Risk factors for surgical complications after anatomic lung resections in the era of VATS and ERAS

Background The aim of this study was to identify risk factors for surgical complications after anatomic lung resections in the era of video-assisted thoracic surgery (VATS) and enhanced recovery after surgery (ERAS). Methods A retrospective analysis of all consecutive adult patients who underwent elective anatomic lung resections between January and December 2020 at our institution was performed. Results Eighty patients (40 VATS, 40 thoracotomy) were included. The 30-day mortality rate was 1.3%. The overall rate of major postoperative complications was 18.8%. Most major complications occurred in patients who underwent open surgery (complication rate 32.5%, share of total complications 86.7%). Major morbidity after VATS resection was rare (complication rate 2.5%, share of total complications 13.3%). In univariable analysis, thoracotomy (p = 0.003), impaired preoperative lung function (p = 0.003), complex surgery (p = 0.004) and sleeve resection (p = 0.037) were associated with adverse outcomes. In multivariable analysis, thoracotomy (p = 0.044) and impaired preoperative lung function (p = 0.028) were the only independent risk factors for major postoperative morbidity. Conclusion Thoracotomy was associated with a 10-fold increased risk for postoperative complications compared with minimally invasive surgery and was an independent risk factor for surgical complications. In the era of VATS and ERAS, the fact that thoracotomy is performed may be a reliable parameter to identify patients at risk for postoperative complications

Uniportal robotic assisted surgery for anatomical lung resection : first German experience

Background: Uniportal robotic‐assisted thoracic surgery (uRATS) has emerged as a promising technique with potential advantages over multiportal approaches. This study aims to evaluate our initial outcomes of uRATS. Material and Methods: Five patients underwent anatomic lung resections with systematic nodal dissection through a uniportal robotic approach by one surgeon. The results were compared to the results of the first five uniportal video‐assisted thoracic surgery (uVATS) anatomical resections performed by the same surgeon. Results: No adverse events occurred during the uRATS‐procedures. Comparable surgical outcomes were observed between uRATS and uVATS, including hospital stays, complication rates, and blood loss. The average procedural time was slightly but non‐significantly longer in the uRATS‐group. Average pain‐scores were lower in the uRATS group. One patient in each group experienced major postoperative complications, with one case of in‐hospital mortality in the uRATS‐group. Conclusion: The outcomes of uRATS/uVATS were comparable, highlighting the potential and the feasibility of this technique. Prospective studies comparing the learning curves, complication rate and hospital‐stay are required in order to justify the superiority of robotics over uVATS

Autologous blood pleurodesis for the treatment of postoperative air leaks : a systematic review and meta-analysis

Background Postoperative air leaks are a common complication after lung surgery. They are associated with prolonged hospital stay, increased postoperative pain and treatment costs. The treatment of prolonged air leaks remains controversial. Several treatments have been proposed including different types of sealants, chemical pleurodesis, or early surgical intervention. The aim of this review was to analyze the impact of autologous blood pleurodesis in a systematic way. Methods A systematic review of the literature was conducted until July 2020. Studies with more than five adult patients undergoing lung resections were included. Studies in patients receiving blood pleurodesis for pneumothorax were excluded. The search strategy included proper combinations of the MeSH terms “air leak”, “blood transfusion” and “lung surgery”. Results Ten studies with a total of 198 patients were included in the analysis. The pooled success rate for sealing the air leak within 48 h of the blood pleurodesis was 83.7% (95% CI: 75.7; 90.3). The pooled incidence of the post-interventional empyema was 1.5%, with a pooled incidence of post-interventional fever of 8.6%. Conclusions Current evidence supports the idea that autologous blood pleurodesis leads to a faster healing of postoperative air leaks than conservative treatment. The complication rate is very low. Formal recommendations on how to perform the procedure are not possible with the current evidence. A randomized controlled trial in the modern era is necessary to confirm the benefits

Microtubule Dynamics Regulate Cyclic Stretch-Induced Cell Alignment in Human Airway Smooth Muscle Cells

