Postsurgical change in the tracheal bifurcation angle after upper lobectomy: radiographic evaluation

Detection of tracheal branching with computerized tomography: The relationship between the angles and age-gender

BACKGROUND

The data obtained on the anatomical knowledge of the tracheobronchial system can be used for diagnosis, treatment and interventional interventions in areas such as anesthesia, thoracic surgery, pulmonary physiology.

AIM

To determine the tracheobronchial branching angles in pediatric and adult populations by using the multislice computed tomography (CT) and minimum intensity projection (MinIP) technique, which is a non-invasive method.

METHODS

Our study was carried out retrospectively. Patients who underwent contrast and non-contrast CT examination, whose anatomically and pathophysiologically good tracheobronchial system and lung parenchyma images were obtained, were included in the study. Measurements were made in the coronal plane of the lung parenchyma. In the coronal plane, right main bronchus-left main bronchus angle, right upper lobe bronchus-intermedius bronchus angle, right middle lobe bronchus-right lower lobe bronchus angle, left upper lobe bronchus-left lower lobe bronchus angle were measured.

RESULTS

The study population consisted of 1511 patients, 753 pediatric (mean age: 13.4 ± 4.3; range: 1-18 years) and 758 adults (mean age: 54.3 ± 17.3; range: 19-94 years). In our study, tracheal bifurcation angle was found to be 73.3° ± 13.7° (59.6°-87°) in the whole population. In the pediatric group, the right-left main coronal level was found to be higher in boys compared to girls (74.6° ± 12.9° vs 71.2° ± 13.9°, P = 0.001). In the adult group, the right-left main coronal level was found to be lower in males compared to females (71.9° ± 12.9° vs 75.8° ± 14.7°, P < 0.001).

CONCLUSIONS

Our study, with the number of 1511 patients, is the first study in the literature with the largest number of patient populations including pediatric and adult demographic data, measuring the angle values of the tracheobronchial system using multislice CT and MinIP technique. Study data will not only be a guide during invasive procedures, but it can also guide studies to be done with imaging methods.

Functional analysis of the airways after pulmonary lobectomy through computational fluid dynamics

Pulmonary lobectomy, which consists of the partial or complete resection of a lung lobe, is the gold standard intervention for lung cancer removal. The removal of functional tissue during the surgery and the re-adaptation of the remaining thoracic structures decrease the patient's post-operative pulmonary function. Residual functionality is evaluated through pulmonary function tests, which account for the number of resected segments without considering local structural alterations and provide an average at-the-mouth estimation. Computational Fluid Dynamics (CFD) has been demonstrated to provide patient-specific, quantitative, and local information about airways airflow dynamics. A CFD investigation was performed on image-based airway trees reconstructed before and after the surgery for twelve patients who underwent lobectomy at different lobes. The geometrical alterations and the variations in fluid dynamics parameters and in lobar ventilation between the pre and post-operative conditions were evaluated. The post-operative function was estimated and compared with current clinical algorithms and with actual clinical data. The post-operative configuration revealed a high intersubject variability: regardless of the lobectomy site, an increment of global velocity, wall pressure, and wall shear stress was observed. Local flow disturbances also emerged at, and downstream of, the resection site. The analysis of lobar ventilation showed severe variations in the volume flow rate distribution, highlighting the compensatory effects in the contralateral lung with an increment of inflow. The estimation of post-operative function through CFD was comparable with the current clinical algorithm and the actual spirometric measurements. The results confirmed that CFD could provide additional information to support the current clinical approaches both in the operability assessment and in the prescription of personalized respiratory rehabilitation.

