**2. Muscle anchoring technique using absorbable strings**

#### **2.1 Anatomical constraints in breast reconstruction using implant**

Of the prosthesis-based reconstructive surgeries that are performed at the same time as radical surgery for breast cancer, the process can be classified into two.

One is direct-to-implant (DTI) reconstruction, in which the space created by resection of mammary tissue is replaced immediately with an implant as it is. Then the reconstruction process is completed at the same time as breast cancer surgery. This procedure does not force the patient to experience breast loss. The other is to temporarily place a tissue expander in the space after resection, and gradually expand it after the wound heal. It is to stretch the chest skin and the surrounding muscles that cover the tissue expander. After obtaining sufficient space for the implant, the tissue expander is replaced with an appropriate implant at the right time. The patients will have to undergo two surgeries (two-stage reconstruction).

The mammary gland is completely removed by nipple-sparing mastectomy (NSM) or skin-sparing mastectomy (SSM), and almost all of the breast skin is preserved in both surgeries. Therefore, it is not necessary to stretch the mammary gland skin primarily. Then why is two-stage process needed after NSM and SSM?

This is because the pectoralis major muscle does not have sufficient area to cover the implant. Both length and width are insufficient (**Figure 1** left). The skin-flap in the lower half area of the breast mound bears the weight of the implant. Because the pectoralis major muscle does not reach that far, the skin bears the implant independently. Certainly, if the surrounding muscles such as the serratus anterior, rectus abdominis, transversus abdominis, and anterior oblique muscles are all mobilized, we could make a complete pocket with the muscles (**Figure 1** right). If you go that far, however, it would be wiser to reconstruct the mammary glands with only muscles. Therefore, in two-stage breast reconstruction, a tissue expander was once inserted, a

#### **Figure 1.**

*The pectoralis major muscle does not have a sufficient area to anatomically cover the surface of the implant, and a sizable portion of the surrounding muscles would need to be sacrificed to adequately conceal the entire implant.*

#### *Direct-to-Implant Breast Reconstruction Method: Muscle Anchoring Technique Using Absorbable… DOI: http://dx.doi.org/10.5772/intechopen.112918*

capsule was created with the pectoralis major muscle and, in some cases, a part of the serratus anterior muscle, and the muscle was stretched over time.

To solve this anatomical problem, in the United States, Alloderm® (Allergan U.S.A. K.K.) is applied as a patch to reinforce the areas that cannot be covered with the pectoralis major muscle. Alloderm® is a commercially available medical material that can be applied to anyone by treating the dermis of the skin collected from a donor's body to inactivate antigenicity. Alloderm*®* is sure that it could patch and reinforce the lower area of breast mound, but it has no blood flow and no immune function that protects from bacterial infection. Since Alloderm® is premised on a body donation so it is not covered by public health insurance in Japan.

#### **2.2 Direct-to-implant reconstruction that can be implemented in Japan**

In 2016, Tessler et al. first reported a method of using VICRYL mesh® (Ethicon, Johnson & Johnson K.K., JAPAN) instead of Alloderm® to connect the pectoralis major muscle and the chest wall to cover the inferior area that cannot be patched by the pectoralis major muscle alone [3]. Unlike Alloderm®, VICRYL mesh® is an absorbable material. It has a temporary reinforcing effect on the flap in the inferior area, but it will continue for 2 weeks, just like VICRYL PLUS® absorbable strings. After absorption, it lost its function. However, they reported the excellent outcomes of their absorbable mesh-sling procedure; 2.6% of cases had flap necrosis, 1.3% had infection, 1.3% required revision surgery due to implant displacement, and only 1.3% had implant removal. We have adopted this procedure since 2016 and have performed it in 123 cases to date.

Faulkner et al. used this technique to perform 227 reconstructions in 227 cases and reported the results of 7 years of observation [4]. As a matter to be noticed, they performed postoperative radiotherapy in 20.5% of cases. As a result, they also showed good results; flap necrosis (requiring invasive procedure) was 3.5%, infection was 2.1%, and implant removal was 4.5%.

Tessler does not use the serratus anterior muscle, only the pectoralis major muscle serves its purpose. Therefore, the only role of the absorbable VICRYL Mesh® is to place the pectoralis major muscle in a caudal stretched state as much as possible and to wait for the adhesion between the pectralis major muscle and the skin flap at the appropriate position intended by the surgeon. Using this absorbable mesh-sling method, then we could perform DTI reconstruction surgery even in Japan, where Alloderm® cannot be used.

#### **2.3 Arrange and place the muscle body and implants appropriately**

**Figure 2** shows our method, which is a modification of Tessler's one, currently in use. The pectoralis major muscle and the serratus anterior muscle are arranged and placed properly to cover the implant, by using absorbable strings like shoelaces. Unlike Tessler, our new method does not use mesh on the purpose. In practice, VICRYL PLUS 4–0® ("4–0" is a USP size and the diameter of the string is 0.2 mm.) is used, but these "shoelaces" are used to make tension and anchor between the muscle and the subcutaneous area of the inframammary sulcus. The pectoralis major muscle is partially dissected at its origin and is separated as needed. The top of the mammary gland mound, around the areola, has the least blood flow. There should be support from underneath with the pectoralis major muscle as much as possible. The serratus anterior can also be mobilized as needed simultaneously. In this case, it is not

#### **Figure 2.**

*The pectoralis major muscle and the serratus anterior muscle are arranged and placed properly to cover the implant, by using absorbable strings as if like shoelaces. VICRYL PLUS 4–0® is used to make tension and anchor between the muscle and the subcutaneous area of the inframammary sulcus.*

necessary to dissect the origin of the muscle body in its entire length. It is possible for the fascia of serratus anterior muscle alone to serve its purpose (**Figure 3**).

