Abstract:

Objective

To explore the effect of initiative irrigation and drainage treatment on postoperative wounds and cytokines in patients with high complex anal fistula.

Methods

This study was a prospective multi-center randomized controlled trial involving 160 patients who were operated on high complex anal fistulas in the Colorectal Surgery Department of 7 hospitals in Jiangsu Province.Patients were randomly assigned to receive IIDT or standard gauze dressing （control group） at a 1：1 ratio.The primary outcome was pain scores within 7 days.Secondary outcomes were quality-of-life scores， healing time，fistula closure rate and the relevant cytokine indexes.

Results

A total of 72 patients were included in each group.Demographics， preoperative comorbidities， and fistula type were comparable between the two groups.Additionally， no significant difference in fistula closure rate was observed between the control and IIDT groups （93.1% vs.91.7%， χ²=0.098， P=0.754）.During the 5 days of IIDT， the maximum pain score in 7 days（Z= -10.262， P＜0.001） and the pain scores on the postoperative day1， 3， 5 and 7 were lower than those of the control group （Z= -10.533， P＜0.001； Z= -10.548， P＜0.001； Z= -10.594， P＜0.001； Z= -10.578， P＜0.001）.In the case of QOL scores， patients in the IIDT group had significantly higher score in physical functioning，physical pain， general health， vitality， social functioning， and mental health（Z= -10.358， P＜0.001； Z= -3.358，P＜0.001； Z= -2.506， P=0.012； Z= -2.564， P=0.010； Z= -5.632， P＜0.001； Z= -7.617， P＜0.001）.By day 5， HE and Masson staining revealed fewer inflammatory cells and more fibroblasts in the IIDT group， the expression levels of VEGF， FGF-2， and TGF-β in the IIDT group were significantly upregulated from baseline（t=2.576，P=0.011； t= -2.268， P=0.025； t=2.009， P=0.046）， whereas a notable reduction was found in inflammatory cytokine concentrations （TNF-α、IL-1β、IL-6） （t=22.891， P＜0.001； t= -3.320， P=0.001； t=2.037， P=0.044）.Western blot analysis revealed that phosphorylated p38 （p-p38） protein was significantly upregulated in the granulation tissue of patients receiving IIDT compared to those in the control group（t= -2.209， P＜0.001）.

Conclusion

It is feasible approuch for high complex anal fistulas， which can alleviate postoperative pain，accelerate wound growth， reduce the expression of the inflammatory cytokines TNF-α， IL-1β， and IL-6， and promote the expression of the growth factors VEGF， FGF-2， and TGF-β.

Key words: Initiative irrigation and drainage treatment（IIDT）, High complex anal fistula, Wound healing