Comparative Study Of End-to-end And End-to-patch Microvascular Anastomosis To Perforator Of Free DEP Flap Transplantation Model In Rat

Background It has been more than 20 years for DIEP flap used in breast reconstruction, however, the caliber of the perforator vessels are very small, which may lead to vascular crisis, flap necrosis, effusion and other related complications after flap transplantation. Therefore, the success rate of breast reconstruction with free DIEP flap will be increased if appropriate methods are taken for the deficiencies of the vessel of the flaps.Objective This study aimed to establish the DEP flap model in rats with end-to-end and end-to-patch microvascular anastomosis, respectively.And then to compare the effects on DEP flaps survival between the two different microvascular anastomotic techniques.Methods A total of 46 Sprague-Dawley(SD) rats with half male and half female, bodyweight 400g-450 g. Six SD rats were randomly selected to analyze the origin,caliber and distribution of deep epigastric perforator(DEP) flap vessels. The rest 40 rats were randomly divided into two group A and group B, with 20 cases for each. The DEP flap animal models in rats were established according to the perfusion and distribution of DEP flap.And the arteriovenous vessels of perforator flap were anastomosed with the ipsilateral femoral arteriovenous respectively by using end-to-end or end-to-patch microvascular anastomosis under operating microscope and the flap was sutured with the cutis around groin.Group A(also called ETE) that the arteriovenous vessels of perforator flap were anastomosed with the ipsilateral femoral arteriovenous by using end-to-end microvascular anastomosis while Group A(also called Patch) that the arteriovenous vessels of perforator flap were anastomosed with the ipsilateral femoral arteriovenous by using End-to-patch microvascular anastomosis. T test was used to analyze the differences among anastomosis time, survival rate of skin flap following operation and post-operative complications incidence.Results 1.The vascular caliber of perforator flap artery and vein(0.30‐0.50)mm and(0.40‐0.50)mm,respectively.Perforator vessel, with 3 or 4 vessel branches, was origined from superior epigastric vessels. After trimming,the edges of vessel into “patch” shapes with the artery and vein diameter(0.30-0.50)mm and(0.40-0.50)mm,respectively(Table 1). 2.The mean anastomosis time of perforating artery-vein in ETE group was longer than ETP group.Among them,the mean anastomosis time of perforating artery as follows:ETE group(37.08±7.96)min,ETP group(28.50±7.87)min,and difference between the two groups has statistical significance(P < 0.05). The mean anastomosis time of perforating artery also had statistical significance: ETE group(54.22±8.59)min, ETP group(45.84±6.61)min(P < 0.05).Moreover,the total time of anastomosis time of perforating artery are statistically significant:ETEgroup( 96.30 ± 15.14) min and ETP group( 79.10 ± 6.59) min,respectively(P <0.05). 3.Twenty-nine rats(39/40) were successfully used for DEP model construction and 1 rat in ETE group died of venous thrombosis. 4.7 days after surgery, with all the incision of donating area healing well but 9 models postoperative complications occurred among the 40 cases DEP flap, accounts for 22.5% of all cases. And 8 cases of them occurred in ETE group,1 cases of them occurred in ETP group. 5.The causes for post-surgical complications in ETE group: 5 models had blood vessel crisis, all of which recovered immediately after effective treatment and partial necrosis of flap occurred in 2 models. Unfortunately, 1 models was failure with venous occlusion and necrosis of the flaps.The causes for post-surgical complications in ETE group: Only 1 model had blood vessel crisis,and eventually survived through the rescue.Conclusion DEP flap was origined from superior epigastric vessels with small blood vessel diameter which the biggest diameter is about 0.5 mm, and it is difficult to anastomosed them. The end-to-patch method is contribute to improve the success rate of surgery because it expand blood vessel anastomosis diameter, simplify the difficulty of vascular anastomosis, shorten the operation time, increasing skin flap survival rate and reduce the incidence of postoperative complications. Therefore,for the majority of vessels with small diameter, such as the perforator vessels of DEP flap,the end-to-patch method is a better selection.And it is worthwhile for spreading in clinical practice.