D36. Shaping Breast Capsule Formation: Impact of Absorbable Antibiotic Beads on Capsule Thickness and Calcification in Device-based Breast Reconstruction

PURPOSE: Absorbable antibiotic beads are an emerging technique for preventing infections in breast reconstruction and therefore may decrease risk of capsular contracture. Our study aims to analyze breast capsules from patients who underwent tissue expander (TE)-based reconstruction with and without absorbable antibiotic beads. METHODS: This was a prospective study of patients undergoing immediate pre-pectoral TE placement with and without antibiotic beads, which were made with 1g vancomycin, 240mg gentamicin, and calcium sulfate. Breasts with radiation therapy were excluded. At the second stage, posterior capsule samples were taken and analyzed by a blinded pathologist. Capsules between the groups were compared. RESULTS: Our study included 16 breasts without beads and 25 breasts with beads. Both groups were comparable in age, BMI, and mastectomy weight. Breasts without beads had significantly thicker capsules compared to those with beads on gross analysis (median: 5.5mm, range:1mm-28mm versus 2mm, range:1mm-11mm, p=0.004). Histological analysis was completed on 16 capsules (7 without beads and 9 with beads). The collagen layer was thicker in capsules without beads versus capsules with beads (median: 3.5mm, range:2mm-5.1mm versus 2.5mm, range:1.1mm-3.2mm, p=0.01). Calcification was present in five of nine capsules with beads compared to none in capsules without beads (p=0.034). Fiber organization and lymphocytic inflammation was similar between groups (p>0.05). CONCLUSION: Our findings suggest that the use of absorbable antibiotic beads in device-based breast reconstruction significantly decreases capsule thickness both on gross and histological examination. There was also increased calcification in capsules with beads, which may be secondary to calcium sulfate residue.