Fig 1.
Schematic presentation of TPC workflow.
TPC procedure for a LAM lung consists of 1) covering the lung’s entire visceral pleura with sheets of ORC mesh and 2) followed by spreading drops of fibrin glue. The entire procedure is performed under VATS.
Fig 2.
Numerical scheme for the order of covering lungs with ORC mesh under VATS.
Each lung is depicted imaginarily as if frontal and lateral views were combined. Numbers indicate the standard order of placing sheets of ORC mesh over the entire visceral pleura in each lung. Beginning at the mediastinal surface of the left lung’s upper lobe, ORC mesh is placed as shown, subsequently laid at the basal area in the lower lobe and lastly positioned at interlobar and lateral surfaces. In the right lung, the surface of middle lobe is covered with ORC mesh just after the upper lobe’s surface is entirely covered.
Table 1.
Characteristics of study population (n = 43).
Fig 3.
Selection of a material suitable for pleural covering.
Microscopic findings of the visceral pleura in a Beagle dog 6 weeks after surgery to cover dog’s lung with either ORC mesh (A, B), VIC mesh (C, D) or PGA sheet (E, F), respectively. The photomicrograph of normal appearance of dog lung is presented (G) for comparison. The visceral pleura covered with ORC (A and B) was approximately 5 times thicker than untreated pleura. There was no adhesion between the visceral pleura and the chest wall. In contrast, VIC and PGA induced severe fibrotic changes associated with pleural symphysis (C, and E): Note that ORC was completely absorbed (B) whereas both VIC and PGA were not: the white dots indicate unabsorbable VIC mesh (D) or PGA sheet (F). A, C, E, andn G: Hematoxylin and eosin staining. B, D, and F: Masson-trichrome staining. A, B, C, E, andn G: low magnification view. D and F: high magnification view.
Fig 4.
Kaplan-Meier estimate of the probability of recurrence-free hemithorax after TPC.
A. All hemithoraces that had TPC (n = 54). The probability of recurrence-free hemithorax after TPC is 80.8% at 2.5 years, 71.7% at 5 years, 71.7% at 7.5 years, and 61.4% at 9 years. Dotted lines indicate the range of 95% confidence interval. B. Comparison of pneumothorax recurrence among hemithoraces where 10 or more ORC sheets were applied for TPC (n = 39) and those where fewer than 10 ORC sheets were used (n = 15) (P = 0.0018). The probability of no recurrence of pneumothorax after TPC was analyzed by Cox regression analysis adjusted for patient’s age and surgical skill by year (era) when TPC was implemented (3 categorized era: 2003–2007, 2008–2011, and 2012–2014).
Fig 5.
Comparison of the frequency of pneumothorax episodes before and after TPC.
A. The number of pneumothorax episodes was divided by the observation period (the months from the first pneumothorax episode to TPC or those after TPC). The frequency of pneumothorax (episodes/month) was significantly reduced after TPC (P<0.0001). B. A Poisson regression model was used to compare the number of pneumothorax episodes before TPC (open circle) and after TPC (closed circle) with log [observation period (years)] as offset and subjects (intercept) as random effect (P<0.0001). The estimated regression equation of the number of pneumothorax before TPC is e1.025 + 0.111×years before TPC (dotted line) and e-2.606 + 0.337×years after TPC (solid line).
Table 2.
The number of pneumothorax episodes per hemithorax before and after TPC.
Table 3.
Results of lung function tests after TPC.