Is the burden of metastatic lymph node stations a prognostic factor in patients with resected lung cancer?

OBJECTIVES: The burden of metastatic lymph node (LN) stations might reflect a distinct N subcategory with a more aggressive biology and behaviour than the traditional N classification. METHODS: Between 2008 and 2018, we analyzed 1236 patients with pN1/2 lung cancer. Survival was analyzed based on LN station metastasis, determining the optimal threshold for the number of metastatic LN stations that provided additional prognostic information. N prognostic subgrouping was performed using thresholds for the number of metastatic LN stations with the maximum chi-square log-rank value, and validated at each pT-stage. RESULTS: Survival showed stepwise statistical deterioration with an increase in the number of metastatic LN stations., Threshold values for the number of metastatic LN stations were determined and N prognostic subgroupswas created as sN-alpha; one LN station metastases (n = 632), sN-beta; two-three LN stations metastases (n = 505), and sN-gamma; ≥4 LN stations metastasis (n = 99). The 5-year survival rate was 57.7% for sN-alpha, 39.2% for sN-beta, and 12.7% for sN-gamma (chi-square log rank = 97.906, p < 0.001). A clear tendency of survival deterioration was observed from sN-alpha to sN-gamma in the same pT stage, except for pT4 stage. Multivariate analysis showed that age (p < 0.001), sex (p = 0.002), tumour histology (p < 0.001), IASLC-proposed N subclassification (p < 0.001), and sN prognostic subgroups (p < 0.001) were independent risk factors for survival. CONCLUSION: The burden of metastatic LN stations is an independent prognostic factor for survival in patients with lung cancer. It could provide additional prognostic information to the N classification.

Could the probability of surgical indication be determined after first episode of primary spontaneous pneumothorax?

OBJECTIVES: To develop a risk score model for primary spontaneous pneumothorax surgery (prolonged air leak or ipsilateral recurrence). The model was internally validated for risk estimation. METHODS: We analyzed 453 patients with primary spontaneous pneumothorax between 2014 and 2018. Patients were randomly assigned a 2:1 ratio to the development dataset (n = 302, study cohort) or the internal validation dataset (n = 151, validation cohort). The final outcomes of patients with primary spontaneous pneumothorax, the presence or absence of surgical indications, were tracked. Multivariable logistic regression models were prepared to estimate the probability of surgical indication and a scoring model was created. It was internally validated using the validation cohort. Calibration was ascertained using the Hosmer-Lemeshow method and Brier score. RESULTS: The surgery indication rate was 47.8% (n = 217) (prolonged air leak, n = 130; ipsilateral recurrence, n = 87). There were no demographic or radiological differences between the validation and the study cohorts. Logistic regression analysis showed that the presence of bullae or blebs (p < 0.001, odds ratio = 3.340, 95%CI = 1.753-6.363) and pneumothorax volume (p < 0.001, odds ratio = 1.033, 95%CI = 1.019-1.048) were independent risk factors for surgical indication. The scoring model significantly predicted surgical indications (area under the curve, AUC = 0.768, 95%CI = 0.714-0.821, p < 0.001). Our model showed acceptable discrimination with an AUC > 0.75 in the validation set (AUC = 0.777, 95%CI = 0.702-0.852, p < 0.001) and had an adequate calibration (Hosmer-Lemeshow test p = 0.249, Brier score = 0.25). CONCLUSION: The internally validated primary spontaneous pneumothorax scoring model was a good predictor of the need for surgery in patients with primary spontaneous pneumothorax. Prospective external validation studies with larger patient cohorts are required.

Which pneumothorax volume/size measurement method can best predict surgical indication in primary spontaneous pneumothorax patients? A comparison of six different methods.

