New technique for lung segmentectomy using indocyanine green injection

Effect of transbronchial or intravenous administration of indocyanine green on resection margins during near-infrared-guided segmentectomy: a review

For early-stage non-small cell lung cancer, surgical resection remains the best treatment option. Currently, sublobar resection, including segmentectomy, is recommended in these cases, as it provides a better quality of life with the same oncological outcomes; however, is requires adequate resection margins. Accurate preoperative planning and proper identification of the intersegmental planes during thoracic surgery are crucial for ensuring precise surgical management and adequate resection margins. Three dimensional computed tomography reconstruction and near-infrared-guided intersegmental plane identification can greatly facilitate the surgical procedures. Three-dimensional computed tomography reconstruction can simulate both the resection and resection margins. Indocyanine green is one of the most frequently used and affordable fluorophores. There are two ways to identify the intersegmental planes using indocyanine green: intravenous and transbronchial administration. Intravenous application is simple; however, its effectiveness may be affected by underlying lung disease, and it requires the isolation of segmental structures before administration. Transbronchial use requires appropriate bronchoscopic skills and preoperative planning; however, it also allows for delineation deep in the parenchyma and can be used for complex segmentectomies. Both methods can be used to ensure adequate resection margins and, therefore, achieve the correct oncological radicality of the surgical procedure. Here, we summarise these applications and provide an overview of their different possibilities.

Simultaneous Visualization of Lung Tumor and Intersegmental Plane during Pulmonary Segmentectomy by Intravenous Injection of Indocyanine Green

Segmentectomy is a targeted surgical approach tailored for patients with compromised health and early-stage lung cancer. The key to successful segmentectomy lies in precisely identifying the tumor and intersegmental planes to ensure adequate resection margins. In this study, we aimed to enhance this process by simultaneously visualizing the tumor and intersegmental planes through the intravenous injection of indocyanine green (ICG) at different time points and doses. Lung tumors were detected by intravenous injection of ICG at a dose of 2 mg/kg 12 h before surgery in a rabbit model. Following the dissection of the pulmonary artery, vein, and bronchi of the target segment, 0.6 mg/kg of ICG was injected intravenously to detect the intersegmental plan. Fluorescent images of the lung tumors and segments were acquired, and the fluorescent signal was quantified using the signal-to-background ratio (SBR). Finally, a pilot study of this method was conducted in three patients with lung cancer. In a preclinical study, the SBR of the tumor (4.4 ± 0.1) and nontargeted segments (10.5 ± 0.8) were significantly higher than that of the targeted segment (1.6 ± 0.2) (targeted segment vs. nontarget segment, p < 0.0001; target segment vs. tumor, p < 0.01). Consistent with preclinical results, lung tumors and the intersegmental plane were successfully detected in patients with lung cancer. Consequently, adequate resection margins were identified during the surgery, and segmentectomy was successfully performed in patients with lung cancer. This study is the first to use intravenous ICG injections at different time points and doses to simultaneously detect lung cancer and intersegmental planes, thereby achieving segmentectomy for lung cancer.

A novel technique proposition for determining the resection margins in lung resection by using a thermal camera

OBJECTIVES

Determination of resection margins is very important in anatomical lung resections for both oncologic outcomes and postoperative complications. Absence of intersegmental plans naturally in segmentectomy surgeries and presence of incomplete fissure variationally in pulmonary lobectomy procedures constitute a challenge for surgeons in determining resection margins. Thoracic surgeons can prefer various techniques such as inflation deflation method, indocyanine green imaging, and three-dimensional segment modeling to cope with this problem. These techniques have some disadvantages such as high cost, the necessity of intravenous drug administration, need for an additional imaging system and ineffectiveness due to emphysema, anthracotic lung surface or interalveolar pores. Here we studied an alternative method for the solution of these disadvantages and aimed to demonstrate the correctness of a hypothesis based on detecting the cooling of the ischemic lung portion by a thermal camera after dividing the related pulmonary artery.

METHODS

We planned determining margins of resection with a thermal camera in patients scheduled for pulmonary lobectomy or segmentectomy. We made some measurements and mapping with a thermal camera before and after the dividing of pulmonary artery of related lobe or segment then processed the images taken with a software on the computer.

