HOW WE DO IT: the Keystone flap for large skin defects: our experience with 30 consecutive cases

The keystone perforator-based fasciocutaneous island flap is a method of locoregional skin defect reconstruction, consisting of two conjoined V to Y advancement flaps. In this article, we report a series of 30 consecutive cases in various body parts with the aim to demonstrate the versatility of the keystone flap in the reconstruction of various skin defects after removal of a suspected malignant skin lesion and evaluate our clinical experience while maintaining oncological safety and good aesthetic results.

Patients who underwent keystone flap reconstruction between January 2016 and January 2021 were retrospectively reviewed. Their demographics, operative details, oncological data and postoperative details were obtained from the institution's internal electronic patient records system.

The majority of the skin defects were the result of an oncologic resection (97%, n = 29) and were located in the pretibial region (47%, n = 14). In five cases (17%) there was a need for a double keystone flap to cover the skin defect. One or more risk factors (hypertension, smoking, anticoagulation, …) were identified in 22 patients (73%). Minor complications (partial wound dehiscence, effusion or surgical site infection) occurred in ten cases (33%) which were resolved with conservative wound management or systemic antibiotics. There were no major postoperative flap-related complications such as flap failure or need for re-surgery.

In our experience, the keystone island flap is an effective and reliable technique to attain a single stage tension-free closure of large skin defects. Due to its low technical complexity and high success rate, we consider it a feasible alternative to other reconstructive flaps and grafts for direct closure of secondary defects.