Two for the price of one: a keystone design equals two conjoined V-Y flaps

Keystone Flaps: Physiology, Types, and Clinical Applications

The keystone perforator flap (KPF) was first introduced in 2003 by Behan et al for use in reconstruction after skin cancer excision. Since its initial description, KPF use has been expanded to complex defects of various etiologies and disorders throughout the body. At its most basic, the KPF is a perforator-type flap designed with a 1:1 flap-to-defect width ratio. Keystone perforator flaps are specifically raised on pedicles arising from musculocutaneous or fasciocutaneous perforator vessels. Major advantages of the KPF derive from the maintenance of perforator vascular territories, perforosomes, permitting increased flap viability. In turn, this allows for more aggressive undermining in sites away from perforators when greater skin mobilization is necessary. Furthermore, the KPF is relatively easy to perform leading to shorter operative times and no postoperative monitoring period. There are basically 4 different types of keystone flaps in order of increasing undermining and disturbance of underlying fascia. These different classifications of KPFs may be used in different anatomical locations over the entire body based on skin laxity and defect size/depth. Numerous advancements and modifications have been documented adapting the KPF to specific conditions, including myelomeningoceles, and scrotal and lower eyelid defects. The purpose of this article is to provide an organized review of the KPF with emphasis on different classifications, applications, and limitations as well as an overview of the surgical technique. We have additionally included a discussion on KPF physiology and review of current literature.

Best Local Flaps for Lower Extremity Reconstruction

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The ideal reconstruction of lower limb defects should replace like with like and minimize morbidity to the donor site, achieving the best possible esthetic and functional outcome. The goal is to obtain stable healing and to resume daily life in an efficient manner. Although the classical local flaps such as gastrocnemius, soleus muscle flap, and the reverse sural flap have allowed to achieve those goals, perforator flaps are now added on to the armamentarium in lower extremity reconstruction using local flaps. A perforator-based local flap, such as a propeller or keystone flap, has made reconstruction efficient while further reducing donor-site morbidity. This article aims to provide a useful review of the best available local flaps for lower limb defects.

Keystone Flap: Overcoming Paradigms

Background:

The physiology and geometry of the keystone flap (KF) are the main factors that support its development. This study reports our experience using the KF and proposes the concept of pedicular area.

Methods:

A prospective cohort study was conducted from October 2014 to December 2016, in which 112 KF procedures were performed with an average follow-up time of 10 months. The conclusions drawn from clinical observations were compared with the findings of a literature review.

Results:

One hundred twelve flaps were performed in 89 patients (45 men and 44 women) with an average age of 64 years (range, 3–89 years). The flap survival rate was 100%. The term pedicular area (PA) was coined to describe a flap segment that remains attached to its bed without vascular detriment and whose location can be randomly selected. In this study, the PA could be reduced up to a 10%, which means that over 90% of each flap was dissected without any harm.

Conclusions:

The KF is a safe, cost-effective technique with better results when compared with other reconstructive procedures. Although research is still needed to better understand the physiological adaptations of KF, the clinical evidence supports its use in many reconstructive scenarios.