Compensation of pulmonary function after upper lobectomy versus lower lobectomy

Clinical Factors Affecting Discrepancy Between Predicted and Long-term Actual Lung Function Following Surgery

PURPOSE

Lung cancer surgery outcomes depend heavily on preoperative pulmonary reserve, with forced expiratory volume in 1 second (FEV1) being a critical preoperative evaluation factor. Our study investigates the discrepancies between predicted and long-term actual postoperative lung function, focusing on clinical factors affecting these outcomes.

METHODS

This retrospective observational study encompassed lung cancer patients who underwent preoperative lung perfusion SPECT/CT between 2015 and 2021. We evaluated preoperative and postoperative pulmonary function tests, considering factors such as surgery type, resected volume, and patient history including tuberculosis. Predicted postoperative lung function was calculated using SPECT/CT imaging.

RESULTS

From 216 patients (men:women, 150:66; age, 67.9 ± 8.7 years), predicted postoperative FEV1% (ppoFEV1%) showed significant correlation with actual postoperative FEV1% (r = 0.667; P < 0.001). Paired t test revealed that ppoFEV1% was significantly lower compared with actual postoperative FEV1% (P < 0.001). The study identified video-assisted thoracic surgery (VATS) (odds ratio [OR], 3.90; 95% confidence interval [CI], 1.98-7.69; P < 0.001) and higher percentage of resected volume (OR per 1% increase, 1.05; 95% CI, 1.01-1.09; P = 0.014) as significant predictors of postsurgical lung function improvement. Conversely, for the decline in lung function postsurgery, significant predictors included lower percentage of resected lung volume (OR per 1% increase, 0.92; 95% CI, 0.86-0.98; P = 0.011), higher preoperative FEV1% (OR, 1.03; 95% CI, 1.01-1.07; P = 0.009), and the presence of tuberculosis (OR, 5.19; 95% CI, 1.48-18.15; P = 0.010). Additionally, in a subgroup of patients with borderline lung function, VATS was related with improvement.

CONCLUSIONS

Our findings demonstrate that in more than half of the patients, actual postsurgical lung function exceeded predicted values, particularly following VATS and with higher volume of lung resection. It also identifies lower resected lung volume, higher preoperative FEV1%, and tuberculosis as factors associated with a postsurgical decline in lung function. The study underscores the need for precise preoperative lung function assessment and tailored postoperative management, with particular attention to patients with relevant clinical factors. Future research should focus on validation of clinical factors and exploring tailored approaches to lung cancer surgery and recovery.

Longitudinal changes in the volume of residual lung lobes after lobectomy for lung cancer: a retrospective cohort study

It is unclear how the residual lobe volume changes over time after lobectomy. This study aims to clarify the temporal patterns of volume changes in each remaining lung lobe post-lobectomy. A retrospective review was conducted on patients who underwent lobectomy for lung cancer at Yueyang Central Hospital from January to December 2021. Lung CT images were reconstructed in three dimensions to calculate the volumes of each lung lobe preoperatively and at 1, 6, and 12 months postoperatively. A total of 182 patients were included. Postoperatively, the median total lung volume change rates relative to preoperative values were -20.1%, -9.3%, and -5.9% at 1, 6, and 12 months, respectively. Except for the right middle lobe in patients who underwent right upper lobectomy, the volumes of individual lung lobes exceeded preoperative values. The volume growth of the lung on the side of the resection was significantly more than that of the lung on the opposite side. For left lobectomy patients, the right lower lobe's volume change rate exceeded that of the right upper and middle lobes. Among right lobectomy patients, the left lower lobe and the relatively inferior lobe of right lung had higher volume change rates than the superior one. Right middle lobe change rate was more in patients with right lower lobectomy than right upper lobectomy. Six months postoperatively, FEV1% and right middle lobectomy were positively correlated with the overall volume change rate. One year postoperatively, only age was negatively correlated with the overall volume change rate. 75 patients had pulmonary function tests. Postoperative FEV1 change linearly correlated with 1-year lung volume change rate, but not with theoretical total lung volume change rate or segmental method calculated FEV1 change. Time-dependent compensatory volume changes occur in remaining lung lobe post-lobectomy, with stronger compensation observed in the relatively inferior lobe compared to the superior one(s). Preoperative lung function and age may affect compensation level.

Compensatory expansion of the right middle lobe: volumetric and functional analysis of the changes after right upper or lower lobectomy

The right middle lobe often poorly expands after right upper lobectomy. Postoperative pulmonary function may be inferior after right upper lobectomy than after right lower lobectomy due to poor expansion of the middle lobe. This study examined the difference in the postoperative right middle lobe expansion and pulmonary function between right upper and right lower lobectomy. Patients who underwent right upper or right lower lobectomy through video-assisted thoracic surgery (n = 82) were enrolled in this retrospective study. Pulmonary function tests and computed tomography were performed preoperatively and at 1 year postoperatively. Using three-dimensional computed tomography volumetry, the preoperative and postoperative lung volumes were measured, and the predicted postoperative forced expiratory volume in 1 s was calculated. Middle lobe volume ratio (i.e., ratio of the postoperative to the preoperative middle lobe volume) and the postoperative forced expiratory volume in 1 s ratio (i.e., ratio of the measured to the predicted postoperative forced expiratory volume in 1 s) were compared between right upper and right lower lobectomy. Compared with the patients who underwent right upper lobectomy (n = 50), those who underwent right lower lobectomy (n = 32) had significantly higher middle lobe volume ratio (1.15 ± 0.32 vs. 1.63 ± 0.52, p < 0.001) and postoperative forced expiratory volume in 1 s ratio (1.12 ± 0.12 vs. 1.19 ± 0.13, p = 0.010). The right middle lobe showed more expansion and better recovery of postoperative pulmonary function after right lower lobectomy than after right upper lobectomy.

