Cumulative Sum Analysis of the Learning Curve of Free Flap Reconstruction in Head and Neck Cancer Patients

Objectives. Owing to the functional and structural complexity of the head and neck area, the reconstruction of defects in these areas is challenging. Free flap surgery has become standard for the reconstruction of the head and neck with improvements in microvascular surgery. The aim of this study was to use the cumulative sum (CUSUM) method to evaluate the learning curve for free-flap head and neck reconstruction performed by a single surgeon. Methods. We retrospectively reviewed the medical records of 47 patients who underwent free-flap reconstruction from 2017 to 2021. The clinical demographics and surgical outcomes were analyzed. The total operation time was analyzed using the CUSUM method, which is an analytical approach for visualizing patterns in data by converting raw data into an accumulation of deviations from the average value. Results. CUSUM analysis showed two phases of the learning curve: phase 1 (cases 1-22) and phase 2 (cases 23-47). The operative time in phase 1 (579.9 +/- 128.2 minutes) was significantly longer than that in phase 2 (418.6 +/- 80.9 minutes) (P < 0.001). The re-exploration rate was higher in phase 1 (31.8%) than in phase 1 (4%) (P=0.018). The flap failure rate was higher in phase 1 (9.1%) than in phase 1 (4%), but this difference was not statistically significant (P= 0.593). Conclusion. The learning curve of free-flap head and neck reconstruction seems to stabilize after approximately 20 cases.