Microtubules are structural components of the cytoskeleton that determine cell shape, polarity, and motility in cooperation with the actin filaments. In order to determine the role of microtubules in cell alignment, human airway smooth muscle cells were exposed to cyclic uniaxial stretch. Human airway smooth muscle cells, cultured on type I collagen-coated elastic silicone membranes, were stretched uniaxially (20% in strain, 30 cycles/min) for 2 h. The population of airway smooth muscle cells which were originally oriented randomly aligned near perpendicular to the stretch axis in a time-dependent manner. However, when the cells treated with microtubule disruptors, nocodazole and colchicine, were subjected to the same cyclic uniaxial stretch, the cells failed to align. Lack of alignment was also observed for airway smooth muscle cells treated with a microtubule stabilizer, paclitaxel. To understand the intracellular mechanisms involved, we developed a computational model in which microtubule polymerization and attachment to focal adhesions were regulated by the preexisting tensile stress, pre-stress, on actin stress fibers. We demonstrate that microtubules play a central role in cell re-orientation when cells experience cyclic uniaxial stretching. Our findings further suggest that cell alignment and cytoskeletal reorganization in response to cyclic stretch results from the ability of the microtubule-stress fiber assembly to maintain a homeostatic strain on the stress fiber at focal adhesions. The mechanism of stretch-induced alignment we uncovered is likely involved in various airway functions as well as in the pathophysiology of airway remodeling in asthma

Complexity of the Tensegrity Structure for Dynamic Energy and Force Distribution of Cytoskeleton during Cell Spreading

Cytoskeleton plays important roles in intracellular force equilibrium and extracellular force transmission from/to attaching substrate through focal adhesions (FAs). Numerical simulations of intracellular force distribution to describe dynamic cell behaviors are still limited. The tensegrity structure comprises tension-supporting cables and compression-supporting struts that represent the actin filament and microtubule respectively, and has many features consistent with living cells. To simulate the dynamics of intracellular force distribution and total stored energy during cell spreading, the present study employed different complexities of the tensegrity structures by using octahedron tensegrity (OT) and cuboctahedron tensegrity (COT). The spreading was simulated by assigning specific connection nodes for radial displacement and attachment to substrate to form FAs. The traction force on each FA was estimated by summarizing the force carried in sounding cytoskeletal elements. The OT structure consisted of 24 cables and 6 struts and had limitations soon after the beginning of spreading by declining energy stored in struts indicating the abolishment of compression in microtubules. The COT structure, double the amount of cables and struts than the OT structure, provided sufficient spreading area and expressed similar features with documented cell behaviors. The traction force pointed inward on peripheral FAs in the spread out COT structure. The complex structure in COT provided further investigation of various FA number during different spreading stages. Before the middle phase of spreading (half of maximum spreading area), cell attachment with 8 FAs obtained minimized cytoskeletal energy. The maximum number of 12 FAs in the COT structure was required to achieve further spreading. The stored energy in actin filaments increased as cells spread out, while the energy stored in microtubules increased at initial spreading, peaked in middle phase, and then declined as cells reached maximum spreading. The dynamic flows of energy in struts imply that microtubules contribute to structure stabilization

Autologous blood pleurodesis for the treatment of postoperative air leaks. A systematic review and meta-analysis

Abstract Background Postoperative air leaks are a common complication after lung surgery. They are associated with prolonged hospital stay, increased postoperative pain and treatment costs. The treatment of prolonged air leaks remains controversial. Several treatments have been proposed including different types of sealants, chemical pleurodesis, or early surgical intervention. The aim of this review was to analyze the impact of autologous blood pleurodesis in a systematic way. Methods A systematic review of the literature was conducted until July 2020. Studies with more than five adult patients undergoing lung resections were included. Studies in patients receiving blood pleurodesis for pneumothorax were excluded. The search strategy included proper combinations of the MeSH terms “air leak”, “blood transfusion” and “lung surgery”. Results Ten studies with a total of 198 patients were included in the analysis. The pooled success rate for sealing the air leak within 48 h of the blood pleurodesis was 83.7% (95% CI: 75.7; 90.3). The pooled incidence of the post‐interventional empyema was 1.5%, with a pooled incidence of post‐interventional fever of 8.6%. Conclusions Current evidence supports the idea that autologous blood pleurodesis leads to a faster healing of postoperative air leaks than conservative treatment. The complication rate is very low. Formal recommendations on how to perform the procedure are not possible with the current evidence. A randomized controlled trial in the modern era is necessary to confirm the benefits

Motion and twisting of magnetic particles ingested by alveolar macrophages in the human lung: effect of smoking and disease