Robust imaging approach for precise prediction of postoperative lung function in lung cancer patients prior to curative operation

BACKGROUND

To create a combined variable integrating both ventilation and perfusion as measured by preoperative dual-energy computed tomography (DECT), compare the results with predicted postoperative (PPO) lung function as estimated using conventional methods, and assess agreement with actual postoperative lung function.

METHODS

A total of 33 patients with lung cancer who underwent curative surgery after DECT and perfusion scan were selected. Ventilation and perfusion values were generated from DECT data. In the "combined variable method," these two variables and clinical variables were linearly regressed to estimate PPO lung function. Six PPO lung function parameters (segment counting, perfusion scan, volume analysis, ventilation map, perfusion map, and combined variable) were compared with actual postoperative lung function using an intraclass correlation coefficient (ICC).

RESULTS

The segment counting method produced the highest ICC for forced vital capacity (FVC) at 0.93 (p < 0.05), while the segment counting and perfusion map methods produced the highest ICC for forced expiratory volume in 1 second (FEV1 ; both 0.89, p < 0.05). The highest ICC value when using the combined variable method was for FEV1 /FVC (0.75, p < 0.05) and diffusing capacity of the lung for carbon monoxide (DLco; 0.80, p < 0.05) when using the perfusion map method. Overall, the perfusion map and ventilation map provided the best performance, followed by volume analysis, segment counting, perfusion scan, and the combined variable.

CONCLUSIONS

Use of DECT image processing to predict postoperative lung function produced better agreement with actual postoperative lung function than conventional methods. The combined variable method produced ICC values of 0.8 or greater for FVC and FEV1 .

Depicting and predicting changes of lung after lobectomy for cancer by using CT images

Lobectomy is an effective and well-established therapy for localized lung cancer. This study aimed to assess the lung and lobe change after lobectomy and predict the postoperative lung volume. The study included 135 lung cancer patients from two hospitals who underwent lobectomy (32, right upper lobectomy (RUL); 31, right middle lobectomy (RML); 24, right lower lobectomy (RLL); 26, left upper lobectomy (LUL); 22, left lower lobectomy (LLL)). We initially employ a convolutional neural network model (nnU-Net) for automatically segmenting pulmonary lobes. Subsequently, we assess the volume, effective lung volume (ELV), and attenuation distribution for each lobe as well as the entire lung, before and after lobectomy. Ultimately, we formulate a machine learning model, incorporating linear regression (LR) and multi-layer perceptron (MLP) methods, to predict the postoperative lung volume. Due to the physiological compensation, the decreased TLV is about 10.73%, 8.12%, 13.46%, 11.47%, and 12.03% for the RUL, RML, RLL, LUL, and LLL, respectively. The attenuation distribution in each lobe changed little for all types of lobectomy. LR and MLP models achieved a mean absolute percentage error of 9.8% and 14.2%, respectively. Radiological findings and a predictive model of postoperative lung volume might help plan the lobectomy and improve the prognosis.

The impact of dissection of station 9 on survival and the necessity of pulmonary ligament division during upper lobectomy for lung cancer

BACKGROUND

We conducted this study to investigate the need for dissection of station 9 lymph nodes during upper lobectomy for non-small-cell lung cancer (NSCLC) and to find out the operative results of inferior pulmonary ligament division.

METHODS

A total of 840 patients who underwent upper lobectomy for NSCLC between January 2007 and June 2020 were evaluated retrospectively. The patients were separated into two groups - those having undergone lymph node dissection of station 9 and inferior pulmonary ligament dissection (Group I) and those who did not (Group II). In these groups, the prognostic value of station 9 lymph nodes and postoperative effects (drainage time, prolonged air leak, dead space and length of hospital stay) of ligament division or preservation were analyzed.

RESULTS

The number of patients with station 9 lymph node metastasis was only one (0.1%) and that was multi-station pN2 disease. Station 9 lymph nodes were found in 675 (80.4%) patients, while 22 (2.6%) patients had no lymph nodes in the dissected material. In the other 143 (17%) patients, the inferior pulmonary ligament and station 9 were not dissected. While 5-year survival was 64.9% in 697 patients of Group I, it was 61.3% in 143 patients of Group II (p = 0.56). There was no statistically significant difference between the groups in postoperative effects of ligament division or preservation.

CONCLUSIONS

In upper lobectomies, status of station 9 does not have a significant impact on patients' survival and lymph node staging. Additionally, preservation or division of the inferior pulmonary ligament has no significant advantage or disadvantage.

