A rabbit model for capsular contracture: development and clinical implications.

BACKGROUND: Capsular contracture remains one of the most common complications involving aesthetic and reconstructive breast surgery; however, its cause, prevention, and treatment remain to be fully elucidated. Presently, there is no accurate and reproducible pathologic in vitro or in vivo model examining capsular contracture. The purpose of this study was to establish an effective pathologic capsular contracture animal model that mimics the formation of capsular contracture response in humans. METHODS: New Zealand White rabbits (n = 32) were subdivided into experimental (n = 16) and control groups (n = 16). Each subgroup underwent placement of smooth saline mini implants (30 cc) beneath the panniculus carnosus in the dorsal region of the back. In addition, the experimental group underwent instillation of fibrin glue into the implant pocket as a capsular contracture-inducing agent. Rabbits were euthanized from 2 to 8 weeks after the procedure. Before the animals were euthanized, each implant was serially inflated with saline and a pressure-volume curve was developed using a Stryker device to assess the degree of contracture. Representative capsule samples were collected and histologically examined. Normal and contracted human capsular tissue samples were also collected from patients undergoing breast implant revision and replacement procedures. Tissue samples were assessed histologically. RESULTS: Pressure-volume curves demonstrated a statistically significantly increased intracapsular pressure in the experimental group compared with the control group. The experimental subgroup had thicker, less transparent capsules than the control group. Histologic evaluation of the rabbit capsule was similar to that of the human capsule for the control and experimental subgroups. CONCLUSIONS: The authors conclude that pathologic capsular contracture can be reliably induced in the rabbit. This animal model provides the framework for future investigations testing the effects of various systemic or local agents on reduction of capsular contracture.

Hemodynamics, electrolytes, and organ histology of larger-volume liposuction in a porcine model.

Liposuction is a procedure that allows the surgical removal of excess adipose tissue in healthy individuals. Lipoplasty is commonly performed with few clinical side effects. However, with increased lipoaspirate volumes, complications have been reported. In addition, the abnormal appearance of fat cells in other tissues subsequent to lipoplasty has been reported in a small number of cases. The authors examined whether larger-volume lipoplasty, in the porcine model, resulted in disturbances in cardiac or pulmonary output levels, electrolytes, and liver chemistry analyses or alterations in organ histology. Nine adult porcine specimens were subjected to either lipoplasty (n = 6) with the superwet technique or no lipoplasty (n = 3). Using a Swan-Ganz catheter, cardiac output and pulmonary artery pressure measurements were obtained from initial placement before lipoplasty until 48 hours postoperatively. Blood analyte measurements were obtained. Upon euthanization, liver, kidney, and lung specimens were collected and tissue sections were prepared. No significant differences or trends were observed in cardiac parameters or blood analytes between control and experimental groups. Significant elevations in serum aspartate aminotransferase and alanine aminotransferase enzyme levels (p < 0.03) were observed in animals postoperatively (10 to 48 hours) subjected to lipoplasty compared with controls. Upon gross examination, the lung tissues of animals subjected to lipoplasty unexpectedly demonstrated patchy petechial hemorrhages on the pleural surface. Tissue sections revealed marked hemorrhagic congestion and evidence of pulmonary edema. Fat emboli were also identified within the pulmonary and renal systems.