Computational fluid dynamics of the airways after left-upper pulmonary lobectomy: A case study

Pulmonary lobectomy is the gold standard intervention for lung cancer removal and consists of the complete resection of the affected lung lobe, which, coupled with the re-adaptation of the remaining thoracic structures, decreases the postoperative pulmonary function of the patient. Current clinical practice, based on spirometry and cardiopulmonary exercise tests, does not consider local changes, providing an average at-the-mouth estimation of residual functionality. Computational Fluid Dynamics (CFD) has proved a valuable solution to obtain quantitative and local information about airways airflow dynamics. A CFD investigation was performed on the airway tree of a left-upper pulmonary lobectomy patient, to quantify the effects of the postoperative alterations. The patient-specific bronchial models were reconstructed from pre- and postoperative CT scans. A parametric laryngeal model was merged to the geometries to account for physiological-like inlet conditions. Numerical simulations were performed in Fluent. The postoperative configuration revealed fluid dynamic variations in terms of global velocity (+23%), wall pressure (+48%), and wall shear stress (+39%). Local flow disturbances emerged at the resection site: a high-velocity peak of 4.92 m/s was found at the left-lower lobe entrance, with a local increase of pressure at the suture zone (18 Pa). The magnitude of pressure and secondary flows increased in the trachea and flow dynamics variations were observed also in the contralateral lung, causing altered lobar ventilation. The results confirmed that CFD is a patient-specific approach for a quantitative evaluation of fluid dynamics parameters and local ventilation providing additional information with respect to current clinical approaches.

How to Review Postlobectomy Posteroanterior Chest Radiographs

Lung cancer is currently the most common malignancy in the world. A lobectomy is the standard of care for most patients with operable lung cancer and accounts for 60% to 70% of lung resection. The chest radiograph may appear normal after a lobectomy, particularly in uncomplicated cases. However, lobectomy usually involves leaving surgical staples at the bronchial stump and causes various changes in the intra- and extrapulmonary thoracic structures on plain radiographs. These changes may differ according to the resected lobe. We retrospectively evaluated the plain radiographic appearances of the postlobectomy chest, free of postoperative complications or recurrent/metastatic lung cancer. On the basis of our observations, the changes that occur in pulmonary and extrapulmonary anatomy can differ according to the resected lobe. Recognition of these changes will make it easier to identify which lobe has been removed surgically.

Tracheo-bronchial angles in the human fetus -- an anatomical, digital, and statistical study

Background

Both the advancement of visual techniques and intensive progress in perinatal medicine result in performing airway management in the fetus and neonate affected by life-threatening malformations. This study aimed to examine the 3 tracheo-bronchial angles, including the right and left bronchial angles, and the interbronchial angle, in the fetus at various gestational ages.

Material/Methods

Using methods of anatomical dissection, digital image analysis with an adequate program (NIS-Elements BR 3.0, Nikon), and statistics, values of the two bronchial angles and their sum as the interbronchial angle were semi-automatically measured in 73 human fetuses at the age of 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

No male-female differences between the parameters studied were found. The 3 fetal tracheo-bronchial angles were found to be independent of age. The right bronchial angle ranged from 11.4° to 41.8°, and averaged 26.9±7.0° for the whole analyzed sample. The values of left bronchial angle varied from 24.8° to 64.8°, with the overall mean of 46.2±8.0°. As a consequence, the interbronchial angle totalled 36.2–96.6°, and averaged 73.1±12.7°.

Conclusions

The tracheo-bronchial angles change independently of sex and fetal age. The left bronchial angle is wider than the right one. Values of the 3 tracheo-bronchial angles are unpredictable since their regression curves of best fit with relation to fetal age cannot be modelled. Both of the 2 bronchial angles and the interbronchial angle are of great relevance in the location of inhaled foreign bodies, and in the diagnosis cardiac diseases and mediastinal abnormalities.

Postlobectomy Chest Radiographic Changes: A Quantitative Analysis

Purpose

To provide a quantative analysis of postlobectomy chest radiographic changes and to evaluate whether the scarring from prior sternotomy affects the size of the hemithorax and the duration of air leak in patients with subsequent lobectomy.

