Advances and innovations in Breast Microsurgery

History of Breast Microsurgery

In order to appreciate how far we have come in terms of the evolution of breast reconstruction it is important to take a look back into our past. We owe our current innovations to the foundation that was laid by those who came before us. One such pioneer was Stuart Milton, MD, who in the 1960s described reconstruction techniques using “random pattern” flaps. These flaps were limited to a length to width ratio of 1.5:1.¹ In the early 1970s he found that flaps with much more area could be harvested when a blood vessel was included. These have come to be known as “axial pattern” pedicled flaps.² This pedicle flap concept lead to an important advancement in breast reconstruction. In 1982, Hartrampf performed the first pedicled flap for breast reconstruction, known as the transverse rectus abdominus myocutaneous (TRAM) flap.³ This became one of the most common autologous tissue options for breast reconstruction performed for decades. The next step in evolution was the development of the free flap for breast reconstruction. The concept of a free flap was first described in 1973 by Taylor and Daniel. They described the transfer of autologous tissue to a distant site based on anastomosing small vessels.⁴ Holmstrom then expanded upon this work and in 1979 reported what he called a free abdominoplasty flap, which was essentially a free TRAM flap.⁵

Perforator Surgery

The technique of microsurgery was first described in the 1970s and initially consisted mainly of the transfer of bulky myocutaneous flaps. Attempts have since that time been made to reduce muscle bulk and limit morbidity as the field of microsurgery has advanced. Early muscle sparing techniques included the split latissimus flap by Elliott⁶ and the partial rectus abdominus muscle flap by Feller.⁷ The first example of true perforator surgery was by Koshima for head and neck reconstruction in which the flap was based off of a paraumbilical perforating vessel from the deep inferior epigastric artery system. Allen and Treece built upon this work and performed the first deep inferior epigastric artery perforator (DIEP) flap for breast reconstruction in 1992.⁸ The recipient vessels are most often the internal mammary artery (IMA) and vein (IMV) between the second and third rib. The DIEP flap was able to provide the same soft tissue reconstruction as the TRAM flap while reducing morbidity, pain, and shortening recovery time.

Abdominally Based Free Tissue Transfer

The abdomen is the ideal donor site for breast reconstruction. Most women have excess adiposity suitable for breast reconstruction. The donor site scar is similar to an abdominoplasty and is overall well accepted. The skin and soft tissue of the abdomen is soft and pliable and can be easily molded into a breast. The DIEP flap is based on the deep inferior epigastric system which has a medial and lateral row of perforating vessels which penetrate the rectus muscle and supply blood and fat. This flap is able to be performed without sacrificing muscle or fascia, by splitting the rectus abdominus muscle in the direction of its fibers. A flap approximately 12cm in height and 21–24cm in width may be harvested from each hemiabdomen. Sensory nerves to the skin run with the perforators and may be dissected with the flap in order to provide sensation. Flaps are inset with the thinner lateral aspect superiorly oriented and the thicker medial aspect inset inferiorly. This may be folded on itself for increased projection. The long pedicle of the DIEP flap allows for ease of inset, with most often a contralateral flap allowing for the ideal orientation when IM recipient vessels are chosen. An alternative option to the DIEP flap is the superficial inferior epigastric artery (SIEA) flap. As the superficial cuts are made through the skin during a DIEP flap dissection, the SIEA vessels are encountered and evaluated. If these vessels are adequate, an SIEA flap is often raised. The SIEA should be >1mm at the level of the anterior superior iliac spine (ASIS) and should have a palpable pulse. There is often an inverse relationship between the SIEA and DIEP vessels in terms of perfusion of the abdominal wall. The SIEA flap is advantageous in that it completely preserves the abdominal wall avoiding the need to even split the rectus fascia and muscle. However, there are increased rates of fat necrosis, likely due to lateral positioning of the pedicle on the flap.⁹ The major complications of abdominally based free tissue transfer are rare, with total flap loss approximately 1–2%. This is usually related to kinking of the pedicle, as problems with the vein are eight times more likely than the artery. Fat necrosis due to inadequate perfusion of fat is approximately 13%, abdominal wall seroma 5% and hernia <1%.¹⁰ The SIEA and DIEP flaps can be safely and reliably performed by a trained microvascular surgeon.

