Predictors of Contralateral Recurrence in Patients With Primary Spontaneous Pneumothorax.

Background: The recurrence of primary spontaneous pneumothorax (PSP) requires readmission to the hospital and additional medical costs. Therefore, the identification of predictors for recurrence may help reduce additional burdens. Objective: To investigate the outcome of asymptomatic contralateral bullae in individuals diagnosed with ipsilateral primary spontaneous pneumothorax (PSP) and examine the risk factors contributing to the incidence of contralateral pneumothorax. Methods: A retrospective analysis from January 2014 to May 2023, of 18-50 years old patients who underwent thoracoscopic bullectomy for PSP management at a university hospital. However, we excluded patients older than 50 years of age, patients with traumatic pneumothorax, and bilateral PSP. Results: A total number of 184 episodes of PSP cases were reviewed and contralateral recurrence was observed in 14.3% of patients. Significant associations were identified between contralateral recurrence and the presence of contralateral bullae on high-resolution CT (HRCT) (p = 0.002), as well as the number (p = 0.003) and side of the affected hemithorax (p = 0.036). Patients lacking contralateral bullae, those with a single bulla, or right-sided PSP had lower contralateral recurrence likelihood. Initial PSP side was a significant predictor, with a 2.8 times higher likelihood (p = 0.046). Additionally, increasing bullae number in chest CT scans was correlated with a 44% decrease in the odds of contralateral pneumothorax (p = 0.038). Conclusion: Patients presenting with PSP and evident contralateral bullae on imaging, should be closely followed up and informed about the significant risk to avoid recurrences and complications.