An investigation of the application of laser-assisted indocyanine green fluorescent dye angiography in pedicle transverse rectus abdominus myocutaneous breast reconstruction

Pedicle transverse rectus abdominus myocutaneous (pTRAM) flaps remain the most common method of autologous tissue breast reconstruction (1). Advantages of this traditional method – as opposed to microsurgical free tissue transfer – include a technically less-demanding procedure, shorter operative time and shorter hospital stay (2). However, complications of pTRAM reconstruction secondary to compromised circulation within the flap are well appreciated and include, among others, flap failure, skin necrosis and fat necrosis. The incidence of these complications have been reported to be as high as 8.5%, 8.9% and 58.5%, respectively (2,3). There are three recognized blood supplies to the lower abdominal tissue that are used in TRAM flap breast reconstruction (4). These are the superior epigastric system (pTRAM), the inferior epigastric system (microsurgical free TRAM and deep inferior epigastric perforator flaps) and the superficial inferior epigastric system. In designing the skin island for TRAM flap transfer, the surgeon must be careful to include ample tissue for reconstruction while maintaining adequate blood supply. The concept of angiosomes, as described by Spear et al (3), Taylor et al (5) and Boyd et al (6), is useful in illustrating the differences in blood supply between free TRAM and pTRAM flaps. In any free TRAM flap, zone 1 is the primary angiosome, and zones 2 and 3 are considered to be the adjacent angiosomes. Zone 4, being two angiosomes away, is believed to be unreliable. By contrast, zone 1 in a pTRAM flap is separated from the primary angiosome (or vascular pedicle) by a choke system of vessels and, therefore, represents an adjacent angiosome. Therefore, according to these principles, it is suggested that zones 2 and 3 in a pTRAM flap are unreliable. Although they are usually reliable, this explains why we occasionally observe intraoperative congestion and ischemia, and subsequent partial flap necrosis in zones 2 and 3 in pTRAM flaps, which may lead to the abovementioned complications described in previous studies and observed in clinical practice (7). Complications can occur even when operating on carefully selected patients and using properly designed pTRAM flaps. Any clinically obvious intraoperative findings of ischemia or congestion would naturally guide the surgeon to alter the flap design to include viable angiosomes and prevent complications. However, ischemia and congestion are often not apparent or certain at the time of surgery. Identification of poor perfusion is more difficult in complex cases such as patients with obesity, a history of smoking, darker skin colour or previous abdominal surgeries. Some of these patients are at an exceptionally high risk for postoperative complications, which can be exacerbated by the uncertainty of clinical judgment (in this instance). When clinical judgment may be confounded, a means to more accurately assess perfusion is necessary. A variety of modalities have been used in an attempt to assist the surgeon intraoperatively in identifying potential sources of complication. These include fluorescein dye, thermography, Doppler ultrasound, tissue oximetry and various radioisotopes, among others. Unfortunately, each has its own set of disadvantages, which has precluded their widespread clinical use for this purpose. The benefits of laser-assisted indocyanine green angiography (LA-ICGA) in microsurgical breast reconstruction have been demonstrated by Newman et al (8). A later report published by Pestana et al (9) described early positive experience with the use of LA-ICGA for free tissue transfer of various types throughout the body. To our knowledge, the use of this technology in pTRAM reconstruction has not been previously described. This technology may provide advantages such as reducing the risks of these commonly noted complications. Several studies (10) have shown a remarkably high ischemic complication rate in pTRAM flaps, which can lead to additional wound care treatments, office visits, surgeries, compromised reconstructive results and increased overall health care costs. For example, a recent study by Janiga et al (11) demonstrated ischemic-related flap complications in 22.4% of ipsilateral pTRAM flaps and in 25% of contralateral pTRAM flaps; advanced patient age was strongly correlated with increasing ischemic complication rates. A study by Andrades et al (12) on ischemic complications of 399 TRAM flaps (147 pTRAMs) in 301 patients demonstrated a pTRAM ischemia rate of 42.9%, with a corresponding reoperation rate of 19.7% and a revision rate of 60.5%. A study by Spear et al (13) of 224 obese and nonobese patients undergoing pTRAM reconstruction demonstrated a partial flap ischemic necrosis rate of 21.6% in obese patients, 7.1% in overweight patients and 5.8% in normal weight patients (13). This form of intraoperative angiography (LA-ICGA) begins with the intravenous injection of indocyanine green fluorescent dye, which may be administered via an existing central line or through peripheral access. The dye, which binds to plasma proteins, travels through the vascular system and courses through the microvasculature. As it does, the subdermal plexus can be visualized through the skin in real time. Images are dynamic and are captured in video format on a monitor in the operating room. The format is black and white – white represents the dye within the microvasculature (eg, perfusion) and black represents the lack of dye (eg, lack of perfusion). Varying shades of grey demonstrate gradients of perfusion throughout the imaged tissue. In an effort to evaluate the efficacy and usefulness of LA-ICGA in reducing or preventing known complications of pTRAM reconstruction, this technology was used in pTRAM breast reconstruction surgery. Two cases illustrating our initial experience, lessons learned and outcomes follow.