Early Postoperative Pneumothorax Might Not Be ‘True’ Recurrence

Objectives: To date, there is no consensual definition of what constitutes a postoperative recurrence of primary spontaneous pneumothorax (PSP), despite there being many studies reporting a high incidence of recurrence. This study aims to describe the long-term recurrence rates of pneumothorax and to suggest a possible way to differentiate recurrence events based on temporal patterns. Methods: This single-center study retrospectively evaluated all postoperative recurrence of PSP from January 2007 to May 2019. Patients’ demographics, history of pneumothorax, radiologic data, surgical technique, and the time between operation and recurrence were analyzed. Univariate and multivariable analyses were conducted to find potential risk factors related to long-term recurrence. Results: Of the 77 postoperative recurrent cases of pneumothorax, 21 (27.2%) occurred within 30 days after surgery and, thus, were classified as early recurrences (ER), while the remaining cases were classified as late recurrences (LR). There was no difference in preoperative variables between the two groups. However, the rate of incidence of second recurrence (SR), which represented a long-term prognosis, was significantly higher in the LR group (28.6% vs. 4.8%, p = 0.030). On univariate and multivariable analyses, late recurrence was the only significant factor predicting later recurrence events. Conclusion: Postoperative recurrence (PoR) within 30 days had a lower SR rate. Therefore, it might not be a ‘true’ postoperative recurrence with a favorable prognosis. Further studies investigating postoperative recurrence based on temporal patterns would be warranted to improve the classification of PoR.