Intramuscular Deep Inferior Epigastric Vessels Are Insulated by Perimysial Fibroadipose Tissue Network.

Background The difficulty of elevating a deep inferior epigastric perforator (DIEP) flap largely depends on the intramuscular course of the vessel and the perforator. Previous studies, however, have lacked histologic descriptions of the vessels and surrounding structures. The present study analyzed the histologic aspects of the deep inferior epigastric vessels and perforators, focusing on their perivascular relationships with muscle fibers. Methods The abdomen of a cadaver was histologically evaluated to identify intramuscular deep inferior epigastric vessels. Tissue samples were stained with hematoxylin and eosin and with Masson trichrome stain to visualize fibrous components. Twenty-one DIEPs from 12 patients were also evaluated to determine the histologic aspects of the perivascular structure. In the cross-section of each perforator and adjacent tissue, the perforator-to-muscle distance and trichrome-stained area were measured, and the correlation of the perforator size with the perforator-to-muscle distance and the percent collagenous portion of the distance were determined. Results Histologic analysis showed that the deep inferior epigastric vessels and perforators were encased by perimysial connective tissue and were not in direct contact with the muscle fibers. The smaller perimysia branched out from the larger perimysia, forming an interconnecting network structure. Correlation analysis showed that larger vessels had more collagenous portions in the perimysial structures (Spearman's rho = 0.537, p = 0.012). Conclusion The deep inferior epigastric vessels and perforators reside in a perimysial fibroadipose tissue network. This may provide surgeons with a microscopic perspective during DIEP dissections.