AICAP Flap: Rebuilding the Inner Breast After Lumpectomy

When breast cancer occurs in the inner (medial) portion of the breast, lumpectomy can leave a noticeable defect that is particularly challenging to reconstruct. Unlike tumors in the outer breast, where techniques like the LICAP flap offer excellent solutions, medial defects have historically had fewer reliable reconstruction options. The AICAP flap — Anterior Intercostal Artery Perforator flap — changes this picture entirely, offering women a specialized technique designed specifically for inner breast reconstruction after lumpectomy.

What Is the AICAP Flap?

The AICAP flap (Anterior Intercostal Artery Perforator flap) is an oncoplastic volume replacement technique that uses tissue from the anterior chest wall — specifically the skin and fat below the breast crease (inframammary fold) — to fill the cavity created by tumor removal in the inner portion of the breast. The flap receives its blood supply through perforating vessels from the intercostal arteries, which run between the ribs along the front of the chest.

This technique belongs to the family of local perforator flaps, alongside the better-known LICAP (Lateral Intercostal Artery Perforator) flap for lateral defects and the TDAP (Thoracodorsal Artery Perforator) flap for upper-outer defects. While these sister techniques address lateral and posterior breast regions, the AICAP flap specifically targets the medial breast — the area closest to the sternum — where other flap options have limited reach.

How Does the Procedure Work?

The AICAP flap procedure is performed in conjunction with the lumpectomy, typically as a single-stage oncoplastic operation. Here is how the process unfolds:

First, the oncological surgeon removes the tumor from the medial breast with clear margins. This creates a cavity in the inner portion of the breast that, if left unfilled, would cause a visible dent or asymmetry.

Next, the plastic surgeon designs the AICAP flap on the anterior chest wall, typically in the area below and medial to the breast crease. Using preoperative imaging such as CT angiography or Doppler ultrasound mapping, the surgeon identifies the strongest perforating vessels from the anterior intercostal arteries. The flap — consisting of skin and subcutaneous fat — is carefully dissected while preserving these critical blood vessels.

The prepared flap is then rotated into the lumpectomy cavity, filling the defect with well-vascularized tissue that closely matches the texture and quality of breast tissue. Because the flap remains connected to its blood supply through the perforator vessels, no microsurgical vessel reconnection is needed — making this a technically reliable procedure with consistent results.

Finally, both the donor site and the breast are closed, and the surgeon carefully shapes the breast to achieve optimal symmetry. The resulting scar at the donor site is typically hidden in or near the inframammary fold.

Benefits of the AICAP Flap

The AICAP flap offers several important advantages for women with medial breast tumors. The tissue from the anterior chest wall provides an excellent match in texture and thickness to native breast tissue, creating natural-looking and natural-feeling results. Because the technique uses a perforator-based approach, no important muscles are sacrificed during the procedure, which means minimal impact on chest wall function and faster recovery.

The procedure brings healthy, non-irradiated tissue into the breast, which is particularly valuable for women who will undergo radiation therapy after surgery. The flap provides substantial volume restoration, allowing correction of significant defects without reducing the opposite breast. Additionally, since the donor site scar is hidden near the breast crease, the cosmetic outcome is often excellent.

Recovery and What to Expect

Recovery after an AICAP flap procedure is generally comparable to other local perforator flap techniques. Most patients stay in the hospital for one to two nights. During the first two weeks, you should expect some swelling, bruising, and discomfort at both the breast and the donor site. Pain is typically well-managed with standard medication.

Most women return to light daily activities within one to two weeks and resume work within two to four weeks, depending on the physical demands of their job. Full recovery, including return to exercise and strenuous activities, typically takes about six to eight weeks. Your surgeon will monitor flap viability closely during the initial recovery period.

If radiation therapy is part of your treatment plan, it can typically proceed on schedule after adequate healing, usually about four to six weeks post-surgery. The healthy, well-vascularized tissue brought in by the AICAP flap tends to tolerate radiation better than tissue that has been simply rearranged.

Who Is a Good Candidate?

The AICAP flap is particularly well-suited for women with tumors in the medial (inner) portion of the breast who are undergoing breast-conserving surgery (lumpectomy). Ideal candidates include women with small to moderate-sized breasts where simple tissue rearrangement would not provide sufficient volume replacement, women who prefer to maintain their natural breast size rather than undergoing reduction of the opposite breast, and patients whose tumor location in the inner breast makes other flap options like the LICAP or TDAP less suitable.

The procedure also works well for secondary reconstruction — correcting deformities that developed after a previous lumpectomy, with or without radiation. Your plastic surgeon will evaluate your individual anatomy, tumor location, and available tissue to determine if the AICAP flap is the optimal choice for your situation.

Frequently Asked Questions

What does AICAP stand for?

AICAP stands for Anterior Intercostal Artery Perforator. It refers to the blood vessels that supply the flap — perforating branches from the intercostal arteries that run along the front of the chest wall between the ribs.

How is the AICAP flap different from the LICAP flap?

The main difference is location. The LICAP flap uses tissue from the lateral (side) chest wall and is ideal for outer breast defects. The AICAP flap uses tissue from the anterior (front) chest wall below the breast and is specifically designed for inner (medial) breast defects. Both are perforator flaps that preserve muscle function.

Will I need microsurgery for an AICAP flap?

No. The AICAP flap remains connected to its blood supply through the perforator vessels. It is rotated into the breast defect without being fully detached, so microsurgical vessel reconnection is not required. This makes the procedure shorter and less complex than free flap techniques like the DIEP flap.

Can I have radiation therapy after an AICAP flap?

Yes. Radiation therapy can typically proceed as planned after adequate healing, usually four to six weeks after surgery. The healthy, well-vascularized tissue from the AICAP flap generally tolerates radiation well, which is one of the advantages of bringing fresh tissue into the reconstructed area.

What kind of scar will I have from the AICAP flap?

The donor site scar is typically located near or within the inframammary fold (the natural crease beneath the breast). This placement means the scar is usually well-hidden by clothing and undergarments. Over time, the scar fades significantly and becomes barely noticeable for most patients.

Written by Dr. Mahyar Foumani, plastic and reconstructive surgeon specializing in breast reconstruction. Based on the book 'Breast Reconstruction Explained.'