Review question
This review compared the effectiveness of the two main treatment options for peritonsillar abscess: needle aspiration and incision and drainage.
Background
Peritonsillar abscesses are infections at the back of the throat in which a collection of pus (abscess) has formed next to the tonsil. The condition is characterised by a severe sore throat, difficulty in swallowing and pain on swallowing, fever and malaise, and trismus (inability to open the mouth completely). Treatment is usually by one of two methods. The first is needle aspiration (sucking the pus out using a syringe and needle) and the second 'incision and drainage' (putting a small knife into the abscess to let the pus drain out). It remains unclear whether one type of treatment is better than the other.
Study characteristics
We included 11 studies with a total of 674 participants. The participants in the studies were aged from 8 to 79. The studies were conducted in a number of countries (six from Pakistan, two from the USA, one from Taiwan and two from South Africa). All but one of the 11 studies reported the difference in recurrence rate between needle aspiration and incision and drainage. Four studies compared symptom scores associated with the procedure and two studies compared time to resumption of normal diet. Three studies reported adverse effects/events associated with the intervention. Two studies reported complications of the disease process itself.
The evidence is current to August 2016.
Key results
Ten studies reported on the recurrence of peritonsillar abscess (our main outcome). Most of them did not clearly define 'recurrence' and they varied in the timing of its assessment, however we were able to combine (pool) the data from these studies. When we pooled the data the recurrence rate was higher in the needle aspiration group compared with incision and drainage. It is important to note that the evidence for this outcome was of very low quality. Some studies found that patients had more pain when they had incision and drainage.
Quality of the evidence
We identified problems or potential problems in all of the included studies. The most important of these was that the studies did not all assess recurrence in the same way, at the same time, using the same criteria. The quality of the evidence for all of the outcomes that we looked at was very low.
Although a number of studies have sought to evaluate whether or not needle aspiration or incision and drainage is more effective in patients with peritonsillar abscess, there is no high-quality evidence to allow a firm conclusion to be drawn and the answer remains uncertain. Very low-quality evidence suggests that incision and drainage may be associated with a lower chance of recurrence than needle aspiration. There is some very low-quality evidence to suggest that needle aspiration is less painful.
Peritonsillar abscess is a common infection presenting as a collection of pus in the peritonsillar area. The condition is characterised by a severe sore throat, difficulty in swallowing and pain on swallowing, fever and malaise, and trismus. Needle aspiration and incision and drainage are the two main treatment modalities currently used in the treatment of this condition. The effectiveness of one versus the other has not been clearly demonstrated and remains an area of debate.
To assess the effectiveness and risks of needle aspiration versus incision and drainage for the treatment of peritonsillar abscess in older children (eight years of age or older), adolescents and adults.
The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2016, Issue 7); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 25 August 2016.
Randomised controlled trials comparing needle aspiration with incision and drainage.
We used the standard methodological procedures expected by Cochrane. Our primary outcomes were recurrence rate (proportion of patients needing repeat intervention) and adverse effects associated with the intervention. Secondary outcomes were time to resumption of normal diet, complications of the disease process and symptom scores. We used GRADE to assess the quality of evidence for each outcome; this is indicated in italics.
We included 11 studies (674 participants). The risk of bias was high or unclear in all of the included studies. All studies compared needle aspiration to incision and drainage.
All but one of the 11 studies reported on the primary outcome of recurrence. When we pooled data from the 10 studies the recurrence rate was higher in the needle aspiration group compared with incision and drainage: risk ratio (RR) 3.74 (95% confidence interval (CI) 1.63 to 8.59; 612 participants). We detected moderate heterogeneity in this analysis (I2 = 48%). In interpreting the pooled result it is important to note that the evidence for this outcome was of very low quality.
None of the other outcomes (adverse effects of the intervention, time to resumption of normal diet, complications of the disease process and symptom scores) were consistently measured across all studies.
Only three studies reported on adverse effects/events associated with the intervention and only one such event in a single patient was reported (post-procedure bleeding following incision and drainage: 1/28, 3.6%) (very low-quality evidence).
Time to resumption of normal diet was compared in two studies; neither found an obvious difference between needle aspiration and incision and drainage (very low-quality evidence).
Only three studies stated that they would report complications of the disease process. In these three studies, the only complication reported was admission to hospital for dehydration in two patients who underwent incision and drainage (2/13, 6.7%).
Symptom scores were measured in four studies; three evaluated pain using different scales and one other symptoms. The data could not be pooled in a meta-analysis. Two studies evaluating procedural pain reported this to be lower in the needle aspiration groups. One study found comparable rates of pain resolution at five days post-intervention between groups. The quality of the evidence for symptom scores was very low.