A 53-year-old woman, gravida 3, para 3, with a BMI of 38 and diabetes, and who is an active smoker presents to your office with a draining seton placed for recurrent fistula in ano. Magnetic resonance imaging (MRI) shows a right anterolateral transsphincteric fistula with an anterior sphincter defect. Which factor places her at the highest risk for anal advancement flap failure?