Abstract: Of 2332 publications obtained through the search strategy, seven studies met the inclusion criteria; one study was ongoing and six studies of 435 participants were eligible for inclusion in the updated review. Data show a significant difference in immediate success rates of procedures favouring tube drainage over simple aspiration for management of primary spontaneous pneumothorax (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.69 to 0.89; 435 participants, 6 studies; moderate-quality evidence). Duration of hospitalization however was significantly less for patients treated by simple aspiration (mean difference (MD) -1.66, 95% CI -2.28 to -1.04; 387 participants, 5 studies; moderate-quality evidence). A narrative synthesis of evidence revealed that simple aspiration led to fewer adverse events (245 participants, 3 studies; low-quality evidence), but data suggest no differences between groups in terms of one-year success rate (RR 1.07, 95% CI 0.96 to 1.18; 318 participants, 4 studies; moderate-quality evidence), hospitalization rate (RR 0.60, 95% CI 0.25 to 1.47; 245 participants, 3 studies; very low-quality evidence), and patient satisfaction (median between-group difference of 0.5 on a scale from 1 to 10; 48 participants, 1 study; low-quality evidence). No studies provided data on cost-effectiveness. Available trials showed low to moderate-quality evidence that intercostal tube drainage produced higher rates of immediate success, while simple aspiration resulted in a shorter duration of hospitalization. Although adverse events were reported more commonly for patients treated with tube drainage, the low quality of the evidence warrants caution in interpreting these findings. Similarly, although this review observed no differences between groups when early failure rate, one-year success rate, or hospital admission rate was evaluated, this too needs to be put into the perspective of the quality of evidence, specifically, for evidence of very low and low quality for hospitalization rate and patient satisfaction, respectively. Future adequately powered research is needed to strengthen the evidence presented in this review.

Plain-language summary: We searched the medical literature (January 2017) and identified seven studies that met the inclusion criteria; one study was ongoing and six studies were eligible for inclusion in the updated review. The six included studies comprised a total of 435 participants with primary spontaneous pneumothorax; 208 of these underwent simple aspiration and 227 underwent intercostal tube drainage. Study results show that tube drainage produced a better rate of immediate treatment success when compared with simple aspiration for primary spontaneous pneumothorax. However, simple aspiration was associated with shorter duration of hospitalization and may have led to fewer adverse events. Researchers noted no significant differences between the two treatments with regard to hospitalization rate, early failure rate, one-year success rate, or patient satisfaction. However, the quality of evidence presented in this review ranged between very low and moderate, making it difficult for review authors to come to definitive conclusions. Results of this review indicate that tube drainage has a better immediate success rate than simple aspiration for treating people with primary spontaneous pneumothorax. However, simple aspiration results in a shorter hospital stay and, although the evidence presented for this outcome is of low quality, may lead to fewer adverse events than are reported with tube drainage. The overall quality of evidence ranges from very low to moderate, and future research is needed to strengthen the evidence presented in this review.