Abstract: Zhao Tao, Chen Hui, Liao Wenjun, Wang Gang Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi′an 710032, China Corresponding author: Wang Gang, Email: xjwgang@fmmu.edu.cn 【Abstract】 Objective To evaluate the efficacy and safety of endoscopy-assisted percutaneous interventional procedure with a 980-nm laser for the treatment of venous malformations. Methods A total of 167 patients with venous malformation were enrolled, including 102 females and 65 males, whose age ranged from 0.5 to 60 years. Skin lesions occurred on the limbs in 66 patients, on the head and face in 48, on the chest and abdomen in 24, on the back in 13, on the neck in 10, as well as on the scrotum in 6. A 980-nm laser operated at pulse width of 0 ms - 2.5 s and pulse energy of 0 - 20 W with a 400 μm-diameter optical fiber. Puncture was performed after circular infiltration anesthesia around skin lesions, and then the optical fiber was inserted at the same puncture point to directly or indirectly destruct the vascular wall by photothermal effects and thermal coagulation. For deep lesions around important anatomical structures, the interventional therapy was performed with the assistance of endoscopy or ultrasound. According to the size and shape of tumors, these tumors were irradiated back and forth with speeds of 2 cm/s - 4 cm/s. The optical fiber was also inserted in different directions in a fan-shaped pattern for 3 - 5 sessions until tumors were shrunken or even disappeared. The time interval between two treatments was 3 months, and all the patients were followed up for 4 months on average. Results Of the 167 patients, 148 （88.6%）were cured, 11 （6.6%） markedly improved, 4（2.4%） improved, and 4（2.4%） unimproved. The response rate was 97.6%. Totally, 159 patients were satisfied with the therapeutic effects after 1 session of treatment, and 8 were improved after 2 sessions of treatment with a time interval of 3 months. In addition, mild postoperative pigmentation occurred in 6（3.6%） cases, and skin burns in 3（1.8%） cases. After 3 months, the above symptoms were improved significantly. Two （1.2%） patients had vascular recanalization and residual lesions, but they were improved after reoperation. No adverse reactions were observed, such as bleeding, scar, tendon and nerve injuries, and dysfunction. Conclusion A 980-nm laser percutaneously delivered through an optical fiber is safe and effective for the treatment of venous malformation.