There are an abundance of tissue flaps used for breast reconstruction. Following early excitement for the TRAM flap, many centers abandoned this flap due to donor site complications. Now, many centers use one of several types of free perforator flaps all of which are known by their own acronym. Whereas most are well known such as the DIEP and GAP, many are performed less frequently and are less known. These include flaps such as SIEA (superficial inferior epigastric), TUG (transverse upper gracilis), PAP (profunda femoris) and TDAP (thoracodorsal artery perforator). Ischemia is the ultimate enemy of all of these flaps. The survival of flaps with vascular compromise is inversely proportional to the time to detection of the defect and time to re-exploration for salvage. In the early days of free flap reconstruction virtually all microsurgeons utilized tissue paddles to monitor flap health.
Skin paddles as noted in the accompanying drawing, allow the staff to identify early ischemia or venous congestion using both visual inspection of the skin paddle, capillary refill or temperature monitor strips. Recently more sophisticated measurements of skin vascular flow have been developed, one of which is laser Doppler flowmetry. Though like direct visualization it is non-invasive, it is unable to distinguish between arterial and venous thrombosis. Moreover, all of these methods require a skin paddle for evaluation.
Internal Doppler Monitoring
Currently internal Doppler monitoring is the only modality in common use that does not require use of an external skin paddle. There are several potential advantages to implantable Dopplers. The most obvious benefit is cosmetic as patients do not have a quilted/mosaic appearance to their reconstruction. Granted, this is transient as long as the skin paddle is small and inset in a location that is favorably excised without distorting the breast shape in a secondary operation. Nonetheless patients appear to appreciate their reconstructed breast when they appear postoperatively, much as they did preoperatively. More substantively, the key appeal of implantable Dopplers is the potential advantage of earlier identification of blood flow loss at the connection point to the recipient vessels feeding the flap. As previously noted, the earlier the identification of flap ischemia the more likely a flap can be salvaged. There are still arguments in the literature as to whether arterial and venous Dopplers are superior to venous Dopplers alone. As the success rate of microsurgical flap breast reconstruction continues to improve, the question will certainly arise as to whether flap monitoring will be necessary at all!