Understanding the vascular anatomy of zone IV in DIEA perforator flaps

Abstract

Introduction: Due to a longstanding controversy over the perfusion reliability of zone IV current this area is routinely discarded despite the mechanism behind zone IV necrosis not being fully understood. The authors review and investigate the vascular anatomy of zone IV with the aim of outlining the reasons for necrosis.Methods: A literature search and review of archival injection studies performed by the authors was undertaken to identify the arterial and venous maps of the abdomen. Unembalmed abdominal wall and full body specimens were used for cadaveric studies to demonstrate the arterial anastomotic patterns and venous drainage pathways of the deep inferior epigastric, superficial inferior epigastric, superficial circumflex iliac and intercostal systems.Results: Cadaveric injection studies demonstrated the presence of true and choke anastomoses between all lower abdominal arterial branch systems. Venous studies found that the dominant venous drainage is through large caliber superficial epigastric and circumflex iliac veins, a system which is interrupted in flap elevation and redirected to the perforator venae comitantes, with inter-territory communicating oscillating veins also becoming a limiting factor between territories.
 Conclusion: The mechanism behind the common failure of zone IV in the DIEP flap is explained with studies demonstrating both potential arterial and venous limiting factors. The authors conclude that the mechanism is indeed multifactorial, however suggest that when zone IV in DIEP tissue transfer is required, fat below Scarpa’s fascia is excised and the contralateral SIEV is preserved for use as an additional venous anastomosis.

Laser Speckle Contrast Imaging in Reconstructive Surgery

“…The basic idea is that the safe clinical vascular territory of a cutaneous perforator, used for example for a flap, extends beyond the anatomical territory of that perforator to include the anatomical territory of the adjacent cutaneous perforator, but if further territories are used, the risk of necrosis increases. [34][35][36] An example of this is the above-mentioned transverse rectus abdominis musculocutaneous (TRAM) flap. In 1983 plastic surgeons Michael Scheflan and Melvyn Dinner published a paper where they showed, based on anatomical studies, that there is a communication between the perforators that supply the skin over the flap.…”