title: The effect of epidural anesthesia on muscle flap tolerance to venous ischemia.
abstract: BACKGROUND
  Venous ischemia is a major cause of failure after free tissue transfers and replantations. The combination of general and epidural anesthesia leads to vasodilatation and improves tissue perfusion. Postoperative pain relief and sympathetic blockage are additional benefits of epidural anesthesia. The purpose of this study was to determine whether epidural anesthesia has benefits on microcirculation and neutrophil functions in muscle flaps subjected to venous ischemia.
  
  
  METHODS
  Thirty Sprague-Dawley rats were divided into three groups: group I, general anesthesia; group II, spinal anesthesia; and group III, epidural anesthesia. Cremaster flaps were prepared, postcapillary venules were selected under intravital videomicroscopy, and flaps were subjected to venous ischemia. Images were recorded from preselected postcapillary venules before venous ischemia (baseline) and following reperfusion. Neutrophil rolling and adhesion, functional capillary density, and diameters of postcapillary venules were evaluated.
  
  
  RESULTS
  The increase in rolling neutrophils in group III was significantly lower than in groups I and II at 60 and 120 minutes. Change of adherent neutrophils in group III was significantly lower than in groups I and II at 15, 60 and 120 minutes. There was significantly more reduction in inner diameter of postcapillary venules in groups I and II compared with group III. Functional capillary density in groups I and II was significantly lower than in group III.
  
  
  CONCLUSIONS
  Epidural anesthesia regulated neutrophil functions, salvaged functional capillaries, and prevented vasoconstriction of postcapillary venules in cremaster muscle flaps subjected to venous ischemia. Spinal and general anesthesia, however, were found to be ineffective in improving microcirculation of muscle flaps subjected to venous ischemia.
authors.affiliation: New York, N.Y.; and Istanbul and Ankara, Turkey From the Department of Surgery, New York Presbyterian Hospital-Weill Cornell Medical College, the Division of Plastic Surgery, New York Presbyterian Hospital-Columbia University Medical Center, the Department of Plastic and Reconstructive Surgery, I.U. Cerrahpasa Medical School, and the UNAM, Institute of Materials Science and Nanotechnology, Bilkent University.
authors.forename: Cenk
authors.initials: C
authors.lastname: Cayci
authors.forename: Can
authors.initials: C
authors.lastname: Cinar
authors.forename: Osman A
authors.initials: OA
authors.lastname: Yucel
authors.forename: Turgay
authors.initials: T
authors.lastname: Tekinay
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Ascherman
mesh_terms: D000767:Anesthesia, Epidural; D000818:Animals; D002196:Capillaries; D007511:Ischemia / Q000503:physiopathology* / Q000517:prevention & control; D008833:Microcirculation; D009504:Neutrophils / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013524:Surgical Flaps / Q000098:blood supply*