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Capsular contracture in implant based breast reconstruction-the effect of porcine acellular dermal matrix.

BACKGROUND
Irradiation of implant-based breast reconstructions (BR) is known to increase capsular contracture (CC) rates on average by 4-fold over non-irradiated reconstructions. The use of acellular dermal matrix (ADM) has been associated with lower CC rates in non-irradiated reconstructions (0-3%). Experimental and clinical studies suggest that ADM may also reduce CC rates in irradiated breasts. The aim of this study was to evaluate CC rates in non-irradiated and irradiated one- and two-stage BRs performed with the assistance of porcine ADM (PADM).


METHODS
A single centre, retrospective, cohort study was designed from December 2008 to October 2012. A total of 200 immediate implant-based BRs were performed using PADM for inferior pole reinforcement. We included non-irradiated BR with a minimum follow up of 6 month from primary surgery (one stage) or from explantation of expander and implantation of the definitive implant (two stage). Of the postoperatively irradiated BR we included patients with 1 year or more follow up time from termination of radiotherapy. CC was graded using the conventional Spear-Baker classification and modified version for irradiated BR. According to the literature Grade III and IV CC were defined as clinically significant CC.


RESULTS
Of 200 BRs with PADM, 122 were included in this study (84 non-irradiated and 38 irradiated). Sixty-five BR were one stage and 57 were two stage BR. Grade III/IV CC was remarkable low in non-irradiated (6%) and irradiated BR (13%). There was a non-significant trend to increased Grade III and IV CC in irradiated BR vs. non-irradiated BR (13% vs. 6%, P=0.216). In this study follow up time (P<0.001) and the stage of ADM reconstruction (two vs. one stage, P=0.022) were significant risk factors for occurrence of grade III/IV CC on univariate analysis and remained significant for the follow up time (P=0.013) and remarkable for the stages (P=0.093) in multivariate analysis.


CONCLUSIONS
Our data support the current clinical evidence that ADM use in implant-based BR is associated with a reduced risk of CC when compared to the standard submuscular techniques in literature. The reduced risk is maintained in the setting of radiotherapy. Two stage procedures in our study population showed increased grade III/IV CC compared to one stage procedures with or without exposure to radiation.