The role of postoperative antibiotics in preventing surgical site infections in uncomplicated appendicitis

A best evidence topic has been constructed using a described protocol. The three-part question addressed was: In patients who underwent appendicectomy for uncomplicated appendicitis is the use of postoperative antibiotics associated with lower rates of surgical site infections? The search has been devised and 6 studies were deemed to be suitable to answer the question. The outcome assessed was the efficiency of postoperative antibiotic therapy in decreasing the rate of surgical site infections in uncomplicated appendicitis. Authors recommend against the use of postoperative antibiotics based on the supported evidence. Hence, its usage was not associated with lower rates of surgical site infections. On the contrary, it might increase the cost, postoperative morbidity and length of stay.


Introduction
This BET was constructed using a framework outlined by the International Journal of Surgery [1]. A BET provides evidence-based answers to common clinical questions, using a systematic approach of reviewing the literature.

Clinical scenario
After performing an appendicectomy for uncomplicated or simple appendicitis for one of your patients. You wonder whether the addition of further postoperative antibiotic therapy would decrease the chances of developing superficial or deep surgical site infections?

Three-part question
In [patients who underwent appendicectomy for uncomplicated appendicitis] is [the use of postoperative antibiotic] associated with lower rates of [superficial or deep surgical site infections]?

Search strategy
The search was conducted as following: Embase 1974 to 2020 and MEDLINE® 1946 to November 2020 using the OVID interface. The results were limited to English articles and human studies: [simple appendicitis OR uncomplicated appendicitis] AND [appendicectomy OR appendectomy] AND [postoperative antibiotic OR postoperative antibiotic] AND [surgical site infection OR SSI OR intraabdominal collection OR intraperitoneal collection OR pelvic collection].

Search outcome
6963 articles were found. Out of these 9 deemed to be suitable and met the criteria of our search. 6954 articles were excluded as they included duplicate, conference abstracts and irrelevant articles based on titles and abstracts. 9 full-text articles were screened and assessed for eligibility. 6 out of 9 articles were chosen as they provided the best evidence and were confined to postoperative antibiotics administration in simple or uncomplicated appendicitis and their role to decrease the postoperative surgical site infections which is the core of our topic. The full articles reviewed carefully to ensure including the best evidence to answer the question.
Different papers have defined acute simple/uncomplicated appendicitis differently but all of them have agreed to define it as inflamed nonperforated appendicitis. Surgical site infections (SSIs) defined as both superficial and deep surgical site infections which occur within 30 days postoperatively. Superficial surgical site infections were defined as superficial wound infection which requires antibiotic therapy or laying the wound open along with wound care. Deep surgical site infections defined as the fluid collection inside the peritoneal cavity confirmed by ultrasound or computed tomography that requires drainage or antibiotic therapy.

Result
(Please refer to the table

Discussion
Post appendicectomy SSIs is one of the common adverse events affecting patient safety worldwide [8]. Preoperative antibiotic therapy is a well-established and evidence-based practice which was found to be efficient to decrease the incidence of postoperative SSIs [9]. However, up to date there is no clear consensus about the role of post appendicectomy antibiotic therapy in patients with simple or uncomplicated appendicitis. Therefore, this search was conducted.
In 2009, Le et al. [2] conducted a retrospective cohort study which included 763 patients who underwent appendicectomy for nonperforated appendicitis over a 10-year period. They have classified the patients into 2 groups: the first group received postoperative antibiotics and the second did not. The authors found that there are no significant differences in the rates of all SSIs (10% vs 9%, P = 0.64) and they have concluded that the use of postoperative antibiotics in patients with nonperforated appendicitis does not decrease the rate of SSIs, while it may increase the cost of care.
In 2011, Coakley et al. [3] came up with the same conclusion and added that postoperative antibiotic therapy can increase the length of stay and the postoperative morbidity. His cohort retrospective study included 728 patients.
Hussain et al. [4] in 2012, conducted a randomized controlled trial which included 377 patients. 195 patients received only a single dose of preoperative antibiotics. While182 patients received an additional one dose of postoperative antibiotics. They concluded that there is no significant difference in rates of SSIs between both the groups (p = 0.9182).
In 2013, Hughes et al. [5] devised a retrospective cohort trial. The study included 188 cases who had simple appendicitis and 78 for complicated appendicitis. In simple/uncomplicated appendicitis 104 patients did not receive postoperative antibiotics and 84 who did. Authors found that there is no significant difference in developing intra-abdominal infection between the two groups (P = 0.63) and concluded that in simple appendicitis, postoperative antibiotics may not be beneficial at all.
In 2015 and 2017, both Rafiq et al. [6] and Moosavi et al. [7] conducted two randomized controlled trials which included 390 and 152 patients consecutively. Both studies concluded that Single dose of preoperative antibiotics was sufficient in reducing SSIs after appendicectomy.
All the above-mentioned studies have strongly agreed on the efficiency of preoperative antibiotic usage for decreasing the incidence of SSIs and that postoperative antibiotics were not beneficial in case of uncomplicated appendicitis.
The observed limitations are the possibility of selection bias and the variability of the selected antibiotic regimen in some of the studies. However overall, they came up with unified strong recommendations.

Clinical bottom line
Six studies including three randomized controlled trials have strongly recommended against the administration of postoperative antibiotics in case of uncomplicated or simple appendicitis as none of the studies has shown evidence of lower SSIs rate with its use. On the contrary, it might increase the cost, length of stay and postoperative morbidity.

Ethical approval
Not applicable.

Sources of funding
None.

Author contribution
SA: devised the idea of the study, conducted literature search and wrote the paper.
RI: assisted in literature search editing and writing the paper. FA: assisted in literature search and collecting the data. HN: assisted in literature search and writing the paper. AA: assisted in writing and editing the paper.

Consent
Not Applicable.

Registration of research studies
Name of the registry: not applicable Unique Identifying number or registration ID Hyperlink to your specific registration (must be publicly accessible and will be checked)

Declaration of competing interest
None.