Continuing Education Activity

Bipedicled TRAM is performed for individuals that have an acquired breast absence desiring unilateral autologous tissue breast reconstruction. The primary indications for bipedicled TRAM include cases where larger tissue volumes are required for reconstruction, history of chest wall irradiation, or history of lower abdominal wall incision. This activity reviews the use of bipedicled TRAM flaps for unilateral breast absence and highlights the role of the interprofessional team in evaluating and treating this condition.

Objectives:

• Identify appropriate candidates for bipedicled TRAM flaps.
• Summarize the risks that are associated with post-operative flap complications.
• Outline the key steps regarding flap elevation and inset.
• Explain the importance of collaboration and communication among the interprofessional team to ensure the appropriate selection of candidates for bipedicled TRAM flap and to enhance postoperative management.

Introduction

Breast cancer affects 1/7 women in the U.S., making it the most common malignancy in women.[1] Despite the equivalence of breast-conserving surgery and mastectomy, 34% of women opt for mastectomy for a variety of reasons.[2] Breast reconstruction is a continually evolving entity that ranges in complexity from the use of prostheses to autogenous tissue. While alloplastic reconstruction remains the most popular option, the use of autogenous tissue has been shown to create a more natural breast, which ultimately requires less subsequent surgical intervention and provides the highest patient satisfaction.[3] 

In the realm of autogenous breast reconstruction, the most commonly used flaps are abdominally based (the muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM), superficial inferior epigastric artery (SIEA), and deep inferior epigastric perforator (DIEP) flaps.[4] However, the differences regarding safety, factors contributing to complications, and overall patient desires, requires that these decisions be highly individualized.

Anatomy and Physiology

The bipedicled free TRAM flap is a Mathes and Nahai type 3 muscle flap with a dual supply consisting of the deep superior epigastric and deep inferior epigastric arteries.[5] The dominant blood supply is based on the deep inferior epigastric vessels which originate from the external iliac artery and then enter the deep and lateral surface of the rectus abdominis below the arcuate line. Perforating branches are given off to supply the overlying skin and fat via medial and lateral row perforators.[6] Typically, a skin island is harvested along with the donor muscle with different zones of blood supply. Hartrampf has described these zones. Zone 1 directly overlies the rectus muscle, zone 2 is across the midline, and zones 3 and 4 represent the ipsilateral and contralateral skin of the flap.[7] The zones that lay farthest from the vascular pedicle are the least reliable. 

Muscle harvest has been described using the classification system ranging from MS0 to MS3. MS0 represents a flap which consists of removing the entire width of the rectus abdominis muscle. MS1 divides the muscle into medial and lateral, which refers to the segment of muscle preserved. MS2 flaps maintain the lateral and medial parts of the muscle, and only a strip of tissue is removed from the middle portion of the muscle.[8] Finally, DIEP flaps are considered to be MS3 flaps that can minimize abdominal donor site morbidity because they avoid removing the rectus abdominis muscle and anterior rectus fascia.[4]

Another variation is the stacked flap in which two single pedicle TRAM flaps can be utilized to reconstruct one breast. Stacked flaps are useful for radical mastectomy defects, patients with a long thorax, meager abdominal donor tissue, breasts which are large without significant ptosis or women who want the reconstruction to be larger than their original breast size.[9] In a bipedicled free TRAM flap, both rectus abdominis are harvested, and both DIEA and double venous flow are utilized to enhance perfusion to the flap.[10]

Indications

Bipedicled TRAM flaps are generally indicated for acquired unilateral breast defects in patients with a limited amount of abdominal tissue, which is resistant to the options of contralateral breast reduction or the placement of an implant underneath a TRAM flap. In some cases, flap tissue beyond the described areas of perfusion is required for volume and projection, and by providing a second vascular pedicle, the perfusion can be enhanced.[11] Other common indications include a history of chest wall radiation, history of lower midline incision, which necessitates the need for the entire lower abdominal flap for reconstruction.[12]

Contraindications

Previous abdominal surgery, which has compromised the blood supply to the TRAM flap, would be the major contraindication to the bipedicled free TRAM. Smoking is a relative contraindication. Obesity and individuals with a higher BMI have a greater chance of partial flap failure and worse overall outcomes.[13] Furthermore, individuals with a history of cardiac disease, hypercoagulable states, or pulmonary disease remain at risk for flap failure.[12]

Equipment

The standard following equipment should be available.

