Techniques of stapler-based navigational thoracoscopic segmentectomy using virtual assisted lung mapping (VAL-MAP)

Comparison of Margin Quality for Intersegmental Plan Identification in Pulmonary Segmentectomy

Background and Objectives: Insufficient margin in lung cancer is associated with an increased locoregional recurrence rate. In pulmonary segmentectomy, two commonly used methods for identifying the intersegmental plane are inflation-deflation and indocyanine green dyeing. The aim of this study was to compare these two methods in terms of quality margins and to evaluate their superiority. Materials and Methods: A total of 63 patients who underwent segmentectomy via video-assisted thoracoscopic surgery (VATS) for pulmonary nodules and underwent preoperative planning with 3D modeling between October 2020 and February 2024 were included in this study. The location of the nodule and the distance to the intersegmental margins were virtually measured preoperatively using an open-source 3D modeling system. Patients were grouped according to the method of identifying the intersegmental margins. Group 1 included segmentectomies performed by the inflation-deflation method (n = 42), and Group 2 included segmentectomies performed by systemic indocyanine green (ICG) injection (n = 21). The area where the histopathological nodule was measured closest to the intersegmental margin was recorded. Values within (+/-10 mm) compared to the value measured in the three-dimensional model were considered successful. The obtained data were statistically compared between the groups. Results: There was no difference between the groups in terms of virtual and pathological margins. However, in terms of margin quality, the rate of deviation detected in the pathological margin compared to the measured virtual margin was significantly different between the groups (p = 0.04). Accordingly, the success rate was 64.3% in Group 1 and 90.5% in Group 2 (p = 0.05). In Group 1, the failure rate was highly against the adjacent parenchyma. There was no significant difference between the groups in the analysis of simple and complex segmentectomies. Conclusions: Intersegmental plane identification with indocyanine green increases the margin quality by defining resection margins closer to the virtual margins. In the inflation-deflation method, unnecessary parenchymal loss occurs due to disadvantages in identifying intersegmental margins.

Identification of the Segmental Bronchus Using Indocyanine Green During Thoracoscopic Segmentectomy

Pulmonary segmentectomy is an established surgical procedure for early-stage lung cancer and metastatic tumors. However, performing complex segmentectomies is challenging owing to the deep intraparenchymal localization of hilar structures and anatomic variations. Moreover, particular attention should be paid to avoid intraoperative bronchial misidentification. The surgeon can consider enhancing the precision of segmentectomy by marking the segmental bronchus preoperatively. Herein, we report a simple technique that employs indocyanine green to identify the segmental bronchus during pulmonary segmentectomy.

A simple and safe surgical technique for nonpalpable lung tumors: One-stop Solution for a nonpalpable lung tumor, Marking, Resection, and Confirmation of the surgical margin in a Hybrid operating room (OS-MRCH)

When performing thoracoscopic partial resections of nonpalpable lung tumors such as ground-glass opacities (GGOs) and small tumors, detecting the location of the lesion and assessing the resection margins can be challenging. We have developed a novel method to ease this difficulty, the One-stop Solution for a nonpalpable lung tumor, Marking, Resection, and Confirmation of the surgical margin in a Hybrid operating room (OS-MRCH), which uses a hybrid operating room wherein the operating table is seamlessly integrated with cone-beam computed tomography (CBCT). We performed the OS-MRCH method on 62 nodules including primary lung cancer presenting with GGO. Identification of the lesion and confirmation of the margin were performed in 58 of the cases, while nodules were detected in all. The frequency of computed tomography (CT) scans performed prior to resection was one time in 51 cases, two times in eight cases, and ≥3 times in three cases. Additional resection was performed in two cases. The median operative time was 85.0 minutes, and the median pathological margin was 11.0 mm. The key advantages of this method are that all surgical processes can be completed in a single session, specialized skill sets are not required, and it is feasible to perform in any facility equipped with a hybrid operating room. To overcome its disadvantages, such as longer operating time and limited patient positioning, we devised various methods for positioning patients and for CT imaging of the resected specimens. OS-MRCH is a simple, useful, and practical method for performing thoracoscopic partial resection of nonpalpable lung tumors.

Uniportal Thoracoscopic Bisegmentectomy of Medial and Posterior Basal Segment (S7+S10)

When a tumor is located in the medial (S7) or posterior (S10) basal segment, it is sometimes necessary to perform a bisegmentectomy of S7 and S10 (S7+S10) to achieve a sufficient surgical margin. In this report, we present surgical techniques for uniportal thoracoscopic S7+S10 bisegmentectomy. The surgical technique consists of anterior and posterior procedures to dissect the basal pulmonary vein. This approach allows en bloc resection of S7+S10 and en bloc preservation of the remaining lobe.

Uniportal thoracoscopic extended right apical segmentectomy with virtual-assisted lung mapping: a case report

BACKGROUND

Pulmonary extended segmentectomy is an optional surgical treatment for early-stage non-small cell lung cancer that helps to achieve optimal surgical margins. Here, we describe a challenging instance of extended segmentectomy via uniportal video-assisted thoracic surgery with virtual-assisted lung mapping, a preoperative bronchoscopic dye marking procedure.

