Characterization and Anatomy of Omental Flap and Gastroepiploic Vascularized Lymph Nodes

Background:  Lymphedema is a chronic and potentially incapacitating condition that can be caused by oncologic axillary and groin lymph node dissection. Vascularized lymph node transfer based on the omental flap has been proposed as a potential solution to lymphedema. However, literature characterizing the gastroepiploic-based omental flap and corresponding lymph nodes does not currently exist. The purpose of this study is to describe lymph node anatomy along the gastroepiploic vasculature using computed tomographic angiography (CTA).

Methods:  A retrospective review of 110 consecutive CTA studies was performed. Measurements of gastroepiploic pedicle length, gastroepiploic vessel caliber, three dimensional lymph node distance from  gastroepiploic origin, and lymph node size were analyzed.  K-means clustering was used to determine lymph node spatial relationships.

Results:  The right gastroepiploic pedicle length was significantly larger in males than in females (p = 0.04). Gastroepiploic vein caliber at the origin was significantly larger in males than females (p = 0.01).Both males and females had an average of three lymph nodes along the gastroepiploic vasculature. Average nodal dimensions were 3.60 x 4.76 mm and did not significantly differ between sexes. Lymph nodes were found to cluster into two groups. Group 1 contained 44% of lymph nodes and had an average distance of 5.85 mm lateral, 5.91 mm cranial and 12.39 mm anterior from the gastroepiploic artery origin. Group 2 contained 56% of lymph nodes and had an average distance of 56.19 mm lateral, 10.46 mm cranial, and 37.20 mm anterior to the gastroepiploic artery origin.

Conclusion:  Understanding the anatomy and caliber of the omental flap can help preoperative planning of vascularized lymph node transfer. Vascularized lymph nodes along the gastroepiploic vasculature can be located at two distinct distances from the gastroepiploic artery origin.