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[3 min read] Surgical ellipse: Are the length-to-width ratio of 3:4 and a vertex angle of 30 ̊ correct?
It has been postulated that elliptical cutaneous excisions must possess a length-to-width ratio of 3:4 and a vertex angle of 30 ̊ or less in order to be closed primarily without creating a “dog ear”. These dimensions became axiomatic in cutaneous surgery and have been taught in the apprenticeship model for years. A study examined the validity of that paradigm.
Researchers collected data from two sources: ellipses described in the literature (57 cases); and elliptical excisions performed at the authors’ outpatient clinic (83 cases). The surgical ellipse lengths, widths, and vertex angles were analysed, and the data were compared to a mathematical formula used to generate a fusiform ellipse.
The length-to-width ratio of 3:4 was found to be inconsistent with the recommended vertex angle of 30 ̊. In fact, a length-to-width ratio of 3:4 determines a vertex angle of 48 ̊ – 63 ̊. A 30 ̊ vertex angle is only feasible with long length-to-width ration of about 7.5.
To conclude, the paradigm that surgical ellipses should have a vertex angle of 30 ̊ with length-to-width ratio of 3:4 is incorrect. Evidence from actual surgical practice and from mathematical formulation shows that either the length-to-width ratio must be larger than 3 – 4 or the vertex angle must be larger than 30 degrees.