CASE PRESENTATION

A 72-year-old woman presented with two tumors that were clinically diagnosed as early-stage lung cancer; extended right apical segmentectomy was indicated. Because the tumors had appeared unidentifiable intraoperatively, we performed virtual-assisted lung mapping for tumor localization and delineation of the optimal resection area. Surgery was conducted through a single port. All virtual-assisted lung mapping markings were visible. After dissection of the apical vessels and bronchi, a putative intersegmental line was determined using collateral ventilation. Based on the putative intersegmental plane identified by collateral ventilation and the virtual-assisted lung mapping markings, the resection line was delineated. Extended apical segmentectomy along the resection line was successfully performed via uniportal video-assisted thoracic surgery. The postoperative course was uneventful. The pathological diagnosis was minimally invasive adenocarcinoma and adenocarcinoma in situ.

CONCLUSIONS

Virtual-assisted lung mapping can help to achieve optimal extended segmentectomy via uniportal video-assisted thoracic surgery.

Learning curve for total thoracoscopic segmentectomy in treating pediatric patients with congenital lung malformation

BACKGROUND

Total thoracoscopic segmentectomy (TTS) is a technically challenging procedure in children but results in more parenchyma preservation, better pain control, better cosmetic results, and a shorter hospital stay. However, definitive data describing the learning curve of TTS has yet to be obtained. Here, we review the safety and efficiency of our initial experiences with pediatric TTS and evaluate our learning curve.

METHODS

This was a retrospective study of all pediatric patients undergoing TTS between December 2016 and January 2020. Pediatric patients who underwent TTS were included, while those undergoing lobectomy or wedge resection were excluded.

RESULTS

One hundred and twelve patients were retrospectively analyzed to evaluate the learning curve and were divided chronologically into three phases, the ascending phase (A), plateau phase (B) and descending phase (C), through cumulative summation (CUSUM) of the operative time (OT). Phases A, B, and C comprised 28, 51, and 33 cases, respectively. OT decreased significantly from phases A to B (p < 0.001) and from phase B to C (p = 0.076). No significant differences were observed in the demographic factors among the three phases. The conversion rate was zero, and the complication rate was 0.9%. Differences in technical parameters, such as length of stay and chest tube duration, were statistically insignificant between phases A and B or B and C. There were no mortalities.

CONCLUSION

CUSUM_OT indicates that the learning curve of at least 79 cases is required for TTS in our institute. We emphasize that the learning curve should be cautiously interpreted because many factors in different institutions may influence the exact parabola and actual learning curve.

Comparison of various lung intersegmental plane identification methods

Keeping a sufficient surgical margin free of tumor is important to prevent local recurrence in lung segmentectomy. Accurate identification of the intersegmental plane is essential to achieve adequate surgical margins. Traditionally, the inflation-deflation method was used to identify the intersegmental plane. However, in recent years, various intersegmental plane identification methods, including systemic indocyanine green injection, have been reported and shown to be useful. The purpose of this review was to evaluate the identification rates, advantages, and disadvantages of various intersegmental identification methods in lung segmentectomy. There are primarily six methods: inflation-deflation method, selective segmental inflation, endobronchial dye injection, virtual-assisted lung mapping, systemic indocyanine green injection, and pure oxygen method. These are broadly classified into those that use bronchi and pulmonary arteries anatomically and those that use air and dye technically. In this review, all methods showed relatively high identification rates. Moreover, high identification rates were expected, especially with systemic indocyanine green injection and the pure oxygen method. Each method has its advantages and disadvantages as varying situations entail different methods. It is necessary to select and apply them effectively; therefore, further improvement for each method will be required in the future.

Single-stage augmented fluoroscopic bronchoscopy localization and thoracoscopic resection of small pulmonary nodules in a hybrid operating room

OBJECTIVES

Hybrid operating rooms (HOR) have been increasingly used for image-guided lung surgery, and most surgical teams have used percutaneous localization for small pulmonary nodules. We evaluated the feasibility and safety of augmented fluoroscopic bronchoscopy localization under endotracheal tube intubation general anaesthesia followed by thoracoscopic surgery as a single-stage procedure in ab HOR.

METHODS

We retrospectively reviewed clinical records of patients who underwent single-stage augmented fluoroscopic bronchoscopy localization under general anaesthesia followed by thoracoscopic surgery in an HOR between August 2020 and March 2022.

RESULTS

Single-stage localization and resection were performed for 85 nodules in 74 patients. The median nodule size was 8 mm [interquartile range (IQR), 6-9 mm], and the median distance from the pleural space was 10.9 mm (IQR, 8-20 mm). All nodules were identifiable on cone-beam computed tomography images and marked transbronchially with indigo carmine dye (median markers per lesion: 3); microcoils were placed for deep margins in 16 patients. The median localization time was 30 min (IQR 23-42 min), and the median fluoroscopy duration was 3.3 min (IQR 2.2-5.3 min). The median radiation exposure (expressed as the dose area product) was 4303.6 μGym2 (IQR 2879.5-6268.7 μGym2). All nodules were successfully marked and resected, and the median global operating room time was 178.5 min (IQR 153.5-204 min). There were no localization-related complications, and the median length of postoperative stay was 1 day (IQR, 1-2 days).

