Abstract: Objective: To investigate the clinical effect of a double-layer closure of large type Ⅳ acquired oro-nasal fistula (AONF) using palatal island flap combined with adjacent soft tissue flap. Methods: Eight patients with large (maximum diameter greater than 5 mm) type Ⅳ (hard palate) AONF admitted to Ward 1 of the Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Medical School, Nanjing University from January 2017 to December 2021 were collected, with age ranged from 24 to 68 years old. A retrospective analysis was performed on the double-layer closure of the defect using palatal island flap combined with palatal margin flap (and) buccal myomucosal flap, and the efficacy was prospectively evaluated at postoperative follow-up. Results: All cases were successfully repaired, and no soft tissue flap necrosis, perforation, infection, or sinusitis was found. No nasal regurgitation, or upper respiratory tract infection was found during the 24-month follow-up, and the function of speech, mastication, and deglutition recovered well. Conclusion: Palatal island flap combined with adjacent soft tissue flap is a convenient and reliable modality for large type Ⅳ AONF if used under appropriate indications, and is worthy of clinical promotion.

Key words: acquired oro-nasal fistula, palatal island flap, palatal margin flap, buccal myomucosal flap