Clinical Report: Development of a Nomogram to Assess Free Flap Necrosis Risk
Overview
This study identifies five independent risk factors for free flap necrosis in lower limb soft tissue reconstruction and develops a nomogram for risk prediction. The nomogram demonstrates robust discrimination and excellent calibration, providing meaningful clinical utility for predicting necrosis risk.
Background
Lower limb soft tissue defects pose significant challenges in orthopedics and microsurgery, often leading to severe complications such as amputation. Free flap reconstruction is the gold standard for addressing these defects, yet free flap necrosis remains a common and serious complication. Understanding risk factors for necrosis is crucial for improving patient outcomes and guiding clinical decision-making.
Data Highlights
Risk Factor
Odds Ratio (OR)
95% Confidence Interval (CI)
Gustilo-Anderson classification IIIB/IIIC
3.74
1.89–7.41
Preoperative D-dimer > 0.5 mg/L
3.16
1.50–6.64
Preoperative albumin < 35 g/L
2.75
1.41–5.34
Operative time > 6 h
2.59
1.35–4.94
Defect size > 50 cm²
2.05
1.10–3.83
Key Findings
Five independent risk factors for free flap necrosis were identified.
The nomogram achieved an optimism-corrected AUC of 0.87 in the training cohort.
Excellent calibration was demonstrated with a slope of 1.00 and intercept of 0.00.
The validation cohort showed an AUC of 0.86 with a Brier score of 0.130.
The nomogram provided superior net clinical benefit compared to standard treatment strategies.
Clinical Implications
The identified risk factors can guide preoperative assessments and inform surgical planning for patients undergoing lower limb reconstruction. The nomogram serves as a practical tool for clinicians to predict the risk of free flap necrosis, potentially improving patient outcomes through targeted interventions.
Conclusion
The development of this nomogram represents a significant advancement in predicting free flap necrosis risk in lower limb reconstruction. Further validation in multi-center studies is necessary to confirm its generalizability and clinical utility.
