The effects of total pleural covering on pneumothorax recurrence and pulmonary function in lymphangioleiomyomatosis patients without history of pleurodesis or thoracic surgeries for pneumothorax.

Background: Total pleural covering (TPC) is an innovative surgical procedure in which the entire visceral pleura is wrapped with sheets of oxidized regenerated cellulose (ORC) mesh under video-assisted thoracoscopic surgery. We have previously reported that TPC could successfully prevent pneumothorax recurrence in patients with lymphangioleiomyomatosis (LAM). However, the actual efficacy and preventive effect of TPC on pneumothorax recurrence remains unclear as many LAM patients already had pleural adhesion prior to TPC that was induced by thoracic surgery and/or pleurodesis. The purpose of this study is to evaluate the effects of TPC on pneumothorax recurrence and pulmonary function in LAM patients with no history of thoracic surgeries or pleurodesis.

Methods: We retrospectively reviewed medical charts of 52 patients (60 hemithoraces) who underwent TPC at our center, from January 2003 to September 2019, as a first surgical intervention for pneumothorax.

Results: Pneumothorax recurrence occurred in 12 patients [14 of 60 hemithoraces (23.3%)] during the observation period [27 months (14.7; 56.4) = median (lower; upper quartiles)]. The probability of recurrence-free hemithorax post TPC was 81.1% at 2.5 years and 64.1% at 5 years. TPC did not produce a significant decrease in either VC %predicted (pred) or FEV1 /FVC. The pre- vs. post-TPC median (lower; upper quartiles) VC %pred was 85.7% (79.7; 98.0) vs. 87.2% (72.3; 95.6), P=0.535 and the FEV1 /FVC was 84.6% (75.7; 89.6) vs. 83.0% (71.8; 87.0), P=0.667. Mechanistic/mammalian target of rapamycin (mTOR) inhibitors (mTORI) were subsequently initiated in 19 patients (36.5%) because of the progression of LAM. The postoperative FEV1% pred was significantly lower in patients who required mTORI than in those who did not [68.1% (57.3; 82.9) vs. 88.7% (84.6; 89.8), P=0.020]; the decline rate in FEV1% pred/year from pre to post TPC was significantly greater in LAM patients who required mTORI than in those who did not [-9.37% (-4.73; 12.9) vs. -1.94% (1.52; -4.50), P=0.029]. Postoperative complications were found in 25 of 52 hemithoraces (48.1%).

Conclusions: TPC can prevent pneumothorax recurrence without causing ventilatory impairment or severe pleural symphysis in LAM patients. TPC is an effective treatment option for LAM-associated pneumothorax based on its efficacy and safety.