The influence of helium-neon laser irradiation on the viability of skin flaps in the rat

Low energy helium-neon (He-Ne) laser irradiation has been shown to induce various therapeutic effects. We investigated its effect on the viability of skin flaps in the rat. Thirty rats underwent skin flap elevation and were then divided into three equal groups. Group I (control) was not irradiated. Groups II and III were irradiated for 5 days postoperatively, Group II to the transition zone (between the live and expected necrotic areas) and Group III to the transitional and distal zones; total energy, 2.9 J/cm2for each rat. Ten days after the last treatment larger surviving areas were demonstrated macroscopically in Groups II and III (P< 0.01 and 0.001, respectively). Histological examination showed tremendous proliferation of capillaries (P≤ 0.05) and fibroblasts in the responsive irradiated areas. In conclusion, postoperative low-energy (2.9 J/cm2) He-Ne laser irradiation of the expected ischaemic zone of the rat flap can enlarge the surviving area. Irradiation of the whole expected ischaemic zone seems to be superior to irradiating the transition zone alone.