title: [A comparative study of the skin expansion rate and instantly expanded skin retraction rate between implantation of double overlapping expanders and implantation of one single expander].
abstract: OBJECTIVE
  To 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.
  
  
  METHODS
  From 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.
  
  
  RESULTS
  During 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).
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Department of Plastic Surgery, the Sun Yat-sun Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.
authors.forename: Gan-Lin
authors.initials: GL
authors.lastname: Zhang
authors.forename: Wei-Qiang
authors.initials: WQ
authors.lastname: Liang
authors.forename: Chen-Yang
authors.initials: CY
authors.lastname: Ji
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Zhang
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000295:instrumentation* / Q000379:methods*; D015626:Tissue Expansion / Q000295:instrumentation* / Q000379:methods*; D015625:Tissue Expansion Devices; D055815:Young Adult