regression.

A total of 680 patients who underwent nonflap reconstruction were matched to 170 patients who underwent flap reconstruction. On univariate analysis, flap coverage was associated with reduced superficial surgical site infection (SSI) (0.6% vs 3.4%, p = 0.049) and increased bleeding requiring transfusion (35.3% vs 5.1%, p < 0.0001). On multivariate analysis, flap reconstruction was independently associated with a 94% reduction in odds of superficial SSI (odds ratio [OR], 0.062; 95% confidence interval [CI], 0.008-0.498; p = 0.022), while higher body mass index (kg/m²) independently predicted SSI risk (OR, 1.09 per unit; 95% CI, 1.03-1.16; p = 0.003). Bleeding requiring transfusion was no longer significant.

Prophylactic muscle flap coverage significantly reduces superficial infection in frail patients (mFI-5 scores ≥2) undergoing spinal surgery. This provides a standardized framework to identify high-risk patients most likely to benefit from this approach.