title: Perfusion, viability, and pedicle dependence in acute and delayed rat island skin flaps.
abstract: OBJECTIVE
  Although surgical delay phenomenon has been widely investigated, its pathophysiology has not been fully elucidated.
  
  
  METHODS
  In 25 Spraque-Dawley rats, an 8 x 8 cm2 epigastric skin flap consisting of 4 vertical zones A through D (farthest from vascular pedicle) was outlined. All animals were perfused twice with colored fluorescent microspheres: immediately before and after flap elevation (Acute, n = 10) and before and after pedicle ligation on POD 8 (Delayed, n = 15).
  
  
  RESULTS
  After acute flap elevation, peripheral perfusion dropped significantly in zone C (0.29 +/- 0.01 vs. 0.19 +/- 0.04 ml g(-1) min(-1); P < 0.01) and zone D (0.33 +/- 0.09 vs 0.01 +/- 0.01 ml g(-1) min(-1); P < 0.01), while global flap perfusion remained unchanged. Total and regional blood flow did not change in the Delayed group after pedicle ligation.
  
  
  CONCLUSIONS
  Elevation of a pedicled flap caused significant decrease in distal flap perfusion while maintaining proximal and total flap perfusion. Eight-day delay was adequate to establish sufficient flap perfusion independent of the vascular pedicle.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Loma Linda University, Loma Linda, CA 92354, USA. etimek@sbcglobal.net
authors.forename: Ewa
authors.initials: E
authors.lastname: Komorowska-Timek
authors.forename: Tomasz A
authors.initials: TA
authors.lastname: Timek
authors.forename: Sandra
authors.initials: S
authors.lastname: Brady
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Buncke
mesh_terms: D000818:Animals; D010477:Perfusion / Q000295:instrumentation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D013524:Surgical Flaps / Q000098:blood supply* / Q000502:physiology; D013997:Time Factors