• An operating microscope
• Microsurgical instrument set
• Papaverine for vascular spasm
• Heparinized saline
• Thrombolytics

Personnel

It is recommended to have an operative team with microvascular experience and familiarity with the equipment and microscope. Postoperative care is crucial for flap survival and requires a nursing staff who have been trained appropriately in regards to flap monitoring.

Preparation

Patients should be adequately counseled regarding all breast reconstruction options available. They should be aware of risk factors that may potentially increase the risk of flap related complications, including smoking, history of chest wall radiation, and previous abdominal surgeries. Those individuals who have a history of abdominal surgery will require a computed tomography angiogram to evaluate the vascular anatomy. Preoperative anticoagulation and antibiotics are necessary for all patients.[10]

Technique or Treatment

The CT angiogram should be reviewed pre-operatively, and a handheld doppler should be used to identify and mark the perforators. The umbilicus should be isolated with a cuff of fat around the stalk. The superior abdominal incision should be carried down to rectus fascia. The inferior abdominal incision should be taken to the fascia only after the identification and dissection of approximately 5 cm of the superficial inferior epigastric vein (SIEV) bilaterally. The skin flap should be elevated in a lateral to medial suprafascial plan with care upon reaching the lateral border of the rectus abdominis as this is where you will begin to identify the lateral row perforators. You will divide the flap and proceed in a medial to lateral fashion once the size of the flap is determined. All medial and lateral row perforators will be preserved. 

Intramuscular dissection is performed in a retrograde manner. The inferolateral edge of the rectus abdominis is elevated first to find both pedicles. After the inferior edge of the muscle is divided, the superior portion will be divided above the upper periumbilical perforators. 

The recipient vessel is typically the internal mammary vessel. The third rib is identified, and the recipient vessels are dissected out. In some cases, the thoracodorsal artery and vein can be used as recipient vessels as they are usually exposed immediately following a mastectomy and axillary dissection. Once the recipient vessels are identified, the abdominal flap is harvested, and microsurgical anastomosis of the veins and arteries are performed.

Complications

Complications related to a bipedicled TRAM have been cited as

• Potential abdominal wall morbidity, including hernias, bulging, and a decreased ability to perform certain physical activities
• Possibility of partial/total flap loss
• Infection
• Hematoma
• Fat necrosis

Clinical Significance

Bipedicled TRAM flap is a possibility for patients requiring unilateral breast reconstruction with significant volume and projection. This technique improves the perfusion to otherwise poorly perfused areas of the flap.

Enhancing Healthcare Team Outcomes

Abdominal based flaps have become the workhorses for autologous breast reconstruction. Options include free bipedicled TRAM, MS-TRAM, DIEP, and SIEA flaps. The decision regarding which approach to use should be individualized to the patient’s needs and history. It is crucial to educate the patient regarding the potential complications and provide them with a complete list of options available. To achieve the best overall outcome, it is essential to have a multidisciplinary approach consisting of the plastic surgeon, breast surgeon, oncologist, anesthesiologist, pharmacists, and nursing staff. 

Intraoperative and postoperative care is of critical importance to ensure the success of the flap. Communication with operative staff and anesthesia will create the most favorable environment. Nursing staff in the postoperative period are often the first to notice any flap issues, and they require appropriate training in regards to what to look for and how to recognize potential flap compromise. A cohesive, multidisciplinary team is necessary to prevent complications and to diagnose and effectively treat any flap issues promptly.