2.2 Inclusion criteria and exclusion criteria
Inclusion criteria: 1) performed surgery in our hospital and confirmed the presence of TFBA; 2) preoperative examination can be collected; 3) the age was under 14 years old. Exclusion criteria: 1) incomplete clinical data; 2) no TFBA was found during operation; 3) refused to do the operation; 4) with acute or chronic infection caused by other confirmed reasons; 5) treated with antibiotics within 72 hours before operation.