With this method, the pectoralis major muscle can be moved to the desired position. Whether the surgery is SSM or NSM with a peri-areolar incision, around the incision is with the highest risk of ischemic skin necrosis. With the mobilization of the pectoralis major muscle, it is possible to support the suture directly from underneath by the muscle body with rich blood microcirculation (**Figure 3**). The papilla, which is prone to ischemia, can also be supported. In a case, if the sub-mammary sulcus is incised, it can be supported from underneath with part of the serratus anterior muscle. Even if the required implant weight is heavy, it can be supported from below by not only skin flap but the serratus anterior muscle. If the surgeon needs the appearance of breast ptosis, surgeons should also consider not using the serratus anterior.

Since 2020, at our facility, we have performed DTI reconstruction in 35 cases using this anchoring technique with absorbable strings. We will retrospectively examine the results and the risk of complications in a group of patients who underwent DTI reconstruction using this technique (without Mesh) and compare them with 123 patients who underwent DTI using the Tessler method (with Mesh).

#### **2.4 Surgical technique**

The operations are performed under general anesthesia. At the start, we perform ultrasonography to confirm the location of tumor. To avoid the tumor contamination *Direct-to-Implant Breast Reconstruction Method: Muscle Anchoring Technique Using Absorbable… DOI: http://dx.doi.org/10.5772/intechopen.112918*

**Figure 3.**

*Even minimal ischemic necrosis at the wound edge can also cause infection. The underlayer of the incision is completely covered by the muscle tissue.*

in the flap, we put a mark at the point where the tumor should edge up to the skin by injecting the pigment. During the operation, we harvested the subcutaneous tissue from the flap side and submitted to the immediate pathological examination.

On a case-by-case basis, sentinel lymph node biopsy or axillary lymph node dissection will be performed. Surgery to the axilla should not influent the indication for, or the procedure of breast reconstruction, aside from skin incision. The surgeon has to choose whether skin incision the inframammary line or the line around the nippleareolar circle and extending to the axilla. In the case requiring the axillar dissection, we routinely select the later incision.

First, it is important to find the superficial layer of superficial fascia in the incision, then we start exfoliation of mammary glands from the skin in appropriate layers. After reaching underneath the nipple, we get the sample of the specimen and provide to the intraoperative pathological examination by frozen section. If the malignant involvement was recognized, we convert the NSM, even if you planned, into SSM with the nipple-areolar complex resection. Similarly, the malignant involvement at the site above the tumor should be coped with widening the skin resection enough and properly. If the area of flap got too tighter to cover the desired implant, we should convert DTI into two-stage using the proper tissue expander.

After completion of skin-preserving mastectomy, we start reconstruction by creating appropriate subpectoral pocket. We release the pectoralis major muscle at its origin on the sternum, if it was right breast, proceeded to the 3- and 9- o'clock levels. Occasionally, we add the slitting the pectoralis along the muscle bundles and adjusted its position (**Figure 4**).

#### **Figure 4.**

*The pectoralis major muscle was partially released from its origin on the sternum. If it was the right breast, the release extended to the 3- and 9-o'clock levels. Occasionally, we also make a slit in the pectoralis along the muscle bundle.*

*Direct-to-Implant Breast Reconstruction Method: Muscle Anchoring Technique Using Absorbable… DOI: http://dx.doi.org/10.5772/intechopen.112918*

#### **Figure 5.**

*After placement of the implant, we start suturing between the pectoralis major muscle and lateral and inferior fold, or between the pectoralis major muscle and the fascia of serratus anterior muscle, using the absorbable string (VICRYL PLUS® 4–0). We refrain from using mesh to anchor the muscle body to the needed site.*

A saline sizer was placed in the subpectoral pocket and inflated to the desired volume. While checking the appearance of the mammary gland, we select the best cohesive according to the size of the sizer and the weight of the removed breast weight.

We decide whether to use the serratus anterior fascia at this time. If the width of the pectoralis major muscle defect covering the implant is likely to exceed 4 cm, it should be used in combination. There are demerits due to detachment and use of the serratus anterior fascia; increased postoperative pain, and loss of breast ptotic appearance.

**Figure 6.** *The photograph depicts a stage where the surgery is nearly finished, and only the skin remains to be sutured.*

After placement of the appropriate implant in the pocket, we start suturing between the pectoralis major muscle and lateral and inferior fold, or between the pectoralis major muscle and the fascia of serratus anterior muscle, using the absorbable string (VICRYL PLUS*®* 4–0). The important thing here is not to overtighten the string to the end (**Figure 5**). We believe that we should not tighten the thread, just like we do with shoelaces. We just keep in mind that it is enough if there is a muscle body under the incision.

Then, suction drains were placed. Adjustments were made as necessary, hemostasis was ensured, and the wound was then closed (**Figure 6**).