Non-Abdominally Based Free Tissue Transfer

Although the DIEP flap has become the gold standard for microsurgical breast reconstruction, some patients are not candidates for this flap and so alternative techniques must be offered. Contraindications would include, but are not limited to, patients who have previously had an abdominoplasty, patients who are too thin or those who prefer another donor site. Thigh-based flaps are often our second choice donor site. There is some reluctance to use a thigh-based flap due to limited volume, issues with wound healing, sensory loss and the potential for lymphedema. Several options including the profundal artery perforator (PAP) flap, lateral thigh perforator (LTP) flap, transverse upper gracilis (TUG), or diagonal upper gracilis (DUG) flap. Of these options, the DUG flap is the author’s preferred choice for several reasons. In contrast to the other thigh-based flaps, this flap is relatively straight forward to dissect, maximizes volume of the thigh flap, and minimizes donor site morbidity. The flap was originally described by Dayan. It is elevated along langers lines of the thigh, which increases volume while minimizing tension of the closure. This also helps to decreased wound healing issues. The positioning of the skin paddle at the posterior border of the adductor longus avoids the femoral triangle minimizing the risk of lymphedema, which is a dreaded complication. The distal third of the skin paddle is more reliable as the orientation is more posterior and more closely follows the angiosome.¹¹

Immediate Lymphatic Reconstruction in Breast Cancer Treatment

As treatments for locally advanced and metastatic breast cancer have improved patient survival, we have seen the sequelae of some of those treatments. Disruption of the lymphatic system after sentinel lymph node biopsy (SLNB), axillary lymph node dissection (ALND), and radiation can lead to upper extremity lymphedema. The incidence of lymphedema after SLNB is 6–13% and after ALND is 13–65%.¹² These rates are significantly increased when combined with radiation therapy. The main symptoms include limb swelling, heaviness, tingling, and discomfort. This can also have a significant psychological, functional and even financial burden on patients. Many hours are spent on physical therapy and in compression garments and many health care dollars are spent on devices to aid in decongestive therapy. The emerging field of lymphatic surgery is beginning to ease that burden. Current established strategies focus on either debulking or physiologic procedures. Debulking procedures aim to remove the fibrofatty deposition caused by the vicious cycle of lymph stasis, which leads to inflammation which then increases the deposition of fibrofatty tissue, which then further disrupts the lymphatic system increasing lymph stasis. Physiologic procedures re-route lymphatic fluid. Utilizing laser angiography, the lymphatic channels may be mapped intraoperatively in order to facilitate lymphovenous bypass (LVB). LVB anastomoses a normal distal lymphatic channel into a nearby vein to redirect lymph fluid into the venous system and bypass a known blockage. Another physiologic strategy is a vascularized lymph node transfer (VLNT), which brings lymphatic tissue on a vascular pedicle and aims to establish new lymphatic connections. The preferred donor sites of the authors include the omentum and the supraclavicular lymph nodes. While these surgeries may provide some improvement for patients already suffering from lymphedema, ideally we could prevent patients from developing the disease. Immediate lymphatic reconstruction aims to do just that. Lymphatic microsurgical preventive healing approach, known as LYMPHA, was first described by Boccardo et al from Italy in 2009.¹² The authors injected methylene blue dye into the upper extremity and found draining lymphatic channels in the axilla at the time of ALND. Following the oncologic resection, they reconnected those lymphatics to branches of the axillary vein to maintain lymphatic drainage of the arm. A year later only 4% developed lymphedema, compared to 6–13% of patients after SLNB or 13–65% of patients after ALND as previously discussed. These results have been extremely promising and several groups across the United States now have prospective trials collecting data on outcomes after immediate lymphatic reconstruction.

Conclusion

At Washington University in St. Louis, we offer comprehensive breast cancer reconstruction with a multidisciplinary team approach. Our fellowship trained surgeons are able to provide patients with the full spectrum of reconstructive options, whether it be implant-based or autologous tissue reconstruction, from a variety of donor sites and immediate lymphatic reconstruction at the time of axillary lymph node dissection. We are also participating in cutting edge research and building a database of outcomes following lymphatic surgery in order to contribute to the growing body of literature. We are committed to constantly reevaluating and improving our technique to stay at the forefront of our specialty, while optimizing outcomes for our patients.