Comparison between functional lung volume measurement and segment counting for predicting postoperative pulmonary function after pulmonary resection in lung cancer patients

BACKGROUND

Functional lung volume (FLV) obtained from computed tomography images was a breakthrough for lung imaging and functional assessment. We compared the accuracy of the FLV measurement method and the segment-counting (SC) method in predicting postoperative pulmonary function.

METHODS

A total of 113 patients who underwent two thoracoscopic surgeries were enrolled in our study. We predicted postoperative pulmonary function by the FLV measurement method and the SC method. Novel formulas based on the FLV measurement method were established using linear regression equations between the factors affecting pulmonary function and the measured values.

RESULTS

The predicted postoperative forced vital capacity (ppoFVC) and forced expiratory volume in 1 s (ppoFEV1) measured by the 2 methods showed high concordance between the actual postoperative forced vital capacity (postFVC) and the forced expiratory volume in 1 s (postFEV1) [r = 0.762, P < 0.001 (FLV method) and r = 0.759, P < 0.001 (SC method) for FVC; r = 0.790, P < 0.001 (FLV method) and r = 0.795, P < 0.001 (SC method) for FEV1]. Regression analysis showed that the measured preoperative pulmonary function parameters (FVC, FEV1) and the ratio of reduced FLV to preoperative FLV were significantly associated with the actual postoperative values and could predict these parameters (all P < 0.001). The feasibility of using these equations [postFVC = 0.8 × FVC - 0.784 × ΔFLV/FLV + 0.283 (R² = 0.677, RSD = 0.338), postFEV1 = 0.766 × FEV1 - 0.694 × ΔFLV/FLV + 0.22 (R² = 0.743, RSD = 0.265)] to predict the pulmonary function parameters after wedge resection was also verified.

CONCLUSIONS

The new FLV measurement method is valuable for predicting postoperative pulmonary function in patients undergoing lung resection surgery, with accuracy and consistency similar to those of the conventional SC method.

Rapid Recovery of Postoperative Pulmonary Function in Patients With Lung Cancer and Influencing Factors

Among malignant tumors, lung cancer has the highest morbidity and mortality worldwide. Surgery is the first-line treatment for early-stage lung cancers, and has gradually advanced from conventional open-chest surgery to video-assisted thoracic surgery (VATS). Additionally, increasingly smaller surgical incisions and less surgical trauma have resulted in reduced pulmonary function damage. Previous studies have found that the level of pulmonary function loss and recovery is significantly correlated with postoperative complications and the quality of life. Thus, an accurate assessment of the preoperative pulmonary function and effective rehabilitation of postoperative pulmonary function are highly important for patients undergoing lung surgery. In addition, pulmonary function assessment after pulmonary rehabilitation serves as an objective indicator of the postoperative pulmonary rehabilitation status and is crucial to facilitating pulmonary function recovery. Furthermore, a complete preoperative assessment and effective rehabilitation are especially critical in elderly patients with pulmonary tumors, poor basic physiological functions, comorbid lung diseases, and other underlying diseases. In this review, we summarize the clinical significance of pulmonary function assessment in patients undergoing lung cancer surgery, postoperative changes in pulmonary function, effective pulmonary function rehabilitation, and the influencing factors of pulmonary function rehabilitation.

The impact of segmentectomy versus lobectomy on pulmonary function in patients with non-small-cell lung cancer: a meta-analysis

Objective

Segmentectomy has been reported as an alternative to lobectomy for small-sized NSCLC without detriment to survival. The long-term benefits of segmentectomy over lobectomy on pulmonary function have not been firmly established. This meta-analysis aims to compare postoperative changes in pulmonary function in NSCLC patients undergoing segmentectomy or lobectomy.

Methods

Medline, Embase, Web of Science and Scopus were searched through March 2021. Statistical comparisons were made when appropriate.

Results

Fourteen studies (2412 participants) out of 324 citations were included in this study. All selected studies were high quality, as indicated by the Newcastle–Ottawa scale for assessing the risk of bias. Clinical outcomes were compared between segmentectomy and lobectomy. ΔFEV1 [10 studies, P < 0.01, WMD = 0.40 (0.29, 0.51)], ΔFVC [4 studies, P < 0.01, WMD = 0.16 (0.07, 0.24)], ΔFVC% [4 studies, P < 0.01, WMD = 4.05 (2.32, 5.79)], ΔFEV1/FVC [2 studies, P < 0.01, WMD = 1.99 (0.90, 3.08)], and ΔDLCO [3 studies, P < 0.01, WMD = 1.30 (0.69, 1.90)] were significantly lower in the segmentectomy group than in the lobectomy group. Subgroup analysis showed that in stage IA patients, the ΔFEV1% [3 studies, P < 0.01, WMD = 0.26 (0.07, 0.46)] was significantly lower in the segmentectomy group. The ΔDLCO% and ΔMVV% were incomparable.

Conclusion

Segmentectomy preserves more lung function than lobectomy. There were significantly smaller decreases in FEV1, FVC, FVC%, FEV1/FVC and DLCO in the segmentectomy group than in the lobectomy group.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01853-3.

