EVOLUTION OF THE FASCIOCUTANEOUS ISLAND FLAP LEADING TO THE KEYSTONE FLAP PRINCIPLE IN LOWER LIMB RECONSTRUCTION

Keystone Flap for Closure of Skin Cancer Defects on the Upper Extremity

Background: We sought to examine the efficacy of the Keystone Design Perforator Island Flap (KDPIF) for the reconstruction of skin cancer excision defects isolated to the upper extremity. In particular, to examine the size of defects repaired and the complications associated with the keystone flap procedure isolated to the upper extremity. Methods: This is a retrospective chart review including all patients older than 18 years of age who received a KDPIF procedure between February 2013 and February 2019 for the oncologic reconstruction of skin cancer defects isolated to the upper extremities by a single surgeon. All procedures were done according to the original description by Behan. Results: A total of 32 patients, 18 (56%) male and 14 (44%) female, received 35 keystone flaps between February 2013 and February 2019. The mean age of the males and females was 70.5 and 79.7 years of age, respectively. Thirty-five lesions suspicious for cancer were excised and 14 (40%) basal cell carcinoma (BCC), 11 (31%) squamous cell carcinoma (SCC), 9 (26%) melanoma, and 1 (3%) actinic keratoses diagnoses were histopathologically determined. Skin defect excisions varied from 3.53 cm2 to 31.42 cm2. No intraoperative or postoperative complications occurred. Conclusions: The keystone flap is a successful versatile flap procedure with a low or absent complication rate for the reconstruction of skin cancer excision defects of various locations (eg arm, hand, elbow, forearm, shoulder, and wrist), cancer pathologies, and sizes on the upper extremity. When needed, a Doppler may successfully identify adequate perforating blood vessels for the relatively larger flaps.

A bipedicled keystone perforator island flap: Pedicle division technique with enhanced advancement potential for chronic wound coverage

Since the first description of the keystone perforator island flap (KPIF) in 2003, several modifications have been suggested to enhance its coverage ability. However, locoregional flaps have limited its use in chronic wounds due to decreased elasticity around the defect. We investigated the use of a bipedicled KPIF (bKPIF), which covers a defect while completely elevating the median part of the flap from the fascia. A retrospective chart review of 20 consecutive patients who underwent classical type I KPIF (n = 10) or bKPIF (n = 10) reconstruction from June 2020 to December 2022 was performed. Baseline characteristics, indications, operative details, healing time, and complications were analyzed and compared between the two groups. The average defect size was 30 cm2 in type I KPIF and 36.6 cm2 in bKPIF, and an average flap size of 86.5 cm2 was covered in type I KPIF, larger than bKPIF at 73.8 cm2. The flap/defect ratio was significantly lower in the bKPIF group (p < 0.02), with an average of only 55% pedicular area. The average advancement distance in the bKPIF group was 1.85 cm (standard deviation 0.78) greater than that in the type 1 KPIF group. There was no significant difference between the groups in terms of operation time, complete healing time, and complications. All ten bKPIFs were successful without any flap necrosis. Even though the mean pedicular area in the bKPIF group was nearly half compared with that in the type I KPIF group, it was sufficient to perfuse the entire flap without any major complications. This novel technique using bKPIF has potential clinical relevance, as evidenced by the enhanced ability to cover chronic defects with severe scarring. Lateralizing the hotspots to the bilateral corners of the flap is the mechanism that facilitates this potential.

Keystone flap: a safe coverage option in the handling of salvage for myelomeningocele

BACKGROUND

Myelomeningocele (MMC) is the most common and severe pathology of open spina bifida compatible with life. Its early closure is an urgent therapeutic objective to reduce the morbidity and mortality of neonates, being a surgical challenge with two major objectives: (1) achieve closure of the dural cerebrum-spinal fluid fistula and (2) ensure a stable and durable soft tissue coverage. The use of fasciocutaneous flaps in keystone design is shown as a safe and stable surgical option with excellent aesthetic results in patients with MMC and who presented failed primary closures.

METHODS

Two clinical cases of fasciocutaneous flaps in keystone design were described as a coverage option in patients with lumbosacral MMC, in whom the primary closure was unsuccessful and required a safe coverage as a priority.

RESULTS

Successful coverage of the lumbosacral defect was performed using keystone flaps in neonatal patients with MMC and previous manipulation of the soft tissues when attempting primary closure, but they have had dehiscence of the wound, with a large area of lumbosacral defect and sizeable defect/back ratio.

CONCLUSIONS

The use of keystone flaps is a useful, accessible, and versatile technique as a management option for lumbosacral coverage defects in MMC, achieving a stable and safe covering of the meninges, without cerebrum-spinal fluid fistulas, which also allows the primary closure of the soft tissues in the donor area. The safety of this type of flap when used as salvage in lumbosacral defects with previously handled and raised tissues could infer that it is reliable enough to be considered as a first surgical option in the initial management of MMC.

Thermal Imaging Facilitates Design of a Keystone Perforator Island Flap for a Myxofibrosarcoma Resection Reconstruction: Case Report

Lower extremity defects are challenging to reconstruct. The keystone perforator island flap proves useful in difficult cases. Traditionally, a handheld Doppler is used to confirm perforator vessel(s) within the flap but has disadvantages including low sensitivity/specificity. Surgeons can use thermal imaging to localize "hot spots" on the skin, corresponding to perforators. FLIR ONE (FLIR Systems Inc., Wilsonville, OR) is a portable thermal camera with high concordance with computed tomographic angiography. In this case, when faced with handheld Doppler failure, we used intraoperative thermal imaging to continue planning and raising of a complex lower extremity keystone perforator island flap.

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.

