These authors contributed equally to this work.
This article was presented as an e-poster at PRS KOREA 2020 on November 13-15, 2020.
Covering a small defect on the anterior lower leg is challenging because less soft tissue is available. This study presents the application of a keystone flap (KF) with omega variation (OV) and Sydney melanoma unit modification (SMUM) for small- and moderate-sized pretibial defects.
This study included a series of six cases of anterior lower leg defect reconstruction with OV and SMUM KF technique by a single surgeon between December 2017 and June 2020. Records and photographs of the patients were collected and analyzed.
The defects’ sizes ranged from 1.5×2.5 to 6×8 cm. All defects were covered with OV KF, SMUM KF, or OV SMUM KF based on the hotspots of surrounding perforators. The flap sizes varied from 3×6 to 8×17 cm. Moreover, all flaps were completely viable. A marginal maceration developed in one case, which was mended with conservative dressing. Outcomes were favorable in all patients during the average follow-up period of 4.83±1.17 months.
This study successfully covered small- and moderate-sized anterior lower leg defects with OV and SMUM KF. We therefore suggest the OV and SMUM KF techniques as good alternative modalities for anterior lower leg reconstruction.
The coverage of defects in the anterior lower leg is often challenging and difficult for reconstructive surgeons because of relatively insufficient soft tissue compared to other areas of the lower leg [
The study involved patients who underwent KF reconstruction with OV and SMUM to cover defects in the anterior lower leg from December 2017 to June 2020. Patients who underwent only KF reconstruction, i.e. only the OV KF, only the SMUM KF, and a combination of the OV and SMUM KF, were included. However, patients who underwent anterior lower leg reconstruction using other types of KF, such as type I (skin incision only), type II (a division of the deep fascia), type III (opposing KFs designed to create a double-KF), and type IV (KF with undermining of up to 50% of the subfascial flap) [
This study was approved by the Institutional Review Board of Konyang University Hospital (approval number: 2017-07-004). Moreover, all research procedures in this study were performed following the ethical guidelines of the 1975 Declaration of Helsinki. All participants provided written informed consent.
Each patient received preoperative management for wound preparation, including serial debridement, conventional wound dressing, negative-pressure wound therapy, and antibiotic treatment to control infection and inflammation of surrounding tissues, for at least 1–2 weeks. The final defect was covered with the KF technique with OV and SMUM after achieving wound preparation and stabilization through these treatments. The operation was performed in the supine position and under local or general anesthesia, depending on the size of the defect and the patient’s general condition. The final defect was measured after complete debridement. Consequently, we tried to check and mark perforator hotspots around the defect using a handheld ultrasound Doppler device as much as possible, especially in larger defects. Both the size of the defect and laxity of surrounding tissue were considered when designing the flap [
Either OV KF alone, SMUM KF alone, or a combination of OV and SMUM KF was used for each case. OV KF was used to add rotational flap movement. The original defect was therefore closed in a fish mouth fashion [
This study recommended that the patients use CICA-CARE (Smith & Nephew, Watford, UK), a silicone gel sheeting designed for postoperative scar management, for 2–3 months postoperatively.
The study included six patients (four men and two women) with an average age of 41.67±22.42 years (range, 14–70 years).
A 70-year-old man suffered from skin necrosis on the lower third of the left anterior lower leg (
A 28-year-old woman suffered from skin necrosis on the lower third of the right anterior lower leg (
A 14-year-old male teenager suffered from a skin avulsion on the upper third of the left anterior lower leg (
The present study described the experience of successfully utilizing the OV and SMUM KF technique to reconstruct six consecutive cases of anterior lower leg defects, conducted by a single surgeon (the corresponding author of this study). As previously stated, reconstruction of anterior lower leg defects is always troublesome and challenging [
Though conventional muscle-based local flaps (e.g., soleus, gastrocnemius, and tibialis anterior muscle flaps) have been used for anterior lower leg defects [
The KF is one type of perforator-based flap devised by Behan in 2003 [
The KF consists of double-opposing V-Y flaps joined together; their advancement toward the flap center (along the longitudinal axis) provides some residual laxity within the flap, which allows for KF movement into the defect (along the horizontal axis) [
From these perspectives, both OV and SMUM are very useful modifications in the KF reconstruction of the anterior lower leg. OV KF provides further flap movement via additional rotational movement, further reducing tension without sacrificing the healthy tissues in wound closure [
This study has some limitations despite its successful results. First, the present study is a nonrandomized retrospective clinical review with very small sample size and no comparison group [
This study successfully covered small- and moderate-sized anterior lower leg defects with OV and SMUM KF with favorable outcomes. Based on the present study experience, the OV and SMUM KF techniques are considered good alternative modalities for anterior lower leg reconstruction.
