title: The composition and behavior of capsules around smooth and textured breast implants in pigs.
abstract: BACKGROUND
  The surface of the implant is one of the many factors often associated with the occurrence of capsular contracture, the etiopathogeny of which remains unclear. The purpose of this study was to analyze the behavior of capsular contracture by means of applanation tonometry and histology using a midsized animal model.
  
  
  METHODS
  Silicone breast implants were implanted into 33 pigs and observed at 30, 60, 180, and 270 postoperative days.
  
  
  RESULTS
  Capsular contracture in smooth implants showed significantly greater pressure values of tonometry, and the smooth implant capsule was significantly thicker than the textured implant capsule. Both pressure and thickness of the capsules increased at each period. The collagenous layer did not show any difference considering the periods of time in which the total thickness was analyzed; on the other hand, the increase in total capsular thickness occurred by thickening of the noncollagenous layer in both smooth and textured implants. Taking into consideration both kinds of implants, histomorphometric analysis showed that thin fibers were replaced by thick fibers in later postoperatives periods (180 and 270 days).
  
  
  CONCLUSIONS
  The greater incidence of capsular contracture in smooth implants was correlated with the progressive increase in total capsule thickness, due to a higher concentration of collagenous fibers, when compared with textured implants (p = 0.011; mean difference, 6.61), and a higher concentration of thick fibers (p = 0.034; average, >5.51 percentage points per field of thick fibers than the textured implants in all periods). Pigs are good animal models for studying the healing process after breast augmentation with implants.
authors.affiliation: São Paulo, Brazil From the Departments of Surgery and Pathology, Federal University of São Paulo, and Department of Pathology, University of São Paulo.
authors.forename: Eliza
authors.initials: E
authors.lastname: Minami
authors.forename: Ivan Hong Jun
authors.initials: IHJ
authors.lastname: Koh
authors.forename: José Carlos Ronche
authors.initials: JCR
authors.lastname: Ferreira
authors.forename: Angela Flávia Logullo
authors.initials: AFL
authors.lastname: Waitzberg
authors.forename: Valcir
authors.initials: V
authors.lastname: Chifferi
authors.forename: Tomás Fortoul
authors.initials: TF
authors.lastname: Rosewick
authors.forename: Max Domingues
authors.initials: MD
authors.lastname: Pereira
authors.forename: Paulo Hilário Nascimento
authors.initials: PHN
authors.lastname: Saldiva
authors.forename: Luiz Francisco Poli
authors.initials: LFP
authors.lastname: de Figueiredo
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000009:adverse effects*; D019928:Breast Implantation / Q000009:adverse effects*; D018427:Breast Implants / Q000009:adverse effects*; D004195:Disease Models, Animal; D005355:Fibrosis / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008365:Manometry; D020034:Silicone Gels / Q000008:administration & dosage / Q000009:adverse effects*; D013552:Swine
chemical_list: D001672:Biocompatible Materials; D020034:Silicone Gels