This clinical trial will compare antibiotic therapy with laparoscopic appendectomy in the treatment of pediatric chronic appendicitis in china. Enrolled patients will be randomised and an allocation ratio of 1:1 will be made via weighted minimisation, where half of the patients will receive antibiotic therapy with intravenous Ceftazidime sodium, while the other half will have a laparoscopic appendicectomy.

In recent years, nonoperative treatment has challenged appendectomy as a first-line treatment of acute uncomplicated appendicitis by demonstrating its safety and short-term efficacy in adults. Several randomized controlled trials comparing appendectomy to antibiotics alone in children with acute uncomplicated appendicitis have been reported from other countries. These studies reveal that non-operative management of appendicitis is a safe treatment for appendicitis and is associated with a significantly lower risk of complications than appendectomy. However, the success rate of nonoperative management was 75% at 1year. Chronic appendicitis has been described as a possible cause of persistent right lower quadrant (RLQ) pain and laparoscopic appendectomy has been shown to benefit a large number of children，but there are no high-quality clinical trials. There are more than 200 million children in China. According to preliminary clinical data, the incidence of pediatric appendicitis in China is higher than Europe and America. Due to the Chinese parents have different cultures and educational backgrounds, more high-quality clinical trials are needed to guide parents to choose appropriate treatment for chronic appendicitis in children. Therefore, the investigators propose a multi-institutional trial in which patients and their families choose between antibiotics therapy (AT group) or laparoscopic appendectomy (LAAPT group) to chronic appendicitis in children aged 3-15 years. The investigators hypothesize that laparoscopic appendectomy will be successful in 90% of patients at 1 year follow-up and will be associated with fewer disability days, higher quality of life scores, and higher pain reduce scores than antibiotic therapy. This study will enroll 200 patients, age 3-15 years, with chronic appendicitis at 8-10 hospitals.

Inclusion Criteria:

1. Patients were eligible if they were between 3 and 15 years of age, and they suffered from chronic appendicitis.
2. US showing hyperemia and fecalith, ≤ 1.1 cm in diameter, compressible or non-compressible, no abscess, no phlegmon or CT showing hyperemia and fecalith, fat stranding, ≤ 1.1 cm in diameter, no abscess, no phlegmon.

Exclusion Criteria:

1. Exclusion criteria consisted of (a history of) chronic back pain
2. previous abdominal surgery (with the exception of diagnostic laparoscopies or a laparoscopic sterilization)
3. specific gastro-intestinal entities (such as inflammatory bowel disease) 4.gynaecological disease (all female patients consulted a gynaecologist)