CONCLUSIONS

Single-stage augmented fluoroscopic bronchoscopy localization under general anaesthesia followed by thoracoscopic surgery was feasible and safe.

Comparison of stapler and electrocautery for division of the intersegmental plane in lung segmentectomy

Background

We retrospectively compared the use of a stapler and electrocautery for division of the intersegmental plane during pulmonary segmentectomy.

Methods

We enrolled 156 patients who underwent pulmonary segmentectomy in our department between March 2006 and August 2020. The patients were divided into electrocautery (n=62) and stapler (n=94) groups based on the device used to divide the intersegmental plane. Patient characteristics, perioperative outcomes, and ratios of actual (calculated using software) to predicted (calculated by counting the resected segments) lung volumes were compared between the two groups. Additionally, we used multivariate analysis to identify the factors that contributed to the incidence of postoperative air leakage after cut-off value was set by receiver operating characteristic (ROC) curve analysis. Moreover, a subset analysis was performed based on the type of segmentectomy (common or uncommon). Common segmentectomies included resection of the basilar or superior segment of the lower lobe, or lingular or upper division of the left upper lobe; all other segmentectomies were classified as uncommon.

Results

Compared to the electrocautery group, the stapler group had shorter operative times (P=0.0027), duration of postoperative drainage (P=0.00037), and duration of postoperative hospitalization (P=0.0021). Moreover, incidence of postoperative ≥3 days drainage was significantly reduced in the stapler group (P=0.003). There were no significant differences between the stapler and electrocautery groups in the actual:predicted lung volumes at 6 months (1.01 and 1.04, respectively; P=0.28) or 12 months (1.06 and 1.07, respectively; P=0.68) after surgery. Preoperative lung volume was significantly correlated with preoperative vital capacity (VC) (γ=0.69; P<0.001) and forced expiratory volume in 1 second (FEV₁) (γ=0.48; P<0.001). The multivariate analysis indicated that the use of stapler for division of intersegmental plane was the only factor that contributed to reducing the incidence of postoperative ≥3 days drainage (P=0.0027, odds ratio: 0.23, 95% CI: 0.086–0.597). In a subset analysis of uncommon segmentectomy, there were no significant differences among the groups in most perioperative results.

Conclusions

Compared to electrocautery, the use of a stapler for division of the intersegmental plane was associated with better perioperative outcomes, especially reduction of postoperative drainage time, and similar postoperative remnant lung volumes and function.

Risk factors for invisible intraoperative markings after virtual-assisted lung mapping

BACKGROUND

Virtual-assisted lung mapping (VAL-MAP) is a preoperative bronchoscopic multi-spot dye-marking technique, which can be combined with bronchoscopic placement of a microcoil (VAL-MAP 2.0). VAL-MAP can identify unpalpable pulmonary lesions; however, the markings are occasionally deemed invisible intraoperatively. We investigated preoperative risk factors for invisible markings after VAL-MAP.

METHODS

We prospectively performed preoperative VAL-MAP in patients at the University of Tokyo between January 2014 and June 2020. Data of 219 patients (257 lesions) and 857 markings were retrospectively reviewed. Dye markings were categorized as Grade 0 (invisible) or 1-5 (visible). The risk factors for Grade 0 markings were assessed using multiple logistic regression analysis. Subsegments of the bronchus showing Grade 0 markings were also evaluated for 133 lesions and 504 markings without missing data for the target segment.

RESULTS

Sixty-one of the 257 lesions (24%) displayed >1 Grade 0 markings. Seventy-six (8.9%) of the 857 markings were Grade 0 intraoperatively. VAL-MAP 1.0 was performed for 202 (79%) and 25 lesions (10%) without and with electromagnetic navigation bronchoscopy, and VAL-MAP 2.0 with a microcoil was performed for 30 lesions (11%). Upper lobe markings were associated with a significantly increased risk of invisible markings. There was no significant difference in the frequency of Grade 0 markings among the VAL-MAP methods. Among all bronchi subsegments, left B1+2c exhibited the highest rate of Grade 0 markings.

CONCLUSIONS

Markings placed using VAL-MAP are more likely to be invisible for upper lobe pulmonary lesions. Injecting markings for lesions in the left S1+2c thus require caution.

Efficacy of the Segment-Counting Method in Predicting Lung Function and Volume Following Stapler-Based Thoracoscopic Segmentectomy

Purpose: To investigate the accuracy of a segment-counting method in predicting lung function and volume after stapler-based thoracoscopic segmentectomy in comparison with lobectomy.

