Table of Contents

Introduction  Vectors of Contraction  Surgical Strategies
Reconstruction  Conclusion  References

Introduction

Resection of breast tissue during mastectomy produces volume and skin surface deficiencies, but also releases mechanical forces that further distort this most difficult deformity. Understanding these vectors of displacement is essential for the correction of the mastectomy deformity.

The breast skin is normally connected to the Pectoralis muscle by a system of Coopers ligaments and fibrous septae that extend through the breast tissue. A dampening effect from the contraction of the muscle is produced by the breast tissue which limits displacement (Figure 1). The connecting system of Coopers ligaments and fibrous septae also provides structural support against the force of gravity. Removal of breast tissue removes these structural dampers and subjects the remaining breast skin envelope to forces of displacement that would not normally be apparent (Figure 2).

Figure 1 Cross section of the breast

Figure 2 Cross section of a mastectomy site

Vectors of Contraction

Strong upward vectors of contraction are produced on the remaining breast skin envelope, which appears to counteract the inherent downward vector of gravity. Upward drift of the skin envelope and mastectomy scar depletes this important resource of reconstruction at the inferior pole. Acknowledgment of these forces allows the development of surgical strategies that limit displacement.

These mechanical forces are produced by active contraction of the Pectoralis major and cellular components of the wound healing sequence. The musculoskeletal contraction of the Pectoralis major creates the initial vector of displacement. The sternocostal fibers of the Pectoralis are subjacent to the breast and course obliquely upward and laterally to the axilla. The clavicular head of the muscle has a horizontal orientation and functions as a powerful adductor and medial rotator of the upper arm. Due to its position along the superior perimeter, the clavicular head has little effect upon breast displacement. For this reason, displacement of the breast skin envelope following mastectomy follows the pull of the sternocostal fibers in an upward and slightly lateral direction (Figure 3).

The wound healing component also provides a net upward vector of contraction as the subcutaneous plane of dissection is larger above than below the mastectomy scar (Figure 4). This wound healing process is similar in cause to the upward migration of a breast implant commonly observed in capsular contracture. Myofibroblasts are produced during wound healing that are present in both the periprosthetic scar capsule enveloping a breast implant and the subcutaneous dissection plane of a mastectomy. These cells have contractile fibrils which are the source of cellular contraction of the breast skin envelope following mastectomy. Subsequent deposition of nascent scar collagen in the plane of dissection will irreversibly establish the displacement.

Figure 3	Figure 4
A standard mastectomy deformity with upward displacement of the scar	Upward displacement of the breast expander

In addition, the entire process of displacement is amplified by these forces acting in concert. The initial upward displacement by the Pectoralis major is aggravated by cellular contraction of the muscle/subcutaneous scar interface. A static supporting matrix of scar collagen on the surface of the muscle becomes permanent if appropriate measures during surgery are not taken.

Surgical Strategies

During mastectomy, these measures consist of techniques that advance and secure the remaining skin envelope to the inferior pole of the breast. Following the creation of the submuscular pocket, stabilization of the Pectoralis major will diminish the muscular component of displacement. This is achieved by resecuring the inferior edge of the Pectoralis muscle to the costal margin.

In most cases, the submuscular pocket of the Pectoralis major and Serratus interior is developed inferiorly by incising the fibers of origin of the Pectoralis major from the costal margin. A cuff of rectus fascia is included with the inferior edge of the muscle which is used as a mooring point when the muscle flap is reattached to the costal margin of the inframammary fold. Reattachment of the muscle flap is performed with a running monofilament suture that will distribute the tension evenly along the entire closure. For many patients, a partial closure is performed due to the paucity of fascia inferiorly. In this instance, the running suture will limit displacement of implant if complete closure is not possible. Securing the inferior edge of the Pectoralis muscle to the inframammary fold reduces upward displacement of the entire breast skin envelope (Figure 5).

The cutaneous component of displacement is secondary to fibroblastic scar contraction in the subcutaneous plane of dissection (Figure 6). Downward advancement of the remaining breast skin envelope during mastectomy counteracts this cutaneous component but also creates a skin redundancy where it is needed the most. The breast envelope is secured inferiorly to the underlying Pectoralis muscle with absorbable subcutaneous sutures that are used to close the mastectomy incision. However, additional suturing in the subcutaneous plane may further compromise the tenuous circulation of this random cutaneous flap (Figure 7).

