Comparison of the effectiveness of gene therapy with vascular endothelial growth factor or shock wave therapy to reduce ischaemic necrosis in an epigastric skin flap model in rats.

The effect of gene therapy with adenovirus-mediated (Ad) vascular endothelial growth factor (VEGF) was compared to that of shock wave (SW) therapy on skin flap survival in a rat model, using the epigastric skin flap, based solely on the right inferior epigastric vessels. Thirty male Sprague-Dawley rats were randomly divided into three groups (SW-group, Ad-VEGF-group, and Control-group) of 10 rats each. Immediately after surgery, the SW-group was administered 2500 impulses at 0.15mJ/mm(2), in the Ad-VEGF-group injections were made to the subdermal space whereas the Control-group received no treatment. Flap viability was evaluated on day 7 after the operation. Standardised digital pictures of the flaps were taken and transferred to the computer, and necrotic zones relative to total flap surface area were measured and expressed as percentages. Overall, significantly smaller areas of necrotic zones were noted in the SW-group and the Ad-VEGF-group compared with the Control-group (SW-group: median 2.23% (range: 0-5.1) versus Control-group: median 17.4% (range: 11.8-22.8) (p<0.05); Ad-VEGF-group: median 9.25% (range: 7.6-11.9) versus Control-group: median 17.4% (range: 11.8-22.8) (p<0.05)). Furthermore, in the SW-group, areas of necrotic zones were significantly smaller than in Ad-VEGF-group (SW-group: median 2.23% (range: 0-5.1) versus Ad-VEGF-group: median 9.25% (range: 7.6-11.9) (p<0.05)). We conclude that treatment with SW enhances epigastric skin flap survival significantly more than Ad-VEGF treatment and also represents a feasible and cost effective technique to improve blood supply in ischaemic tissue.