A 'modified' keystone flap in a single-surgeon case series: A new design in 32 patients

The keystone island flap was described in 2003 by Dr Felix Behan. The design is a curvilinear, trapezoidal random perforator island flap with 4 classic subtypes (I-IV). It was named 'keystone' as it is identical in shape to the central pillar (keystone) used in architecture. It has shown its versatility in the closure of complex skin defects and wounds as an alternative to skin grafts and other reconstruction options (pedicled, transposition or rotation-advancement flaps). This case series reviews the practical design, use and applications of a 'modified flap'. The key modification is the use of only lateral limb fasciotomy incisions to the keystone flap.

A retrospective single-surgeon case series (32 patients), each of whom underwent the 'modified' technique. Data were obtained from folder review on consenting adults who underwent surgery (01 January 2018 to 01 January 2022). Permission was obtained telephonically, and data were captured in a standardised sheet and electronically. Approval was granted by the ethical review board.

Defects (4 cm² - 72 cm²) were reconstructed in adults (21-94 years). The most common site was the lower limb (23/32). There were two minor cases of epidermolysis and no flap loss (100% success rate).

The 'modified' keystone flap is versatile and reliable with applications in multiple sites as a reconstructive tool.

The authors propose a modification to the existing system to include a Type IIC with the 'modified' design.