title: Histology and physiology of tissue expansion.
abstract: BACKGROUND
  Tissue expansion is a concept based on the skin's natural ability to stretch in response to an underlying force.
  
  
  OBJECTIVE
  The purpose of this article is to review the histological and physiological changes that occur within the soft tissue and underlying structures during tissue expansion.
  
  
  METHODS
  An extensive search of the literature reviewing these changes is summarized herein.
  
  
  RESULTS
  Conventional tissue expansion may result in epidermal hypertrophy, decreased dermal, muscle, and adipose thickness, and bone resorption. A vascular capsule and angiogenesis provides a highly vascular flap and improves flap viability. Few soft tissue changes occur during rapid tissue expansion. The ability of the skin to increase in surface area during conventional tissue expansion is primarily because of biological tissue creep. Rapid expansion may result from mechanical tissue creep.
  
  
  CONCLUSIONS
  Many soft tissue changes occur during tissue expansion. Most of these changes return to the pre-expansion state over time following discontinuation of the expansion process.
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor 48109.
authors.forename: T M
authors.initials: TM
authors.lastname: Johnson
authors.forename: L
authors.initials: L
authors.lastname: Lowe
authors.forename: M D
authors.initials: MD
authors.lastname: Brown
authors.forename: M J
authors.initials: MJ
authors.lastname: Sullivan
authors.forename: B R
authors.initials: BR
authors.lastname: Nelson
mesh_terms: D000818:Animals; D062109:Dermatologic Surgical Procedures; D006801:Humans; D007430:Intraoperative Care; D012867:Skin / Q000033:anatomy & histology*; D012879:Skin Physiological Phenomena; D013524:Surgical Flaps / Q000379:methods; D015626:Tissue Expansion / Q000379:methods