Lobar Sliding Reduces Parenchymal Distortion More in the Right Lung Than the Left Lung

Interlobar sliding has long been suspected to help the lungs adapt to changes in thoracic cavity shape by reducing parenchymal distortion. Our previous controlled computational experiment tested the hypothesis that lung lobar sliding reduces parenchymal distortion during breathing, but only the left lung was studied. The goal of this study was to extend this analysis to the right lung which has three lobes and two fissures compared to the left lung's two lobes and single fissure. Finite elastic contact mechanics models of the right lung were used to perform paired subject-specific simulations of lung deformation with and without lobar sliding from end inhale to end exhale at both tidal breathing volumes (n = 8) and breath hold volumes near total lung capacity and functional residual capacity (n = 6). Consistent with the hypothesis, we found that parenchymal distortion, quantified with the spatial mean of the anisotropic deformation index (ADI) throughout each lung model, was lesser in the models with lobar sliding than their nonsliding counterparts (p = 0.008, 13% median difference for tidal breathing and p = 0.03, 19.6% median difference for breath holds). This effect was several times larger than was previously observed in the left lung (p = 0.008, 5.3% median difference for tidal breathing and p = 0.03, 3.2% median difference for breath holds), likely due to the greater number of sliding interfaces in the right lung than the left which better allow the right lung to adapt to the thoracic cavity.