[Continuous irrigating mode endoscopic ear surgery for closure of cholesteatomatous labyrinthine fistula]

Objective:To analyze the application experience and operation result of continuous irrigating mode of otoendoscopic surgery in patients with lateral semicircular canal fistula as a complication of cholesteatoma, so as to provide a basis for the feasibility and safety of the operation. Methods:A total of 45 patients diagnosed with middle ear cholesteatoma who underwent transcanal endoscopic surgery in our department between November 2022 and March 2025 were enrolled, among whom 13 presented with labyrinthine fistula. Mastoid opening and lesion removal were performed in continuous irrigating mode, patients with labyrinthine fistula underwent external semicircular canal fistula repair and tympanoplasty were completed at the same time, and outpatient re-examination was performed at 1 week, 3 weeks, 8 weeks and 12 weeks after surgery, of which endoscopic examination was performed at 3 weeks, 8 weeks and 12 weeks after surgery, and pure tone hearing threshold test was performed 6 months after surgery. Thereafter, regular re-examinations will be conducted every 3 to 6 months. The operation time, preoperative and postoperative vertigo symptoms, changes in bone conduction threshold of pure tone auditory threshold, the time of postoperative dry ear and surgical cavity epithelialization were analyzed. Results:A total of 13 patients were collected, all of whom had external semicircular canal fistulas, including 5 males and 8 females, aged 21 to 77 years, with a mean age of （47.62±15.40） years, with lesions located on the left side in 7 cases, 6 cases on the right side, 6 cases of type Ⅰ fistula and 7 cases of type Ⅱ fistula.The average operation time was（164.77±12.77） min, There was no statistically significant difference in the operation time compared with patients without labyrinth fistula（155.13±9.15） minutes（P=0.563）. 11 cases（84.62%） had dry ears 3 weeks after surgery, 9 cases（69.23%） reached cavity epithelialization at 8 weeks after surgery, and all cases reached epithelialization at 12 weeks after surgery. There was no statistically significant difference in the average bone conduction threshold before and after the operation（P=0.064）, and the average air-bone conduction difference was statistically significant（P=0.012）. One patient had vertigo symptoms after surgery, which was relieved 1 week after surgery, and the bone conduction hearing threshold of this patient did not change compared with that before surgery. Conclusion:①Continuous irrigating mode in otoendoscopic surgery provides a clear surgical field and allows for safe lesion removal, with operation times comparable to those in patients without labyrinthine fistula. ②No significant postoperative decline in bone conduction hearing thresholds was observed, while the air-bone gap was significantly improved. ③The low incidence of postoperative vertigo, along with shorter time to dry ear and cavity epithelialization, suggests that transcanal endoscopic surgery with continuous irrigation is a safe and effective approach for managing labyrinthine fistula.