A preliminary study of rat posterior thigh perforator flap model and its blood perfusion evaluation method

Objective To establish posterior thigh perforator flap model in rats and detect effective methods for evaluating flap blood perfusion. Methods Twelve Wistar rats were divided into 2 groups and left side was set as experimental side. The posterior thigh perforator flap was designed and pedicled with perforator artery of branch to the biceps femoris muscle (PABBFM). The flap was divided into the perforator pedicle group and trunk pedicle group according to the vascular characteristics of the flap. Inner diameter and blood flow velocity of caudal femoral artery (CFA) and PABBFM were measured by high frequency color doppler flow imaging (HFCDFI) respectively, and all the data were analyzed statistically. The perfusion unit (PU) values and blood perfusion maps of two groups were observed by laser doppler perfusion imager (LDPI) at 2 hours, 1 day, 3 days, 5 days, 7 days and 14 days after the operation. Results The inner diameters of CFA in the perforator pedicle group and trunk pedicle group were (0.92±0.09) mm and (0.85±0.22) mm, respectively, and the blood flow velocities were (14.36±7.86) cm/s and (13.10±6.78) cm/s. The inner diameters of PABBFM in the perforator pedicle group and trunk pedicle group were (0.68±0.09) mm and (0.64±0.17) mm, respectively, and the blood flow velocities were (11.11±3.87) cm/s and (9.41±3.08) cm/s. There was no significant difference in blood vessel diameter and blood flow velocity between different groups (P>0.05). LDPI showed that the blood flow of the perforator pedicle group and the trunk flap presented different PU values at different time after operation, and the blood perfusion showed different changes with different rules. Conclusion The posterior thigh perforator flap can be divided into perforator and trunk type according to the vascular pedicle for easy cutting. HFCDFI can stably and accurately obtain the inner diameter and blood flow velocity of the flap. LDPI can be used to noninvasively and timely observe the blood supply of the flap after operation. Key words: Surgical flaps; Models,animal; High frequency ultrasound; Laser doppler