Contralateral Recurrence and Temporal Trend After First Side Surgery for Primary Spontaneous Pneumothorax: A...

Background: Contralateral recurrence following surgically treated primary spontaneous pneumothorax represents clinical concern yet remains poorly understood. This study aims to expand the current understanding by evaluating a large, multicenter cohort over a 10-year period and to determine the true incidence of contralateral recurrence assessing the potential role of clinical factors in risk stratification. Methods: A total of 479 patients surgically treated for PSP (2012-2024) across three Italian high-volume centers were retrospectively reviewed. Secondary pneumothorax, patients <18 years old, lung emphysema or intraparenchymal large bullae, and the thoracotomy approach were excluded. The association between categorical variables and contralateral recurrence was assessed using the chi-square (χ²) test, while the association with continuous variables was evaluated using the t-test. Time to recurrence was analyzed using Kaplan-Meier survival curves. Variables with a p-value < 0.05 were considered statistically significant. Results: We identified 59 patients who experienced contralateral recurrence: 45 were males, the mean age was 26.66 ± 12.32 and the mean BMI was 22.00 ± 2.92; only 13 were active smokers. Age (p < 0.001) and smoking history (p = 0.029) were significantly associated with contralateral recurrence in univariate analysis, though these were not confirmed in multivariate analysis. Among the cohort of recurrence, 53 patients only had a recurrence on the contralateral side, with a median time to recurrence of 139 days. The incidence rate ratio (IRR) of recurrence for patients with a mean age of <34 years was 1.23, which translates to a 23% increased risk. No significant impact of age (p = 0.25), sex (p = 0.67), or smoking (p = 0.59) on the time to recurrence on the other side was observed through Kaplan-Meier analysis. The peak incidence for the first episode of PNX surgically treated and contralateral recurrence was observed in October, November and January. Conclusions: This study highlights a 12% contralateral recurrence rate after PSP surgery. Younger age is associated with earlier contralateral recurrence. Seasonality may influence recurrence patterns. Further studies should explore underlying mechanisms and preventive strategies.