RESULTS

We detected a significant decrease in temperature in the ischemic lung area and demonstrated mapping the demarcation line between ischemic and perfused areas effectively by thermography in a total of 32 patients underwent lung resection.

CONCLUSION

Pulmonary resection margins can be detected effectively by thermography in patients.

An optimal thoracoscopic segmentectomy approach: Combined ultra-high-definition 4K endovision systems with "no-waiting" technique in S8-9 complex segmentectomy

Thoracoscopic segmentectomy might be an alternative to lobectomy for small size lung cancer. Precise identification of the pulmonary intersegmental plane was needed for an optimal segmentectomy. Recently, (1) the ultra-high-definition 4K systems had claimed to overcome the lack of depth perception by secondary visual cues; (2) the no-waiting procedure was induced as an alternative and optimized method for identifying the plane. It was unclear whether combined ultra-high-definition 4K endovision systems with "no-waiting" technique in thoracoscopic segmentectomy could achieve an excellent result. A 68-year-old female patient was admitted into our hospital for occasional pulmonary nodule during her routine physical examination. The nodule is located between S8 and S9 segment, and was suspected to be an early-stage lung cancer. She underwent a thoracoscopic S89 complex segmentectomy using ultra-high-definition 4K endovision systems and "no-waiting" surgical technique. The intersegmental plane was clearly detected and easily treated by the endoscopic linear cutting staplers. The patient recovered well and was discharged without complications. Combining ultra-high-definition 4K endovision systems with "no-waiting" technique seems to be an optimal thoracoscopic segmentectomy approach for the management of lung cancers.

Identification of the intersegmental plane by arterial ligation method during thoracoscopic segmentectomy

Background

Thoracoscopic segmentectomy is a common surgical procedure in thoracic surgery today. However, identifying the intersegmental plane is difficult in the surgical process. Therefore, we evaluated the feasibility of the arterial ligation method for determining the intersegmental plane and compared the demarcation status with the intravenous indocyanine green (ICG).

Methods

We retrospectively reviewed the records of 35 patients with peripheral small lung nodules who underwent thoracoscopic segmentectomy between May and December 2020. First, the preoperative three-dimensional reconstruction was performed to distinguish the location of lung nodules and the anatomical structures of targeted segmental arteries, veins, and bronchi. Second, the targeted segmental arteries were ligated, and the intersegmental plane was determined by the inflation-deflation technique. The waiting time for the appearance of the inflation-deflation line was recorded. Thirdly, the intersegmental plane was identified again using the ICG fluorescence method. Finally, the consistency of the two intersegmental planes was evaluated.

Results

The intersegmental planes were successfully observed in all patients using the arterial ligation method. Thirty-four patients underwent segmentectomy as planned, and one patient finally underwent lobectomy due to insufficient surgical margin. The waiting time for the appearance of the intersegmental plane by arterial ligation method was 13.7 ± 3.2 min (6–19 min). The intersegmental planes determined by the arterial ligation method and the ICG fluorescence method were comparable, with a maximum distance of no more than 5 mm between the two planes. The mean operative duration was 119.1 ± 34.9 min, and the mean blood loss was 76.9 ± 70.3 ml. No evident air leakage was found during the operation. Only one patient experienced a prolonged air leak (≥ 5 days) during the postoperative recovery. No atelectasis occurred in all cases. The chest tube duration was 3.1 ± 0.9 days.

Conclusion

The arterial ligation method can efficiently and accurately identify the intersegmental plane, comparable to the ICG fluorescence method.

Clinical application of bronchial high-frequency ventilation in 2-port thoracoscopic segmentectomy

