The Effect of Duration of Lipo-PGE1 Administration on Flap Survival in a Rat TRAM Model

This study was designed to find out an effective duration of pharmacological delay using Lipo-PGE1 to prevent the ischemic compromise of TRAM flap in rats. Fifty Sprague-Dawley rats were divided into 5 groups evenly and a left inferior epigastric vessel pedicled TRAM flap, sized 5.0 X 3.5 cm was created on the abdomen. Experimental groups included group I(control): no procedure before the flap elevation; group II, III, IV and V(pharmacological delay groups): Lipo-PGE1(0.5mug) was given daily intraperitoneally for 3, 5, 7 and 14 days before the flap elevation. On the seventh day after the operation, we evaluated and compared the results of flap survival rate, vessel distribution through Barium microangiography and histological findings by the hematoxylin-eosin stain and the VEGF immunohistochemistry. The results were as follow: 1) The mean percentage of the flap survival area of group II(52.84 +/-27.03%), III(63.15+/- 16.57%), IV(63.53+/- 13.15%), V(61.44+/- 17.17%) were higher than that of group I(30.42 +/- 14.58%) significantly (p < 0.05). 2) The vessel distribution of the pharmacologic delay groups were more abundant than that of the control group. 3) the vascularity of the pharmacological delay groups were more diffused than that of the control group in the hematoxylin-eosin stain. 4) There was no difference in the expression of VEGF protein within the endothelial cell between the control and the pharmacological delay groups. In conclusion, the use of Lipo-PGE1 for a relatively short term period(about 3-5 days) could remarkably increase the flap survival area in rat TRAM model compared to the surgical delay(2 weeks).

Delay Effect of PGE1 on Rat Transverse Rectus Abdominis Musculocutaneous Flap

This study was designed to find an effective delay method for preventing the ischemic compromise of TRAM flap in rat. Forty Sprague-Dawley rats were divided into 4 groups evenly and a left inferior epigastric vessel pedicled TRAM flap, sized 5.0 x 3.5 cm was created on the upper abdomen. Experimental groups included group 1(control): no delay procedure before elevation of flap, group 2(surgical delay): the left superior epigastric vessels and the contralateral rectus perforators were ligated 2 weeks before elevation of flap, group 3(pharmacological delay): prostaglandin E>(0.5 microgram) was given intraperitoneally for 2 weeks before elevation of flap daily, group 4(surgical and pharmacological delay): the same surgical and pharmacological delay have been done simultaneously. On the seventh day after operation, we evaluated and compared the results by the measurement of the flap survival area, the observation of the vessel distribution through Microfil casts and the measurement of vessel surface area through histologic slides. The results were as follows; 1) The mean percentages of the flap survival area of group 2(73.32+/-21.07%), 3(71.77+/-l 17.49%) and 4(89.54 +/-11.38%) were higher than that of group 1(41.23 +/- 14.26%) significantly(p < 0.05). 2) The vessel distributions of group 2, 3 and 4 were much abundant than that of group 1 in Microfil casts. 3) The vessel surface areas of group 2, 3 and 4 were higher than that of group 1 significantly(p < 0.01) and that of group 4 was higher than that of group 2(p < 0.05). In conclusion, prostaglandin E could be used to increase the flap survival area in rat TRAM flap model as a pharmacological delay and the effect of prostaglandin E was comparable to that of the surgical delay.