Versatility of the Propeller Flap for Reconstructing Defects of Distal Third of the Leg

Soft tissue defects involving the distal third of the leg still represent a challenge for reconstructive surgeons, mainly due to bony prominences, biomechanics, and paucity of soft tissues. Perforator propeller flaps in defects involving the distal third of the leg provide an excellent option in the reconstructive armamentarium. This paper describes the evolution, design, harvesting technique, and successful clinical applications of the propeller flaps in the reconstruction of soft tissue defects in this region.

The approach for reconstruction of a soft tissue defect is based on its location, dimension, types of tissues involved, and functional requirements. Additional factors to be considered are the zone of injury, donor-site morbidity, bone fixation type, functional demands, and aesthetic outcomes.^1,2 The options for reconstruction of soft tissue defects in the distal third of the leg are limited. Although free tissue transfer has been the first choice for reconstruction of distal leg defects in recent years, this requires adequate training and an upgraded setup for microvascular surgery; it is also time-consuming and technically demanding. Perforator propeller flaps are extremely versatile alternatives to free tissue transfer in the armamentarium of a reconstructive surgeon; as originally described by Hyakusoku et al³, the length of this flap type exceeds its width and is rotated 90 degrees on its central axis, based on a central subcutaneous pedicle. The procedure was technically refined by Teo,⁴ who used a higher degree of rotation by completely skeletonizing the perforating vessel.

The application of the propeller flap for the reconstruction of soft tissue defects has multiple advantages. The propeller flap technique can replace “like with like” by using tissue of similar texture, thickness, and color. The major vessels and muscles are preserved. Flap harvest is relatively fast, and the need to perform microvascular anastomosis is avoided. In addition, reconstruction of defects with the propeller flaps has minimal donor site morbidity as no major vessel or muscle is being sacrificed.

In the current study, the authors’ main objective was to explore and establish the versatility of the propeller flaps as an alternative to free tissue transfer for the reconstruction of small to medium soft tissue defects involving the distal third of the leg.

The study included 30 patients in the Department of Plastic Surgery at the authors’ hospital between October 2014 and June 2019 who had soft tissue defects involving the distal third of the leg reconstructed with the perforator propeller flap. Patients with concomitant involvement of the proximal third or middle third of the leg were not included in the study. Procedures followed were in accordance with the protocols of the ethical committee on human experimentation and the Helsinki Declaration of 1975, as revised in 2000. Informed consent was obtained from the patients included in this study.

During preoperative planning, the clinician marked the vascular access of the leg (ie, anterior tibial artery, peroneal artery, and posterior tibial artery) on which to base the perforating vessel of the propeller flap. Next, perforators were marked by handheld audio Doppler with an 8-Mhz probe according to the location of the defect to be covered. A provisional flap was designed according to the requirements of the defect and the location of the suitable perforator as chosen by audio Doppler, keeping the perforator as the pivot point of the flap. First, the distance between the perforator and the distal edge of the defect was measured. This value plus 1 cm (to compensate for flap contraction) was then transposed proximally along the axis of the source vessel measured from the perforator. This formed the proximal limit of the flap. Next, the width of the flap was determined by measuring the width of the defect (1 cm was again added to allow for flap contraction). The elevation of the flap was performed with the patient in a supine position with a controlled tourniquet at the thigh and a continuous pressure of 250 mm Hg without performing exsanguination.

In the beginning, only 1 edge of the flap was incised. The incision was made up to the deep fascia; the deep fascia was identified and incised, followed by subfascial dissection under magnification. All the dissected perforators were preserved (Figure 1). During dissection, the perforators were moistened with 4% lignocaine on and off to prevent spasm. If 2 sizeable adjacent perforators were found, both were kept until the flap’s dissection was complete and the tourniquet was released. Then, 1 perforator was ligated after alternate clamping with a microvascular clamp and observing the pattern of dermal bleeding. Once the best perforator was chosen (according to its location, size, orientation, and pattern of dermal bleeding), the final design of the flap was accomplished. Then, the chosen perforator was dissected intramuscularly or in the septum and cleared of all branches and fascial strands for about 2 cm. The flap incision and harvesting could then be completed. The flap was rotated in a clockwise or counterclockwise direction to the defect, and attention was paid to choosing the right rotational direction to avoid kinking or torsion of the perforator by checking the pattern of dermal bleeding. The donor site was not closed under tension, which could impede the flap’s vascularity. If primary closure was not possible, the donor site was partially covered with the short arm of the propeller flap, and the remaining defect was grafted with a split-thickness skin graft (Figure 2). 

In the current study, the authors operated on 30 patients with soft tissue defects involving the distal third of the leg. Patient ages ranged from 17 to 63 years (mean, 42.7 years) and most patients were male (n = 21; 70%). Among the patients included, 5 had comorbidities, such as diabetes and hypertension (Table). Flap dimensions ranged from 9 to 91 cm², with an average size of 50 cm². These sizes are mostly consistent with the concept proposed by Morris et al⁵ that a perforating vessel of 0.7-cm caliber reliably irrigates approximately 47 cm². The flaps were based on a single perforator of the posterior tibial artery in 18 cases (60%) and the peroneal artery (Figure 2B) in 9 cases (30%); in 3 cases (10%), the anterior tibial artery was chosen. The flap rotation was 180 degrees in 24 cases (80%) and 90 degrees (Figure 1C) in 6 cases (20%). In all 30 cases, the donor site was resurfaced with a split-thickness skin graft.

Complications developed in 4 patients (13.3%); partial necrosis involving less than 15% of the flap developed in 2 patients (Figure 3), complete necrosis developed in 1 patient, and infection developed in 1 patient. Among these 4 patients, 3 had comorbid conditions, such as diabetes and hypertension. 

