Nonsurgical delay of dorsal rat cutaneous flap using a long-pulsed 1064-nm Nd:YAG laser with a contact cooling device

Background: This study evaluated the efficiency of a long-pulsed neodymium.yttrium-aluminum-garnet laser, operating at 1064 nrn and equipped with a contact cooling device, in the delay of a caudally based dorsal rat skin flap (10 × 3 cm). This laser has deeper tissue penetration and has not been used for this purpose before. Methods: Twelve male Sprague-Dawley rats were used in each of six groups. The delay effects of three different laser treatment patterns (only longitudinal borders, cephalic and longitudinal borders, and entire surface of the 10 × 3-cm flap) were compared with an acute untreated control flap as well as two surgical delay methods (incision of longitudinal borders and incision of longitudinal borders plus flap undermining). The laser effects on the cutaneous vasculature and perfusion were assessed by intravenous fluorescein injection, histologic study, microangiography, and in vivo real-time video monitoring. Results: Selective thermocoagulation of subdermal vessels was achieved using a 6-mm spot, 140-J/cm² fluence, and 40-msec pulse width. In the cephalic and longitudinal borders laser-treated group, a delay effect was achieved. The maximum delay effect was achieved by the surgical delay group that used the method of incision of the longitudinal borders plus flap undermining. Laser treatment of only the longitudinal borders did not improve flap survival, whereas treatment of the entire flap surface significantly reduced flap survival. Conclusion: Nonsurgical delay of a dorsal rat cutaneous flap is possible by selective occlusion of the subdermal plexus at the longitudinal and cephalic borders of the planned flap using a long-pulsed 1064-nm neodymium:yttrium-aluminum-garnet laser equipped with a contact cooling device.