O2T Advancement Flaps and Mercedes Repairs for Complex Mohs Defect Reconstruction

The speaker, a Stanford Mohs surgeon, reviews O2T advancement flaps and the Mercedes repair as practical reconstruction techniques for complex Mohs defects. She explains that O2T flaps are versatile, have excellent vascularity, are relatively easy to design by converting a linear closure into a T, and are forgiving for trainees because the incision and undermining can be extended until closure is tension-free. Key drawbacks are the need for significant undermining, limited recruitment along one vector, and risk of bleeding or poor healing in tightly sebaceous or anticoagulated patients. She shares multiple cases showing strong results on the forehead, neck, submental area, antecubital fossa, cheek-eyelid junction, and nose, but also illustrates complications such as atrophic scarring, hypopigmentation, leading-edge necrosis, and train-track scarring when flaps are too tight or sutures are left in too long. Practical tips include undermining incrementally, using skin hooks to test apposition, excising standing cones last, oversizing flaps when needed, choosing non-dissolving sutures in higher-risk patients, and removing sutures on time. She then describes Mercedes tripod three-point advancement closures, which distribute tension in multiple directions, minimize undermining, and can be combined with burrow’s full-thickness skin grafts. These are highlighted as especially useful on the temple and large forehead/temple defects, and can be combined with grafts or interpolation flaps for larger, more complex wounds. The talk concludes that both O2T flaps and Mercedes repairs are workhorse options for difficult defects near key structures or subunit junctions, especially when standard linear closure is not feasible.