Breast Reconstruction With the Pedicled Transverse Rectus Abdominis Musculocutaneous (TRAM) Flap

Key Words

Breast Reconstruction, Pedicled, TRAM, Autologous, Abdominal

Introduction

Pedicled transverse rectus abdominis musculocutaneous (TRAM) breast reconstruction has been performed in patients for nearly four decades now. Many technical modifications have developed since Dr. Hartrampf’s first operation, and these strategies have improved our ability to offer this operation to our patients while minimizing morbidity.

Plastic surgeons continue to perform pedicled TRAM flaps on a frequent basis. The choice to perform a pedicled TRAM flap is typically multifactorial, contingent on the presence or absence of microsurgical expertise, capability, comfort with the procedure and, if applicable, the patient’s desire to avoid or ability to tolerate a prolonged operation.

The goal of autologous breast reconstruction is to reconstruct the breast with minimal morbidity while maximizing reconstructive result. In this chapter, the authors describe their preferred techniques for pedicled TRAM flap breast reconstruction, emphasizing several refinements so that a good outcome of the reconstruction with minimal abdominal donor-site morbidity can still be accomplished. In addition, patient selection, preoperative evaluation, management of complications, and secondary procedures are also described.

Indications and Contraindications

Unilateral pedicled TRAM flap breast reconstruction can be offered to patients with BMI <30 who desire autologous breast reconstruction and who have adequate lower abdominal adipose tissue and skin laxity, with a few anatomic contraindications. Ipsilateral Kocher or complete subcostal incisions disrupt the direct and collateral blood flow to the rectus abdominis muscle, and serve as absolute contraindications to pedicled TRAM breast reconstruction. Patients without those incisions and with adequate abdominal tissue who desire to avoid the risks associated with extended operations can also be considered for pedicled TRAM breast reconstruction. Patients with low midline abdominal scars can still be considered for unilateral hemi-TRAM flap or bi-pedicled TRAM flap.

Preoperative Evaluation and Special Considerations

Medically acceptable candidates for abdominally based autologous breast reconstruction must have adequate excess abdominal adipose tissue for reconstructed breast size and excess abdominal skin for primary closure of the donor site ( Fig. 1.1 ). This is best determined by performing a pinch test with the patient in supine position with both knees moderately flexed. If the patient is large breasted, she should understand the inevitable need for symmetry procedure(s) to reduce the size of the contralateral breast as well as the possibility of requiring an implant in addition to the pedicled TRAM flap to achieve a symmetric result.

Abdominal scarring patterns must also be thoroughly considered and reviewed with the patient. As discussed above, a low midline abdominal scar does not prevent the use of a unilateral pedicled TRAM; however, the patient can be offered a hemi-TRAM flap, a bi-pedicled TRAM flap, or a hemi-TRAM flap with a unilateral free TRAM or deep inferior epigastric perforator (DIEP) flap to achieve adequate sized reconstruction.

It is imperative to consider the patient’s level of activity preoperatively. In considering pedicled TRAM reconstruction, it remains possible that physically active patients will have noticeable abdominal weakness, and could be more prone to develop bulging and hernias, though the evidence-based literature remains inconclusive on the topic.

Other important areas of consideration that will allow for adequate surgical planning are evaluation of rectus diastasis, typically best assessed on preoperative CT or MRI imaging; this can also be reasonably assessed while having the patient flex their trunk on the examination table and asking them to “lift your shoulders off the table.” Ventral and umbilical hernias, though difficult to detect in patients that have more abdominal tissue, must be screened for through physical examination.

Based on what we have learned to perform the free DIEP flap, the senior author prefers to evaluate the number of abdominal perforators and their locations and flow status immediately prior to the operation. This is done via duplex scanning in the preoperative holding area with both the vascular lab technician and the surgeon present to assist with preoperative marking. This has led to significant intraoperative time savings as well as increased confidence of side and perforator dominance, resulting in increased flap perfusion, decreased fat necrosis, and decreased need for the amount of rectus fascia that will be included with the flap dissection. In a unilateral pedicled TRAM flap for breast reconstruction, this allows the surgeon to select a better flap, based on the number of perforators and their locations and flow status, so a preferred side of the flap can be selected as the surgeon would do for a free DIEP flap ( Fig. 1.2 ).

Due to the secondary and retrograde venous drainage provided by the superior epigastric vessels, pedicled TRAM flaps have indeed been associated with higher rates of fat necrosis, which is the rationale behind the Hartrampf zone classification ( Fig. 1.3 ). In a unilateral reconstruction, this can be minimized by eliminating zone IV and portions of zone III. If a larger amount of flap tissue is needed for breast reconstruction or for smokers, a surgical delay procedure can be performed one to three weeks prior to the TRAM flap elevation so that its ischemic complications can be minimized.