Reconstruction of defects involving the distal third of the leg continues to be challenging when vital structures and/or hardware are exposed, and flap coverage is generally needed.^1-5 Local flaps, such as fasciocutaneous or muscle flaps, are the traditional reconstructive tools for coverage of the proximal and middle third of the leg defects, while microvascular free flaps are the first choice for the distal third of the leg due to the paucity of local tissues to plan locoregional flaps.^1,6,7 However, the use of local fasciocutaneous flaps that include the fascial plexus, as described in the 1980s by Ponten⁸ and Hallock,⁹ opened new vistas to the reconstruction of the soft tissue defects of the lower extremity. Nakajima et al¹⁰ subsequently demonstrated that this fascial plexus was nourished by deep perforating vessels originating from the underlying major source vessels of the limb.

As a result of this evolution and the works published by Koshima and Soeda¹¹ in 1989, the era of perforator flaps began. The detailed vascular anatomy and the extensive clinical experience confirm that local and regional perforator flaps are safe and reliable in the successful reconstruction of defects involving the lower third of the leg. As shown by Geddes et al,¹² the lower extremity appears to have the greatest potential for harvesting perforator flaps. The work of Saint-Cyr and colleagues defined the vascular territories of perforators as perforasomes, contributing to a better understanding of the dynamic potential of these perforasomes and their surgical implications in reconstructions of distal leg defects.^13-16 As with angiosomes, neighboring perforasomes are connected by direct and indirect linking vessels.¹⁷ According to Rubino et al,¹⁸ the harvesting of a flap based on a single perforator produces a hyperperfusion of this perforator, leading to the recruitment of adjacent perforasome territories that enhance the flap’s vascularity and dimension.

The concept of the propeller flap was devised by Hyakusoku et al¹⁹ in 1991 and was described for reconstruction of a defect following release of scar contracture in the axilla and groin. The term "propeller flap" was first used by Hallock²⁰ in 2006 to define a flap based on a skeletonized perforator and rotated 180 degrees to reach the defect. The ultimate definition and terminology of the propeller flap was given by an advisory panel of the First Tokyo Meeting on Perforator and Propeller Flaps in 2009.²¹ According to this consensus, a propeller perforator flap is designed as a skin island with 2 paddles that may or may not be of the same dimensions; the demarcation limit between these paddles is the perforator vessel. To be a propeller flap, it must rotate around the perforator vessel for at least 90 to 180 degrees. The propeller flap is a reliable and versatile option for stable coverage of defects involving the distal third of the leg; it is based on a skeletonized perforator in relation to the site and size of the defect.

In the current study, the average dimensions of the flaps were 50 cm², consistent with the concept proposed by Morris et al⁵ that a perforating vessel of 0.7 cm caliber provides an approximate irrigation of 47 cm². The ability to rotate the propeller flaps to 180 degrees (Figure 2C), which was done in 80% of the patients in this study, makes it extremely versatile for reconstructing distal leg defects. 

Postoperative complications developed in 4 patients (13.3%) in the current study. Partial flap necrosis developed in 2 patients (Figure 3C), and complete necrosis and infection developed in 1 patient each. These rates are lower than those reported in the meta-analysis of 15 case series with 186 cases of propeller flaps performed by Gir et al²², who found a complication rate of 25.8%.

In all patients, a unidirectional hand-held audio Doppler with an 8-MHz probe was used to identify suitable perforators. In their evaluation of handheld audio Doppler with an 8- to 10-MHz probe for this purpose, Khan and Miller reported a sensitivity of 90% with a confidence interval of up to 95% and positive predictive value of 84%.²³

For soft tissue defects involving the distal third of the leg, reconstructions with propeller flaps have gained huge popularity over the years due to their reliable vascularity, minimal or no donor-site morbidity, and excellent aesthetic outcome; there is no sacrifice of any major vessel or muscle of the lower limb. The propeller flap technique obviates the need for a microsurgical anastomosis and provides replacement of "like with like."

This study has some potential limitations. The estimated result is based on the interventional and prospective observational study. They are therefore subject to biases and confounding that may have influenced our results. Another limitation of this study is its shorter duration, due to which our sample size was restricted to only 30 patients.

For patients with soft tissue defects of the distal third of the leg with exposed vital structures and/or hardware, the propeller flap represents an ingenious technique in the surgeon’s armamentarium. This noble technique becomes successful by revisiting vascular anatomy and gaining extensive clinical experience, obviating the need for microvascular free tissue transfer. It is relatively simple, less time-consuming than other strategies, and beneficial for patients who are elderly or have multiple comorbidities. Moreover, the propeller flap technique replaces “like with like” by using tissues of similar texture and color, eliminating the need for technically demanding free tissue transfer. In addition, reconstruction of defects with the propeller flaps is associated with minimal donor site morbidity because no major vessel or muscle is being sacrificed. 

The propeller flaps based on the perforators of all 3 major axial vessels of the leg are very reliable for repairing defects involving the distal third of the leg. In well-selected cases, the strategy can provide a versatile reconstructive option for complex defects.

Affiliations: ¹Department of Plastic Surgery, R.G. Kar Medical College, Kolkata, India; ²Department of Plastic Surgery, UPUMS, Saifai, Etawah, India; ³Department of General Surgery, N.R.S. Medical College, Kolkata, India

Correspondence: Atul Saxena, MCh; atul.plasticsx@gmail.com

Ethics: This study was approved by the institutional ethical committee of R.G. Kar Medical College and registered with Drug Controller general India, registration no. ECR/322/Ins/WB/2013.

Disclosures: The authors disclose no relevant financial or nonfinancial interests.