[Evaluation of perfusion in skin flaps by laser-induced indocyanine green fluorescence].
Prediction of necrosis in critically perfused skin flaps is difficult and rarely precise. An early detection of insufficiently perfused skin is highly desirable since it may lead to surgical decisions such as operative flap revision or early resection. The application of laser-induced indocyanine green (ICG) fluoroscopy allows an objective quantification of skin perfusion and a high topographical resolution. Aim of the present study is to determine a threshold value for flap perfusion under well-defined experimental conditions and test the validity of the results in the clinical application. Twenty overdimensioned random pattern flaps with a length to width ratio of 4 : 1 (8 x 2 cm) were dissected at the anterior abdominal wall of 20 male Sprague-Dawley rats weighing 365 g on average. ICG fluorescence was performed at the end of the operation by intravenous injection of 1 g ICG/kg bodyweight into a tail vein and digital recording. On the seventh postoperative day, both the necrotic and surviving areas of the flaps were measured and the ICG-fluorescence was analysed in the areas that had undergone necrosis. 41 flaps with areas of critical perfusion (18 skin flaps, 13 muscle flaps, 8 replantations) were analysed in 39 patients. The surviving part of the flap had a mean perfusion index of 62 % compared to reference skin. The distal parts of the flap that necrotized during the experiment showed an average perfusion index of 19 % postoperatively. Differences were statistically significant (p < 0.001). In clinical application, a number of 13 flaps were found to have a perfusion index less than 25 % in a region of critical perfusion. Eleven of these developed a partial necrosis in that region, one flap underwent total necrosis. Indocyanine green fluoroscopy allows a detailed topographical analysis of flap perfusion and the prediction of necrosis. Experimental findings presented a threshold value for the perfusion index of 25 % which could be confirmed in clinical application.
Holzbach
T
T
Abteilung für Plastische und Wiederherstellungschirurgie, Klinikum rechts der Isar, Technische Universität München.
Taskov
C
C
Henke
J
J
Busch
R
R
Gänsbacher
B
B
Biemer
E
E
Giunta
R E
RE
D000818:Animals; D005451:Fluorescein Angiography; D015316:Genetic Therapy; D006801:Humans; D007208:Indocyanine Green; D007511:Ischemia / Q000175:diagnosis*; D007834:Lasers; D008297:Male; D009336:Necrosis; D011379:Prognosis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D013524:Surgical Flaps / Q000098:blood supply*; D014022:Tissue Survival / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D007208:Indocyanine Green