Figure 5	Figure 7
Figure 6

Reconstruction

The lateral to medial orientation of the mastectomy incision is also important if the resultant scar is to be confined to the proposed site of the reconstructed nipple-areolar complex. For a skin preservation mastectomy, the closure of the circular defect is performed in a double V-Y advancement. This type of closure produces a bowtie-shaped redundancy that is used subsequently for a Bowtie nipple-areolar reconstruction with the Pectoralis Peg. Without the appropriate orientation over the muscle, this incision will typically drift upward and laterally due to the unrestrained contraction of the Pectoralis major. For this reason, the skin preservation incision is secured medially and inferiorly if the appropriate orientation is to be maintained for the second stage. For most patients, lateral displacement vectors are less than upward vectors and less correction is required in the horizontal axis than the vertical axis (Figure 8). This initial alignment of the mastectomy incision will allow the reconstructive process to proceed in a more predictable fashion. Subsequent inflation of the expander will provide ptosis of the inferior pole of the breast without upward displacement of the mastectomy scar (Figures 9 and 10).

Figure 8	Figure 10 Neovascularization and stabilization of the breast skin envelope
Figure 9

Conclusion

In conclusion, the delivery of the remaining skin envelope to the inferior pole of the breast provides significant benefits for any type of breast expansion reconstruction. The subsequent expansion is more effective in producing ptosis of the breast with accentuation of the inframammary fold. The mastectomy scar is not allowed to "drift" upward and becomes less obvious due to a lower relative position on the reconstructed breast. With a skin-sparing mastectomy and the Pectoralis Peg reconstruction, the scar can be reliably positioned at the proposed site of the reconstructed nipple-areolar complex. In many of these patients, the entire mastectomy can now be camouflaged within the border of the reconstructed nipple-areolar complex. Following micropigmentation of this structure, the mastectomy scar is no longer visible. Additional incisions from skin grafts or autologous flaps are not required. Upon completion of the patient's breast reconstruction, any and all visible remnants of the patient's oncologic procedure are eliminated. Due to this less extensive approach, breast reconstruction with the Pectoralis Peg is typically performed in an outpatient facility.

References

1. Dao, T.L., Nemoto, T. "The Clinical Significance of Skin Recurrence After Mastectomy in Women with Cancer of the Breast." Surg. Gynecol. Obstet, 117:447, 1963.

2. Fourquet A., Campana F., Zafrani B., Mosseri V., Veilh P., Durand J.C., Vilcoq J.R. "Prognostic factors of breast recurrence in the conservative management of early breast cancer: a 25-year follow up." Int J Radiat Oncol Biol Phys, 1989 Oct.17, 719-725.

3. Grossman, P.H., Novack, B.H., Karlan, S.R., Uyeda, R.Y. "An Alternative Technique for Modified Radical Mastectomy with Immediate Reconstruction." Contemp. Surg. 38 (6):20, 1991.

4. Lovaas, M.E. "Immediate Pedicled TRAM Breast Reconstruction and Simultaneous Nipple Reconstruction with a Skate Flap: A Review of 50 Patients." Plastic Surgery Forum, 17:136, 1994.

5. Olivari, N. "The Latissimus Flap." Br. J. Plast. Surg. 29:126, 1976.

6. Knowlton, E.W. "Release of Axillary Scar Contracture with a Latissimus Dorsi Flap." Plast. Reconstr Surg. 74 (I):124, 1984.

7. Knowlton, E.W., Gorey, R., Taekman, H. "Total Immediate Breast Reconstruction with 'Peg', Latissimus Dorsi Flap." Contemp Surg. 41(3): l5, 1992.

8. Knowlton, E.W., "The 'Peg' Latissimus Dorsi F1ap Procedure: A One-Stage Breast Reconstruction." Plastic Surgery Forum, 17:180, 1994.

9. Knowlton, E.W. "The 'Peg' Latissimus Dorsi Flap Procedure: A One-Stage Breast Recons-truction Video." Vol. I, Mill Valley, CA: Medical Media Productions, 1992.

10. Knowlton, E.W. "The 'Peg' Latissimus Dorsi Flap Procedure: A One-Stage Breast Recons-truction Video." Vol. II, Mill Valley, CA: Medical Media Productions, 1994. Presented at the annual meeting of the American Society of Plastic and Reconstructive Surgeons (1994, San Diego, CA).

11. Knowlton, E.W. "The Pectoralis Peg with Bowtie Nipple-Areolar Reconstruction: On Video." Vol. III, Mill Valley, CA: Medical Media Productions, 1997.

12. Web site: www.peg-procedure.com

13. Knowlton, E.W. US Patent No. 5,301,692, April 12, 1994. Method for Total Immediate Post-Mastectomy Breast Reconstruction Using a Latissimus Dorsi Myocutaneous Flap.

14. Knowlton, E.W. US Patent No. 5,765,567, June 16, 1998. Surgical Method for Breast Reconstruction Using a Tissue Flap.

15. Knowlton, E.W. US Patent No. 5,824,076, Oct 20, 1998. Surgical Method for Breast Reconstruction Using a Neovascular Tissue Peg.

16. "Efficacy of Bilateral Prophylactic Mastectomy in Women with a Family History of Breast Cancer." New England Journal of Med. 2:340, 1999

Illustrations by Walter Denn.