Rat tail revascularization model for advanced microsurgery training and research.

We describe a time-saving microsurgical exercise for continuing microsurgical training and research. The rat tail replantation model was simplified by excluding bone detachment. Rats were divided into two groups: devascularization only ( N = 3) and revascularization after devascularization ( N = 7). The tail was devascularized by ligation and division of artery and veins in the first group to reveal if a collateral circulation from bone existed. The divided vessels were reanastomosed in the second group. The circulation of the rat tails was followed for 1 week. The tails showed total necrosis in the devascularization group, whereas only two of seven tails showed partial necrosis in the revascularization group. Reexploration showed thrombosis narrowing the lumen at the anastomotic site of the partially necrosed tails, most likely due to an anastomotic insufficiency. The present study revealed that total amputation is not necessary for tail devascularization. The rat tail revascularization model provides a practical tool for advanced and continuing microsurgical training and research.

Experimental study on axial pedicled composite flap prefabrication with high density porous polyethylene implants: medporocutaneous flap.

Composite flaps including soft tissues with bone or cartilage are widely used in reconstruction of three-dimensional defects, but have some disadvantages. Flap prefabrication with alloplastic implants is an alternative procedure. Axial pattern vascularised high density porous polyethylene (HDPP) implants are capable of sustaining skin grafts. The purpose of this study was to examine the vascularisation pattern of the skin island in a composite flap prefabrication model prepared with vascularised HDPP implants. Forty male Wistar rats divided into four groups were used. A 9.5 x 6 x 2 mm HDPP block was centered on the dissected saphenous pedicle and anchored under the abdominal skin in the experimental group I (n=10). In experimental group II (n=10) saphenous artery and vein were put between the skin and the implant. Thus, the structures were laid as skin, HDPP block, pedicle in experimental group I and skin, pedicle, HDPP block in experimental group II. HDPP block-implanted and pedicle-implanted only groups served as control groups I and II, respectively. Eight weeks after prefabrication, skin islands 1.5 x 5 cm in size incorporated with implants were elevated based on saphenous vessels in the experimental groups and skin islands only based on the pedicle in control group II. Skin islands of the same dimensions were raised as grafts in control group I. Nylon sheets were put under the flaps and grafts to prevent vascularisation from the recipient bed. Flap viability was assessed by measuring the surface area on the 7th day. Total necrosis developed in composite grafts of control group I. Flap survival was higher in experimental group II and control group II (45% and 46.8%) than in group I (29.28%). Histologic studies demonstrated fibrovascular ingrowth into the HDPP implants, except in control group I, with significant inflammatory response and necrosis. Vascularisation of skin and implants from the pedicle was seen also microangiographically. In conclusion, a composite flap prefabrication model including vascularised HDPP implant, skin and vascular carrier was developed. This new flap was termed a 'medporocutaneous flap'.