No potential conflict of interest relevant to this article was reported.
Schematic illustration of OV and SMUM. (A) OV keystone flap. Further undermining of the flap (blue circles) with preserving the central hot spot of perforators (red x marks). (B) SMUM keystone flap (maintenance of a skin bridge along the greater arc of the keystone design perforator island flap). Red arrows indicate directions of the flap movement. OV, omega variation; SMUM, Sydney melanoma unit modification. Reprinted from Lim et al. World J Clin Cases 2020;8:1832-47 [
A 70-year-old man (case 1). (A) The final post-debridement defect (1.8×4 cm) was at the lower third of the anterior lower leg, and a 3.5×7.5-cm keystone flap was designed on the lateral side of the defect. (B, C) The defect was successfully covered with the Sydney melanoma unit modification keystone flap. (D) Postoperative clinical photograph after 2 months.
A 28-year-old woman (case 3). (A) The lesion was located on the lower third of the anterior lower leg. (B) The final post-debridement defect was measured to be 1.8×3.5 cm, and a 3.5×8-cm keystone flap was designed on the lateral side of the defect. (C) The defect was successfully covered with the omega variation and Sydney melanoma unit modification keystone flap. (D) Postoperative clinical photograph after 7 months.
A 14-year-old male teenager (case 5). (A) The final post-debridement defect (3×4 cm) was located on the upper third of the anterior lower leg, and a 5×12-cm keystone flap was designed on the lateral side of the defect. (B, C) The defect was successfully covered with the omega variation and Sydney melanoma unit modification keystone flap. (D) Postoperative clinical photograph after 5 months.
Patients data
Case | Sex/age (yr) | Defect cause | Defect location | Defect size (cm) | Flap size (cm) | Intraoperative handheld ultrasound Doppler tracing | KF type | Anesthesia | Flap survival | Complications | Follow-up period (mon) |
---|---|---|---|---|---|---|---|---|---|---|---|
1 | M/70 | Skin necrosis due to trauma | Lower 1/3 of left anterior lower leg | 1.8×4 | 3.5×7.5 | Imprecise perforator mapping | SMUM KF | LA | Fully survived | None | 5 |
2 | M/52 | Skin necrosis due to burn | Middle 1/3 of right anterior lower leg | 2×3.5 | 3.5×7 | Imprecise perforator mapping | OV and SMUM KF | GA | Fully survived | None | 4 |
3 | F/28 | Skin necrosis due to trauma | Lower 1/3 of right anterior lower leg | 1.8×3.5 | 3.5×8 | Imprecise perforator mapping | OV and SMUM KF | LA | Fully survived | None | 7 |
4 | M/25 | Skin necrosis due to trauma | Middle 1/3 of left anterior lower leg | 1.5×2.5 | 3×6 | Imprecise perforator mapping | OV and SMUM KF | LA | Fully survived | Marginal maceration | 4 |
5 | M/14 | Skin avulsion due to trauma | Upper 1/3 of left anterior lower leg | 3×4 | 5×12 | Precise perforator mapping | OV and SMUM KF | GA | Fully survived | None | 5 |
6 | F/61 | Skin and soft tissue defect due to trauma | Middle 1/3 of left anterior lower leg | 6×8 | 8×17 | Precise perforator mapping | OV KF and additional skin graft | GA | Fully survived | None | 4 |
KF, keystone flap; M, male; F, female; SMUM, Sydney melanoma unit modification; OV, omega variation; LA, local anesthesia; GA, general anesthesia.