"Pingpong racket" flap model for evaluating flap survival.

Background: Random skin flap is widely used to repair tissue defects; however, it is often accompanied by ischemia and necrosis of the distal flap due to inferior axial vascularity. Even though different drugs, biomaterials, and stem cell therapies have been developed to improve the survival of random flap, evaluating the promotion of flap survival remains a big challenge. Based on successful clinical practice, we designed a "Pingpong racket" shape flap in the rat. Without the predetected blood vessels procedure, the "pingpong racket" flap provides a preferable option to evaluate the function of drugs and biomaterials in promoting flap survival. Materials and methods: "Pingpong racket" dorsal flaps with different pedicle lengths were developed in the rats. The survival area was evaluated by digital photography and computer‐assisted analysis. The quantitative survival area was considered a useful indicator for analyzing drugs' applicability in improving skin flap survival. Results: A new model with a pedicle width of 1 cm and a flap diameter of 3 cm, in which the length of the pedicle could be tuned, was established. No iliolumbar vessels passed through the pedicle. The necrosis ratio (round) of the flap was 29.88% in the 2 cm long pedicle, 74.69% in the 3 cm long pedicle, 95.52% in the 4 cm long pedicle, and in the 5 cm long pedicle; necrotic area could be found in both the round part and in the pedicle. Conclusion: The new 3 cm long pedicle flap is suitable for evaluating the drugs for promoting skin flap survival. Rat dorsal "Pingpong racket" flap can be easily handled, thus avoiding blood vessels' detection. The flap could achieve comparable results to clinical and alleviate the negative influence of the flap's longitudinal contraction. Besides, it is intuitive and aesthetically pleasing. [ABSTRACT FROM AUTHOR]