Key messages
- Early open or keyhole (where surgery is performed through a very small cut) removal of the appendix (a tube at the connection of the small and the large intestines) may reduce the rate of abdominal abscess (a collection of pus in the abdomen) in people with appendiceal phlegmon (a diffuse inflammation in the bottom right of the appendix), but we are very uncertain about the results.
- We do not know if early open or keyhole removal of the appendix has an important effect on the overall complication rate or on other complications in people with appendiceal phlegmon. Early open or keyhole removal of the appendix may reduce the total length of hospital stay and may increase the time away from normal activities, but we are very uncertain about the results.
- We do not know if early keyhole removal of the appendix has an important effect on outcomes in children with appendiceal abscess.
What is an appendiceal mass?
The appendix is a tube located at the connection between the small and large intestines. 'Appendicitis' is when the appendix becomes swollen and painful (inflamed). In some cases, appendicitis can cause a lump called an appendiceal mass to form on the appendix. This could be a 'phlegmon', which is a diffuse inflammation in the bottom right of the appendix, or an 'abscess', which is a collection of pus in the stomach.
How is appendiceal mass treated?
People with appendiceal masses usually need surgical removal of the appendix to relieve their symptoms (abdominal pain, loss of appetite, nausea, and vomiting) and avoid complications (such as peritonitis). The timing of the surgery is controversial. Immediate surgery is difficult because it is challenging to suture (stitch up) the inflamed appendix stump. However, some experts think that removing the appendix weeks later (delayed surgery) is unnecessary, as people are unlikely to experience recurrence after successful non-surgical treatment. However, it is sometimes difficult to find the cause of the lump on the appendix, and waiting to remove the appendix could delay the diagnosis of any underlying disease.
What did we want to find out?
We wanted to find out if early removal of the appendix (immediately after hospital admission or within a few days) was better than delayed removal of the appendix (several weeks later in a subsequent hospital admission), in terms of:
- overall complication rate, including wound infection, abdominal abscess, faecal fistula (an abnormal opening between the intestine and the abdomen);
- death rate;
- total length of hospital stay;
- time away from normal activities.
What did we do?
We searched for studies that looked at early removal of the appendix compared with delayed removal of the appendix in people with appendiceal phlegmon or abscess. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We identified eight studies, involving 828 participants, that compared early versus delayed appendicectomy for either appendiceal phlegmon (7 studies) or appendiceal abscess (1 study).
People with phlegmon
We found seven studies with 788 children and adults with appendiceal phlegmon. Of these, 394 had early open or keyhole and 394 had delayed open or keyhole removal of the appendix.
We do not know if early removal of the appendix has an effect on overall complications (including wound infection and faecal fistula).
Compared with delayed removal of the appendix, early removal of the appendix may reduce abdominal abscesses (43 fewer abdominal abscesses per 1000 participants), and reduce the total length of hospital stay by about two days, but we are very uncertain about these results.
There were no deaths in the studies.
Early removal of the appendix may increase the time away from normal activities by about five days, but we are very uncertain about this result.
People with abscess
We found one study with 40 children. Twenty children had early keyhole removal of the appendix and 20 children had delayed keyhole removal of the appendix.
The study did not report overall complications (including wound infection, abdominal abscess, and faecal fistula), or time away from normal activities.
There were no deaths in the study.
We do not know if early removal of the appendix has an effect on the total length of hospital stay.
What are the limitations of the evidence?
We are not confident in the evidence because it is possible that people in the studies were aware of what treatment they were getting, and because not all of the studies provided information about everything we were interested in. In addition, some studies did not clearly report how they were conducted, and there are not enough studies available for us to be certain about the results.
How up to date is this evidence?
This review updates our previous review. The evidence is current to June 2023.
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.
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.
To assess the effects of early appendicectomy compared to delayed appendicectomy on overall morbidity and mortality in people with appendiceal phlegmon or abscess.
We searched CENTRAL, MEDLINE, Embase, two other databases, and five trials registers on 11 June 2023, together with reference checking to identify additional studies.
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.
We used standard methodological procedures expected by Cochrane.
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).