[Hair removal with IPL on expansion flap via subcutaneous route in a swine model].

Objective: To investigate the effect and safety of hair removal via subcutaneous route with IPL in expanded flap.

Methods: A total of 14 experimental zones were established in two healthy Guizhou mini-pigs with dark hair and white skin.All these skin zones were allocated in seven groups: group 1-6 underwent skin soft tissue expansion(stage I: implantation of expander, stage Ⅱ: removal of expander).The subcutaneous tissue in group 1 received IPL irradiation of common level during stage Ⅰ and Ⅱ of skin expansion, group 2 received irradiation of high level during stage Ⅰ, group 4 received irradiation of common level during stage Ⅱ, group 5 received irradiation of high level during stage Ⅱ, group 6 received irradiation of low level during stage Ⅰ and Ⅱ as well as flap trim during stage Ⅱ, group 3 received no irradiation, and the skin in group 7 received irradiation of common level through epidermal route during stage Ⅰ and Ⅱ. Treatments were conducted using a contact tip with IPL(λ =650-950 nm) radiant exposures of different fluencies (common level 18 J/cm2,high level 22 J/cm2,and low level 15 J/cm2) with single pulsed duration of 50 ms. The temperature of tissue surface was determined by infrared thermograph. The microcirculation of expansion flap was determined with PeriFlux System. Digital images were taken for the calculation of hair density count by software Image J.

Results: The temperature of tissue surface received IPL irradiation decreased soon within 2 minutes. The microcirculation of skin expansion flap in group 1,2,3,6 were all restrained, which began to restore within 4 hour post operation. The hair density in group 1 was the lowest with hair removal rate of 79.17％ ± 2.81％,which was higher than the others significantly(P ＜ 0.05).The hair removal rate in group 6 was 72.95％ ± 13.10％.The hair removal rates in group 4 and 5 were lower than 40％.The hair removal rates in group 7 was 67.38％ ± 7.10％.

Conclusions: IPL irradiation via subcutaneous route may restrain microcirculation of expansion flap transiently, which was reversible. The hair removal rates can reach above 80％ over 6 months post treatment. It indicates that IPL irradiation via subcutaneous route might be a safe and effective hair removal methods, which may be more effective when it is initiated before the implantation of skin expander.