The free Transverse Rectus Abdominis Muscle (TRAM) flap was developed to address some of the concerns with the pedicled TRAM flap.
In a free TRAM flap the same amount of skin and fat are harvested from the abdominal wall, but only the lower part of the rectus abdominis muscle is sacrificed. Blood flow to the tissue is supplied by the deep inferior epigastric artery and vein which are divided in the groin and the TRAM flap completely detached from the patient (fig. 1).
The tissue is transferred to the chest wall where both the artery and vein are reconnected to similar vessels, either in the armpit (thoracodorsal vessels) or beside the sternum (internal mammary vessels). These blood vessels have a diameter of 15 to 25 mm and are joined together under the operating microscope. This is very delicate, precise surgery which prolongs the operating time.
Figure 1: The free TRAM flap gets its normal blood flow from vessels coming from the groin (the inferior epigastric artery and vein). (b) These vessels are hooked up to recipient vessels through microsurgery.
A similar amount of skin and fat can be utilised, but with a smaller piece of the rectus abdominis muscle. This is called a muscle sparing free TRAM flap (fig. 2). It causes less muscle weakness post-operatively and a lower incidence of abdominal wall problems.
Figure 1: The muscle-sparing free TRAM flap gets its normal blood flow from the same vessels coming from the groin (the inferior epigastric artery and vein). (b) Similar to the free TRAM flap, these vessels are hooked up to recipient vessels through microsurgery.
It is the microsurgical connection or anastomosis that can potentially give rise to problems. A blood clot (thrombosis) occurs at this site in approximately 3 to 4 % of patients. It most frequently happens during the first 48 hours following surgery and therefore every patient is closely monitored by specialized nurses during this period. If a thrombosis occurs, a further operation is required to remove the clot and re-establish the blood flow. If the clot cannot be removed this leads to complete loss of the flap (0.5 to 1% of cases).
However, in addition to reducing the abdominal wall deficit, the free TRAM has an improved blood supply because there is no twisting of the flap during transfer. It is also easier to create an aesthetically pleasing breast shape.
Incidence of complications:
|Return to theatre||2|
|Partial flap necrosis||11.1|
|Total flap loss||1.3|
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Larson DL, Yousif NJ, Sinha Rk, et al. A comparison of pedicled and free TRAM flaps for breast reconstruction in a single institution. Plast Reconstr Surg. 1999;104:674-680.
Blondeel PN, Arnstein M, Verstraete K, Depuydt K, Van Landuyt KH, Monstrey SJ, Kroll SS. Venous congestion and blood flow in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg. 2000;106(6):1295-9.
Kroll SS. Fat necrosis in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg. 2000;106:576–583.
Blondeel PN. Venous augmentation of the free TRAM flap. Br J Plast Surg. 2002;55(1):87.
Blondeel PN. Discussion: perfusion-related complications are similar for DIEP and muscle-sparing free TRAM flaps harvested on medial or lateral deep inferior epigastric artery branch perforators for breast reconstruction. Plast Reconstr Surg. 2011;128(6):590e-2e.
Blondeel PN, Neligan P. Are bilateral TRAM flaps as good as bilateral DIEP flaps? Plast Reconstr Surg. 2011;128(2):590-1; author reply 591-2.