The effect of antiadhesion agent on peri-implant capsular formation in rabbits

Purpose: Capsular contracture is the most troublesome complication after aesthetic breast surgery. Capsule formation can be seen as a normal foreign body reaction caused by implant insertion into the body. Pathological capsular contracture can lead to severe symptoms including pain, tenderness, and breast distortion. Hypertrophic scar hypothesis, one of the prevailing theories, implicates hematoma, granuloma, or other factors in capsular contractures. There are also animal studies that measure adhesion-induced capsule using fibrin glue. The authors performed the experiment to evaluate reductions in capsule formation using antiadhesion agent (AAA). Methods: Twelve smooth-surfaced cohesive-gel implants were implanted in 12 New Zealand white rabbits weighing 1.8 to 2.6 kg. These 5 × 5 × 1 cm sized miniature implants were designed in accordance with products currently used for breast augmentation. After skin incision, the exposed latissimus dorsi muscle was elevated, and a submuscular pocket was made. The rabbits were divided into 2 groups. In the experimental group (n = 6), the implant and 2 mL of AAA (Guardix) were inserted into the pocket under the muscle. In the control group (n = 6), implants and 2 mL of saline were inserted into the pocket. During the 2-month follow-up period, the rabbits were imaged monthly by 3-dimensional computed tomography to study capsule formation changes. After 2 months, the animals were euthanized, and implants with peri-implant capsule were excised. We evaluated capsule thickness, collagen pattern, and myofibroblast ratio on ventral, lateral, and dorsal aspects in a blinded fashion. Results: No significant differences in capsule thickness or capsular contractures were observed on gross examination or 3-dimensional computed tomography. On histological evaluation, capsule was thinner on all aspects (ventral, P = 0.027; lateral, P = 0.027; dorsal, P = 0.028; all P < 0.05), the pattern of collagen had more parallel alignment at low density, and the myofibroblast ratio was lower (ventral, P = 0.009; lateral, P = 0.002; dorsal, P = 0.004; all P < 0.05) in the experimental group than in control group. Conclusions: We suggest that AAA can be helpful in reducing capsule formation. Later, clinical trials are needed to evaluate this finding.