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Causative relationship between biofilm formation and capsular contracture is difficult to prove

Researchers suggest that bacterial biofilms likely contribute to a proportion of capsular contractures, but not all, among women undergoing a tissue expander/implant exchange procedure.

Twenty-five women were included in the study. All had received their last expander fill 4 to 8 weeks prior to exchange. The study also included a positive control,, a patient with a frank Grade IV capsular contracture after breast augmentation with a textured implant.

Researchers evaluated capsular contracture with both Baker Grade and applanation tonometry. Applanation tonometry is less frequently used; however, it may be a more sensitive measure, according to researchers.

Capsule, breast prosthesis and acellular dermal matrix (ADM) specimens stored in RNAlater were evaluated with real-time quantitative PCR in all patients.

All breast prostheses were textured and the ADM used was Alloderm, Ready to Use or Regenerative Tissue Matrix (LifeCell Corporation,).

Implant duration ranged from 91 to 1,115 days.

A total of 77 of 78 cultures from minced and vortexed implant shell, ADM and capsule biopsies showed no growth but a single tissue expander shell had a positive culture for Staphylococcus luadunensis.

Among 25 of 26 patients evaluated with scanning electron microscopy, there was no evidence of biofilm formation.

Biofilm formation was found in specimens from a patient with Baker Grade III capsule, an intramammary pressure of 777 N/m² and negative cultures.

Cellular infiltration scores were significantly greater in capsules but no difference was found in cell type or vascularity.

Researchers found that intramammary pressure increased significantly with Baker Grade.

Type I collagen and the I:III ratio decreased with increases in intramammary pressure in capsular tissue but not within ADM.

Persister cells may be a mechanism allowing biofilms to migrate to involve more widespread areas of the prosthesis surface and its adjacent capsule, concluded the researchers.

The research showed no correlation between biofilm formation and capsular contracture. – by Abigail Sutton

Disclosure: Poppler disclosed no relevant financial disclosures. For all remaining authors’ financial disclosures please see the full study.