Bipedicled TRAM flap with rectus abdominis muscle preservation below the arcuate line without reinforcing mesh
TRAM bipediculado com preservação dos músculos retos do abdome abaixo da linha arqueada e sem o uso de tela de reforço

1.The anterior and lateral walls of the abdomen are formed by a distributed muscular complex in planes, whereby the external and internal oblique, transversus abdominis, and rectus muscles, covered by their respective aponeuroses, form a containing wall for the intraabdominal organs. In the anterior midline, external oblique muscle aponeurosis, and anterior and posterior laminae of the internal oblique muscle, together with the transversus muscle, are joined to form the linea alba from the xiphoid process to the pubis. The association of the aponeurosis of the 3 lateral muscles of the abdomen extends from the ribs to the pubis along the lateral margin of each rectus muscle, forming the semilunar line. The semilunar line and the linea alba form important vertical structures of support, whose preservation should be maintained in the dissection of the rectus abdominis muscles when preparing the TRAM flap. From the arcuate line (typically positioned halfway between the umbilicus and the pubis) to the pubic crest, the posterior face of the rectus abdominis muscles are coated exclusively by their aponeurosis, transverse muscle aponeurosis, and peritoneum. This detail makes the region thinner and less resistant. During the single-pedicled TRAM flap preparation, several authors report the transverse resection of the rectus abdominis muscle with its respective sheath in order to integrate it with to the cutaneous flap, without specifying how many centimeters below the arcuate line this is done. However, all agree that for cases where both the rectus abdominis muscles are mobilized, weakening of the abdominal wall is a reality, as it is maintained only by the transverse fascia and the posterior face of the rectus abdominis muscle. Therefore, the reinforcement mesh is required to decrease the possibility of herniations in the middle to long term.

2.The understanding of rectus abdominis muscle vascularization increased after it was studied in detail after the development of TRAM flap14-16 for new breast reconstructions. The rectus abdominis muscle is supplied by the superior epigastric, inferior epigastric, and intercostal arteries. The superior epigastric artery originates from the internal thoracic artery, penetrates the abdomen about 3 cm lateral from the midline and below the costal rim, and immediately crosses the posterior sheath of the rectus abdominis muscle. It continues caudally along the middle third of the posterior face of the rectus abdominis to approximately 2 to 4 cm above the umbilical line, giving off several branches that anastomose with the branches of the inferior epigastric artery. The inferior epigastric artery originates from the external iliac artery and rises obliquely and laterally out of the rectus abdominis muscle sheath to approximately 6 cm below the arcuate line, where it emits numerous muscular branches. These branches run upward to reach the branches of the superior epigastric artery, which together form a rich vascular network that anastomoses with the one on the opposite side. Moon and Taylor,17 through a detailed vascular study, proved that the inferior epigastric artery of a vascular pedicle is dominant, constituting a greater caliber vessel to nourish the rectus abdominis muscle. However, the TRAM flap survives with the pedicle from the superior epigastric artery. Surgical attempts at previous autonomization of the TRAM to reverse the flap's blood flow are being selectively applied by several authors already mentioned. The inferior epigastric artery is used for cases of free flaps in microsurgery. Several intercostal arteries that penetrate through the lateral edge of the rectus abdominis muscle follow the nerves in a segmental manner. In TRAM flap dissection, these vessels and nerves are surgically sectioned. These studies enabled the division of the cutaneous flap according to the muscular single pedicle position into 4 zones18: zone I, the myocutaneous segment directly perfused by the perforating arteries; zone II, the segment perfused by the axial vessels that cross the midline and reach the contralateral dermal plexus; zone III, the ipsilateral segment with the muscle, perfused by the axial vessels; zone IV, the extremity of the contralateral segment, perfused from the previous dermal plexus after autonomization of the flap. Surgical practice has shown that zones I and II, and only the limit of the zone III with the zone I survive without major risk of necrosis. In order to solve this problem and have a greater utilization and vascular safety in zone IV, the TRAM flap is autonomized by surgeons who use a single muscular pedicle. Under local anesthesia and by using a small access route close to the pubis, the inferior epigastric artery is sectioned and the incision is then sutured. With this technique, the definitive surgery can usually be performed in 1 to 3 weeks.

