The best management of primary spontaneous pneumothorax is unclear. Conservative treatment has been proposed, but no studies comparing conservative with invasive management have been carried out where pneumothorax size has been numerically quantified. This study aimed to evaluate the feasibility of conservative management for primary spontaneous pneumothoraces of any size.

Retrospective cohort study of adult patients with primary spontaneous pneumothorax treated at an Australian tertiary hospital from 2006–2011, carried out by case‐note and chest radiograph review. Patient demographics, smoking status, and outcome data were collected. Pneumothorax size was calculated using the Collins method, based on the sum of interpleural distances.

One hundred and twenty‐seven episodes from 116 patients were identified. Males (86) comprised 75% of patients, and the median age at presentation was 37 years. Eighty‐two percent of cases (106) were ever‐smokers. Of the episodes in which pre‐treatment radiographs were available, 53 were treated conservatively and 58 invasively with tube thoracostomy, and all were clinically stable. When cases were stratified by pneumothorax size, age, sex, ethnicity, and smoking status had no effect on outcome. Compared to invasive treatment, conservative management resulted in no complications, an equal recurrence rate, and a significantly shorter length of stay.

Our results suggest that it may be feasible to adopt a conservative approach as the first‐line treatment of primary spontaneous pneumothorax in clinically stable patients. However, given the limitations of this study, a large randomised controlled trial is required to conclusively prove this assertion.