A clinical application for arterial coupling and histomorphometric comparison of internal mammary and thoracodorsal arteries for safe use.

Background: In breast reconstruction, arterial coupling has been reported to be more favorable in the thoracodorsal artery (TDA) than the internal mammary artery (IMA). This technique may help overcome anastomosis in a small, deep space. Understanding the arteries' mechanical properties is crucial for breast reconstruction's safety and success.

Methods: Abdominal-based free flap breast reconstructions performed by a single surgeon between 2020 and 2022 were retrospectively analyzed. The patients were classified by microanastomosis technique (handsewn and coupler device) to compare the rate of vascular revision. Histomorphometric analysis of arterial coupling in TDA and IMA was performed in 10 fresh cadavers for comparing wall thickness and composition, including densities of elastic fiber, smooth muscle, and collagen.

Results: A total of 309 patients (339 reconstructed breasts) were included. There were 29 patients in the TDA handsewn group (A), 38 patients in the TDA coupler group (B), and 242 patients in the IMA handsewn group (C). The rates of arterial revision in groups A, B, and C were 0.00% (95%CI: 0.00%-11.03%), 2.5% (95%CI: 0.44%-12.88%), and 1.49% (95%CI: 0.58%-3.77%), respectively, with no statistically significant differences (p-value = .694). Histologically, the thickness of the tunica media and adventitia between IMA and TDA showed no significant difference. The density of elastic fiber was significantly higher in IMA (16.70%) than in TDA (0.79%) (p-value <.001).

Conclusion: The histologic characteristics of TDA are more favorable for arterial coupling than those of IMA. Arterial coupling is a safe option in situations where TDA anastomosis must be performed through a narrow and deep incision.