Methods

In this retrospective case-controlled series, 10 consecutive patients who had a lobectomy after a prior sternotomy and 30 controls, 3 for each case, matched for lobectomy site were identified. Pre- and postoperative chest radiographs were quantitatively analysed for diaphragmic elevation, size of each hemithorax, mediastinal shift, and the presence of pneumothorax. Charts were reviewed for air-leak duration, surgical complications, and duration of hospitalization.

Results

There was no difference between patients with lobectomy and with and without prior sternotomy for the following variables expressed as mean (SD): hemidiaphragm elevation (1.5 ± 2.5 vs 0.5 ± 2.0 cm; P = .2), change of hemithorax size (mean transverse, 0.99 ± 0.05 vs 0.97 ± 0.07; P = .5; craniocaudal, 0.93 ± 0.08 vs 0.91 ± 0.08; P = .4) and mediastinal shift (upper, 1.2 ± 0.4 vs 1.3 ± 0.6; P = .5; lower, 1.2 ± 0.4 vs 1.2 ± 0.3; P = .8), the latter 2 were expressed as the ratio of post- to preoperative measurements. These postlobectomy radiographic findings varied, depending on the resected lobe, and became progressively more pronounced during the first 12 months after surgery. There was no difference in pneumothorax duration (mean [SD]) (9.5 ± 21 days vs 6.4 ± 7.5 days; P = .5), air leak duration (mean [SD]) (0.7 ± 0.8 days vs 1.3 ± 3.9 days; P = .6), complication rate (20% vs 30%; P = .5), or hospital stay (mean [SD]) (6.0 ± 1.7 days vs 6.9 ± 4.7 days; P = .6).

Conclusion

There are specific patterns of volume loss, mediastinal shift, and hemidiaphragm displacement that can be quantified on postlobectomy chest radiographs. Prior sternotomy did not affect postlobectomy radiographic changes or patient outcome.

CT assessment of tracheal carinal angle and its determinants

The aim of this study was to investigate the effect of body habitus, dimensions of the thoracic cavity, location of the carina within the mediastinum, and left atrial size on tracheal carinal angle using CT scan. The study population was drawn from the patients referred to CT scan for various indications. A total of 120 patients (65 men and 55 women; age range 17-85 years; mean age 56 years) who denied a history of prior thoracic surgery, and in whom CT scan excluded pulmonary fibrosis, moderate or severe emphysema, atelectasis, intrathoracic mass or adenopathy, pericardial or pleural effusion were prospectively enrolled. The interbronchial (IBA) and subcarinal (SCA) angles were measured on coronal reformatted images. The presternal and retrovertebral fat thickness, the anteroposterior and transverse diameters of the thorax, the distances from carina to the sternum and to the vertebral column were obtained at the level of carina. Three orthogonal dimensions and the volume of the left atrium were also assessed. The mean interbronchial angle was 77 degrees +/-13 degrees (range 49-109 degrees ) and subcarinal angle was 73 degrees +/-16 degrees (range 34-107 degrees ). IBA positively correlated with the female gender (r=0.25, p=0.007), body mass index (r=0.28, p=0.002), presternal (r=0.40, p=0.001) and retrovertebral fat thickness (r=0.31, p=0.001). The interbronchial angle was significantly greater in obese patients compared with lean patients (p=0.02). Both IBA and SCA were positively correlated with the left atrial volume (r=0.40, p=0.001 and r=0.34, p=0.001, respectively), and its transverse and craniocaudal dimensions. The carina-vertebral column distance inversely correlated with IBA (r=-0.42, p=0.001) and SCA (r=-0.41, p=0.001). The size of the thoracic cavity did not show significant relation to tracheal bifurcation angle. Tracheal bifurcation angle ranges widely in normal subjects, and absolute measurements of the carinal angle is of little diagnostic value. In addition to left atrial enlargement, female gender, obesity and close situs of carina relative to vertebral column are associated with greater tracheal bifurcation angle.