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.

Accelerated right heart failure due to lung resection in the setting of chronic respiratory failure

A 68-year-old woman with a past medical history of chronic obstructive pulmonary disease and squamous cell carcinoma of the lung with recent right upper and middle lobectomy was admitted for dyspnea and volume overload. She was diagnosed with right-sided heart failure (RHF) through clinical, laboratory, and echocardiographic means. In the setting of chronic respiratory failure, the recent right lung lobectomy was deemed to be the inciting factor of the RHF. The mechanism by which RHF occurs in this situation is multifactorial, and it is essential to undergo pre-operative risk stratification and post-operative monitoring to avoid emergent events. <Learning objective: New-onset right heart failure can be a detrimental complication of lung resection surgery in patients with chronic respiratory failure. With proper pre-operative risk stratification and its corresponding post-operative monitoring, we can anticipate such occurrences and avoid emergent admissions, enabling better outcomes in a high-risk patient population.>.

The difference in postoperative pulmonary functional change between upper and lower thoracoscopic lobectomy

OBJECTIVES

Through 3-dimensional lung volumetric and morphological analyses, we aimed to evaluate the difference in postoperative functional changes between upper and lower thoracoscopic lobectomy.

METHODS

A total of 145 lung cancer patients who underwent thoracoscopic upper lobectomy (UL) were matched with 145 patients with lung cancer who underwent thoracoscopic lower lobectomy (LL) between April 2012 and December 2018, based on their sex, age, smoking history, operation side, and pulmonary function. Spirometry and computed tomography were performed before and 6 months after the operation. In addition, the postoperative pulmonary function, volume and morphological changes between the 2 groups were compared.

RESULTS

The rate of postoperative decreased and the ratio of actual to predicted postoperative forced expiratory volume in 1 s were significantly higher after LL than after UL (P < 0.001 for both). The tendency above was similar irrespective of the resected side. The postoperative actual volumes of the ipsilateral residual lobe and contralateral lung were larger than the preoperatively measured volumes in each side lobectomy. Moreover, the increased change was particularly remarkable in the middle lobe after right LL. The change in the D-value, representing the structural complexity of the lung, was better maintained in the left lung after LL than after UL (P = 0.042).

CONCLUSIONS

Pulmonary function after thoracoscopic LL was superior to that after UL because the upward displacement and the pulmonary reserves of the remaining lobe appeared more robust after LL.

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.

Measured versus predicted postoperative pulmonary function at repeated times up to 1 year after lobectomy

OBJECTIVES

Postoperative pulmonary function is difficult to predict accurately, because it changes from the time of the operation and is also affected by various factors. The objective of this study was to assess the accuracy of predicted postoperative forced expiratory volume in 1 s (FEV1) at different postoperative times after lobectomy.

METHODS

This retrospective study enrolled 104 patients who underwent lobectomy by video-assisted thoracic surgery. Pulmonary function tests were performed preoperatively and postoperatively at 3, 6 and 12 months. We investigated time-dependent changes in FEV1. In addition, the ratio of measured to predicted postoperative FEV1 calculated by the subsegmental method was evaluated to identify the factors associated with variations in postoperative FEV1.

RESULTS

Compared with the predicted postoperative FEV1, the measured postoperative FEV1 was 8% higher at 3 months, 11% higher at 6 months and 13% higher at 12 months. The measured postoperative FEV1 significantly increased from 3 to 6 months (P = 0.002) and from 6 to 12 months (P = 0.015) after lobectomy resected lobe, smoking history and body mass index were significant factors associated with the ratio of measured to predicted postoperative FEV1 at 12 months (P < 0.001, P = 0.036 and P = 0.025, respectively).

CONCLUSIONS

Postoperative FEV1 increased up to 12 months after lobectomy by video-assisted thoracic surgery. The predicted postoperative pulmonary function was underestimated after 3 months, particularly after lower lobectomy.

Endobronchial valve therapy for severe emphysema: an overview of valve-related complications and its management

INTRODUCTION

Bronchoscopic lung volume reduction treatment with one-way valves is an effective guideline treatment option for patients with severe emphysema. However, important challenges and adverse reactions may occur after treatment.

AREAS COVERED

This review summarizes the complications after endobronchial and intrabronchial valve treatment that have been described by the currently published randomized controlled trials and other relevant papers regarding the complications and its management. In case there was no relevant literature regarding these subjects, recommendations are based on expert opinion. Complications include pneumothorax, post-obstruction pneumonia and hemoptysis. Also, the treatment may not be effective due to the presence of collateral ventilation or misplaced valves. Furthermore, an initial beneficial effect may vanish due to granulation tissue formation, valve dysfunction or valve migration. Careful follow-up after treatment with valves is important. Evaluation with a CT-scan and/or bronchoscopy is needed if there is no improvement after treatment, loss of benefit, or occurrence of important adverse events during follow-up.

EXPERT OPINION

Treating severe emphysema patients with one-way valves requires continuous dedication and expertise, especially to achieve an optimal outcome and elegantly deal with the various complications after treatment.

