[Ear reconstruction using porous polyethylene implants. Effect of cortisone on edema reduction and healing process]. / Ohrrekonstruktionen mit Hilfe poröser Polyethylenimplantate. Einfluss der Ödemprophylaxe mit Kortison auf den Heilungsverlauf.

INTRODUCTION: Porous polyethylene implants are increasingly used for ear reconstruction. Although the material used exhibits good biocompatibility, swelling and edema formation frequently occur after implantation, which may be treated by prophylactic cortisone therapy. The aim of the present study was to analyze the effects of cortisone therapy on the postoperative healing process. PATIENTS AND METHODS: Between 2006 and 2010 porous polyethylene implants (Medpor®) were used for ear reconstruction of high-grade ear deformities in 23 patients (m:f=11:12; age: 17.2±12.4 years). For this purpose, 11 patients were treated systemically with cortisone (3 mg/kg body weight Solu-Decortin H) for the first 3 postoperative days, whereas 12 patients (controls) did not receive cortisone. Postoperatively, we analyzed the time course of edema formation, complications and the reconstructive result. RESULTS: Rejection or extrusion of the polyethylene implants was not observed in any of the patients (n=23) during a postoperative observation period of up to 3.5 years. Within 3-12 months after ear reconstruction all patients exhibited a completely shaped ear. Administration of cortisone had no significant effect on postoperative edema formation or the reconstructive end result. CONCLUSION: Porous polyethylene implants are well suited for the reconstruction of moderate to high-grade ear deformities. Since administration of cortisone does not significantly affect the postoperative healing process, prophylactic cortisone treatment following ear reconstruction with porous polyethylene implants should be omitted with regard to potential side effects.

Perioperative steroid administration inhibits angiogenic host tissue response to porous polyethylene (Medpor) implants.

Porous polyethylene (Medpor) is an alloplastic biomaterial, which is commonly used in plastic and reconstructive surgery. In the present study, we analyzed the effect of perioperative steroid administration on the inflammatory and angiogenic host tissue response to implanted Medpor. For this purpose, Medpor was implanted into the dorsal skinfold chamber of prednisolone-treated and vehicle-treated (control) balb/c mice and analyzed by means of intravital fluorescence microscopy over a 14-day period. Incorporation of the implants was evaluated by histology. An aortic ring assay and Western blot analyses were performed to determine in vitro the effect of prednisolone on angiogenesis. Implantation of Medpor did not induce a leukocytic inflammatory host tissue response. However, in prednisolone-treated and control animals giant cells could be detected at the interface between the implants and the surrounding granulation tissue as a typical indicator for a chronic foreign body reaction. Interestingly, perioperative prednisolone administration inhibited vascularisation of the implants, as indicated by a significantly decreased functional density of newly developing capillary blood vessels. Accordingly, prednisolone suppressed in vitro endothelial sprouting and tube formation in the aortic ring assay and reduced proliferating cell nuclear antigen (PCNA), Tie2, vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9 expression of murine endothelioma cells. In conclusion, prednisolone treatment inhibits the early vascularisation of Medpor implants due to direct inhibition of distinct angiogenic mechanisms. Therefore, perioperative steroid therapy should be avoided in case of Medpor implantation to achieve a rapid incorporation of the biomaterial at the implantation site.