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

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.