Assessment of mathematical model for elliptical excision: solving the doubt about vertex angle and predicting postoperative wound length

BACKGROUND: Elliptical excision is the most commonly used method for small benign tumour excision and primary closure. However, elliptical excision remains the topic of debate. The aim of this study was to explore the relationship among postoperative incision, vertex angle, and the length and width of fusiform excision through a mathematical model. METHODS: We collected data from fusiform circle excisions performed at the author’s hospital (101 cases). The measured values were applied to the mathematical model formula for statistical analysis. RESULTS: The functional relationships among the length, width, arc, and angle of the fusiform circle were obtained. The mean apical tangent angle was 100.731°±15.782°, and the mean apical inner angle was 50.366°±7.891°. There was no significant difference between the preoperatively designed arc length preoperative and the postoperative incision length (P < 0.001). The apical vertex push-out distance equals half of the value of the fusiform length subtracted from arc. CONCLUSIONS: The mathematical model can be used to design the incision for ellipse fusiform excision to predict the final wound length.