Reverse Sural Artery Flap for Dorsum of Foot Reconstruction

INTRODUCTION

Skin loss over the dorsum of foot is commonly encountered by the plastic surgeon. The etiology includes trauma, diabetic foot, peripheral vascular disease, and venous insufficiency. It is very important to ascertain that the local infection has been adequately controlled before a definitive wound cover is provided. The patient’s comorbidities, such as diabetes and concomitant illnesses, also need to be addressed prior to surgical intervention. As the skin over the dorsum of foot is very thin, without much subcutaneous tissue, its loss may lead to exposure of underlying tendons and bones. Exposure of vital structures will necessitate a full thickness cover. Skin graft alone may not be enough in majority of the cases and one must look for local, locoregional, or distant options for providing a full thickness cover. The reconstruction should facilitate use of footwear. An ideal cover for the dorsum of foot should be soft, supple, thin, and durable.¹ Reverse sural artery flap is a versatile flap for dorsum of foot reconstruction.

PROTOCOL AND OPERATIVE STEPS

The choice of cover is based on the wound condition. If the bed has adequate granulation tissue and no secondary procedure is planned in future, a split thickness skin graft can be used. However, if a secondary procedure in the form of tendon reconstruction or bone grafting is planned, a vascularized cover in the form of a flap is provided.

The final choice of technique is determined by patient factors and availability of local or regional flaps. Patient factors like peripheral vascular disease may preclude the use of a perforator-based flap.² The paucity of local options may force the surgeon to choose a distant flap for cover. The risk of prolonged anesthesia also has bearing on the decision-making. Logistic issues like operation theater time, availability of a microsurgeon may also determine the final plan for reconstruction. Last but not the least, the financial constraints of the patient should also be taken into consideration. These factors are considered and a final plan for reconstruction is devised.

Here, we describe the operative steps of the reverse sural artery flap. The reverse sural artery flap can be raised in three designs: Peninsular, islanded, and adipofascial. The technique described here is a peninsular design of the reverse sural artery flap.

DISCUSSION

Several options are available for covering dorsum of foot defects. The choice of the modality depends on the site of the defect, the exposed structures, secondary procedures if needed, and the functional outcomes achievable. The decision also depends on the age of the patient, comorbid illnesses, and other injuries present at the time of presentation. Some of the prerequisites for the reconstruction are a stable cover, non-bulky tissue, and esthetic appeal.

Vacuum-assisted dressing of the dorsum of the foot defect provides an excellent option for infection control at the local wound. They reduce inflammation, promote angiogenesis, and decrease the overall bacterial burden in the wound.^5,6 The resultant granulation tissue is generally healthy and covers the tendons and makes the bed ready for skin graft take. It is also helpful in cases where a flap is planned as it reduced the bacterial load and reduces the incidence of wound-related complication after the flap has been performed.

Split thickness skin graft provides an easy option to achieve wound closure. The procedure is simple, less time-consuming, and with reliable outcomes. It does not increase the bulk and contours better to the dorsum. It does not cause any hindrance to footwear use in the postoperative period. However, there is the possibility of breakdown of the epithelial cover in the long run and the fact that secondary procedure cannot be planned through the skin-grafted area. Hence, split thickness graft is an option where only the skin is lost, no secondary procedures are planned, and in cases where prolonged surgery is difficult.

The ideal cover over the dorsum of foot should be thin, pliable, and allow comfortable shoe wearing. It becomes mandatory to provide a full thickness cover in situations where future reconstructive procedures are warranted. Such situations could be reconstruction of missing tendons and replacing the missing bony segments. The local viable flaps can cover only smaller defects. However, larger tissue requirements can be met with locoregional flaps such distally based sural artery based skin or fasciocutaneous flaps. A preliminary delay procedure is needed if a larger flap is needed. For larger defects, free flaps, such as an anterolateral thigh flap, latissimus dorsi, or gracilis muscle flap, become very handy. These flaps can fill up the contour defects and provide a well-vascularized environment for effectively combating infection. The earlier belief that muscle flaps are better in improving local infection and promote healing as compared to a fasciocutaneous flap have been refuted in the recent “equivalence” studies.⁷ The fasciocutaneous flap makes flap reelevation and secondary procedures a lot easier than a muscle flap. Following a fasciocutaneous flap cover, the patient may need to undergo multiple thinning procedures to achieve the final contour. The “muscle based flap” undergoes atrophy and may eventually contour to the dorsum of the foot defect.

The reverse sural artery is a neurocutaneous flap that maybe harvested from the ipsilateral leg and a reliable local option. The cross leg flap from the contralateral leg is a regional option available and used as a “life boat” in cases of failed primary attempts to reconstruction. The free anterolateral thigh and gracilis flaps have the advantages of execution under regional anesthesia without change of position and with minimal donor site morbidity. The latissimus dorsi flap has the advantage of providing a large amount of tissue. However, it requires general anesthesia and a change of position for flap harvest. The radial artery forearm flap provides relatively large skin island and can be performed with two teams simultaneously.

Fasciocutaneous flaps gained popularity after Pontén described them in 1981.⁸ Since then, a variety of distally based fasciocutaneous flaps were planned and performed for foot defects based on the perforators of the posterior tibial, the anterior tibial, and the peroneal artery perforators. Masquelet described the distally based superficial sural artery flap for small to medium sized foot defects.⁹ The flap is long with reliable vascularity. The flap has been designed in an islanded, peninsular, or adipofascial fashion. Delay procedures are described as refinements to enhance flap safety. The flap is an excellent local option and very reliable for small to medium sized defects (Fig. 5).

The reconstruction of dorsal foot defect becomes trickier as the size of the defect increases. There are no local options available; this necessitates a microvascular tissue transfer. The popular choices for free tissue transfer is and anterolateral thigh flap, latissimus dorsi flap, gracilis flap, and radial artery forearm. The anterolateral thigh flap is an option that replaces like with reliable skin paddle. The procedure can be performed in supine position with regional anesthesia. The donor site morbidity of the flap is also minimal. Any secondary procedure if planned can be performed with ease. The other options like gracilis, latissimus dorsi, and radial artery forearm have their own advantage and disadvantages when used for reconstruction of the dorsum of foot defects. The microvascular transfers of tissue have substantially increased the flexibility of options. This in turn has increased the chances of limb salvage and decreased the frequency of amputation for complex defects. Flowchart 1 represents a free anterolateral thigh flap being used to reconstruct the dorsum of foot.

CONCLUSION

Reconstruction of the dorsum of foot defects is a challenge to the reconstructive surgeon and requires a great amount skills and planning. The various techniques follow a classic ascendance up the reconstructive ladder from a simple to a complex solution. The split thickness graft, reverse flow sural artery flap, and free anterolateral thigh flap described in the article are all highly reliable options for dorsal foot reconstruction. The reverse sural artery flap represents a reliable, easily available local option for dorsum of foot defects. It forms an integral part of the armamentarium of the plastic surgeon. The modern day reconstructive options and protocols make salvage of severely injured foots possible, thus decreasing the amputation rates for such limbs.

REFERENCES

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