The Value of BMI for Breast Reconstructions with the SIEA Flaps: Predicting the Ideal Intercostal Plane for the End-to-End Microvascular Anastomosis and the Possibility of Utilizing the TDA as a Salvage Recipient Choice.

Abstract

The superficial inferior epigastric artery (SIEA) diameter and the matching degree between the donor and the recipient arteries in terms of diameter are key factors affecting the outcome of the procedure in breast reconstructions with the SIEA flaps. A diameter of the SIEA ≥ 1.5mm and a matching degree ≥ 1:2 (50%) of the diameters of the donor and the recipient arteries are recognized standards for the SIEA and the internal mammary artery (IMA) to achieve an end-to-end anastomosis. However, further refinements of the population characteristics and the ideal microscopic anastomosis intercostal planes are currently lacking for the criteria. In this study, based on 20 sides of hemiabdomen with computed tomography angiography (CTA) data suggesting the presence of the SIEA, we analysed the diameters of the donor and the recipient arteries as well as their matching degrees. The correlations between the parameters above and body mass index (BMI) were assessed. Based on the lower bounds of the 95% confidence intervals of the matching degrees and the two critical nodes of 50% and 67%, we theoretically evaluated the possibility of an end-to-end anastomosis of the SIEA and the IMA at different levels of BMIs and intercostal spaces, and predicted the possible intraoperative management measures for the SIEA. The SIEA diameter, the thoracodorsal artery (TDA) diameter, and the diameters of the IMA at the 2nd to the 5th intercostal levels were positively correlated with the BMI (p <0.05). A value of BMI ≥ 24kg/m2 could indirectly reflect the application premise of the diameter of the SIEA ≥ 1.5mm. The matching degrees of the SIEA with the TDA or the IMA at the 2nd to the 5th intercostal level were linearly and positively correlated with the BMI (p < 0.001). Based on the confidence interval analysis, we predicted different management techniques that might be needed intraoperatively for the SIEA at different BMI levels, when the SIEA and the IMA or the TDA were to be anastomosed in an end-to-end way. For patients with preoperative CTA data suggesting the presence of the SIEA in the second-stage breast reconstructions, when a value of BMI ≥ 24kg/m2 is met, the SIEA and the IMA can theoretically achieve an end-to-end anastomosis at the 3rd to the 5th intercostal level, and when 24kg/m2 ≤ BMI ≤ 25kg/m2, due to the large difference in diameters, the SIEA and the IMA at the 2nd intercostal level might need to adopt an end-to-side anastomosis or switch to the TDA recipient site. Based on this study's findings and aesthetic effect considerations, we think that the 3rd and the 4th intercostal planes are ideal choices for the end-to-end anastomosis. As a salvage recipient option, the TDA can theoretically achieve an end-to-end anastomosis with the SIEA at a value of BMI ≥ 24g/m2. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .