[Temperature determination of the skin surface for the estimation of blood supply disorders in myocutaneous island flaps of rats].

In rectus abdominis myocutaneous island flaps (3.0 x 1.5 cm) of rats (Uje:WIST) skin surface temperature was measured by an infrared pyrometer for monitoring flap viability following experimentally induced blood flow insufficiency. The insufficiency was caused by ligation of the pedicle vessels (epigastric superior artery and vein) on the 3rd, 4th, 5th and 7th d after flap replantation, and by occlusion of these vessels with microclips for 2 h. Only the temperature differences between the intact and the operated skin surface were used to estimate blood flow efficiency not, the absolute values. These differences were statistically insignificant between the intact right and left abdominal skin areas and between the intact skin and the vital flap surfaces. In these cases the maximal temperature differences were 0.52 degree C. Only during the early postoperative period (3-days ligation group) a correlation between blood flow insufficiency and flap viability is expressed by temperature differences (2.14 degrees C). Later on (7-days ligation group) a temperature difference of 1.87 degrees C was no evidence of disturbed wound healing. Thus in advanced stages in myocutaneous flaps differences of blood flow and neovascularization respectively cannot be estimated reliably by measurements of skin surface temperature. However, temperature differences greater than 2 degrees C signal impaired flap viability.