Methods: Between 2014 and 2018, patients who underwent these procedures were retrospectively reviewed. Thoracic computed tomography and spirometry data before and 1 year after the surgery were assessed. We evaluated the differences between the predicted values using a segment-counting method and the actual postoperative values for lung function and volume in each group. Sub-analyses were also performed to assess the impact of the number of staples and resected segments in predicting patient outcomes.

Results: We included 116 patients (segmentectomy, 69; lobectomy, 47). Actual postoperative lung function and volume values matched the predicted values in the stapler-based segmentectomy group, and significantly exceeded the predictions in the lobectomy group (P <0.01). Sub-analyses revealed lower postoperative lung function values than predicted existed after single segmentectomy, with an odds ratio of 3.29 (95% confidence interval: 1.02–10.70, P = 0.04) in a multivariable analysis. The degree of predicted error regarding lung function was negligible.

Conclusions: The segment-counting method was useful in predicting lung function after stapler-based thoracoscopic segmentectomy. Segmentectomy rarely yielded lower- than-predicted lung function and volume values.

Video-Assisted Thoracic Surgery Segmentectomy

Although lobectomy remains the gold-standard surgical treatment for non-small-cell lung cancer, the frequency of thoracoscopic segmentectomy is increasing. Multiple factors must be considered in the choice of the procedure, ranging from adequate surgical planning or simulation, tumor localization, and identification of the intersegmental plane to severing the intersegmental plane to achieve an oncologically safe surgical margin with no or minimal manual palpation and different landmarks. In this article, we present an overview of methods for each procedural step of thoracoscopic segmentectomy, from preoperative planning to division of the intersegmental plane.

"Selective bronchus-blowing" method for effective inflate-deflate line identification in lung segmentectomy

Background

We examined two methods for the intraoperative selective bronchial delivery of air, and compared their effectiveness.

Methods

We recruited patients undergoing lung resection with the selective bronchus-blowing method in pulmonary segmentectomy for lung tumors. We assessed two types of bronchial ventilation methods: high-frequency jet ventilation (HFJV) and the bronchus-blowing method, which deliver air to target bronchi using HFJV or a 20G cannula inserted directly into the bronchi, respectively. The inflate-deflate line was classified as clear, slightly clear, and unclear. We examined the relationships between clinicopathological findings and the inflate-deflate line classification, as well as group differences in surgical-related factors.

Results

Among the 86 patients enrolled, 45 received HFJV ventilation and 41 received the bronchus-blowing method of ventilation. There was a significantly higher incidence of complex-type segmentectomies among patients in the bronchus-blowing group than in the HFJV group. The inflate-deflate line was classified as clear, slightly clear, and unclear in 16/7/11 and 25/3/3 patients in the HFJV and bronchus-blowing groups, respectively, according to the inflate-deflate criteria. The inflate-deflate line was identifiable in more cases in the bronchus-blowing group than in HFJV group (P=0.02). Complete resection was significantly less frequent in the HFJV group (73.5%) than in the bronchus-blowing group (90.3%). The rate of unsuccessful surgery was significantly higher among patients with severe emphysema, interstitial pneumonia, and anthracosis.

Conclusions

Intraoperative selective bronchial air supply was attempted for the safe identification of target lung segments. The bronchus-blowing method easily enabled effective visualization of the segmental area within the operative field.

Uniportal VATS approach to sub-lobar anatomic resections: literature review and personal experience

Surgical scientific literature contains relatively little information regarding the surgical outcomes of anatomic sublobar resections performed with the uniportal video-assisted thoracoscopic surgery (U-VATS) technique. This paper attempts to evaluate the role of U-VATS segmentectomies in the landscape of a minimally invasive approach to the treatment of early stage non small cell lung cancer (NSCLC).

How to identify intersegmental planes in performing sublobar anatomical resections

Pulmonary segmentectomy is a common surgical procedure in thoracic surgery nowadays. Though this technique helps preventing postoperative pulmonary function loss, potential challenges are the management of air leaks and the difficulty of palpating ground-glass components during surgery, as well as how to deal with the intersegmental planes. Several techniques have been proposed for the identification and treatment of the intersegmental planes during sublobar anatomical resections: this review focuses on preoperative planning and workup and intraoperative strategies. Three-dimensional computed tomography bronchography and angiography (3D-CTBA), virtual-assisted mapping (VAL-MAP) using bronchoscopy multi-spot dye marking and three-dimensional computed tomography (3D-CT) are preoperative tools that may facilitate the planning of operation. Inflation-deflation techniques, infrared-fluorescence-enhanced method combined with bronchial and intravenous injection of indocyanine green (ICG) and near-infrared fluorescence (NIF) mapping with ICG have been described as intraoperative strategies to identify the intersegmental plane. The treatment and section of the intersegmental planes is mainly accomplished by stapler and electrocautery or energy devices. The use of staplers reduces postoperative air leaks, bleeding risks and operative time but seems to reduce preserved lung volume, compromising adjacent lung expansion; in addition, higher costs and sometimes non-adequate oncological margins, being a non-anatomical technique have been described. The electrocautery and energy devices allow for a more anatomical and precise dissection maintaining safe oncological margins, with a better lung expansion and so an increased postoperative lung function. Time consuming procedure and frequent requirement of aero-haemostatic tools to treat air and blood leaks are the main drawbacks. In conclusion, there are several methods to identify and treat the intersegmental planes but there are no significant differences between the different tools, therefore the use of one technique rather than another depends overall on surgeon's preference and the location of the segment.

Early postoperative inflammatory response by procedure types: stapler-based segmentectomy versus lobectomy

OBJECTIVE

Perioperative C-reactive protein (CRP) levels have become a contentious topic on the surgical outcome of lung cancer, but the influence of the procedure types has not been precisely investigated. From this viewpoint, we compared two types of thoracoscopic anatomical lung resection: segmentectomy and lobectomy.

METHODS

This was a retrospective study involving patients who underwent standardized anatomical lung resection at a single institute from 2014 to 2017; CRP levels were routinely measured on postoperative days 1, 3, and 5. Changes in the CRP levels from the preoperative period were calculated (ΔCRP), and factors associated with a higher ΔCRP value were analyzed.

RESULTS

Among 186 patients included, 91 (48.9%) patients underwent stapler-based segmentectomy and 95 (51.1%) patients underwent lobectomy. The segmentectomy group showed significantly higher ΔCRP values on every measurement day than the lobectomy group, in spite of shorter operation time, smaller blood loss, shorter drainage periods, shorter dissection time, and limited lymph node dissection. The number of stapler cartridges for the lung parenchyma was significantly larger in the segmentectomy group. Regression analyses indicated that procedure type and smoking history were associated with a higher ΔCRP value, whereas no significant difference was indicated in the smoking history between the groups.

CONCLUSION

In our cohort, stapler-based thoracoscopic segmentectomy was associated with an increase in acute inflammatory response despite favorable perioperative outcome compared to lobectomy. Local surgical stress and damage in the remaining segments might play a key role and warrants further investigation.

Cumulative experience of preoperative real-time augmented fluoroscopy-guided endobronchial dye marking for small pulmonary nodules: An analysis of 30 initial patients

BACKGROUND/PURPOSE

Cone-beam computed tomography-derived augmented fluoroscopy (CBCT-AF) for use in guiding endobronchial dye marking of small pulmonary nodules prior to thoracoscopic surgery is still under development. We sought to evaluate the effect of the cumulative experience on procedural parameters of CBCT-AF-guided endobronchial dye marking for preoperative localization of small pulmonary nodules.

METHODS

Clinical variables and treatment outcomes of the 30 initial patients with small pulmonary nodules who were managed with CBCT-AF-guided endobronchial dye marking followed by thoracoscopic resection in our institution were analyzed. Two sequential groups of patients (group I and group II, n = 15 each) were compared with regard to localization time and radiation doses. The Mann-Whitney U test and chi-square test or Fisher exact test were used in the statistical analyses.

RESULTS

In the entire cohort, the median size of solitary pulmonary nodules on preoperative computed tomography (CT) images was 9.3 mm (interquartile range, 7.4-13.6 mm), and their median distance from the pleural surface was 15.2 mm (interquartile range, 10.3-27.1 mm). The median tumor depth-to-size ratio was 1.6 (interquartile range, 1.1-2.3). A significant reduction in single DynaCT radiation (3690.4 versus [vs.] 1132.3 μGym²; P < 0.001) and total radiation exposure (median, 4878.8 vs. 1673.8 μGym²; P < 0.001) was noted in group II (late patients) compared with group I.

CONCLUSION

Our initial results of CBCT-AF-guided lung marking demonstrate that the cumulative experience with several technical modifications can achieve the same purpose of endobronchial localization with less procedure-related radiation exposure.

The AMAGAMI technique: an easy technique to achieve precise stapling in thoracoscopic segmentectomy

The "AMAGAMI" or "incomplete grasping" technique is used to adjust the location of the lung while gently grasping the lung tissue with a stapler. Thoracoscopic segmentectomy requires precise but complex stapling, while the surgical view and the number of available instruments are limited. In the AMAGAMI technique, instead of moving the stapler to the targeted position of the lung tissue, an unlocked stapler is used to hold the lung tissue at an easily accessible position, and the lung tissue can then be slid to the ideal resection line using forceps. To use the AMAGAMI technique effectively, "standing stitches" are very helpful in enabling visualization of the ideal resection lines. Standing stitches are placed along intersegmental lines that have been determined based on the information provided by virtual-assisted lung mapping (VAL-MAP) or other marking techniques; these stiches are usually placed at the corner of the targeted segment and in-between if necessary. Monofilament suture is used for standing stitches, and about 1 cm lengths are left to enable later visualization. As these stitches stick out of the lung surface even when viewed from a tangential angle, the direction of stapling is easily visualized in thoracoscopic surgery. These techniques are particularly useful in challenging segmentectomy requiring complex staple lines, such as S10 segmentectomy, and in surgery with limited instrumental access, such as uniportal thoracoscopic surgery.

Quantitative feature analysis of CT images of transbronchial dye markings mimicking true pulmonary ground-glass opacity lesions

Background

Transbronchial dye marking is a preoperative localization technique aiding pulmonary resection. Post-marking computed tomography (CT) is performed to confirm the locations of the actual markings. This study aimed to evaluate the CT images of dye markings that present as ground-glass opacities (GGO), using quantitative feature analysis.

Methods

Thin-slice (1 mm) CT images of the dye markings and true ground glass nodule (GGN) lesions were obtained for quantitative analysis with gray-level co-occurrence matrix (GLCM) features. The quantification features including correlation, auto correlation, contrast, energy, entropy, and homogeneity were evaluated. Statistical analysis with boxplot was performed.

Results

GLCM features of multi-detector computed tomography (MDCT) images of the dye markings (n=13) and true GGN lesions (n=13) differed significantly in contrast, energy, entropy, auto correlation, and homogeneity. Cone beam computed tomographic (CBCT) image features of another group of dye markings (n=15) also showed a different distribution of feature values, than those of the MDCT images.

Conclusions

Quantitative analysis of the dye marking images revealed a discriminative variance, compared with those of the true GGN lesions. Furthermore, the image textures of dye markings on MDCT and CBCT also presented with obvious discrepancies.

Single-stage hybrid localization: a combination of bronchoscopic lung mapping followed by post-mapping computed tomographic reconstruction and additional transthoracic needle localization in a cone beam computed tomography room

Background

Bronchoscopic lung mapping is a multispot dye-marking technique, which should be performed under real-time fluoroscopic guidance and post-mapping computed tomographic reconstruction. This study aimed to investigate the feasibility of lung mapping followed by post-mapping computed tomography (CT) and additional needle localization in a cone bean CT (CBCT) room.

Methods

Between February 1, 2018 and August 31, 2018, 11 consecutive patients presenting with 14 lung lesions underwent bronchoscopic lung mapping in a CBCT room followed by thoracoscopic surgery. The efficacy and safety of the procedure were assessed through a retrospective chart review.

Results

The median size of the pulmonary lesions was 8.1 mm [interquartile range (IQR), 7.2-10.8 mm] with a median depth-to-size ratio (D-S) ratio of 2.43 (IQR, 1.56-2.79). Additional needle localizations were performed in 4 patients, of which 3 and 1 patients underwent dual localization with dye and microcoil and localization with dye only, respectively. The median total localization time was 28 min (IQR, 18-69 min), and the median radiation exposure was 345.0 mGy (IQR, 161.8-486.6 mGy). A total of 8 wedge resections, 5 segmentectomies, and 1 lobectomy were performed. The final pathological diagnoses were as follows: primary lung cancer (n=6), lung metastases (n=4), and benign lung lesions (n=4). No adverse events were observed, and the median length of postoperative stay was 4 days (IQR, 3-5 days).

Conclusions

Bronchoscopic lung mapping followed by post-mapping CT and additional needle localization can be performed together in a single examination room equipped with a C-arm CBCT, and the results of localization are contributory to the surgery.

Concepts and techniques: how to determine and identify the appropriate target segment in anatomical pulmonary segmentectomy?

Anatomical segmentectomy is gathering increasing interest among thoracic surgeons because of increased detection of pulmonary nodules with ground-glass opacity (GGO) as well as an increase in the number of compromised patients. Accurate determination of intersegmental planes is a challenge in anatomical segmentectomy, and multiple methods have been proposed including developing inflation/deflation lines and injecting indocyanine green either intravenously or intrabronchially. Considering resection margins, adding a localization technique to conventional methods, or conducting virtual-assisted lung mapping (bronchoscopic multi-spot dye marking) may be an optional approach for optimal anatomical segmentectomy to identify intersegmental planes and obtain adequate resection margins. To determine optimal resection lines in anatomical segmentectomy, surgeons must also consider oncological validity such as venous and lymph drainage, resection margins, and lung anatomy to avoid complications such as venous congestion, infarction, and air leakage. Although anatomical segmentectomy is an attractive approach to resect small early-stage lung cancer and some metastatic lung tumors, caution is needed to optimally perform this technically demanding surgery.

Latest update about virtual-assisted lung mapping in thoracic surgery

Virtual-assisted lung mapping (VAL-MAP) is a preoperative bronchoscopic multi-spot dye-marking technique using virtual images developed to assist in navigational lung resection. The technique of VAL-MAP has been shown to be safe and effective surgical assistive tool for performing pulmonary sublobar resections. The technique is applicable for treating multiple small pulmonary lesions that are hardly palpable including ground glass nodules (GGNs). It also may help shorten surgical duration in wedge resection cases. Electromagnetic navigation bronchoscopy (ENB) may eliminate the need for post-mapping computed tomography (CT) scans in logistically challenged situations. In the most recent, multicenter prospective single-arm study, conventional VAL-MAP had reasonable efficacy for obtaining good surgical margin in pulmonary sublobar resections, although the successful resection rate did not reach the primary goal most significantly due to deep resection margins. The technique of VAL-MAP in combination with microcoil may be the next step to acquire better surgical margins.