The impact of surgical chest wall damage caused by classic thoracotomy on pulmonary function and morphology

OBJECTIVES

Postoperative changes in pulmonary function (PF) and morphology due to surgical chest wall damage by thoracotomy with rib resection are unclear. Therefore, we evaluated the effects of surgical damage on PF and morphology at > 6 months postoperatively by comparing different lung lobectomy approaches.

METHODS

A total of 140 patients who underwent lobectomy for lung diseases between January 2006 and March 2016 were analyzed. Patients who underwent PF tests and computed tomography (CT) scans preoperatively and postoperatively were divided into posterolateral thoracotomy with one rib resection (PT) group and video-assisted thoracoscopic surgery (VATS) group. A 1:1 propensity score-matched (PSM) analysis was used to balance clinically important confounders between the groups. Regarding morphology, lung volume was measured semi-automatically using image analysis software and reconstructed three-dimensional (3D) images.

RESULTS

After PSM, 31 patients in each group were compared. Perioperative reduction ratios in forced vital capacity (FVC) (- 23% vs. - 13%; P = 0.006) and forced expiratory volume in 1 s (FEV1) (- 19% vs. - 12%; P = 0.02) were significantly larger for the PT group. No significant differences in lung volume values based on 3D CT volumetry (PT vs. VATS; total lung volume: - 7.9% vs. - 7.2%, P = 0.82; non-resected ipsilateral lung volume: + 36% vs. + 40%, P = 0.69; contralateral lung volume: + 9.3% vs. + 9.4%, P = 0.98) were found in either group.

CONCLUSIONS

Among the patients underwent lobectomy, classic thoracotomy decreased PF by an additional FVC loss of 10% and FEV1 loss of 7% compared with VATS, without affecting residual lung volume.

Structural and functional alterations of the tracheobronchial tree after left upper pulmonary lobectomy for lung cancer

Background

Pulmonary lobectomy has been a well-established curative treatment method for localized lung cancer. After left upper pulmonary lobectomy, the upward displacement of remaining lower lobe causes the distortion or kink of bronchus, which is associated with intractable cough and breathless. However, the quantitative study on structural and functional alterations of the tracheobronchial tree after lobectomy has not been reported. We sought to investigate these alterations using CT imaging analysis and computational fluid dynamics (CFD) method.

Methods

Both preoperative and postoperative CT images of 18 patients who underwent left upper pulmonary lobectomy are collected. After the tracheobronchial tree models are extracted, the angles between trachea and bronchi, the surface area and volume of the tree, and the cross-sectional area of left lower lobar bronchus are investigated. CFD method is further used to describe the airflow characteristics by the wall pressure, airflow velocity, lobar flow rate, etc.

Results

It is found that the angle between the trachea and the right main bronchus increases after operation, but the angle with the left main bronchus decreases. No significant alteration is observed for the surface area or volume of the tree between pre-operation and post-operation. After left upper pulmonary lobectomy, the cross-sectional area of left lower lobar bronchus is reduced for most of the patients (15/18) by 15–75%, especially for 4 patients by more than 50%. The wall pressure, airflow velocity and pressure drop significantly increase after the operation. The flow rate to the right lung increases significantly by 2–30% (but there is no significant difference between each lobe), and the flow rate to the left lung drops accordingly. Many vortices are found in various places with severe distortions.

Conclusions

The favorable and unfavorable adaptive alterations of tracheobronchial tree will occur after left upper pulmonary lobectomy, and these alterations can be clarified through CT imaging and CFD analysis. The severe distortions at left lower lobar bronchus might exacerbate postoperative shortness of breath.

Postoperative Imaging After Lobectomy: Predicting the Displacement and Change in Orientation of Nonresected Lung Nodules

OBJECTIVES

The objective of this study was to determine the effect of a lobectomy to the location and orientation of nonresected lung nodule and its corresponding airway.

METHODS

We reviewed preoperative and postoperative computed tomography of patients who underwent lobectomies and have a separate nonresected nodule in the ipsilateral lung. Displacement of the nonresected nodule and angulation of its corresponding segmental bronchus were measured.

RESULTS

Fifty nodules from 40 patients (30 females, 10 male; mean ± SD age, 67 ± 7 years) were assessed. Nodules are displaced clockwise after right upper, right middle, and left lower lobectomies and counterclockwise after right lower and left upper lobectomies. Displacement of the remaining nodules was greater in the craniocaudal plane, followed by anteroposterior and transverses planes (mean, 3.7, 2.5, and 1.9 cm, respectively).

CONCLUSIONS

Remaining ipsilateral nodules and their associated segmental airways are displaced in a predictable fashion after lobectomy. This may help in the assessment of follow-up imaging.

Lung function in the late postoperative phase and influencing factors in patients undergoing pulmonary lobectomy

BACKGROUND

Lung function in the late postoperative phase after pulmonary lobectomy is insufficiently characterized. This study aimed to appraise lung function in the late postoperative phase according to vital capacity (VC) and forced expiratory volume in 1 second (FEV1) in patients who underwent pulmonary lobectomy.

