Overview
Definition:
The reverse sural fasciocutaneous flap is a versatile, distally-based flap that utilizes the skin and subcutaneous tissue overlying the posterior aspect of the lower leg, with its blood supply originating from the sural neurovascular bundle (peroneal perforators and branches from the posterior tibial artery)
It is designed to be raised without a delay procedure, making it efficient for reconstruction.
Epidemiology:
Indications for fasciocutaneous flaps, including the reverse sural flap, are common in reconstructive surgery for soft tissue defects resulting from trauma, oncological resection, or chronic wounds
The incidence of use varies geographically and by center expertise but represents a significant tool in limb salvage.
Clinical Significance:
This flap is crucial for reconstructing defects in the distal leg, ankle, and foot, especially when local tissue is compromised or absent
Its ability to cover exposed bone, tendons, or hardware, combined with its relative ease of elevation and predictable vascularity, makes it a vital option for preserving limb function and preventing amputation, thus improving patient outcomes and quality of life.
Indications
Soft Tissue Defects:
Large or deep soft tissue defects of the distal leg, ankle, heel, and foot, particularly those exposing vital structures like bone, tendons, nerves, or joints.
Trauma Reconstruction:
Reconstruction following crush injuries, degloving injuries, and open fractures of the lower extremity where primary closure or local flaps are insufficient.
Oncologic Resection:
Coverage of defects resulting from the surgical removal of tumors in the lower limb, especially those involving soft tissues or periosteum.
Chronic Wounds:
Management of recalcitrant ulcers, pressure sores, or diabetic foot ulcers that have failed conservative treatment and require soft tissue coverage.
Osteomyelitis Coverage:
Coverage of exposed bone in cases of osteomyelitis to facilitate healing and prevent further infection.
Contraindications
Vascular Insufficiency:
Significant peripheral arterial disease or venous insufficiency affecting the lower leg and foot, compromising flap viability.
Infection At Donor Site:
Active, uncontrolled infection in the sural nerve or posterior tibial artery territory that would preclude safe flap elevation.
Donor Site Morbidity:
Pre-existing conditions affecting the skin or subcutaneous tissue of the posterior calf that would compromise flap design or healing.
Patient Factors:
Uncontrolled diabetes mellitus, severe malnutrition, or systemic conditions that significantly impair wound healing and increase surgical risk.
Preoperative Preparation
Patient Assessment:
Thorough clinical evaluation including assessment of lower limb vascular status (Doppler, ABI), nutritional status, and co-morbidities
Patient counseling regarding risks, benefits, and alternatives is essential.
Donor Site Marking:
Careful planning and marking of the flap based on the defect size and location, ensuring adequate length-to-width ratio and the pedicle course
The flap typically incorporates skin from the lateral or medial aspect of the calf, based on the sural artery system.
Imaging:
Consideration of duplex ultrasonography or CT angiography to precisely map perforator vessels if perforator anatomy is unclear or previous surgery has altered the anatomy.
Anesthesia Planning:
Choice of anesthesia based on patient factors and surgical complexity, often general or regional anesthesia.
Procedure Steps
Flap Elevation:
The flap is designed and incised, elevating skin and subcutaneous tissue off the deep fascia
Care is taken to identify and preserve the sural neurovascular bundle along the length of the flap
The flap is raised in a distally based orientation, with the pedicle remaining attached at the distal aspect.
Defect Preparation:
The recipient bed is prepared by debridement of necrotic tissue, irrigation, and hemostasis
If bone or tendon is exposed, it may require further preparation such as decortication or freshening of edges.
Flap Transfer And Inset:
The flap is tunneled or directly transposed to the defect
The pedicle is carefully positioned to avoid kinking or tension
The flap is then inset into the recipient site, with meticulous closure of the donor site, often using skin grafts or local rotational flaps.
Pedicle Division:
Depending on flap length and inset, the pedicle may be divided after a period of time (typically 7-14 days) if a delay procedure is deemed necessary, though often it can be inset with the pedicle intact and divided later, or the flap can be designed as a free flap if indicated.
Postoperative Care
Monitoring:
Close monitoring of flap perfusion using clinical assessment (color, capillary refill, Doppler signal) and potentially non-invasive methods (e.g., infrared thermography).
Dressing:
Appropriate dressings to protect the flap and donor site, minimizing shear forces and maintaining a moist environment for healing
Immobilization of the limb is crucial.
Activity Restriction:
Restricted weight-bearing and activity for a specified period to allow for flap integration and healing, typically 2-4 weeks, followed by gradual mobilization.
Pain Management:
Adequate analgesia to ensure patient comfort and compliance with the rehabilitation protocol.
Complications
Early Complications:
Partial or complete flap necrosis due to venous congestion or arterial insufficiency
Infection of the flap or donor site
Hematoma formation
Seroma
Wound dehiscence.
Late Complications:
Granuloma formation around sutures
Scar hypertrophy or contracture
Donor site morbidity (e.g., scar, altered sensation)
Chronic pain or discomfort
Recurrence of ulceration if underlying pathology is not addressed.
Prevention Strategies:
Meticulous surgical technique, precise flap design, careful preservation of the vascular pedicle, adequate flap inset with no tension, vigilant postoperative monitoring, and prompt management of any signs of compromise are key to preventing complications.
Prognosis
Factors Affecting Prognosis:
The success of the reverse sural flap is influenced by the patient's overall health, the extent and nature of the defect, the quality of the recipient bed, and the meticulousness of surgical technique and postoperative care.
Outcomes:
When performed appropriately for indicated defects, the reverse sural flap offers a high success rate for limb salvage and reconstruction, restoring soft tissue coverage and function
Long-term graft survival and patient satisfaction are generally good.
Follow Up:
Regular follow-up appointments are necessary to monitor wound healing, assess flap viability, manage any emerging complications, and guide rehabilitation
Long-term follow-up may be required for patients with underlying chronic conditions like diabetes or vascular disease.
Key Points
Exam Focus:
Understanding the vascular supply (sural artery, perforators from tibial/peroneal arteries)
Indications for distal vs
proximal harvest
Principles of flap design and inset
Management of potential complications like venous congestion or arterial insufficiency.
Clinical Pearls:
Careful preoperative assessment of vascularity is paramount
Preserve the integrity of the sural nerve to minimize sensory deficits
Adequate flap bulk is important for cushioning
Consider perforator mapping for complex cases
Donor site closure options (primary, graft, local flap) are critical for minimizing morbidity.
Common Mistakes:
Failing to adequately debride the recipient bed
Kinking or tension on the flap pedicle
Inadequate monitoring of flap perfusion postoperatively
Overlooking co-morbidities that affect healing
Poor donor site management leading to poor aesthetic or functional outcomes.