Evaluation der Perfusion von Lappenplastiken mittels Laserfluoreszenz von Indocyaningrün

Abstract

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.

Non‐viral VEGF165 gene therapy – magnetofection of acoustically active magnetic lipospheres (‘magnetobubbles’) increases tissue survival in an oversized skin flap model

“…ICG‐fluorescence was induced and recorded using a laser‐fluorescence imaging device (IC‐View ® , Pulsion Medical Systems AG), comprising a NIR laser light source (0.16 W, wavelength λ 780 nm) and a NIR‐filtered digital camcorder. In groups A1–A5, a bolus of 0.3 mg/kg bodyweight was injected directly after surgery into a tail vein under general anaesthesia [16, 17]. The fluorescence was recorded with a digital camera and the grey scale images transferred to an image analysing system (IC‐Calc ® , Pulsion Medical Systems AG).…”

“…Upon completion of the assay procedure standard and samples were read at 450 and 550 nm -correction. [16,17]. The fluorescence was recorded with a digital camera and the grey scale images transferred to an image analysing system (IC-Calc ® , Pulsion Medical Systems AG).…”

“…In this study, we used acoustically active magnetic lipospheres containing the VEGF 165 cDNA in a lipid shell. We investigated the potential of magnetofection of the VEGF 165 gene on the survival and perfusion of the well‐established oversized random‐pattern‐flap model in the rats [1, 16, 17] and compared the results to our previous findings using an adenoviral vector construct [1]. We evaluated the method with respect to the significance of applied magnetic field and ultrasound.…”

Role of Indocyanine Green in Fluorescence Imaging with Near-Infrared Light to Identify Sentinel Lymph Nodes, Lymphatic Vessels and Pathways Prior to Surgery – A Critical Evaluation of Options

“…Two different aspects can be investigated with ICG angiography. ICG angiography can be used to make a valid assessment of the vascular anastomosis and its patency 71 , 72 , and it can also be used to make predictions about the perfusion of the transplanted tissue 73 , 74 . While this technology was described quite early on 63 , it was initially not introduced into standard clinical practice for the perioperative evaluation of the perfusion of tissue transplants.…”

“…Im Rahmen der ICG-Angiografie kann zwischen 2 verschiedenen Aspekten unterschieden werden. Zum einen kann durch die ICG-Angiografie eine valide Aussage über die Gefäßanastomose und deren Durchgängigkeit getroffen werden 71 , 72 , zum anderen kann aber auch eine Prädiktion bezüglich der Durchblutung des transplantierten Gewebetransplantats erfolgen 73 , 74 . Während diese Technik bereits früh beschrieben wurde 63 aber zunächst keine relevante Einführung in den klinischen Alltag zur perioperativen Beurteilung der Durchblutung der Transplantate fand, wurde die objektive Beurteilung durch die Implementierung in das Operationsmikroskop und durch eine spezielle Software unterstützt 74 , 75 , 76 .…”