Microvascular vessel preparation: What are we really removing during adventitial stripping?

Although adventitial stripping has been routinely recommended and practiced during vessel preparation for microsurgical anastomoses, detailed descriptions vary regarding the adequate extent of such maneuver. We aimed to histologically clarify which components of the vessel are removed during adventitial stripping, using arterial samples harvested during microsurgical breast reconstruction.

Thirteen deep inferior epigastric arteries, nine internal mammary arteries, and four thoracodorsal arteries were evaluated in each step of vessel preparation, which were (1) grossly as a vascular bundle, (2) before vessel preparation, and (3) after vessel preparation under the operative microscope. Histologic components of each sample were evaluated under light microscopy. The combined thickness of the intima and the media and the thickness of the adventitia were measured and compared.

Two distinctive layers of connective tissue were observed outside the media before vessel preparation. Outer loose areolar tissue with coarse fibers was mostly removed during vessel preparation. However, the inner adventitial layer with dense, fine collagen fibers consistently remained after vessel preparation and ostensible adventitial stripping. The average thickness of this layer was comparable with that of the media. Although there was no definitive demarcation between the two differential connective tissue layers, a vasa vasorum layer was distinctly seen between the two layers.

The tissue removed during standard microsurgical vessel preparation or vessel stripping is not the entire layer of the adventitia, and the inner adherent layer of adventitia with fine collagen fibers should be preserved and included in the microsuture with the intima and media during anastomosis.