Combined virtual-assisted lung mapping (VAL-MAP) with CT-guided localization in thoracoscopic pulmonary segmentectomy

BACKGROUND/OBJECTIVE

Virtual assisted lung mapping (VAL-MAP) is a bronchoscopic lung marking technique developed to assist in navigational lung resection. It can be used for nodule localization and segmental identification. This article presents our initial experience of thoracoscopic pulmonary segmentectomy using combined VAL-MAP and computed tomography (CT)-guided localization.

MATERIAL AND METHODS

Markings with India Ink were made bronchoscopically, before surgery, using a virtual bronchoscopy system (LungPoint® Planner) without fluoroscopy guidance. Post VAL-MAP CT scans localized the actual markings. All data on patients, markings, and outcomes were retrospectively collected, and the contribution of VAL-MAP to the operation was graded by the surgeon.

RESULTS

From March 2017 to September 2017, 24 consecutive patients received the VAL-MAP marking procedure before thoracoscopic segmentectomy. Nineteen patients also received pre-operative CT-guided percutaneous localization after VAL-MAP; fifteen patients received CT-guided localization with dye (patent blue V) and microcoil, and four patients received with dye only. Of the 101 marking attempts made in all the patients, 71 (70.3%) were identified as contributing to the surgery. No clinically evident complications were associated with the procedure. A total of 24 segmentectomies were thoracoscopically conducted for 18 cases of lung cancer and six cases of benign diseases.

CONCLUSION

The combination of VAL-MAP and CT-guided percutaneous localization contribute to precise thoracoscopic pulmonary segmentectomy.

The role of virtual-assisted lung mapping in the resection of ground glass nodules

Background

Virtual-assisted lung mapping (VAL-MAP), a bronchoscopic multi-spot dye-marking technique, was tested for its ability to resect ground glass nodules (GGNs) in sublobar lung resections.

Methods

All patients were prospectively registered in the multi-institutional lung mapping (MIL-MAP) study using VAL-MAP. The data were retrospectively analyzed, focusing on GGNs. GGN characteristics, pathological findings, operation type, and the surgical contribution of VAL-MAP were evaluated.

Results

The 370 GGNs in 299 patients included 257 pure and 113 mixed GGNs. There were 146 wedge resections (43.6%), 99 simple segmentectomies (29.6%), and 60 complex segmentectomies (18.0%). The largest number of marks were used in complex segmentectomy (4.05±0.74), followed by simple segmentectomy (3.35±0.97) and wedge resection (2.96±0.80). The overall successful resection rate was 98.6%. Multiple [2-5] GGNs were concurrently targeted by VAL-MAP in 53 patients (17.7%) with 123 GGNs. Two concurrent resections were conducted in 36 patients (12.1%), most commonly wedge resection and segmentectomies (21 patients). Among 190 sub-centimeter GGNs, 24 out of 51 GGNs ≤5 mm in diameter (47.1%) and 113 of 139 GGNs >5 mm in diameter (81.3%) were primary lung cancer (P<0.0001). Regarding the contribution of VAL-MAP to successful resection, wedge resection and pure GGNs were graded higher than both other resection types and mixed GGNs.

Conclusions

VAL-MAP enabled thoracoscopic limited resection of GGNs. Its multiple marks facilitated resections of multi-centric GGNs. Resected suspicious GGNs >5 mm in diameter are likely to be lung cancer. VAL-MAP may impact decision-making regarding the indications and type of surgery for suspicious small GGNs.

Resection of synchronous bilateral multiple lung adenocarcinomas using virtual-assisted lung mapping

Background

Virtual-assisted lung mapping (VAL-MAP) is a novel marking technique to assist sub-lobar resection of small hardly palpable lung tumors. Here, we present the first case of synchronous bilateral multiple lung adenocarcinomas that were successfully resected with VAL-MAP navigation.

Case presentation

A 73-year-old female with multiple nodules (1 in the right upper lobe, 2 in the right lower lobe, 1 in the left upper lobe, and 1 in the left lower lobe) was referred. Complete resection was achieved with left lower lobectomy in combination with sub-lobar resections (wedge resection for a lesion in the left upper lobe, segmentectomy for a lesion in the right upper lobe, and complex segmentectomy for lesions in the right lower lobe) in which resection lines with securing adequate margins were determined with VAL-MAP navigation.

Conclusions

VAL-MAP is useful in sub-lobar resections including complex segmentectomy for multiple lung adenocarcinomas.

