Key messages

• We do not know if drain (tube) use after open (where a large cut is made to access underlying organs or tissues) or keyhole (surgery performed through a very small surgical cut) removal of the appendix has an important effect on the abdominal abscess (collection of pus in the abdomen) rate, wound infection rate, or overall complication rate in children and adults with complicated appendicitis (death, decay, or perforation of the appendix).

• Use of drain after open removal of the appendix probably increases the death rate in children and adults with complicated appendicitis.

• Use of drain after open or keyhole removal of the appendix may increase the length of hospital stay in children and adults with complicated appendicitis, but we are very uncertain about the results.

What is complicated appendicitis?

The human appendix is a tube located at the connection between the small and large intestines. The term 'appendicitis' covers a variety of conditions resulting from painful swelling of the appendix. Complicated appendicitis is defined as gangrenous appendicitis (death and decay of the appendix) or perforated appendicitis (bursting of the appendix).

How is this managed?

People with complicated appendicitis (gangrenous or perforated appendicitis) usually need surgical removal of the appendix to relieve their symptoms and avoid complications. Individuals undergoing surgical removal of the appendix for complicated appendicitis are more likely to suffer complications after surgery in comparison to uncomplicated appendicitis. The routine placement of a surgical drain to prevent abdominal abscess after surgical removal of the appendix for complicated appendicitis has been questioned. Use of a drain may decrease the risk of abdominal abscess, but it may also have no benefit and may even cause harm.

What did we want to find out?

We wanted to find out whether the use of a drain after open or keyhole removal of the appendix is effective in reducing the abdominal abscess rate for people with complicated appendicitis in any care setting.

We wanted to compare the use of a drain versus no drain by looking at:

• abdominal abscess rate;

• wound infection rate;

• overall complication rate;

• death rate;

• length of hospital stay.

What did we do?

We searched for studies that compared the use of a drain with no drain after surgical removal of the appendix for people with complicated appendicitis. There were no restrictions on language, date of publication, or study setting. 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 found eight studies in which 739 children and adults with complicated appendicitis were randomly assigned to either use of drain (370 participants) or no drain (369 participants) after open or keyhole removal of the appendix.

We are uncertain whether the use of a drain in children and adults after open or keyhole removal of the appendix reduces:

• abdominal abscess rate (9 more abdominal abscesses per 1000 participants);

• wound infection rate; or

• overall complication rate.

Compared with no drain, the use of a drain probably increases the death rate in children and adults after open removal of the appendix. Use of a drain may increase the length of hospital stay in children and adults after open or keyhole removal of the appendix, but we are very uncertain about this result.

What are the limitations of the evidence?

We have very little confidence in the evidence because it is possible that people in the studies were aware of what treatment they were getting, and not all studies provided data about everything that we were interested in. In addition, some studies did not clearly report how they were conducted, and there were not enough studies to be certain about the results of our outcomes.

How up-to-date is this evidence?

This review updates our previous review. The evidence is current to October 2023.