OBJECTIVETo comparatively study the difference of the skin expansion rate and instantly expanded skin retraction rate between implantation of double overlapping expanders and implantation of one single expander.

METHODSFrom Mar. 2009 to Mar. 2012, 22 cases with 39 sites for skin expansion, received double overlapping expanders in 24 sites, single expander in 15 sites. The area of original skin and expanded skin was measured by "wet-cloth sampling". Then the skin expansion rate was calculated. A distance of 5 cm at the center of expanded skin was re-measured after taking out the expanders. Then the instantly skin retraction rate was calculated.

RESULTSDuring the same expansion period, the skin expansion rate was (3.5 +/- 0.9)% with the double overlapping expanders and (2.6 +/-0.6)% with one single expander, showing a significant difference between the two groups (P = 0. 002), while the instantly skin retraction rate was not statistically different [(30.3 +/- 0.8)% vs (32.3 +/- 0.9)%; P = 0.47)]. There was a negative relationship between the instantly skin retraction rate and the expansion period (r = -0.768).

CONCLUSIONSThe skin expansion rate can be increased with double overlapping expanders, while the instantly skin retraction rate doesn' t decrease. So the skin expansion efficiency is increased to reduce the re-expansion times for the patients with large lesions.