Difference in the Occurrence of Capsular Contracture According to Tissue Characteristics in an Irradiated Rat Model

This study was performed to evaluate the hypothesis that capsule formation varies according to the radiation dose in muscle tissues; chest wall tissues, including the ribs; and acellular dermal matrices (ADM) that are in contact with the silicone implant.In this study, 20 Sprague-Dawley rats underwent submuscular plane implant reconstruction using ADM. They were divided into four groups: an unradiated control group ( n = 5), nonfractionated radiation at a dose of 10 Gy ( n = 5), nonfractionated radiation at a dose of 20 Gy ( n = 5), and fractionated radiation at a dose of 35 Gy ( n = 5). Three months after surgery, hardness was measured, and histologic and immunochemical analyses of the capsule tissues of the ADM, muscle tissues, and chest wall tissues were analyzed.As the radiation dose increased, the silicone implant became harder, but no significant difference in capsule thickness according to the radiation dose was observed. Based on the tissue in contact with the silicone implant, ADM had a thinner capsule thickness than the muscle tissues, as well as less inflammation and less neovascularization compared with the other tissues.This study describes a new rat model of clinically relevant implant-based breast reconstruction using a submuscular plane and ADM with irradiation. The ADM in contact with the silicone implant, even after irradiation, was protected from radiation compared with the other tissues.These research results could support the use of ADM in implant-based breast reconstruction for prevention of the capsular contracture, even after radiation.