The skin incision was made using the marked limits and was taken through all layers up to the aponeurotic plane. In the upper extension of the incision, the incision was beveled to contain as much of the supraumbilical vascular plexus as possible.

The dissection of the supraumbilical cutaneous flap was performed up to the xiphoid process and the costal arches and, laterally, up to the oblique muscles. The dissection was prolonged in the direction of the recipient bed of the new breast to form a tunnel whose dimensions were sufficient to pass the surgeon's open hand. A selective thinning of the adipose tissue along the tunnel was done, when there was excess.

The next step was to mark the delimitation over the TRAM flap to estimate the projection of the rectus muscles still in the interior of their sheaths, particularly on the internal edges in order to assess them for diastasis (Figure 1).

Figure 1 - Schematic appearance of the cutaneous flap delimitation in the shape of an ellipse in the hypogastric region. The scheme also illustrates the projection of both the rectus abdominis muscles, the limits of the arcuate line (usually halfway between the umbilicus and the pubis), and the periumbilical vascular plexus, between both the superior epigastric arteries.

A periumbilical skin incision, about 1 cm in diameter, and the dissection of its pedicle completely released the umbilicus from the cutaneous flap.

The dissection started at the lower edge of the flap close to the pubis, throughout the aponeurotic plane up to the limit of the arcuate line, generally at half the distance between the umbilicus and the low transversal pubic incision, preserving the integrity of the rectus muscles and the linea alba. The dissection was continued bilaterally in the medial direction, following the same aponeurotic plane until the visualization of larger caliber perforating vessels, usually 1 to 2 cm medial to the semilunar line.

Next, on both sides, the aponeurosis was incised transversely at 1 cm above the limit of the arcuate line, continuing laterally and medially in the cranial direction, parallel to the body of the rectus abdominis muscle to the upper edge of the incised cutaneous flap.

Above the upper limit of the myocutaneous flap, the anterior aponeurosis of both the rectus muscles was incised in the longitudinal direction until the xiphoid process was approached; next, whole muscles were removed from their bed.

A long Kocher clamp was passed close to the arcuate line and exteriorized on the opposite side. Next, the muscle was transversally sectioned.

In the lower face of the cutaneous flap, isolated sutures with nonabsorbable thread were applied in the musculoaponeurotic layer with the flap's adipose tissue for better fixation. Both muscular pedicles with their respective aponeuroses integrated with the cutaneous flap were able to be mobilized to the recipient area (Figure 2).

Figure 2 - Schematic appearance of the dissected and everted cutaneous flap, as well as of both the rectus muscles dissected from their beds to the limit of the arcuate line and sutured in the subcutaneous cellular tissue of the flap.

The rectus muscles' aponeuroses and their plication along the linea alba were sutured with isolated sutures of 0-Prolene, similar to the plication performed in abdominoplasties. The rectus muscle stumps and the respective aponeuroses were sutured in the arcuate line.

Isolated quilting sutures19 were applied along the whole extent of the dissected cutaneous abdominal wall, from the xiphoid process to the pubis, with 2-0 or 3-0 absorbable thread. Two drains with continuous aspiration were positioned from the epigastrium and exteriorized close to the pubis.

The final suture, in the entire extent of the low abdominal incision, was held with isolated threads of 2-0 Monocryl, approximating the aponeurosis and the adipose tissue. Isolated sutures were passed in the dermis and intracuticular continuous suture was performed with 3-0 Monocryl.

A noncompressive dressing was applied with micropore adhesive tape directly on the suture line and cotton wad covering the operated areas.

Figure 3 - Transoperative sequence of late breast reconstruction with bipedicled TRAM flap, in a 46-year-old patient who underwent mastectomy without preservation of the pectoralis major muscle. In A, Marking the cutaneous flap in the hypogastrium. In B, Exposure of the left pectoral area to receive the abdominal flap. In C, Cutaneous flap dissected with the rectus muscles still in the interior of their sheaths. In D and E, The dissected rectus abdominis muscles are ready to be sectioned, and bilaterally sutured into the subcutaneous cellular tissue of the mobilized abdominal flap. In F, The appearance of the beds and of the respective arcuate lines after mobilization of the rectus muscles, before the routine suture of the preperitoneal layers to the posterior face of the rectus muscles upstream. In G, TRAM flap migration, showing in the back the rectus abdominis muscle sheaths still not sutured. In H, Plication of the rectus muscles sheath, bilaterally. In I, TRAM flap with its larger axis transversally positioned and the umbilicus hole close to the lower edge of the recipient incision. Details of the normal appearance of the vascularization of TRAM flap's extremities.

Figure 4 - Computed tomography scan of an athlete (tennis player), 9 months after the operation.


Figure 5 - Computed tomography scan of a patient 9 months after an abdominoplasty using mesh.


Figure 6 - Computed tomography scan of a patient 10 months after the operation.

Figure 7 - A 39-year-old patient with a biopsy-confirmed malignant tumor in the left breast, with moderate bulging in the hypogastrium, who underwent mastectomy with immediate reconstruction with TRAM flap. In A, B, and C, Anterior views after the operation, 2 years after the operation, without modeling of the new breast, and 1 year after the second operation, with modeling of the new breast, new areola, and papilla, in addition to homolateral mastopexy. In D, E, and F, Lateral view, showing maintenance of the hypogastrium's normal characteristics without bulging and without the use of mesh.


Figure 8 - A 55-year-old patient with hypertrophy and breast ptosis who underwent left mastectomy with immediate reconstruction with bipedicled TRAM flap and treatment of the donor bed without using mesh. In A and B, Anterior preoperative view and anterior view after a second operation for retouching the cutaneous flap, new papilla, and new areola, as well as right mastoplasty for breasts symmetrization, demonstrating the hypogastric conditions without bulging and without using mesh, 8 months after the operation. In C and D, Lateral views in the preoperative period and after the second operation.


Figure 9 - A 36-year-old patient who underwent right mastectomy 2 years before, via a transverse incision, with partial preservation of the pectoralis muscle close to the axilla. She also had, prior to the surgery, a clear adipose protrusion in the hypogastrium. In A and B, Anterior view before the operation and 6 months after the operation, without abdominal protrusion and without use of mesh. In C and D, Lateral view before the operation and 6 months after the operation.


Figure 10 - A 48-year-old patient who underwent right mastectomy and immediate reconstruction with bipedicled TRAM flap without the use of mesh. In A and B, Anterior views before the operation and in the eleventh month after the operation, without retouching of the new breast and demonstrating the hypogastrium without bulging. In C and D, Lateral views in the preoperative period and in the eleventh month after the operation.


Figure 11 - A 43-year-old patient who underwent left mastectomy and immediate reconstruction with bipedicled TRAM flap. Thirteen months after the radical mastectomy, a subcutaneous mastectomy was performed on the opposite breast, with a prosthetic implant. In A and B, Anterior views of the preoperative appearance and final postoperative appearance 18 months after the mastectomy and reconstruction without retouching of the second operation. Absence of bulging in the hypogastrium, not using mesh. In C and D, Lateral views, before the operation and 18 months after the operation.

Figure 12 - Illustration of the technique of single-pedicled flap dissection from its aponeurotic sheath, elongating it caudally beyond the arcuate line.


Figure 13 - In A, Schematic detail of the technique usually applied in the single-pedicled flap, in which dissection of the rectus abdominis muscle crosses the arcuate line. In B, Total and partial resection of zones IV and III, respectively, with the purpose of reducing the possibility of necrosis by vascular limitation.