Mark D Redden, Tze Yang Chin, Mieke L van Driel

Empyema refers to pus in the pleural space, commonly due to adjacent pneumonia, chest wall injury, or a complication of thoracic surgery. A range of therapeutic options are available for its management, ranging from percutaneous aspiration and intercostal drainage to video-assisted thoracoscopic surgery (VATS) or thoracotomy drainage. Intrapleural fibrinolytics may also be administered following intercostal drain insertion to facilitate pleural drainage. There is currently a lack of consensus regarding optimal treatment. To assess the effectiveness and safety of surgical versus non-surgical treatments for complicated parapneumonic effusion or pleural empyema. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 9), MEDLINE (Ebscohost) (1946 to July week 3 2013, July 2015 to October 2016) and MEDLINE (Ovid) (1 May 2013 to July week 1 2015), Embase (2010 to October 2016), CINAHL (1981 to October 2016) and LILACS (1982 to October 2016) on 20 October 2016. We searched ClinicalTrials.gov and WHO International Clinical Trials Registry Platform for ongoing studies (December 2016). Randomised controlled trials that compared a surgical with a non-surgical method of management for all age groups with pleural empyema. Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked the data for accuracy. We contacted trial authors for additional information. We assessed the quality of the evidence using the GRADE approach. We included eight randomised controlled trials with a total of 391 participants. Six trials focused on children and two on adults. Trials compared tube thoracostomy drainage (non-surgical), with or without intrapleural fibrinolytics, to either VATS or thoracotomy (surgical) for the management of pleural empyema. Assessment of risk of bias for the included studies was generally unclear for selection and blinding but low for attrition and reporting bias. Data analyses compared thoracotomy versus tube thoracostomy and VATS versus tube thoracostomy. We pooled data for meta-analysis where appropriate. We performed a subgroup analysis for children along with a sensitivity analysis for studies that used fibrinolysis in non-surgical treatment arms.The comparison of open thoracotomy versus thoracostomy drainage included only one study in children, which reported no deaths in either treatment arm. However, the trial showed a statistically significant reduction in mean hospital stay of 5.90 days for those treated with primary thoracotomy. It also showed a statistically significant reduction in procedural complications for those treated with thoracotomy compared to thoracostomy drainage. We downgraded the quality of the evidence for length of hospital stay and procedural complications outcomes to moderate due to the small sample size.The comparison of VATS versus thoracostomy drainage included seven studies, which we pooled in a meta-analysis. There was no statistically significant difference in mortality or procedural complications between groups. This was true for both adults and children with or without fibrinolysis. However, mortality data were limited: one study reported one death in each treatment arm, and seven studies reported no deaths. There was a statistically significant reduction in mean length of hospital stay for those treated with VATS. The subgroup analysis showed the same result in adults, but there was insufficient evidence to estimate an effect for children. We could not perform a separate analysis for fibrinolysis for this outcome because all included studies used fibrinolysis in the non-surgical arms. We downgraded the quality of the evidence to low for mortality (due to wide confidence intervals and indirectness), and moderate for other outcomes in this comparison due to either high heterogeneity or wide confidence intervals. Our findings suggest there is no statistically significant difference in mortality between primary surgical and non-surgical management of pleural empyema for all age groups. Video-assisted thoracoscopic surgery may reduce length of hospital stay compared to thoracostomy drainage alone.There was insufficient evidence to assess the impact of fibrinolytic therapy.A number of common outcomes were reported in the included studies that were not directly examined in our primary and secondary outcomes. These included duration of chest tube drainage, duration of fever, analgesia requirement, and total cost of treatment. Future studies focusing on patient-centred outcomes, such as patient functional scores, and other clinically relevant outcomes, such as radiographic improvement, treatment failure rates, and amount of fluid drainage, are needed to inform clinical decisions.