Developed by Clough et al., superior pedicle mammoplasty with inverted T skin scar is a technique that can mitigate the risk of bird’s beak deformity occurring.^7,8,15,16 The procedure involves a number of steps as follows.¹⁶ It begins with de-epithelialization of the area surrounding the nipple-areolar complex (NAC) and an inframammary skin incision (Figure 1A). Then, the breast tissue is detached from the pectoralis fascia through an inframammary incision (Figure 1B), and the NAC is raised on a superior-based flap (Figure 1C). The tumor is removed en bloc with at least a 1-cm macroscopic margin of the normal tissue, the overlying skin, and the tissue excised for the remodeling procedure (Figure 1D). After resection is completed, the breast tissue is reapproximated to repair the breast defect, followed by NAC recentering (Figure 1E). The contralateral breast is made symmetrical during the procedure.

Superior pedicle mammoplasty is regarded as the standard method for performing volume displacement in OPS. However, it is important to note that this technique is less suitable for patients with small or medium-sized breasts due to the constraints posed by limited tissue availability.^17,18 Furthermore, the technique involves NAC transposition with a single dermal pedicle. This poses the risk of ischemia, potentially resulting in partial or total necrosis of the NAC.¹⁹ Challenges may also arise when surgical margins are involved and require re-excision. In such cases, total mastectomy is usually unavoidable as the limited volume of remaining breast tissue precludes any further resection without causing major deformity.¹⁵

Rotation flap using the Burow’s triangle (Rotation technique) is a procedure that has been developed to improve cosmetic outcomes for patients with lower pole breast cancers.²⁰ The Rotation technique has been described as follows.²⁰ Following segmentectomy or quadrantectomy, a long S-shaped or reverse S-shaped incision is made from the axilla to the tumor site along the anterior axillary line and inframammary fold (IMF) (Figure 2A). A triangular section of the axillary skin (Burow’s triangle) is removed along with the underlying axillary fat in order to reduce tension on the breast (Figure 2B). The breast tissue is then detached from the pectoralis muscle, allowing it to be positioned to close the breast defect. Arrows are drawn to indicate the direction of the skin movement along the long incision line (Figure 2B). Once the breast tissue and additional fatty tissue of the lateral chest wall have been appropriately mobilized, the breast defect is closed at the mid-point of the parenchymal thickness (Figure 2C). Although this procedure requires a relatively long skin incision, there is usually no deviation of the NAC. However, when the tumor is located near the NAC, this procedure may result in NAC displacement towards the tumor. Additionally, it is not easy to design a triangle above the mass that avoids invading the NAC.²¹

Developed by Noguchi et al., the downward-mobilization procedure is specifically designed for patients with lower pole breast cancer.^22,23 In the literature, the procedure has been described as follows. First, a wide excision with a 1-cm macroscopic margin of normal tissue is performed through an inframammary skin incision (Figure 3A). Next, a skin flap with a 0.5-cm thick layer of subcutaneous fat is carefully developed, and the retroareolar breast tissue is detached from the NAC to facilitate maximal mobilization of the breast tissue (Figure 3B). Breast tissue from the upper pole is then mobilized downward to fill in the breast defect and is sutured to the inframammary fatty tissue (Figure 3C). Although the volume of the remaining breast tissue is limited in the lower pole after BCS, a substantial volume of breast tissue from the upper pole is still available to fill in the breast defect. In this procedure, parenchymal blood flow through perforators is maintained, as the breast tissue remains attached to the underlying pectoral fascia. Moreover, there is no deviation of the NAC, so neither NAC transposition nor contralateral symmetrization is required. However, it is important to recognize that the efficacy of the downward-mobilization procedure, as a volume displacement technique, depends on the availability of sufficient breast tissue in the upper pole, which can be limited. As a result, this approach is indicated in cases where less than 20% of the breast tissue is excised.

Quadrantectomy with immediate partial reconstruction using the LD myo-subcutaneous flap is a volume replacement procedure developed by Noguchi et al.^13,14,24 The procedure, initially detailed in a previous study²⁵, involves excising a small section of the skin and breast tissue overlying the tumor, and then extending the incision into the axilla for axillary lymph node dissection (ALND). After completing the quadrantectomy and ALND, a portion of the LD muscle and its subcutaneous adipose tissue is carefully dissected, preserving the thoracodorsal artery, vein, and nerve. This dissected section of the LD muscle and adipose tissue is then transposed to the anterior chest to fill in the space left by the excised breast tissue. This procedure marked the first instance of using volume replacement to prevent breast deformity post-quadrantectomy, as opposed to performing delayed breast reconstruction.¹⁰ Raja et al.²⁶ and Rainsbury et al.^27,28, subsequently adapted the procedure, implementing a wide excision by a lazy S-shaped incision that extends from the apex of the axilla to the IMF, regardless of the tumor’s location in the breast. The LD myo-subcutaneous flap (which they termed the “LD mini-flap”) is transposed as reported by Noguchi et al.^13,14 This technique can be performed to reconstruct post-quadrantectomy defects in the breast’s lower pole^26,29,30 (Figure 4), but it obtains better results in cases where the tumor is located in the upper outer quadrant. The LD mini-flap allows for an excellent blood supply and provides sufficient fatty tissue and muscle to fill the breast defect. It suits patients with small-to-medium-sized breasts. In addition, transposition of the LD mini-flap does not complicate postoperative mammograms, as the transferred muscle and fatty tissue are radiolucent. However, it is recommended that the initial muscle harvest be approximately 30% greater than the volume of the resected breast tissue to account for some degree of expected muscle atrophy.³¹ Despite its benefits, some practitioners suggest reserving the LD flap as a rescue option for cases where complications or recurrences arise.^15,32,33 Over time, volume replacement techniques have evolved from using the LD muscle to now also employing perforator flaps.