Thoracoscopic stapler-based "bidirectional" segmentectomy for posterior basal segment (S10) and its variants

Thoracoscopic segmentectomy for the posterior basal segment (S10) and its variant (e.g., S9+10 and S10b+c combined subsegmentectomy) is one of the most challenging anatomical segmentectomies. Stapler-based segmentectomy is attractive to simplify the operation and to prevent post-operative air leakage. However, this approach makes thoracoscopic S10 segmentectomy even more tricky. The challenges are caused mostly from the following three reasons: first, similar to other basal segments, "three-dimensional" stapling is needed to fold a cuboidal segment; second, the belonging pulmonary artery is not directly facing the interlobar fissure or the hilum, making identification of target artery difficult; third, the anatomy of S10 and adjacent segments such as superior (S6) and medial basal (S7) is variable. To overcome these challenges, this article summarizes the "bidirectional approach" that allows for solid confirmation of anatomy while avoiding separation of S6 and the basal segment. To assist this approach under limited thoracoscopic view, we also show stapling techniques to fold the cuboidal segment with the aid of "standing stiches". Attention should also be paid to the anatomy of adjacent segments particularly that of S7, which tends to be congested after stapling. The use of virtual-assisted lung mapping (VAL-MAP) is also recommended to demark resection lines because it flexibly allows for complex procedures such as combined subsegmentectomy such as S10b+c, extended segmentectomy such as S10+S9b, and non-anatomically extended segmentectomy.

Safety and reproducibility of virtual-assisted lung mapping: a multicentre study in Japan

OBJECTIVES: Virtual-assisted lung mapping (VAL-MAP) is a preoperative bronchoscopic multispot dye-marking technique using virtual images. The purpose of this study was to evaluate the safety, efficacy and reproducibility of VAL-MAP among multiple centres.

METHODS: Selection criteria included patients with pulmonary lesions anticipated to be difficult to identify at thoracoscopy and/or those undergoing sub-lobar lung resections requiring careful determination of resection margins. Data were collected prospectively and, if needed, compared between the centre that originally developed VAL-MAP and 16 other centres.

RESULTS: Five hundred patients underwent VAL-MAP with 1781 markings (3.6 ± 1.2 marks/patient). Complications associated with VAL-MAP necessitating additional management occurred in four patients (0.8%) including pneumonia, fever and temporary exacerbation of pre-existing cerebral ischaemia. Minor complications included pneumothorax (3.6%), pneumomediastinum (1.2%) and alveolar haemorrhage (1.2%), with similar incidences between the original centre and other centres. Marks were identifiable during operation in approximately 90%, whereas the successful resection rate was approximately 99% in both groups, partly due to the mutually complementary marks. The contribution of VAL-MAP to surgical success was highly rated by surgeons resecting pure ground glass nodules (P < 0.0001), tumours ≤ 5 mm (P = 0.0016), and performing complex segmentectomy and wedge resection (P = 0.0072).

CONCLUSIONS: VAL-MAP was found to be safe and reproducible among multiple centres with variable settings. Patients with pure ground glass nodules, small tumours and resections beyond conventional anatomical boundaries are considered the best candidates for VAL-MAP.

Clinical Trial Registration Number: UMIN 000008031. University Hospital Medical Information Network Clinical Trial Registry (http://www.umin.ac.jp/ctr/).

VATS segmentectomy: past, present, and future

Video-assisted thoracoscopic surgery (VATS) has gradually been implemented in thoracic surgery, and the VATS approach has now been extended to technically challenging procedures, such as segmentectomy. The definition of VATS segmentectomy is changing over time, and the repertoire of segmentectomy is getting wider with increasing reports on atypical segmentectomy. VATS segmentectomy bears surgical, oncological, and technical advantages; however, there are still areas of controversy, particularly regarding oncological outcomes. The indication of VATS segmentectomy is diverse and is used for treating lung cancer, metastatic lung tumors, or a variety of nonmalignant diseases. It is particularly valuable for the lung-sparing resection of deeply located small nodules or repeated surgery for multiple lung lesions. VATS segmentectomy requires a thorough analysis of segmental anatomy and a tailored preoperative planning with the assessment of surgical margins. Technical challenges include intraoperative navigation, methods to identify and dissect the intersegmental plane, and the prevention of air leakage. This review will discuss the present state of VATS segmentectomy, with a focus on past studies, current indications and techniques, and future view.

Bilateral segmentectomies using virtual-assisted lung mapping (VAL-MAP) for metastatic lung tumors

Background

Virtual-assisted lung mapping (VAL-MAP) has been used not only in wedge resection but also in segmentectomy for hardly palpable lung nodules. We herein report a case of bilateral segmentectomy using VAL-MAP with chronological change of pulmonary function test results.

Case presentation

A 50-year-old female was found to have a colorectal cancer with pulmonary nodules in both sides of the lungs considered as synchronous lung metastases. After sigmoidectomy for primary cancer and chemotherapy, treatments for small nodules in both sides of the lungs were planned. Most nodules were small and supposed to be impalpable. We performed thoracoscopic segmentectomy of right S8 with the aid of VAL-MAP and, after 2 months, combined subsegmentectomy of left S8a and 9a and wide wedge resection of left S8b with the aid of VAL-MAP. All nodules suspected of lung metastases were successfully resected with adequate margins, and the decrease in pulmonary function was minimal compared with predicted postoperative forced vital capacity (FVC) and forced expiratory volume (FEV) 1.0 calculated by the numbers of subsegments.

Conclusions

Bilateral segmentectomies of small impalpable metastatic tumors were performed successfully with the aid of VAL-MAP.