BACKGROUND: Magnetic microparticles being ingested by alveolar macrophages can be used as a monitor for intracellular phagosome motions and cytoskeletal mechanical properties. These studies can be performed in the human lung after voluntary inhalation. The influence of cigarette smoking and lung diseases on cytoskeleton dependent functions was studied. METHODS: Spherical 1.3 μm diameter ferrimagnetic iron oxide particles were inhaled by 17 healthy volunteers (40 – 65 years), 15 patients with sarcoidosis (SAR), 12 patients with idiopathic pulmonary fibrosis (IPF), and 18 patients with chronic obstructive bronchitis (COB). The retained particles were magnetized and aligned in an external 100 mT magnetic field. All magnetized particles induce a weak magnetic field of the lung, which was detected by a sensitive SQUID (superconducting quantum interference device) sensor. Cytoskeletal reorganizations within macrophages and intracellular transport cause stochastic magnetic dipole rotations, which are reflected in a decay of the magnetic lung field, called relaxation. Directed phagosome motion was induced in a weak magnetic twisting field. The resistance of the cytoplasm to particle twisting was characterized by the viscosity and the stiffness (ratio between stress to strain) of the cytoskeleton. RESULTS: One week after particle inhalation and later macrophage motility (relaxation) and cytoskeletal stiffness was not influenced by cigarette smoking, neither in healthy subjects, nor in the patients. Patients with IPF showed in tendency a faster relaxation (p = 0.06). Particle twisting revealed a non-Newtonian viscosity with a pure viscous and a viscoelastic compartment. The viscous shear was dominant, and only 27% of the shear recoiled and reflected viscoelastic properties. In patients with IPF, the stiffness was reduced by 60% (p < 0.02). An analysis of the shear rate and stress dependence of particle twisting allows correlating the rheological compartments to cytoskeletal subunits, in which microtubules mediate the pure viscous (non-recoverable) shear and microfilaments mediate the viscoelastic (recoverable) behavior. The missing correlation between relaxation and particle twisting shows that both stochastic and directed phagosome motion reflect different cytoskeletal mechanisms. CONCLUSION: Faster relaxation and a soft cytoskeleton in patients with IPF indicate alterations in cytoskeleton dependent functions of alveolar macrophages, which may cause dysfunction's in the alveolar defense, like a slower migration, a retarded phagocytosis, a disturbed phagosome lysosome fusion and an impaired clearance

On the behaviour of lung tissue under tension and compression

Lung injuries are common among those who suffer an impact or trauma. The relative severity of injuries up to physical tearing of tissue have been documented in clinical studies. However, the specific details of energy required to cause visible damage to the lung parenchyma are lacking. Furthermore, the limitations of lung tissue under simple mechanical loading are also not well documented. This study aimed to collect mechanical test data from freshly excised lung, obtained from both Sprague-Dawley rats and New Zealand White rabbits. Compression and tension tests were conducted at three different strain rates: 0.25, 2.5 and 25 min−1. This study aimed to characterise the quasi-static behaviour of the bulk tissue prior to extending to higher rates. A nonlinear viscoelastic analytical model was applied to the data to describe their behaviour. Results exhibited asymmetry in terms of differences between tension and compression. The rabbit tissue also appeared to exhibit stronger viscous behaviour than the rat tissue. As a narrow strain rate band is explored here, no conclusions are being drawn currently regarding the rate sensitivity of rat tissue. However, this study does highlight both the clear differences between the two tissue types and the important role that composition and microstructure can play in mechanical response

PPARγ deficiency results in reduced lung elastic recoil and abnormalities in airspace distribution

Background: Peroxisome proliferator-activated receptor (PPAR)-γ is a nuclear hormone receptor that regulates gene expression, cell proliferation and differentiation. We previously described airway epithelial cell PPARγ deficient mice that develop airspace enlargement with decreased tissue resistance and increased lung volumes. We sought to understand the impact of airspace enlargement in conditionally targeted mice upon the physio-mechanical properties of the lung. Methods: We measured elastic recoil and its determinants, including tissue structure and surface forces. We measured alveolar number using radial alveolar counts, and airspace sizes and their distribution using computer-assisted morphometry. Results: Air vs. saline-filled pressure volume profiles demonstrated loss of lung elastic recoil in targeted mice that was contributed by both tissue components and surface tension, but was proportional to lung volume. There were no significant differences in surfactant quantity/function nor in elastin and collagen content between targeted animals and littermate controls. Importantly, radial alveolar counts were significantly reduced in the targeted animals and at 8 weeks of age there were 18% fewer alveoli with 32% more alveolar ducts. Additionally, the alveolar ducts were 19% larger in the targeted animals. Conclusions: Our data suggest that the functional abnormalities, including loss of recoil are secondary to altered force transmission due to differences in the structure of alveolar ducts, rather than changes in surfactant function or elastin or collagen content. These data further define the nature of abnormal lung maturation in the absence of airway epithelial cell PPARγ and identify a putative genetic determinant of dysanapsis, which may serve as a precursor to chronic lung disease