title: Prediction of flap necrosis with laser induced indocyanine green fluorescence in a rat model.
abstract: Prediction of necrosis has a clinical relevance in all fields of plastic surgery. The new application of indocyanine green (ICG) fluoroscopy in plastic surgery allows an objective quantification of skin perfusion and a high topographical resolution. The aim of the present study is to determine threshold values for flap perfusion under well-defined experimental conditions. Twenty random pattern flaps with a length to width ratio of 4:1 (8 x 2 cm(2)) were dissected on the anterior abdominal wall of 20 male Sprague-Dawley rats. ICG fluoroscopy was performed at the end of the operation. The animals were sacrificed at the seventh postoperative day with a reliable necrosis of the distal part of the flaps. Postoperative ICG fluoroscopy then was analysed both in regions that will survive and undergo necrosis. At day 7 a mean area of 5.5 cm(2) (57% of the total flap area) survived and a mean of 3.8 cm(2) (43%) became necrotic. The surviving part of the flap had a mean perfusion index of 62% compared to reference skin. The distal parts of the flap that necrotised showed an average perfusion index of only 19% postoperatively. Differences were statistically highly significant (p<0.001). Indocyanine green fluoroscopy is a useful tool to evaluate perfusion topographically and predict necrosis. From a statistical point of view a perfusion index of less than 25% of the reference skin can be considered as a sign of developing flap necrosis.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Rechts der Isar Hospital, University of Technology, Ismaningerstrasse 22, 81675 Münich, Germany. r.giunta@ltz.tu-muenchen.de
authors.forename: R E
authors.initials: RE
authors.lastname: Giunta
authors.forename: T
authors.initials: T
authors.lastname: Holzbach
authors.forename: C
authors.initials: C
authors.lastname: Taskov
authors.forename: P S
authors.initials: PS
authors.lastname: Holm
authors.forename: T
authors.initials: T
authors.lastname: Brill
authors.forename: R
authors.initials: R
authors.lastname: Busch
authors.forename: B
authors.initials: B
authors.lastname: Gansbacher
authors.forename: E
authors.initials: E
authors.lastname: Biemer
mesh_terms: D000818:Animals; D004396:Coloring Agents; D004195:Disease Models, Animal; D005453:Fluorescence; D005471:Fluoroscopy; D006084:Graft Rejection / Q000473:pathology; D007208:Indocyanine Green; D007834:Lasers; D008297:Male; D008833:Microcirculation; D009336:Necrosis / Q000175:diagnosis; D011379:Prognosis; D051381:Rats; D012867:Skin / Q000098:blood supply; D013524:Surgical Flaps / Q000098:blood supply / Q000473:pathology*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green