OBJECTIVES: We determined whether patients requiring surgery could be identified using pneumothorax volume/size in the first episode of primary spontaneous pneumothorax (PSP) and confirmed which of six different measurement methods of pneumothorax volume/size best predicted surgical indication (prolonged air leak, PAL, or ipsilateral recurrence). METHODS: Between 2013 and 2017, 282 patients with PSP were analysed. The volume of the pneumothorax (%) was calculated using volumetric methods (Collins, Rhea, Kircher, Light), while its size (large or small) was determined using the British Thoracic Society (BTS) and American College of Chest Physicians (ACCP) guidelines for the first PSP episode. The optimal cut-off points of pneumothorax volume in patients requiring surgery were based on the most sensitive and specific scores, calculated using receiver operating characteristic analysis. RESULTS: Surgery was indicated in 162 patients (57.4%) because of PAL (n = 92) or ipsilateral recurrence (n = 70). Kircher's method had a better area under the curve (AUC) value than the others (AUC = 0.731, 95% confidence interval [CI] 0.676-0.782). Comparing the calculated cut-off points for each volumetric method and the known thresholds from the BTS/ACCP, the best predictor for surgical indications (for both PAL and ipsilateral recurrence) was Kircher's method (odds ratio = 5.636, 95% CI 3.338-9.516, p < 0.001). The four volumetric methods were significantly correlated with pneumothorax volume (rho ≥ 0.8, p < 0.001, for all comparisons). CONCLUSIONS: Pneumothorax volume/size calculated in the first PSP episode may help predict surgical candidates, with Kircher's method being the best predictor. There was a correlation between all the volumetric methods of the pneumothorax volume.

Incidence and risk factors for pneumomediastinum in COVID-19 patients in the intensive care unit.

OBJECTIVES: The incidence of pneumomediastinum (PNMD), its causes of development and its effect on prognosis in the coronavirus disease 2019 (COVID-19) are not clear. METHODS: Between March 2020 and December 2020, 427 patients with real-time reverse transcriptase-polymerase chain reaction-confirmed COVID-19 admitted to the intensive care unit were analysed retrospectively. Using receiver operating characteristic analysis, the area under the curve (AUC) for initial invasive mechanical ventilation (MV) variables such as initial peak inspiratory pressure (PIP), PaO2/FiO2 (P/F ratio), tidal volume, compliance and positive end-expiratory pressure was evaluated regarding PNMD development. RESULTS: The incidence of PNMD was 5.6% (n = 24). PNMD development rate was 2.7% in non-invasive MV and 6.2% in MV [odds ratio (OR) 2.352, 95% confidence interval (CI) 0.541-10.232; P = 0.400]. In the multivariate analysis, the independent risk factors affecting the development of PNMD were PIP (OR 1.238, 95% CI 1.091-1.378; P < 0.001) and P/F ratio (OR 0.982, 95% CI 0.971-0.994; P = 0.004). P/F ratio (AUC 0.815, 95% CI 0.771-0.854), PIP (AUC 0.780, 95% CI 0.734-0.822), compliance (AUC 0.735, 95% CI 0.677-0.774) and positive end-expiratory pressure (AUC 0.718, 95% CI 0.668-0.764) were the best predictors for PNMD development. Regarding the multivariate analysis, independent risk factors affecting mortality were detected as age (OR 1.015, 95% CI 0.999-1.031; P = 0.04), comorbidity (OR 1.940, 95% CI 1.100-3.419; P = 0.02), mode of breathing (OR 48.345, 95% CI 14.666-159.360; P < 0.001), PNMD (OR 5.234, 95% CI 1.379-19.857; P = 0.01), positive end-expiratory pressure (OR 1.305, 95% CI 1.062-1.603; P = 0.01) and tidal volume (OR 0.995, 95% CI 0.992-0.998; P = 0.004). CONCLUSIONS: PNMD development was associated with the initial P/F ratio and PIP. Therefore, it was considered to be related to both the patient and barotrauma. PNMD is a poor prognostic factor for COVID-19.

Evaluation of functions after surgical treatment in patients with arterial thoracic outlet syndrome using QuickDASH.

BACKGROUND: The aim of this study was to examine the validity and reliability of the Quick Disability of the Arm, Shoulder and Hand questionnaire in patients with arterial thoracic outlet syndrome. METHODS: A total of 106 patients (15 males, 91 females; mean age: 30.7±10.2 years; range, 13 to 60 years) with arterial thoracic outlet syndrome were included in this prospective study between January 2015 and December 2018. The questionnaire was administered to all patients before and six months after surgery. The patients were operated using a transaxillary or supraclavicular approach under general anesthesia. RESULTS: The Cronbach"s alpha value of the questionnaire was found to be 0.85 and the scale consisted of two factors. The change in both the functional status subscale scores (p<0.001) and the physical pain subscale scores (p<0.001) were statistically significantly different before and after surgery. At the end of six months, 53% of the patients with at least one mild difficulty continued to have complaints related to hand, arm and shoulder. CONCLUSION: Based on our study results, this questionnaire is a valid and reliable tool for measuring and monitoring disease symptoms in patients with arterial thoracic outlet syndrome.

The Outcomes of Chest Wall Stabilization in Flail Chest Patients in the Intensive Care Unit.