METHODS

Pre- and postoperative VC and FEV1 were reviewed in 112 patients who underwent pulmonary lobectomy. Postoperative lung volume was assessed >1 year after surgery. Postoperative decreases in VC and FEV1 were compared with preoperative predicted values among patients who underwent resection of specific lobe. Determinants effecting a decrease in lung function were also investigated.

RESULTS

A mean postoperative decreased VC of 10.5%±1.8% was recorded in patients who underwent right upper lobectomy (RU), 7.2%±1.5% for right middle lobectomy (RM), 14.3%±2.3% for right lower lobectomy (RL), 16.6%±3.0% for left upper lobectomy (LU), and 14.7%±2.5% for left lower lobectomy (LL). Corresponding FEV1 values were 14.8%±1.8% for RU, 11.9%±4.0% for RM, 14.9%±2.3% for RL, 17.9%±2.9% for LU, and 15.1%±2.4% for LL. The actual decreasing rate of VC was overestimated in patients who underwent RU, RL, LU, and LL. In contrast, FEV1 was overestimated only in patients who underwent RL and LL. Patients with chronic obstructive pulmonary disease (COPD) exhibited significantly better preservation of FEV1.

CONCLUSIONS

Patients scheduled for RL and LL, or those with COPD, appeared to exhibit preserved lung function in the late postoperative phase after pulmonary lobectomy.

Radiologic and Functional Analysis of Compensatory Lung Growth After Living-Donor Lobectomy

BACKGROUND

Whether compensatory lung growth occurs in adult humans is controversial. The aim of this study was to confirm compensatory lung growth by analyzing ipsilateral residual lung after lower lobectomy in living lung transplant donors with quantitative and qualitative computed tomography assessments.

METHODS

Chest computed tomography and pulmonary function tests were performed in 31 eligible donors before and 1 year after donor lobectomy. Ipsilateral residual lung volume was measured with three-dimensional computed tomography volumetry. The computed tomography-estimated volumes of low, middle, and high attenuations in the lung were calculated. Assessment of the D value, a coefficient of the cumulative size distribution of low-density area clusters, was performed to evaluate the structural quality of the residual lung.

RESULTS

Postoperative pulmonary function test values were significantly larger than preoperative estimated values. Although postoperative total volume, low attenuation volume, middle attenuation volume, and high attenuation volume of the ipsilateral residual lung were significantly larger than the preoperative volumes, with 50.2%, 50.0%, 41.5%, and 43.1% increase in the median values, respectively (all p < 0.0001), the differences in D values before and after donor lobectomy were not significant (p = 0.848). The total volume of ipsilateral residual lung was increased by more than 600 mL (50%).

CONCLUSIONS

The volume of ipsilateral residual lung increased, but its structural quality did not change before and after donor lobectomy. The existence of compensatory lung growth in adult humans was suggested by quantitative and qualitative computed tomography assessments.

Predictors of long-term compensatory response of pulmonary function following major lung resection for non-small cell lung cancer

BACKGROUND AND OBJECTIVE

Long-term pulmonary function which might include compensatory response (CR) significantly influences quality of life of long-term survivor after major lung resection. We investigated long-term pulmonary function after major lung resection.

METHODS

A total of 137 patients who had undergone lobar resection for non-small cell lung cancer (NSCLC) from May 2013 to June 2014 had spirometry at 10-14 months after surgery. Actual post-operative forced expiratory volume in 1 s (FEV₁ ) (FEV_1apo )/predicted post-operative FEV₁ (FEV_1ppo ), actual post-operative forced vital capacity (FVC) (FVC_apo )/predicted post-operative FVC (FVC_ppo ), its relationship with clinicopathological factors and immunohistochemistry for pro-surfactant protein C (pro-SPC), thyroid transcription factor-1 (TTF-1) and vascular endothelial growth factor receptor 2 (VEGFR2) were investigated.

RESULTS

FEV_1apo /FEV_1ppo showed strong correlation with FVC_apo /FVC_ppo (r = 0.628; P < 0.001). We defined greater CR as both FEV_1apo /FEV_1ppo and FVC_apo /FVC_ppo were >120%. Greater CR was significantly associated with decreased smoking index (P < 0.001) and greater resected subsegments (P = 0.037). The never-smoker group revealed significantly greater CR compared with the smoker group in both FEV_1apo /FEV_1ppo (119.9 ± 12.5% vs 107.5 ± 14.2%; P = 0.030) and FVC_apo /FVC_ppo (117.9 ± 9.98% vs 107.2 ± 13.1%; P = 0.046) in case-matched comparison. The expression of pro-SPC, TTF-1 and VEGFR2 in the normal lung parenchyma of greater CR group was significantly higher than those of lesser CR group (P < 0.001 for each). In addition, pro-SPC, TTF-1 and VEGFR2 expressions showed a significant correlation to the degree of CR especially in the smoker group (r = 0.631, 0.705 and 0.732, respectively; P < 0.001 for each).

CONCLUSION

Our data suggest that smokers may develop lesser long-term CR after major lung resection. Decreased expression of pro-SPC, TTF-1 and VEGFR2 may indicate decreased capacity of CR, especially in patients who smoke.

