[Postoperative recurrence of spontaneous pneumothorax]

Few reports on recurrence after thoracoscopic bullectomy for spontaneous pneumothorax specify the follow-up period and follow-up ratio. Because of the variation in follow-up periods, many reported recurrence rates were not comparable. Some reports compared simple recurrence rate (number of recurrent cases/number of operated cases) of different groups with different follow-up periods. In this study, we employ the Kaplan-Meier method along with a set of optimal follow-up periods and ratios in order to determine a more reliable recurrence rate. Consecutive 68 patients (74 surgical procedures) underwent thoracoscopic bullectomy for spontaneous pneumothorax at our institution between November 2000 and December 2005. A follow-up survey was conducted by phone to determine the rate of recurrent pneumothorax. The follow-up ratio and the mean follow-up period were 92.6% and 1,316 +/- 481 days, respectively. Postoperative recurrence was confirmed for 4 patients. The interval up to recurrence was 144, 345, 476 and 616 days after the bullectomy, respectively. All cases of recurrent pneumothorax occurred within 2 years following the bullectomy. The 1-year, 2-year and 3-year cumulative recurrence rate was 3.0%, 6.3% and 6.3%, respectively. In light of these findings, we feel that comparison analysis of pneumothorax recurrence rates should be evaluated using the Kaplan-Meier method, furthermore, our data suggests that a follow-up period of 2 or more years is advisable.