Objectives: In this study, the effect of multi-trauma on treatment results in flail chest patients who underwent chest wall stabilization was investigated. Methods: The data of thirty-six flail chest cases between the ages of 18-79 who were consulted for thoracic surgery were retrospectively analyzed in the study. The presence of flail chest in the patients was confirmed by thoracic surgeons, and the multi-traumas were confirmed through the diagnoses made by specialist physicians reexamining clinical methods. Results: It was found that 27 (75%) of flail chest cases evaluated had multi-trauma, and 3 (8.3%) of the cases had mortality in the study. It was found that the duration of the intensive care unit stay and the number of days on invasive mechanical ventilation of the cases were positively correlated with the number of surgical areas exposed to trauma (p<0.05). According to the univariate binary logistic regression analysis, it was found that the total number of rib fractures (OR = 1.44, p=0.055), the number of fixed ribs (OR = 0.76, p=0.558), the number of plates placed for fixation (OR = 0.70, p=0.368), and the number of additional trauma areas outside the thorax (OR = 6.76, p=0.076) were not statistically significant in increasing the mortality risk. Conclusion: Considering that multi-trauma is an effective factor in the prolongation of the duration of treatment, the management of traumas with different specialties can positively affect the treatment results and reduce the risk of mortality.

Pneumothorax in patients with coronavirus disease 2019 pneumonia with invasive mechanical ventilation.

OBJECTIVES: Our goal was to evaluate the prevalence of and risk factors for pneumothorax in patients with invasive mechanical ventilation in the intensive care unit (ICU) diagnosed with coronavirus disease 2019 pneumonia. METHODS: The prevalence of pneumothorax was retrospectively reviewed in 107 patients diagnosed with coronavirus disease 2019 pneumonia and treated in an ICU in Turkey between 11 March 2020 and 30 April 2020. RESULTS: The patients were aged 19-92 years; 37 (34.6%) were women. Pneumothorax developed in 8 (7.5%) of the intubated patients. Four (50%) of the patients with pneumothorax and 68 (68.7%) of those without it died. In the univariable logistic regression analysis of the presence of comorbid diseases (P = 0.91), positive end-expiratory pressure (P = 0.18), compliance (P = 0.93), peak pressure (P = 0.41) and the Horowitz index (P = 0.13) did not show statistically significant effects in increasing the risk of pneumothorax. CONCLUSIONS: There was no significant increase or decrease in the risk of pneumothorax in patients treated with invasive mechanical ventilation after the diagnosis of coronavirus disease 2019-related pneumonia/acute respiratory distress syndrome. However, consideration of the risk of pneumothorax in these individuals may have the potential to improve the prognoses in such settings.

Thoracic trauma and mortality in geriatric Turkish population: 6-month follow-up study.

AIM: The aim of this study was to evaluate survival rates in elderly individuals who have undergone thoracic trauma and to investigate the risk of mortality for 6 months. METHOD: In this study, the mortality rate was evaluated in 400 thorax trauma cases referred to thoracic surgery, between 65 and 101 years of age. Six-month survival rates in discharged cases of thoracic trauma were examined by using Turkey's Health Ministry Death Notification System. RESULTS: It was found that thoracic traumas evaluated in the study were due to 314 (78.5%) falls and 51 (12.8%) exterior vehicle traffic accident. It was found that the presence of hemopneumothorax (OR 5.82; 95% CI 1.31-25.98; p = 0.021), and the presence of multiple trauma (OR 16.49; 95% CI 3.13-86.91; p = 0.001) had statistically significant effects on the mortality risk from the moment of the event to the emergency treatment period. In addition, it was found that age (OR 1.06; 95% CI 1.01-1.11; p = 0.011), male gender (OR 2.55; 95% CI 1.15-5.68; p = 0.022), and the presence of comorbidities (OR 3.07; 95% CI 1.29-7.31; p = 0.011) statistically significantly increased mortality during the six months after trauma. CONCLUSION: It should be kept in mind that the presence of multiple trauma and the presence of hemopneumothorax increase the risk of death in elderly thoracic trauma cases consulted for thoracic surgery.

Electronic phase separation in multilayer rhombohedral graphite.