Pleural Hypercarbia After Lung Surgery Is Associated With Persistent Alveolopleural Fistulae

BACKGROUND

Persistent air leak (PAL) > 5 days due to alveolopleural fistulae is a leading cause of morbidity following surgical resection. Elevated CO2 levels reportedly inhibit alveolar epithelial cell proliferation and impair wound healing in vitro. Because the injured lung surface is in direct communication with the pleural cavity, we investigated whether the pleural gaseous milieu affected lung healing.

METHODS

Oxygen and CO2 levels in pleural gas were determined prospectively in consecutive patients (N = 116) undergoing lung resection by using an infrared spectroscopy-based analyzer. Poisson and logistic regression analyses were used to determine the relationship between time to resolution of air leaks and pleural oxygen and CO2. In addition, patients with pleural CO2 concentrations ? 6% on postoperative day 1 (n = 20) were alternatively treated with supplemental oxygen and extrapleural suction to reduce the pleural CO2 levels.

RESULTS

Poisson analyses revealed that every 1% increase in CO2 was associated with a delay in resolution of air leak by 9 h (95% CI, 7.1 to 10.8; P < .001). Linear regression showed that every 1% increase in CO2 increased the odds of PAL by 10-fold (95% CI, 2.2 to 47.8; P = .003). In patients with pleural CO2 ? 6%, a reduction in CO2 promoted resolution of air leak (6.0 ± 1.2 vs 3.4 ± 1.1 days; P < .001).

CONCLUSIONS

Pleural hypercarbia seems to be associated with persistent alveolopleural fistulae following lung resection. Analysis of pleural gases could allow for better chest tube management following lung resection. Patients with intrapleural hypercarbia seem to benefit from supplemental oxygen and suction, whereas patients who do not have hypercarbia can be maintained on water seal drainage.

Dividing inferior pulmonary ligament may change the bronchial angle

BACKGROUND

Whether dissecting the inferior pulmonary ligaments (IPLs) during superior video-assisted thoracoscopic (VATS) lobectomy for early stage lung cancer remains controversial. This study aimed to evaluate the influence of dissecting the IPLs during VATS superior lobectomy on bronchial distortion and recovery of pulmonary function.

MATERIALS AND METHODS

This was a retrospective study of 72 patients with non-small cell lung cancer who underwent VATS superior lobectomy from March 2012-August 2013 at the First People's Hospital of Yunnan Province. Patients were grouped according to IPLs preservation (group P) or dissection (group D). The preoperative and postoperative pulmonary function and the postoperative complications were analyzed. The changes in bronchi angles and pulmonary capacity were measured using computed tomography.

RESULTS

There were no significant differences in the complication rate and volume of chest drainage between the two groups. The changes in bronchus angle in group P were significantly smaller than those in group D after left lung operation (P = 0.046 at 3 mo; P = 0.038 at 6 mo); in the right lung, the changes were not significant between the two groups (P = 0.057 at 3 mo; P = 0.541 at 6 mo). The forced expiratory volume of 2% and forced expiratory volume in 1 s (FEV1%) were significantly better in group P than those in group D at 3 and 6 mo (P < 0.05). The pulmonary capacity in group P was significantly larger than that in group D at 6 mo (P = 0.002).

CONCLUSIONS

Preservation of IPLs during VATS lobectomy might have an impact on the bronchus angle, lung function, and lung volume.

Prediction of postoperative dyspnea and chronic respiratory failure

BACKGROUND

Even among patients considered to be functionally eligible for major lung resection, some experience postoperative dyspnea. Based on our previous study with quantitative computed tomography (CT), we hypothesized that postoperative dyspnea is associated with the collapse of the remaining lung, and thus, prediction of the postoperative lung volume may contribute to risk assessment for postoperative dyspnea.

METHODS

We measured the emphysematous lung volume and functional lung volume (FLV) separately on whole lung CT using an image analysis software in 290 patients undergoing major lung resection for cancer between January 2006 and December 2012. The postoperative FLV was predicted by a stepwise multiple regression analysis.

RESULTS

Fourteen patients complained of postoperative dyspnea (complicated group), five of them presented with chronic respiratory failure. The postoperatively measured FLV was significantly lower in the complicated group than in the control group (P < 0.01). The postoperative FLV could be calculated using preoperative variables, including the forced vital capacity, number of resected segments, FLV, and emphysematous lung volume. The predicted postoperative FLV was significantly lower in the complicated group than in the control group (P < 0.01, area under the curve = 0.78; sensitivity 86%; specificity 73%). The predicted postoperative FLV was also useful in distinguishing complicated patients from matched-control patients who had similar preoperative pulmonary function (P = 0.02).

CONCLUSIONS

Postoperative dyspnea is likely accompanied by a collapse of the remaining lung. Quantitative assessment of the lung morphology on preoperative CT is useful to screen for patients at risk of postoperative dyspnea.

Risk of Pneumonitis After Stereotactic Body Radiation Therapy in Patients With Previous Anatomic Lung Resection

BACKGROUND

Stereotactic body radiation therapy (SBRT) has emerged as a standard treatment of early-stage, medically inoperable lung cancer. Limited data have evaluated the radiation pneumonitis (RP) risk with SBRT after previous anatomic lung resection (ALR). We assessed the incidence of RP and all pulmonary toxicity (PT) in patients who underwent lung SBRT after ALR and compared them with those of patients without previous ALR.

