Refinements in Microcirculation of the Deep and Superficial Venous Territories & Contribution of the Dermal Plexus in DIEP Flap Reconstruction: An Anatomical Study

Introduction: Complications associated with venous microcirculation remains prevalent to autologous reconstruction with the free deep inferior epigastric artery perforator (DIEP) flap. It has been previously been demonstrated that retaining the dermal component in DIEP flap harvest has a significant role in overall flap perfusion. Studies of venous perforator anatomy and assessment of perforator vascular territories (venosomes) has not received the same attention compared to arterial studies. This study evaluates the venous microcirculation of the anterior abdominal wall integument of the DIEP and superficial inferior epigastric venous systems and the impact on the dermis on venous microvascular perfusion.

Methods: Fourteen hemi-abdominal flaps from the midline to mid-axillary line were harvested in fresh, non-frozen human cadavers. Following perforator mapping, the venae comitantes of the largest DIEP perforator and the superficial inferior epigastric vein cannulated using a 27-gauge butterfly catheter. Flaps were evaluated with high resolution computed tomography (CT) following an injection of iodinated contrast (Omnipaque ®) to the DIEP venae comitantes and SIEV. The contrast agent was flushed out from the flap between injections. The dermis was subsequently removed with cautery at the subdermal dissection plane and flaps were re-imaged with CTA following injection in the DIEV perforator. Three-dimensional CT angiography of the venous territories allowed detailed assessment at each stage including perfusion areas, volume and pattern of perfusion.

Results: Average territory of the largest DIEV perforator was 180cm2 and extended to 47% of the hemi-abdominal integument. Patterns of venous territory distribution from individual venous perforators were assessed in hemi-abdominal flaps of the anterior abdomen. The perfusion territory without the dermis was significantly reduced by a mean of 142cm2, P=0.01. Mean volume of perfusion was significantly reduced on average by 10cm3, P=0.01. A direct communication of the DIEV perforator with the superficial system was seen in 10/14 flaps (71%).

Conclusion: Venous microcirculation plays a critical role in success of DIEP flap harvest. This study details patterns of venosomes of DIEV perforators, the comparison with the superficial system but appreciates the critical role of the preservation of the dermal integrity to preserve and optimize venous drainage of the flap by avoiding aggressive de-epithelialization.