Abstract:Objective To investigate the effect of video-assisted anal fistula treatment on complex anal fistula and its impact on the expression of wound healing factors in granulation tissue and the level of pain factors in serum.Methods A prospective randomized controlled trial was performed on 92 patients with complex anal fistula from October 2016 to December 2018.The patients were randomly divided into video-assisted group and traditional surgery group ( n=46,each).The video-assisted anal fistula treatment was conducted in video-assisted group,and the traditional incision and thread hanging drainage was performed in traditional surgery group.The curative effect,operation situation and complications were compared between two groups;the levels of serum pain factors［5-hydroxytryptamine (5-HT),substance P(SP)］ were detected before and 1th and 3th days after operation;the expressions of wound healing factors ［vascular endothelial growth factor (VEGF),vascular endothelial growth factor receptor-2 (VEGFR-2)］ were detected before operation and 1th and 2th weeks after operation.Wexner anal function scores at 6 months and 1 year after operation and one -year recurrence rate were compared between two groups.Results Compared with traditional operation group,the blood loss,visual analog score (VAS),the time of operation,hospital stay and wound healing statistically decreased in video assisted group ( P<0.01).The incidence of postoperative complications in video-assisted group was significantly lower than that in traditional surgery group(8.70% vs 23.91%, χ2=3.903, P<0.05).On the 1st and 3rd postoperative days,the serum 5-HT and SP levels were significantly higher than those before operation in both groups and were statistically higher in video-assisted group than those in traditional operation group ( P<0.05, P<0.01).At 1 week and 2 weeks after operation,the expression levels of VEGF and VEGFR-2 were higher than those before operation in two groups and were higher in video assisted group than those in traditional operation group ( P<0.05, P<0.01).At 6 months and 1 year after surgery,Wexner scores was significantly lower in video-assisted group than that in traditional surgery group ( P<0.05).At 1 year after surgery,there was no significant difference in relapse rate between the two groups( P>0.05).Conclusion For the patients with complex anal fistula,video-assisted anal fistula treatment has the advantages of less trauma and bleeding,no damage to the anal sphincter,mild postoperative pain and quick recovery after operation,and has a significant effect.