[Clinical observation of the application of disposable decomposing soft injection probe in the treatment of complex anal fistula under local infiltration anesthesia induced by propofol].

Objective: Summarize the clinical efficacy of using a disposable decomposed soft injection probe under propofol induced local infiltration anesthesia for the treatment of complex anal fistula. Methods: This technology is applied to patients with complex anal fistulas with clear diagnosis and no surgical contraindications. Using propofol to induce local infiltration anesthesia, a disposable decomposed soft injection probe (invention patent number: ZL 2014 1 0173127.3) soft catheter is gently introduced from the outer opening, passing through a cord like hard structure that can be touched on the surface of the body, and exiting through the rectum and anal canal. According to preoperative identification, each probe is explored one by one. If the inner opening and fistula are below the anorectal ring, a "V" - shaped incision is made to the skin and mucosal transition area between the inner and outer openings, and the fistula and inner opening are removed; If the exploration of the internal opening and fistula is above the anorectal ring, the internal opening should be enlarged and trimmed, and the skin of the external opening should be cut off in a shuttle shape. A soft catheter should be used to pull out a rubber strip for loose floating drainage. The two ends of the drainage rubber strip should be tied and fixed with 1 # silk thread. Connect a disposable decomposed soft injection probe with extracted methylene blue mixture (methylene blue 0.5 ml+0.9% sodium chloride 9.5 ml), press the external opening of the anal fistula to form a blind tube that seals the external opening, inject methylene blue mixture, implant an anal hook, explore the remaining blue anal sinus area, and inject methylene blue mixture again to determine the accurate position of the internal opening. Trim and enlarge the inner openings that have been accurately detected one by one. For the main fistula that runs below the anorectal ring, perform a "V" incision to cut open the soft tissue in the skin and mucosal transition area between the inner and outer openings, and remove the inner opening and fistula at once; For anal fistulas with fistulas above the anorectal ring, internal incision trimming and enlargement, sinus scraping, and floating bridge drainage surgery should be performed; For a complex anal fistula with multiple internal and external openings, the main lesion should be incised and treated with branch drainage. Record the successful time of internal port exploration, intraoperative and postoperative pain score (VAS), degree of fecal incontinence (Wexner incontinence score), wound healing time, and 3-month postoperative recurrence rate. Results: From January 2020 to December 2023, the Proctology Department of Zaozhuang Fourth Hospital and the Proctology Department of Tengzhou Traditional Chinese Medicine Hospital (Workers' Hospital) treated 54 patients with complex anal fistula using a disposable decomposed soft injection probe under propofol induced local infiltration anesthesia. The average successful internal exploration time was 2.80 minutes, and the average healing time was (22.3±2.6) days. The VAS scores (points) during surgery, 2 days after surgery, 4 days after surgery, and 6 days after surgery were 0.9±0.2, 1.5±0.2, 1.2±0.1, and 0.6±0.2, respectively. The Wexner score at 1 month after surgery was 0.80±0.20, All patients were followed up until April 2024, and the recurrence rate at 3 months after surgery was 5.6%. Conclusion: The use of disposable decomposed soft injection probes under propofol induced local infiltration anesthesia for the diagnosis and treatment of complex anal fistulas has shortened exploration and surgical time, improved treatment comfort and cure rate, and is safe and effective.