Effect of muscle flap denervation on flow hemodynamics: a new model for chronic in vivo studies

The purpose of this study was to evaluate microcirculatory dynamics following muscle flap denervation. A modification of standard cremaster muscle flap was used. Fifty male Sprague-Dawley rats were studied in two experimental groups of 25 rats each, as follows: Group I (control), after flap isolation, the neurovascular pedicle was left intact; group II (denervation), following muscle isolation at 1 cm segment of genitofemoral nerve was excised and denervated muscle was preserved in the medial border of rat hind limb. For chronic evaluation the cremaster was withdrawn from the leg and prepared for in vivo observations after days 1, 3, 7, and 14. The following measurements were taken: vessel diameters, red blood cell velocities, and number of perfused capillaries. In group II a 15% increase in arteriolar diameter was observed. Throughout the entire 14 day period denervated flaps presented 27% more perfused capillaries. Flap denervation proved to increase capillary perfusion significantly (P < 0.05). The cremaster muscle tube-flap model introduced in this study allows for chronic observation of the microcirculation.