Knowledge about incidence, risk factors and genetic predispositions of primary spontaneous pneumothorax in young adults is very limited, and treatment has also been controversial.The Aim of this study is to optimize the treatment, estimate the actual incidence, and identify possible risk factors including genetic predispositions.

• Background Knowledge about incidence, risk factors and genetic predispositions of primary spontaneous pneumothorax in young adults is very limited, and treatment has also been controversial. Typically, the first incidence is treated conservatively with simple chest tube drainage and only if the disease reoccurs is surgery considered. However, conventional treatment may be associated with increased morbidity, prolonged hospitalization and many young adults are concerned about the high recurrence of this disease. The latter has been reported in as many as 25-35% of patients. Because spontaneous pneumothorax in young adults usually is associated with apical blebs, the investigators hypothesized that primary surgery (Video-Assisted Thoracoscopic Surgery = VATS) with resection of such blebs at the time of the first episode of pneumothorax might be an effective first line treatment associated with lower morbidity and shorter hospital stays, and a definite decline in recurrence rate.
• Method From July 2009 the investigators conducted a nationwide study , where 300 consecutive patients admitted to a Danish hospital with primary spontaneous pneumothorax undergo a high resolution CT of the thorax. Based upon the CT the patients are randomised to conventional conservative treatment (chest tube drainage) or primary VATS with bleb resection and mechanical pleurodesis.

Participants are followed for ten years. The primary endpoint is ipsilateral recurrence of pneumothorax. Secondary endpoints are length of hospitalization, duration of chest tube drainage and miscellaneous complications.

Simultaneously, a research biobank containing blood samples and pulmonary tissue is created for future studies of biomarkers and possible genetic causes.

Finally, the investigators are conducting a national epidemiological study, where the incidence in the Danish population is investigated.

*Perspective This study contributes new knowledge on incidence, genetics and best treatment of primary spontaneous pneumothorax in young adults which will have an impact on the future strategy of both understanding and treatment of this disease on a global level.

Inclusion Criteria:

• First incidence of primary spontaneous pneumothorax.
• Age between 18 and 40.
• No known preexisting pulmonary disease.
• Patient must accept randomization.
• Able to read and understand information regarding the study.
• The condition must require treatment with a chest-tube.

Exclusion Criteria:

• Age above 40.
• Previously pulmonary og cardiac surgery.
• Pregnant or breastfeeding.
• Patients who do not tolerate anesthetics.