MATERIALS AND METHODS

We reviewed the medical records of 84 consecutively treated patients with stage T1-T2b non-small-cell lung cancer (NSCLC) treated with 88 courses of SBRT for 94 lung tumors from January 2007 to December 2014, including 17 patients with previous ALR. The rates of RP and all PT were compared between the patients with and without previous ALR.

RESULTS

At a median follow-up duration of 18.3 months (range, 1.8-85.6 months), the crude grade 2+ RP rate was 5.9% and 2.8% for patients with and without previous ALR, respectively (P = .51). The corresponding 2-year estimates of freedom from RP were 89% and 97% (P = .51). The crude rate of all grade 2+ PT was 11.8% and 2.8% for those with and without previous ALR (P = .11), with 2-year estimates of freedom from PT of 97% and 84% (P = .11), respectively. The 2 cohorts were well matched by the mean lung dose, percentage of lung volume receiving 20 Gy (P = .86), and prescribed dose (P = .75). The 2-year estimates of local control, cause-specific survival, and overall survival were similar between the 2 cohorts.

CONCLUSION

The observed rates of PT were low among all patients, with a trend toward increased grade 2 and 3 lung toxicity among patients with previous ALR. Previous ALR did not increase the risk of grade 4 and 5 RP, and SBRT appears safe and effective in this population.

Lobar analysis of collapsibility indices to assess functional lung volumes in COPD patients

Background

We investigated correlations between lung volume collapsibility indices and pulmonary function test (PFT) results and assessed lobar differences in chronic obstructive pulmonary disease (COPD) patients, using paired inspiratory and expiratory three dimensional (3D) computed tomography (CT) images.

Methods

We retrospectively assessed 28 COPD patients who underwent paired inspiratory and expiratory CT and PFT exams on the same day. A computer-aided diagnostic system calculated total lobar volume and emphysematous lobar volume (ELV). Normal lobar volume (NLV) was determined by subtracting ELV from total lobar volume, both for inspiratory phase (NLV_I) and for expiratory phase (NLV_E). We also determined lobar collapsibility indices: NLV collapsibility ratio (NLV_CR) (%) = (1 − NLV_E/NLV_I) × 100%. Associations between lobar volumes and PFT results, and collapsibility indices and PFT results were determined by Pearson correlation analysis.

Results

NLV_CR values were significantly correlated with PFT results. Forced expiratory volume in 1 second, measured as percent of predicted results (FEV₁%P) was significantly correlated with NLV_CR values for the lower lobes (P<0.01), whereas this correlation was not significant for the upper lobes (P=0.05). FEV₁%P results were also moderately correlated with inspiratory, expiratory ELV (ELV_I,E) for the lower lobes (P<0.05). In contrast, the ratio of the diffusion capacity for carbon monoxide to alveolar gas volume, measured as percent of predicted (DL_CO/V_A%P) results were strongly correlated with ELV_I for the upper lobes (P<0.001), whereas this correlation with NLV_CR values was weaker for upper lobes (P<0.01) and was not significant for the lower lobes (P=0.26).

Conclusion

FEV₁%P results were correlated with NLV collapsibility indices for lower lobes, whereas DL_CO/V_A%P results were correlated with NLV collapsibility indices and ELV for upper lobes. Thus, evaluating lobar NLV collapsibility might be useful for estimating pulmonary function in COPD patients.

Diaphragm motion and lung function prediction in patients operated for lung cancer--a pilot study on 27 patients

Background

The influence of the diaphragm motion to the accuracy of postoperative lung function prediction after the lung resction is still debatable.

Methods

Prospective study that included 27 patients who underwent a lung resection for cancer. Diaphragm movements were assessed radiographically and by ultrasonography before the operation and postoperatively, with the lung fully expanded. The relationship between the diaphragm movements and differences between ppo FEV₁ and measured postoperative FEV₁, was analysed by expressing diaphragm movements as preoperative diaphragm amplitudes, preoperative-postoperative amplitude differences or in relation to fixed intrathoracic distances.

Results

The mean difference between preoperative and postoperative diaphragm amplitudes of the diseased side was 2.42 ± 1.25 cm and 2.11 ± 2.04 cm when measured radiographically and by ultra sound respectively (p > 0.05). A significant positive correlation was found for the entire group only between the patients’ height and the differences ppo FEV₁ - actual FEV₁: the prediction was more unprecise in taller patients. With the cut-off value of 550 ml for differences between ppo FEV₁ and actual FEV₁, a significant inverse correlation was found only if the preoperative ipsilateral diaphragm amplitude was presented as a percentage of the preoperative apex-base distance in inspiration. For right-sided tumours, the greater the difference between preoperative and postoperative ipsilateral diaphragm amplitudes, the greater discrepancy between predicted and actual postoperative FEV_1. For left-sided tumours, inverse correlation existed if the preoperative diaphragm amplitude was presented as a percentage of the preoperative distance apex-base.

Conclusion

Diaphragm movements influence the accuracy of the postoperative lung function prediction.