PAP flap reconstruction

What the operation is

A PAP flap — short for Profunda Artery Perforator flap — is a breast reconstruction using skin and fat from the upper inner or posterior thigh, transferred to the chest with its own blood supply and reconnected under an operating microscope. No muscle is taken. The technique is the thigh equivalent of a DIEP flap: a perforator-based, microsurgical, muscle-sparing flap.

PAP is offered when the abdomen is not a suitable donor site — the most common situations being insufficient abdominal tissue, previous abdominal surgery that has divided the DIEP perforators, or a strong patient preference to avoid an abdominal scar. It is typically used for smaller-volume reconstructions because the volume of tissue available from the thigh is more limited than from the abdomen.

When PAP is offered

PAP is considered when:

The abdomen is not suitable for a DIEP — for example after previous abdominoplasty, complex hernia repair, or extensive abdominal surgery that has divided the perforators.
There is insufficient abdominal tissue for the size of breast reconstruction wanted — common in slim patients.
The patient has good thigh-tissue volume and the breast being reconstructed is not too large.
Bilateral reconstruction is needed and the abdomen alone cannot provide enough tissue for both sides — sometimes a stacked reconstruction (DIEP plus PAP, or two PAPs) is performed.

It is not suitable when there is very little thigh tissue, when a large-volume reconstruction is needed, or when there are vascular problems in the legs that would compromise the donor site.

How the operation works

The flap is taken from the upper part of the thigh. The scar position depends on which PAP variant suits the perforator anatomy: a transverse PAP places the scar in the buttock-thigh crease; a diagonal or vertical PAP places it on the upper inner or posterior thigh. Pre-operative imaging (CT angiogram or MRI) maps the vessels and guides the choice.

The skin, fat, and one or more perforating blood vessels are raised as a single unit. The vessels — the profunda femoris perforators — are followed back to their origin from the deep femoral artery, divided, and the flap is transferred to the chest.

At the chest, the vessels are reconnected under an operating microscope, usually to the internal mammary artery and vein. The flap is shaped into the new breast contour and sutured into the mastectomy cavity.

The thigh donor site is closed in layers; the scar is placed in the crease or thigh position chosen at planning and is usually well hidden by underwear.

What the operation involves

Anaesthetic: general anaesthetic.
Length of operation: typically 6–8 hours for unilateral PAP; longer for bilateral.
Hospital stay: typically 4–5 nights.
Drains: in the chest and the thigh donor site, usually removed in the first 1–2 weeks.
Microsurgery: the operation requires microsurgical capability and is performed jointly with a plastic-surgery colleague at the chosen hospital.
Sentinel lymph node biopsy is performed at the same operation if relevant.

Recovery

First week — in hospital with drains in place. Sitting and walking are restricted in the first few days because of the thigh donor site; specific positioning advice is given to avoid pressure on the wound. Pain relief is structured.
Weeks 2–4 — at home, gradual increase in mobility. Driving usually resumes at around 6 weeks, longer than for DIEP, because sitting comfort from the thigh donor site is the limiting factor. Check with your motor insurer before resuming. Sitting on hard chairs may be uncomfortable for a few weeks.
Weeks 4–6 — return to desk-based work for most patients. Continued attention to the thigh wound; supportive shorts or compression garments are sometimes recommended.
Three months — most patients back to full activity. The breast continues to settle for 3–6 months.

The thigh donor site is the main recovery difference from DIEP. Most patients tolerate it well, but specific things — sitting in low chairs, squatting, certain forms of exercise — take a few weeks longer to be comfortable than abdominal recovery typically does.

Cosmetic outcome and what to expect

The reconstructed breast has the natural feel and weight of body tissue, like other autologous reconstructions, with the shape it is given at the operation. PAP reconstructions are typically smaller-volume than DIEP, suiting smaller and medium-sized breast reconstructions; very large reconstructions may need a different approach.
The thigh scar is well hidden in the natural skin crease and beneath underwear lines, but it is a long horizontal scar. Scars continue to mature and fade over 12–18 months; final appearance varies and depends on skin type, tension, and donor-site position.
The thigh donor site contour can change after PAP — most often a flattening or slight tethering of the upper inner thigh, sometimes with a small contour difference between the two thighs in unilateral reconstructions. For most patients this is not visible in clothing or swimwear.
Sensation in the thigh is reduced in the area of the flap; this usually improves over months but may not return fully.

A small number of patients have a revision operation at 6–12 months to refine the breast shape, the scar, or the thigh donor site contour. This is part of the usual reconstructive arc.

Common questions The questions patients ask first

Why am I being offered PAP and not DIEP?

Because something about your abdomen — usually previous surgery or insufficient tissue — makes DIEP either unfeasible or not the best operation in your case. The thigh tissue is the next-best autologous donor site for breast reconstruction. The reasoning in your specific case is explained at consultation.

Is PAP a smaller operation than DIEP?

The operations are similar in length and complexity. The chest part of the operation is essentially the same; the donor-site part (thigh vs abdomen) is different. Recovery is similar in length, though the donor-site limitations are different — DIEP restricts bending and lifting more than sitting, while PAP restricts sitting and certain leg movements more than core activity.

Will my legs look symmetrical after a unilateral PAP?

For most patients, yes — at rest and in clothing, the difference is not visible. Some asymmetry of the upper inner thigh contour is possible, particularly when only one side has a flap taken; bilateral PAP gives more reliable thigh symmetry. This is discussed at consultation.

Can PAP and DIEP be combined?

Yes, in selected cases — particularly in bilateral reconstruction where each side has limited tissue available. This is called a stacked flap and is a more complex operation requiring careful planning. It is suitable for some patients but not all.

Will my insurance cover PAP reconstruction?

Yes, where it is part of breast cancer treatment. Pre-authorisation requires the procedure code and the indication. Most insurers approve autologous reconstruction at the relevant tier when the abdomen has been documented as unsuitable.

How does long-term outcome compare to DIEP?

Long-term outcomes — for the breast itself, for symmetry, for revision rate — are broadly similar. The donor-site outcomes are different: PAP avoids the abdominal-wall risks of TRAM but introduces a thigh donor site instead. There is no universally “better” autologous flap; the right one depends on the patient’s anatomy and circumstances.