Surgical Techniques

Relevant Anatomy

In the virgin abdomen, the dominant arterial inflow to one side of the abdominal skin is the deep inferior epigastric artery. In the majority of patients, there are three branching patterns that are relevant when performing perforator or muscle-sparing (MS-)TRAM reconstructions. However, for the pedicled TRAM flap, the dominant arterial inflow is the superficial inferior epigastric artery ( Fig. 1.4 ). Its venous outflow is accompanied to the artery and because the inferior epigastric vein is the dominant drainage system for the flap, it can be preserved to allow supplemental venous drainage for supercharge if needed.

More relevant to the pedicled TRAM procedure are rectus inscriptions, which must be treated with meticulous technique as they run intimately across the epigastric artery arcade. Typically there exist three inscriptions, two of which will usually be encountered during the pedicled TRAM dissection. Should a pedicle vessel be injured, the flap may have enough collateral inflow to continue with the procedure based on the branching patterns previously referred to.

It is imperative to be aware of and respect the arcuate line when harvesting the inferior aspect of the rectus muscle. Below the arcuate line (typically below the level of the iliac crests) there is no posterior rectus fascia. Imperfect dissection posterior to the rectus muscle below the arcuate line can unnecessarily result in exposure of bowel contents and peritoneal fluid, causing additional strife and morbidity postoperatively.

Preoperative Markings

With the patient in standing position, the midline from umbilicus to pubic symphysis is marked. Next the inferior aspect of the flap is marked. The lateral extension of our inferior marking is frequently taken out into a natural skin crease but can be higher if we feel the need to move the flap superiorly. The superior aspect of the flap is then marked based on a pinch test in the lower abdomen with the understanding that this will be adjusted in the operating room ( Fig. 1.5 ). The lateral border of the rectus abdominis muscle on each side is marked and based on the side of the selection for the flap and the location of perforators, the extent of fascial inclusion can also be marked ( Fig. 1.6 ).

Surgical Delay Prior to Flap Elevation

If the flap delay is indicated, the procedure can be performed under general anesthesia at a minimum of two weeks prior to the planned procedure to minimize the combined effects of two general anesthetics. It is imperative that all markings described above are made at the time of the initial procedure to ensure the incisions employed during the delay procedure can be incorporated during the flap elevation. The deep inferior epigastric vessels, after adequate exposure, are divided during the delay procedure ( Fig. 1.7 ).

Flap Elevation

Unilateral

The umbilicus is first dissected free with preservation of adequate fat around it and down to the anterior rectus sheath. The TRAM flap skin paddle is then incised but beveled superiorly and inferiorly in the zone I and zone II areas to catch more flap tissue. Once the superficial inferior epigastric vessels are identified in each side, they are divided with hemoclips. From the non-flap side, the suprafascial dissection can be quickly done to about 1 cm beyond the midline. On the flap side, the suprafascial dissection is done towards the lateral border of the rectus abdominis muscle. The fascial incision is safely performed about 1– 2 cm beyond the midline and about 2 cm medial to the lateral border of the rectus muscle. The dissection is taken down to elevate the entire rectus muscle in the lower part of the abdomen. During dissection, the inferior epigastric vessels under the muscle are identified and incorporated with the flap. The distal portion of the rectus abdominis muscle is then divided with protection of the inferior epigastric vessels. Once the muscle is divided inferiorly, the inferior epigastric artery and the vein are easily identified. The artery is divided with hemoclips but the vein is divided with hemoclips placed on the proximal end. The distal end of the vein is left open for temporary drainage throughout the case and will be clipped before the final flap inset.

The TRAM flap is then dissected free and elevated easily above the posterior rectus sheath. The superior epigastric vessels are identified within the deep surface of the flap and marked clearly with a marking pen. The superior abdominal skin is elevated to the xiphoid and an incision over the anterior rectus sheath is then extended to the level of the subcostal margin. All inscriptions in the superior part of the rectus muscle are dissected free and near the costal margin, the lateral part of the muscle is divided off the lateral costal margin to allow for more mobilization and a tension-free inset of the flap. A subcutaneous tunnel is made between the breast pocket and the upper abdomen ( Fig. 1.8 ). The portion or entire zone IV of the flap is usually discarded before the flap tunneling ( Fig. 1.9 ). The flap can be tunneled either ipsilaterally or contralaterally depending on the side of the flap selected. The tunnel should be wide enough, typically to pass through four fingers, to avoid any compression on the muscle within the tunnel. With the aid of lubricating jelly, the flap is passed through the tunnel and inset into the breast pocket. The pedicle should be checked for possible kinking and twisting and a few tacking sutures can be placed to secure the muscle so that kinking and twisting of the pedicle can be further prevented ( Fig. 1.10 ).

Bilateral

There are some differences when performing a bilateral pedicled TRAM flap compared to a unilateral procedure. The entire skin paddle of the lower abdomen is sectioned down the middle to allow for easier dissection from the midline to each medial side of the flap. We recommend midline sectioning following maximal lateral dissection, as this gives the surgeon perspective when trying to preserve specific perforators and save as much of the fascia as possible so that the size of its defect can be minimized. Once the deep inferior epigastric vessels are divided, the flap including the entire zones I and III from each side is elevated as the unilateral procedure but is tunneled ipsilaterally only ( Fig. 1.11 ).