Background: Although bullectomy is the most curative treatment in primary spontaneous pneumothorax (PSP), postoperative recurrence is not uncommon. New bulla formation at the staple line is the most common cause of recurrence. However, the mechanism is not known. We believe that the pressure gradient plays the main role in new bulla formation. A large resection amount induces a prolonged pressure gradient for obliteration of the residual space. This study aimed to identify the association between resected lung volume and recurrence.
Methods: The medical records of patients who underwent video-assisted thoracoscopic surgery (VATS) bullectomy were reviewed between October 2010 and December 2017. A total of 396 patients underwent surgery for spontaneous pneumothorax. The electronic medical records (EMRs) of the patients were reviewed. Patients with secondary spontaneous pneumothorax were excluded. Patients who were diagnosed with emphysema on CT were excluded. Patients with PSP were excluded from the study if the bulla was not located in the apex or if there was no ruptured bulla at the time of the operation. Patients who lacked EMRs were also excluded. We reviewed the medical records of 276 patients. The apical resected lung volume was estimated using a conical volumetric formula with the use of the specimen size. The risk factors for postoperative recurrence were analyzed.
Results: The median age was 19 years old (range 13-36). A total of 261 patients were male (94.6%). The median body weight and body mass index (BMI) were 58 kg (range 40-82) and 18.92 (range 15.21-26.47), respectively. In 24 patients, both sides were operated on simultaneously. The resected lung volume was obtained by using a conical volumetric formula, and the value was divided by the BMI value. The median value was 1.43 (0.03-5.67). The median operative time was 35 min (range 15-120). The median postoperative day was 4 (range 2-12). Age (p = 0.006), the value of the resected lung volume divided by BMI (p = 0.003), bilateral bullectomy (p = 0.013) and transverse diameter (p = 0.034) were associated with postoperative recurrence according to the univariate analysis. According to the multivariate analysis, age and the value of the lung volume divided by BMI were significant risk factors for postoperative recurrence.
Conclusions: Younger age and a large resected lung volume and a low BMI are associated with postoperative recurrence after VATS bullectomy for PSP.