2.1 Clinical data
A retrospective study reviewed hospital records of 51 subjects with DNSI who were admitted to the Department of Otolaryngology- Head and neck surgery of the First Affiliated Hospital of Anhui Medical University from November 2017 to October 2019 (Table1), including 26 males and 25 females with an average age of 54.82 years old (range: 24-89 years old). The average length of stay was 17.55 days (range: 3-87 days). There were 25 cases (49.0%) with type 2 diabetes mellitus, 5 cases with hypertension, 2 cases with hematological diseases and 1 case with panniculitis. 34 cases underwent tracheotomy. Exclusion criteria: peritonsillar abscess, patients with pharyngeal leakage or esophageal fistula, and patients with infection secondary to malignant tumor. This study was approved by the local ethics committee.