BACKGROUND: This is an update of a Cochrane review first published in 2017. Acute appendicitis (inflammation of the appendix) can be simple or complicated. Appendiceal phlegmon and appendiceal abscess are examples of complicated appendicitis. Appendiceal phlegmon is a diffuse inflammation in the bottom right of the appendix, while appendiceal abscess is a discrete inflamed mass in the abdomen that contains pus. Appendiceal phlegmon and abscess account for 2% to 10% of acute appendicitis. People with appendiceal phlegmon or abscess usually need an appendicectomy to relieve their symptoms (e.g. abdominal pain, loss of appetite, nausea, and vomiting) and avoid complications (e.g. peritonitis (infection of abdominal lining)). Surgery for people with appendiceal phlegmon or abscess may be early (immediately after hospital admission or within a few days of admission), or delayed (several weeks later in a subsequent hospital admission). The optimal timing of appendicectomy for appendiceal phlegmon or abscess is debated.
OBJECTIVES: To assess the effects of early appendicectomy compared to delayed appendicectomy on overall morbidity and mortality in people with appendiceal phlegmon or abscess.
SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, two other databases, and five trials registers on 11 June 2023, together with reference checking to identify additional studies.
SELECTION CRITERIA: We included all individual and cluster-randomised controlled trials (RCTs), irrespective of language, publication status, or age of participants, comparing early versus delayed appendicectomy in people with appendiceal phlegmon or abscess.
DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane.
MAIN RESULTS: We included eight RCTs that randomised 828 participants to early or delayed appendicectomy for appendiceal phlegmon (7 trials) or appendiceal abscess (1 trial). The studies were conducted in the USA, India, Nepal, and Pakistan. All RCTs were at high risk of bias because of lack of blinding and lack of published protocols. They were also unclear about methods of randomisation and length of follow-up. 1. Early versus delayed open or laparoscopic appendicectomy for appendiceal phlegmon We included seven trials involving 788 paediatric and adult participants with appendiceal phlegmon: 394 of the participants were randomised to the early appendicectomy group (open or laparoscopic appendicectomy as soon as the appendiceal mass resolved within the same admission), and 394 were randomised to the delayed appendicectomy group (initial conservative treatment followed by delayed open or laparoscopic appendicectomy several weeks later). There was no mortality in either group. The evidence is very uncertain about the effect of early appendicectomy on overall morbidity (risk ratio (RR) 0.74, 95% confidence interval (CI) 0.19 to 2.86; 3 trials, 146 participants; very low-certainty evidence), the proportion of participants who developed wound infections (RR 0.99, 95% CI 0.48 to 2.02; 7 trials, 788 participants), and the proportion of participants who developed faecal fistulas (RR 1.75, 95% CI 0.36 to 8.49; 5 trials, 388 participants). Early appendicectomy may reduce the abdominal abscess rate (RR 0.26, 95% CI 0.08 to 0.80; 4 trials, 626 participants; very low-certainty evidence), reduce the total length of hospital stay by about two days (mean difference (MD) -2.02 days, 95% CI -3.13 to -0.91; 5 trials, 680 participants), and increase the time away from normal activities by about five days (MD 5.00 days; 95% CI 1.52 to 8.48; 1 trial, 40 participants), but the evidence is very uncertain. 2. Early versus delayed laparoscopic appendicectomy for appendiceal abscess We included one trial involving 40 paediatric participants with appendiceal abscess: 20 were randomised to the early appendicectomy group (emergent laparoscopic appendicectomy), and 20 were randomised to the delayed appendicectomy group (initial conservative treatment followed by delayed laparoscopic appendicectomy 10 weeks later). There was no mortality in either group. The trial did not report on overall morbidity, various complications, or time away from normal activities. The evidence is very uncertain about the effect of early appendicectomy on the total length of hospital stay (MD -0.20 days, 95% CI -3.54 to 3.14; very low-certainty evidence).
AUTHORS' CONCLUSIONS: For the comparison of early versus delayed open or laparoscopic appendicectomy for paediatric and adult participants with appendiceal phlegmon, very low-certainty evidence suggests that early appendicectomy may reduce the abdominal abscess rate. The evidence is very uncertain whether early appendicectomy prevents overall morbidity or other complications. Early appendicectomy may reduce the total length of hospital stay and increase the time away from normal activities, but the evidence is very uncertain. For the comparison of early versus delayed laparoscopic appendicectomy for paediatric participants with appendiceal abscess, data are sparse, and we cannot rule out significant benefits or harms of early versus delayed appendicectomy. Further trials on this topic are urgently needed and should specify a set of criteria for use of antibiotics, percutaneous drainage of the appendiceal abscess prior to surgery, and resolution of the appendiceal phlegmon or abscess. Future trials should include outcomes such as time away from normal activities and length of hospital stay.