Dimensions of capsular collagen fibrils: image analysis of rapid compared with slow tissue expansion for breast reconstruction.

Thirty women who were to undergo breast reconstruction by tissue expansion were randomly divided into two groups. Those in the first group were to undergo expansion once a day (rapid expansion) and the second group once a week (slow expansion). When the expanders were replaced by permanent prostheses, biopsy specimens were taken from the capsules around the expanders, and were examined by transmission electron microscopy at a magnification x 22,000. The diameters of the collagen fibrils in the capsules were analysed by an interactive image analysis system and measured. An analysis of variance was performed on a test series to optimize the sample. Ninety fibrils from each patient (two patients were excluded), were analysed and there were no significant differences in collagen fibrillar diameters (about 50 nm) between those who had undergone rapid or slow expansion, or between patients who had also undergone radiotherapy to the chest wall and those who had not. These results indicate that the collagen fibrils may still be in a transitional stage, and that further longer term studies are desirable. It is difficult, however, to see how they could be justified ethically in patients who are otherwise well.