SP23. Quantitative Risk Stratification in Fibula-free Flap Surgery Using Bollinger Scores: A Preliminary Analysis

PURPOSE: The fibula-free flap has become a mainstay in head and neck reconstructive surgery. A major complication of these surgeries includes donor-site flap failure because of vascular insufficiency. Computed Tomography Angiography (CTA) has become standard for preoperative risk assessment, offering crucial information on lower extremity vascular anatomy and stenosis. However, current methods rely on qualitative assessments to determine surgical eligibility and lack a quantitative scoring system for predicting complications based on peripheral atherosclerosis. This study aims to use the Bollinger scoring system from preoperative CTAs to better risk stratify patients. METHODS: A retrospective chart review was completed for all head and neck microvascular fibula-free flaps performed by three surgeons at a university-affiliated tertiary care center from August 2021 to March 2023. Data collected included demographics, medical history, operative details, and post-operative complications within 90 days. Bollinger scores were calculated from preoperative CTAs using Bollinger’s method and log-transformed to account for the data’s right-skew. Statistical analysis included descriptive statistics, Student’s t-tests, chi-squared tests with Fisher’s exact test, and multivariable regressions controlling for comorbidities. RESULTS: A total of 48 patients were included, with 25 males and 23 females. The average age was 51.2 years (SD=20.3). Twenty-six patients (54.17%) had a Bollinger score of 0. Non-zero total Bollinger scores were associated with increased post-operative complications (OR=5.96, p=0.027) and length of stay (LOS) (IRR=1.65, p<0.001). Non-zero ipsilateral lower extremity Bollinger scores were also significantly associated with longer LOS (IRR=1.36, p=0.006). As the total (IRR=1.23, p<0.001) or ipsilateral (IRR=1.25, p<0.001) lower extremity Bollinger score increased, there was a corresponding rise in the LOS. Although not reaching statistical significance, there was a trend suggesting higher post-operative complications associated with higher total and ipsilateral lower extremity Bollinger scores. CONCLUSION: Despite being limited by a small sample size, this study serves as a preliminary exploratory analysis aimed at implementing a quantitative scoring system to better stratify patients undergoing fibula flap surgeries. Our results suggest that non-zero and increased Bollinger scores correlate with worsened fibula-free flap patient outcomes. Future studies should include a larger patient cohort to develop a model that accurately stratifies risk for these patients.