The Keystone Flap-A Case Series Demonstrating Practical Design, Use, and Applications

INTRODUCTION

The keystone design perforator island flap is a trapezoidal-shaped random perforator island flap with many advantages over primary closure, skin grafting, and other local flaps for soft tissue reconstruction commonly encountered with cancer excisions.

METHODS

This case series of 39 keystone flaps in 37 patients reviews the practical design, use, and applications of the flap while highlighting certain important considerations. Keystone flaps were designed as in the original description, with a minor modification in the lower extremity where a higher flap to defect width ratio was used.

RESULTS

Defects varying in size from 6 to 63 cm² were reconstructed in 23 males and 14 females ranging in age from 49 to 89. In all 39 cases, there were 2 minor complications of partial flap dehiscence and no major complications such as partial or complete flap loss.

CONCLUSION

The keystone flap is a versatile and reliable flap with applications almost anywhere on the body. A higher ratio of flap width to defect width up to 1:3 is more appropriate for the lower extremity where tension is higher.

Evolving Concepts of Keystone Perforator Island Flaps (KPIF): Principles of Perforator Anatomy, Design Modifications, and Extended Clinical Applications

BACKGROUND

Keystone flaps have demonstrated growing clinical applications in reconstructive surgery in the past decade. This article highlights flap modifications and their versatility for clinical applications and management of complex defects.

METHODS

A retrospective chart review was conducted of consecutive patients undergoing keystone flap reconstruction at the authors' institution from January of 2012 to December of 2014. Patient demographics, indications, and operative and postoperative details were abstracted.

RESULTS

Forty-two keystone flaps were performed in 36 patients. Indications included malignant melanoma (n = 14), soft-tissue sarcoma (n = 12), benign pathologic conditions (e.g., exposed hardware, enterocutaneous fistula, tissue necrosis) (n = 6), and nonmelanoma skin cancer (n = 4). Twenty-eight percent received neoadjuvant irradiation, and 70 percent of these were for sarcoma. Locoregional adjunct flaps were performed in eight patients. The deep fascia was nearly completely in a circumferential manner in 18 of 36 patients (50 percent), in 92 percent of the sarcoma reconstructions, and located mainly in the lower extremity. Average defect size was 215 cm (range, 4 to 1000 cm). Average defect size was 474 cm and 35.8 cm after sarcoma and malignant melanoma resection, respectively. Average flap size was 344 cm (range, 5 to 1350 cm). Ninety percent of cases had flap sizes exceeding the traditional 1:1 ratio. There was no flap loss or partial necrosis. Mean time to mobilization was 1.8 days, and mean hospital length of stay was 6.8 days.

CONCLUSIONS

Keystone flaps offer an excellent versatile tool for reconstructive surgeons. Fundamental principles behind the vascular basis of the keystone flap and its modifications permit their greater utility in complex wounds in the settings of large oncologic resections, irradiation, and trauma.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Geometrical analysis of the V-Y advancement flap applied to a keystone flap

BACKGROUND

The V-Y advancement flap and, more recently, the keystone flap are commonly used to cover skin defects. Both flaps allow for primary closure after advancement by substituting the initial defect for a narrower defect distributed over a greater length. The first objective of this study was to develop a geometrical analysis of the V-Y advancement flap. The second objective was to explain the benefit of using the keystone flap compared to a single V-Y advancement flap.

MATERIAL AND METHOD

A geometrical analysis is proposed using a two-dimensional analysis in which the flaps are assumed to have a rigid-body behaviour. First, in the case of the V-Y advancement flap, a trigonometric relationship is defined between the distance of closure before and after advancement, thus implying the value of the flap's apex angle. Second, by considering the keystone flap as the association of three V-Y advancement flaps, the trigonometric relationship is applied to the keystone flap.

RESULTS

In the case of the V-Y advancement flap, the optimal apex angles are between 20° and 60°. At less than 20°, the length of the flap increases in an exaggerated manner. At greater than 60°, the distance of closure, particularly at the apex of the flap where a corner stitch is performed, is greater than the distance of closure of the initial defect. In the case of the keystone flap, the width of the final defect around the flap is clearly smaller and more regular compared to the final defect around a single V-Y advancement flap.

CONCLUSION

The geometrical analysis of the V-Y advancement flap in our description illustrates the major benefit of the keystone flap over a single V-Y advancement flap.

Keystone flap reconstruction of primary melanoma excision defects of the leg-the end of the skin graft?

BACKGROUND

During the last 4 years, the keystone-design fasciocutaneous island flap has become the principal form of reconstruction in our unit for primary melanoma defects of the leg distal to the knee where primary closure is not possible.

METHODS

Data describing the primary tumor, surgical management, and outcome were collected prospectively for consecutive keystone flap cases. The study's primary end points were complication rates and length of hospital stay.

RESULTS

A total of 176 patients with new primary melanomas of the lower limb were treated over 4 years. The average Breslow thickness was 1.33 mm (range, in situ to 9.0 mm), and the average width of the defect was 3 cm. The reconstructions comprised 106 standard, 65 modified, and 5 double-opposing keystone type flaps performed from the knee to the dorsum of the foot. Complications that required further therapeutic intervention were seen in eight patients (4.6%), with only one partial flap necrosis (.6%) and one total flap loss (.6%). In this series, modification of the flap design significantly decreased the complication rate (Fisher's exact test, P = .033). There was no increase in complications in the distal third of the leg. The procedure was performed in day-only surgery setting in almost a quarter of patients.

CONCLUSION

We present the largest series of flap reconstructions for melanoma of the leg. The keystone flap is extremely reliable, affords excellent cosmesis, and is technically straightforward to perform. At the Sydney Melanoma Unit, reconstruction after primary melanoma excision on the leg has been transformed so that skin grafts are now rarely performed.