The reverse sural flap takes skin from the back of the calf and turns it downwards to cover the ankle, heel or lower shin. It solves a problem that has troubled surgeons for years, how to cover the lowest part of the leg without microsurgery.
A reverse sural flap is a patch of calf skin raised with the tissue around the sural nerve and its vessels, then swung downwards on a narrow base near the outer ankle. Blood reaches it backwards through connections with the peroneal artery, which lets it cover the lower third of the leg, the ankle and the heel.
Covering the lowest part of the leg has always been difficult. There is little spare skin around the ankle, bone and tendon lie close to the surface, and a graft alone will not survive on them. Muscles that could help sit higher up and cannot reach. The reverse sural flap was developed to solve exactly this, using skin from the calf, which has plenty to spare.
The flap is raised around the sural nerve and the small vessels that accompany it down the back of the calf. Rather than remaining attached at the top, it is left attached low down, near the outer ankle, where perforating vessels from the peroneal artery link into the same network. Blood therefore flows down into the flap in reverse, which is where the name comes from. The flap is then swung around to cover the wound.
Cover is achieved without microsurgery, which matters in settings where a free flap is not practical. The price is a patch of numbness on the outer border of the foot, because the sural nerve travels with the flap, and a donor area on the calf that usually needs a split thickness skin graft.
Everything depends on the vessels near the outer ankle being healthy, because those connections are what keep this flap alive.
Dead and infected tissue is removed until healthy bleeding tissue is reached. Sometimes this is done at an earlier sitting, with dressings in between, before cover is attempted.
The perforating vessels above the outer ankle are found by feel or with a handheld doppler. That point sets how far the flap can rotate and where it can reach.
A patch of calf skin is lifted along with the underlying fascia, the sural nerve and its accompanying vessels. A generous strip of tissue is kept at the base to protect the blood supply.
The flap is rotated downwards and inset without tension. The connecting strip is either tunnelled or laid open and grafted, so nothing presses on it.
The raw calf area is covered with a split thickness skin graft, usually taken from the thigh. Dressings and a back slab hold the leg still while everything settles.
The leg stays elevated and the flap is watched for congestion. Bed rest with the foot raised is the rule, and pain relief is given regularly.
Dressings and the calf graft are checked. Gentle dangling of the leg begins in short spells, building up slowly so the flap learns to cope with being down.
Weight bearing usually starts under guidance, often with a support boot. Sutures are out and the flap starts to flatten.
Swelling settles and the flap softens. Numbness on the outer foot commonly persists, and footwear may need adapting.
Most flaps settle and give durable cover, which allows fractures and bone infections to be treated properly. Bulkiness early on is common and often needs thinning before comfortable footwear is possible. Numbness on the outer border of the foot is expected and usually stays. The calf carries a grafted patch for life. Swelling of the foot on standing can persist for many months.
This flap works well when selected carefully, though it is less forgiving than flaps in better supplied parts of the body.
The calf is the donor area and the ankle or heel is the recipient. A third site, the thigh, supplies the skin graft.
Grafts need a bed with a blood supply. Over exposed bone, tendon or metalwork they will not take, so tissue with its own circulation is needed.
It can, through connections between vessels near the outer ankle. That reverse flow is the whole basis of the technique.
The sural nerve travels within the flap by design. Loss of feeling on the outer foot is expected and is discussed before surgery.
Weight bearing is introduced gradually, and the leg must be conditioned to being down. Rushing this stage risks congestion and breakdown of the flap.
Lower limb wounds at Elegance Clinic in Surat are assessed with attention to circulation, infection and bone before any cover is planned, and Dr. Ashutosh Shah explains why a particular flap suits a particular part of the leg.
No price is listed on a technique page, because this flap is a method of covering a wound rather than a treatment in itself. Cost depends on the injury or condition being treated, the number of debridements needed, grafting, anaesthesia and how long you stay in hospital.
Bands for the underlying treatments appear on their own pages, and a written estimate is prepared after assessment so families can plan before admission.
These are the questions that come up most often in consultation. If yours is not here, send it on WhatsApp and the team will reply, usually the same day.
Ask your question →A technique page carries no price. The total depends on the injury being treated, how many cleaning procedures are needed, grafting, anaesthesia, dressings and hospital stay. A written estimate is prepared after assessment.
It is less forgiving than flaps elsewhere, since it relies on reverse blood flow. Congestion and partial loss are the main concerns. Poor leg circulation, smoking and uncontrolled diabetes raise the risk considerably.
The leg stays elevated for the first week or so, then dangling begins in short spells. Weight bearing usually starts after several weeks with a boot or walking aid, guided by how the flap looks.
A patch of numbness along the outer border of the foot is expected, because the sural nerve travels with the flap. Feeling rarely returns fully, so daily checking of the numb skin becomes important.
Anyone with poor arterial circulation in the leg, a crush injury damaging the vessels near the outer ankle, active bone infection or uncontrolled diabetes needs a different plan or further treatment first.
The wound is cleaned first, sometimes more than once, and cover follows once the tissue looks healthy and infection is controlled. Waiting a few days is common and generally safer than covering a dirty wound.
Pulses and circulation in the leg are checked, the wound and any exposed bone are examined, and imaging is reviewed. Alternatives including free flaps are discussed, along with expected numbness and the calf donor area.
Seeing patients from across the city and beyond: read about the practice on the plastic surgeon in Surat page, or check what a written estimate covers on the costs and insurance page.
