In short. What a pedicled or free flap does, why free tissue transfer exists, and what it means to move tissue with its own blood supply.
Key points
- There are defects that no local tissue can repair: an open leg fracture with no healthy skin for a hand’s breadth, a jaw removed with its bone and lining, or an extensive scalp defect over bare skull.
- Free tissue transfer brings a large amount of well-vascularised tissue from a distance, tolerates a bed that would kill a graft, resists infection far better, and can carry bone in the same block.
- The cost is a long operation, often six to twelve hours, a period of close monitoring afterwards, and a genuine if small risk of complete flap loss that has to be discussed before the operation begins.
When a defect is too large, too deep, or too badly supplied for local tissue, reconstruction moves a bigger block of tissue from further away. That is still a flap, but now the blood supply is no longer incidental. It is the whole point of the operation. Understanding vessels and blood supply is what makes free tissue transfer make sense.
Regional flaps
A regional, or pedicled, flap stays attached to its original blood supply. A block of skin and muscle is lifted and tunnelled or rotated to reach the defect, keeping its artery and vein intact but stretched along a pedicle. Because the pedicle remains connected, the flap has an uninterrupted circulation. The limitation is reach: a pedicled flap can only go as far as its vessels will stretch without kinking.
Free flaps
A free flap removes that limitation by dividing the pedicle and reconnecting it. The surgeon detaches a block of tissue — skin, fat, muscle, fascia or bone, or a combination — along with its artery and vein, transfers it to the defect, and joins those vessels to recipient vessels nearby under a microscope. Two common examples are a free forearm flap from the arm, and a free fibula flap from the leg used to rebuild the jaw. Nothing about the tissue itself changes. Only where its blood supply is plugged in.
Why free tissue transfer exists
There are defects that no local tissue can repair: an open leg fracture with no healthy skin for a hand’s breadth, a jaw removed with its bone and lining, or an extensive scalp defect over bare skull. Free tissue transfer brings a large amount of well-vascularised tissue from a distance, tolerates a bed that would kill a graft, resists infection far better, and can carry bone in the same block. The cost is a long operation, often six to twelve hours, a period of close monitoring afterwards, and a genuine if small risk of complete flap loss that has to be discussed before the operation begins.
The operation and its aftermath
The donor site is a second surgical area with its own scar, sometimes requiring a graft to close it, and it can leave weakness if muscle is taken. After surgery the flap is monitored closely, usually for several days, because most problems declare themselves early. Nothing is guaranteed: free flaps fail in a small percentage of cases even with careful technique, and partial loss is more common than complete loss.
Honest limits and follow-up
A free flap is a major operation with real risks to discuss: bleeding, clotting of the reconnected vessels, infection, delayed healing, and problems at the donor site. Sensation in the transferred tissue is reduced, and it never looks exactly like the skin it replaced. Function and contour continue to change for months, and the honest point of assessment is six to twelve months.
Report immediately if
- The flap becomes pale, mottled, cold, or changes from pink to dusky blue or black.
- A dressing is soaked with blood, or the area swells rapidly within the first day.
- Fever, spreading redness, severe new pain, or a limb that feels cold, pale or numb develops.
Frequently asked questions
What is the difference between a pedicled and a free flap?
A pedicled or regional flap stays attached to its original blood supply, so circulation is uninterrupted, but it can only reach as far as its vessels stretch without kinking. A free flap divides the pedicle and reconnects the artery and vein to recipient vessels under a microscope, which removes that limit.
Why would a surgeon choose a free flap?
Because some defects no local tissue can repair: an open leg fracture with no healthy skin for a hand’s breadth, a jaw removed with its bone and lining, or an extensive scalp defect over bare skull. Free tissue transfer brings a large amount of well-vascularised tissue from a distance and tolerates a bed that would kill a graft.
How long does a free flap operation take, and what are the risks?
Often six to twelve hours, followed by a period of close monitoring. Bleeding, clotting of the reconnected vessels, infection and donor-site problems are real risks. Free flaps fail in a small percentage of cases even with careful technique, and partial loss is more common than complete loss.
Risks & Limitations
- Partial or complete failure of a graft or flap, which may need further surgery.
- Donor-site scarring, delayed healing and pain. A donor site leaves its own permanent scar.
- Infection, bleeding under a graft, or fluid collecting beneath a graft or flap.
- Contracture, and recurrence of contracture after a release procedure.
- Reconstruction is usually staged: more than one operation and months of healing are normal.
- Colour, texture and contour mismatch between reconstructed skin and the surrounding area.
- Reduced or altered sensation in grafts, flaps and donor sites.
- Scars are permanent. They mature and fade but never disappear.
- Final assessment is made at 6–12 months, and longer in growing children.
When to Seek Care
- A graft or flap that turns dark, cold, dusky, purple or black, or stops bleeding when pricked.
- A dressing soaked with blood, or bleeding that does not stop with gentle pressure.
- Fever above 38 °C, or spreading redness, warmth or discharge around a wound.
- New or severe pain, or rapid swelling under a graft or flap in the first days.
- A limb that becomes pale, cold or numb after flap surgery.
- Any change in a grafted or flap-covered area that concerns you, however minor.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — reconstructive surgery and skin graft guidance
- Cochrane Library — systematic reviews in wound care and surgical reconstruction
- Wounds International — wound bed preparation and graft survival guidance
- Chinese Medical Association, Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.