Clinical Study Of The Change Of The Area And The Correlation Of The Changed Area And Prognosis Of The Plantar Wart With Liquid Nitrogen Cryotherapy

Objective:To observe the rule of the changed area of the plantar warts with liquid nitrogen cryotherapyand research the relationship of the cure rate and the plantar warts of the changed area after the first cryotherapy.Methods:Choose the method of treating every 3 to 4 weeks,frozen up to therapy for the treament of 4 times.For the first time record baseline data and take photos before treatment.Record and caculate the area of every plantar wart before and after each cryotherapy.Serve the warts untreated after first crytherapy as the researth object.According to the area reduced percentage of the plantar warts after the first cryotherapy,the plantar warts were allocated to two groups:area reducing 50% or higher group and area reducing lower than 50% group, which was a prospective cohort study.The outcome was assessed by dermatological specialists at the site and the pictures would be sent to the outer court dermatologists to assess blindly whether heal or not.The cure rates of the both groups were compared with each other.And the relative risk(RR) and the adjusted relative risk(adjusted RR) were caculated.Results:There was about 45% plantar warts area reducing greater than or equal to 50% and about 55% plantar warts area reducing less than 50% after every cryotherapy,including about at least 30% plantar warts area becoming bigger. According to the outcom assessment of dermatological specialists at the site, the cure rates of ≥50%group and <50%group were 67.7%,95%CI(61.9%-73.5%)and55.6%,95%CI(51.2%-60.0%) respectively,c2=2.6250,P=0.1052,RR=1.22,95%CI(0.97-1.53)and adjusted RR was 1.45,95%CI(0.96-1.18).According to the blinded outcom assessment, the cure rates of ≥50%group and <50%group were 46.8%,95%CI(40.5%-53.1%) and 35.1%,95%CI(30.6%-39.6%) respectively,c2=2.2589,P=0.1328,RR=1.44,95%CI(0.99-2.10)and adjusted RR was RR =1.45,95%CI(1.04-2.03).Conclusion:There are a certain regularity with changed area of the plantar warts after treatment with cryotherapy.There isa trend of positive correlation between the extent of the area reduction and the cure rate.The plantar warts with area increasing after first treatment shuold continue to be treated.