Perforator flaps use tissue supplied by perforating vessels stemming from a deep vascular system that extends through the underlying muscles or intermuscular septa. This form of reconstructive surgery includes the thoracodorsal artery perforator (TDAP) flap^34,35 and anterior intercostal artery perforator (AICAP) flap^34,36, both of which were initially introduced by Hamdi et al.³⁴ The use of perforator flaps has enhanced the range of indications for BCS, filling defects in all quadrants, reducing mastectomy rates and the associated revision and symmetrizing procedures.³⁷

The TDAP flap utilizes perforators originating from the descending branch of the thoracodorsal artery. In the literature, the procedure has been described as follows.³⁸ Preoperatively, the TDAP is located and marked on the skin using Doppler ultrasonography. Donor skin markings are then made to delineate the permissible dimensions of the skin paddle based on the anticipated flap volume needed. The incision at the donor site is strategically performed to ensure that the resultant scar can be concealed under a bra strap (Figure 5A). A subcutaneous tunnel is then created between the anterior border of the LD muscle and the defect. The flap is passed through this tunnel and then transposed onto the lower pole breast defect (Figure 5B). As a surgical technique, the TDAP flap constitutes a minimally invasive evolution of the LD flap, enabling the preservation of the LD muscle and reduced donor site morbidity.^35,39 Nonetheless, complications with the procedure have been reported, the most common of which is partial flap necrosis, particularly at the edge farthest from the perforator vessel.³⁵ Due to its complexity, this technique requires the expertise of specialized plastic surgeons.

The AICAP flap is based on a perforator from the anterior intercostal artery. While it is a versatile flap, the use of AICAP is limited by the size of the defect. Recently, however, a modified crescentic AICAP flap has been developed to better address breast reconstruction in patients with lower pole breast cancer and small to medium-sized, minimally ptotic breasts. The procedure has been described as follows.³⁶ The IMF is identified and marked, and Doppler ultrasonography is used to identify the appropriate perforator located within 1 to 3 cm lateral to the sternal border. The flap is then marked with the patient in an upright position, with the pedicle forming the center of the 3 limbs of the flap (medial extension, lateral extension, and inferior extension). A crescent is marked in the same manner as is done for a traditional crescentic AICAP flap. The superior border is delineated by the curvature of the IMF (Figure 6A). Intraoperatively, the crescentic section is de-epithelialized. The inferior extension is crafted from subcutaneous fat. The medial and lateral limbs of the crescent and inferior tongue are then raised, maintaining the pedicle (Figure 6B). Then, all three limbs of the flap are brought together and sutured to form a single body of tissue (Figure 6C). A new IMF is created and fixed at the level of the pedicle, slightly lower than the previous IMF position (Figure 6D). The inferior extension is a key aspect of the modified technique.

The inframammary adipofascial (anterior rectus sheath) flap, conceived by Sakai et al., was originally developed for breast reconstruction after a subcutaneous mastectomy.⁴⁰ The technique was later adapted to repair defects in the lower pole of the breast following BCS.^41,42 The procedure has been described as follows.⁴¹ First, a skin incision is made along the inframammary line. Following BCS, the skin of the intended inframammary area is undermined in the subcutaneous fat plane at a depth of 3 or 4mm (Figure 7A). This undermining extends down along the chest to a length of 7 cm from the original IMF skin incision, preparing the area for the creation of a flap. The subcutaneous fatty tissue and the anterior sheath of the rectus abdominis muscle are then cut following a parabolic contour to form a tongue-shaped flap. Using forceps, the tip of the tongue-shaped flap is lifted, and the edge adjoining the anterior sheath is cut, releasing the flap from the rectus abdominis muscle. Then, the flap is folded back and placed in the cavity left by the surgery. The elevated flap is positioned and adjusted further to adequately fill the size and shape of the defect (Figure 7B). It is recommended that the flap be approximately 30% greater in volume than the defect to account for the atrophy of the flap that will occur over time. While the technique has demonstrated success, it is still constrained by the availability of fatty tissue in the target area. For some patients, it may be difficult to harvest a sufficient volume of fatty tissue to refill the breast defect.^43,44 The technique may also carry a risk of fat necrosis as a delayed complication.^44,45

Lipofilling has been used for immediate reconstruction to improve poor cosmetic results after BCS. However, performing lipofilling directly into the cavity resulting from the lumpectomy or quadrantectomy is not recommended due to the risk of abscess formation, reabsorption of fat, or the need for external drainage. Immediately injecting fat into a lumpectomy cavity without proven negative margins is also not recommended, as stem cells from the injected fat could interact with residual cancerous cells at the positive margins, posing a significant oncological risk.⁴⁶ Consequently, it is recommended that lipofilling be performed in the subcutaneous and intraglandular breast tissue around the breast defect rather than directly into the post-surgical cavity.⁴⁷ In their matched retrospective cohort study, Stumpf et al.⁴³ reported no significant differences in locoregional recurrence rates or disease-free survival rates between patients who received immediate autologous lipofilling post-BCS and those who underwent BCS alone. However, it should be noted that tumor location was not specified in their study. In fact, there have been few reports of BCS with immediate lipofilling in lower pole breast cancer.⁴⁸ The OPS is originally an oncoplastic breast conserving surgery: partial mastectomy followed by immediate partial breast reconstruction.⁹