Of the two stable forms of graphite, hexagonal and rhombohedral, the former is more common and has been studied extensively. The latter is less stable, which has so far precluded its detailed investigation, despite many theoretical predictions about the abundance of exotic interaction-induced physics1-6. Advances in van der Waals heterostructure technology7 have now allowed us to make high-quality rhombohedral graphite films up to 50 graphene layers thick and study their transport properties. Here we show that the bulk electronic states in such rhombohedral graphite are gapped8 and, at low temperatures, electron transport is dominated by surface states. Because of their proposed topological nature, the surface states are of sufficiently high quality to observe the quantum Hall effect, whereby rhombohedral graphite exhibits phase transitions between a gapless semimetallic phase and a gapped quantum spin Hall phase with giant Berry curvature. We find that an energy gap can also be opened in the surface states by breaking their inversion symmetry by applying a perpendicular electric field. Moreover, in rhombohedral graphite thinner than four nanometres, a gap is present even without an external electric field. This spontaneous gap opening shows pronounced hysteresis and other signatures characteristic of electronic phase separation, which we attribute to emergence of strongly correlated electronic surface states.

Stacking Order in Graphite Films Controlled by van der Waals Technology.

In graphite crystals, layers of graphene reside in three equivalent, but distinct, stacking positions typically referred to as A, B, and C projections. The order in which the layers are stacked defines the electronic structure of the crystal, providing an exciting degree of freedom which can be exploited for designing graphitic materials with unusual properties including predicted high-temperature superconductivity and ferromagnetism. However, the lack of control of the stacking sequence limits most research to the stable ABA form of graphite. Here, we demonstrate a strategy to control the stacking order using van der Waals technology. To this end, we first visualize the distribution of stacking domains in graphite films and then perform directional encapsulation of ABC-rich graphite crystallites with hexagonal boron nitride (hBN). We found that hBN encapsulation, which is introduced parallel to the graphite zigzag edges, preserves ABC stacking, while encapsulation along the armchair edges transforms the stacking to ABA. The technique presented here should facilitate new research on the important properties of ABC graphite.

Author Correction: Planar and van der Waals heterostructures for vertical tunnelling single electron transistors.

The original version of this Article contained an error in the spelling of the author Matthew Holwill, which was incorrectly given as Mathew Holwill. This has now been corrected in both the PDF and HTML versions of the Article.

Planar and van der Waals heterostructures for vertical tunnelling single electron transistors.

Despite a rich choice of two-dimensional materials, which exists these days, heterostructures, both vertical (van der Waals) and in-plane, offer an unprecedented control over the properties and functionalities of the resulted structures. Thus, planar heterostructures allow p-n junctions between different two-dimensional semiconductors and graphene nanoribbons with well-defined edges; and vertical heterostructures resulted in the observation of superconductivity in purely carbon-based systems and realisation of vertical tunnelling transistors. Here we demonstrate simultaneous use of in-plane and van der Waals heterostructures to build vertical single electron tunnelling transistors. We grow graphene quantum dots inside the matrix of hexagonal boron nitride, which allows a dramatic reduction of the number of localised states along the perimeter of the quantum dots. The use of hexagonal boron nitride tunnel barriers as contacts to the graphene quantum dots make our transistors reproducible and not dependent on the localised states, opening even larger flexibility when designing future devices.

Bedside talc pleurodesis for malignant pleural effusion: factors affecting success.

INTRODUCTION: To determine the factors affecting the success of bedside talc slurry (TS) used for symptomatic treatment of patients with malignant pleural effusion (MPE). METHODS: Data of 113 effusions in 103 MPE patients treated between 1999 and 2007 were retrospectively evaluated for the study. The study group involved 73 patients whose follow-up information was available out of 81 patients treated by TS. Causes of MPE were lung cancer in 22 patients (30.1%) and breast carcinoma in 21 patients (28.8%). RESULTS: The success rate of TS was significantly higher if the time period between radiological diagnosis of effusion and administration of TS was less than 30 days (P= .02), or spontaneous expansion was attained after chest tube drainage (CTD) (P= .01). Success rate was higher for patients with daily drainage of less than 200 ml before TS than patients with more than 200 ml of daily drainage (P= .01). Dose of talc, either 4 g or above (P= .34), primary cause of MPE (P= .53), time to termination of CTD (P= .57), amount of drainage when CTD was terminated (P= .23), and time period between CTD and administration of TS (P= .20) did not show a statistically significant effect on the success of TS. CONCLUSION: In the treatment of malignant pleural effusion, patients with daily drainage of less than 200 ml before TS developed less recurrence than patients with daily drainage of more than 200 ml. Longer time period between the diagnosis of MPE and onset of CTD increased recurrence.