Reverse Flow Axial Skin Flap: The Studies Of Survival Mechanism And Clinical Application

Objectives (1) To establish an experimental model for reverse flow axial skin flap. (2) To investigate the pathway and power of artery inflow and venous outflow of the reverse flow flap and then to analyse it's survival mechanisms. (3) To retrospect the the complications about circulation of the reversed-flow flaps used clinically. On the basis of experimental study and clinical review, the reliability and the circulatory complications of the reverse flow flaps are evaluated.Methods (1)The cutaneous vascular anatomy over the dorsum of Wistar rats was studied by means of anatomical dissection, Chinese ink injection into axial arteries and hyalining technique. It demonstrated that the rat's dorsal skin derives its blood supply from lateral thoracic artery, 10th posterior intercostal artery and deep circumflex iliac artery. Among the three groups of vessels, the deep circumflex iliac artery is the most suitable axial vessel for establishing reversed-flow flap model for experimetal study because of it's territory, size, axial orientation and especially the anastomosis across midline. So a flap measuring 8.0 X 2.5cm based on left deep circumflex iliac artery was designed over the rat's dorsum with 4.0cm of it's length crossing midline. The flap was immediately sutured to their respective beds then the viability was observed. (2)With the established experimental model, assessment of the arterial perfusion, venous drainage and the survival area of the flaps were made clinically. In the pedicle, midline and distal region of the flap, the dynamic microcirculation, the number, caliber, pressure and microvasculature were investigated respectivelly at 6h, 24h, 48h, 72h, 7 and 14day after operation. At the same time the blood flow of flap was meassured in the same region.(3) 139 cases of reverse flow flap used clinically were reviewed. They included retroauricular flaps based on superficial temporal artery, auricular composite flaps based on supraocular vessels, submental flaps based on contralateral submental vessels, cervico-scapulo-dorsal reverse-flow flaps and pudendal-thigh flaps. The rates of complete survival, partial survival, total loss, inadequate arterial perfusion, venous congestion, and the rate of flap failure attributed to ischemia or inadequate venous outflow were assessed In order to evaluate the reliability of reverse flaps, these parameter were in compared with that of anterograde flow axial flaps used in our hospital during the same time. Combined with the results of the experiment, the disorder or failure of flaps circulation were discussed in detail.Results: (1)The model flaps designed over the dorsum of Wistar rat revealed the anatomical and physiological characteristic of reversed-flow axial flap. Survival of thirty...