Abstract / Summary
Abstract Background Sigmoid colovaginal fistula (SVF) is a rare high vaginal fistula easily misdiagnosed as common rectovaginal fistula (RVF) due to identical vaginal flatus and fecal leakage, which frequently causes failed transperineal repair and persistent recurrence. Postoperative anatomical distortion such as pseudocervical ostium further interferes routine digital rectal examination and colposcopy diagnosis. Multidisciplinary team (MDT) combined dual-endoscopic minimally invasive repair for misdiagnosed recurrent high SVF has rarely been reported. Case presentation A 57-year-old postmenopausal female presented with continuous vaginal gas and feculent discharge 6 months after failed transperineal RVF repair. Routine colposcopy with rectal methylene blue test revealed blue fluid leaking from a pseudocervical ostium at posterior vaginal fornix. Pelvic MRI combined with colonoscopy confirmed a 1.5 cm fistulous tract originating from a 0.6×0.8 cm sigmoid diverticulum 25 cm above the anal verge. Endoscopic titanium clip closure of the fistula orifice failed intracolonoscopically. Intervention & Outcomes Preoperative MDT reclassified the diagnosis from recurrent RVF to diverticular high SVF. Intraoperative hysteroscopic transillumination was applied to precisely locate the fistula tract under laparoscopic visualization. Complete fistula resection, sigmoid diverticulectomy and primary colorectal anastomosis were performed simultaneously. The patient recovered uneventfully and was discharged on postoperative day 5. No vaginal fistula recurrence was observed at 6-month follow-up, with significant improvement of fecal incontinence-related quality of life. Conclusion Recurrent high sigmoid colovaginal fistula originating from sigmoid diverticulitis is highly prone to misdiagnosis as RVF, especially in patients with post-surgical vaginal fornix deformation. MDT multimodal imaging combined with colonoscopic staining is mandatory for differential diagnosis. Combined hysteroscopic transillumination and laparoscopic resection serves as a safe, accurate minimally invasive strategy for complex misdiagnosed SVF and reduces reoperation failure risk.