To evaluate the safety and clinical application of a computer-aided surgery system (CAS) combined with high-frequency bronchial ventilation in 2-port thoracoscopic anatomical segmentectomy. A total of 301 patients who underwent 2-port thoracoscopic segmentectomy between January 1, 2019 and March 1, 2022 in the 960th Hospital of the People's Liberation Army and the Department of Thoracic Surgery of Zibo Municipal Hospital were retrospectively analyzed. The experimental and control groups were created according to the different methods of appearing the intersegmental plane of the lung. The experimental group comprised 152 patients who underwent CAS reconstruction combined with high-frequency ventilation, and the control group comprised 149 patients who underwent CAS reconstruction combined with expansion collapse. The characteristics of the patients, including age, sex, smoking history, forced expiratory volume in 1 second/forced vital capacity, Maximal ventilation, diameter of pulmonary nodules, intraoperative blood loss, postoperative drainage volume, drainage tube removal time, length of hospital stay after extubation, postoperative complication rate, operation time and appearance time of the intersegmental plane, were compared between the 2 groups. All patients completed the operation between high-frequency bronchial ventilation and expansion collapse group. There was no significant difference in Forced expiratory volume in 1 second/Forced vital capacity [(101.05 ± 11.86) vs (101.86 ± 11.61)], maximum expiratory volume [(86.36 ± 17.59 L) vs (85.28 ± 17.68 L)], the diameter of lung nodules [(13.61 ± 3.51 cm) vs (13.21 ± 3.41 cm)], intraoperative blood loss [(47.50 ± 45.90 mL) vs (48.49 ± 34.65 mL)], postoperative drainage volume [(425.16 ± 221.61 mL) vs (444.70 ± 243.72 mL)], drainage tube removal time [(3.88 ± 1.85 days) vs (3.43 ± 1.81 days)], or postoperative hospital stay [(6.07 ± 2.14 days) vs (5.82 ± 1.88 days) between the experimental group and the control group (P > .05)]. There were significant differences in operation time [(95.05 ± 26.85 min) vs (117.85 ± 31.70 min), P = .017] and intersegmental plane appearance time [(2.37 ± 1.03 min) vs (14.20 ± 3.23 min), P < .001]. High-frequency bronchial ventilation is safe and feasible when used in quickly and accurately identifying the intersegmental plane and is worthy of clinical application in 2-port thoracoscopic segmentectomy.

Near-infrared fluorescence guided surgery: State of the evidence from a health technology assessment perspective

Different applications of near-infrared fluorescence-guided surgery are very promising, and techniques that help surgeons in intraoperative guidance have been developed, thereby bridging the gap between preoperative imaging and intraoperative visualization and palpation. Thus, these techniques are advantageous in terms of being faster, safer, less invasive, and cheaper. There are a few fluorescent dyes available, but the most commonly used dye is indocyanine green. It can be used in its natural form, but different nanocapsulated and targeted modifications are possible, making this dye more stable and specific. A new active tumor-targeting strategy is the conjugation of indocyanine green nanoparticles with antibodies, making this dye targeted and highly selective to various tumor proteins. In this mini-review, we discuss the application of near-infrared fluorescence-guided techniques in thoracic surgery. During lung surgery, it can help find small, non-palpable, or additional tumor nodules, it is also useful for finding the sentinel lymph node and identifying the proper intersegmental plane for segmentectomies. Furthermore, it can help visualize the thoracic duct, smaller bullae of the lung, phrenic nerve, or pleural nodules. We summarize current applications and provide a framework for future applications and development.

Intraoperative Identification of the Intersegmental Plane: From the Beginning to the Future

Segmentectomy has played a crucial role in the treatment of early-stage lung cancer after the publication of JCOG0802, which indicated that patients with small-sized peripheral non-small-cell lung cancer could receive better survival from segmentectomy than lobectomy despite a higher local recurrence. The intraoperative identification of the intersegmental plane ensures complete resection of the lesion with sufficient margin so that it is deemed as the critical part of segmentectomy. Diverse methods have been developed to acquire distinguishable and lasting borderline between segments, but none of them is proved perfect. In this review, we searched and classified these techniques that emerged from the beginning when segmentectomy was used for bronchiectasis until now. Comparisons between different ways in mechanisms, facility, and safety were made to depict a comprehensive landscape for surgeons to select fit one. Furthermore, we presented our vision for the future of intersegmental plane identification.

Intraoperative margin assessment by wireless signals in thoracoscopic anterior (S3) segmentectomy using a radiofrequency identification marker

Despite the use of near-infrared thoracoscopy with intravenous indocyanine green, intraoperative assessment of the surgical margin for the resection of non-palpable tumors located near the intersegmental plane requires highly advanced surgical skill for the prevention of local recurrence. Because the demarcation line is limited to the pleural surface, to overcome uncertainty in tumor palpation for deeply located small-sized lesions, other supplemental localization techniques have been proposed. Here, we present a novel surgical technique using radiofrequency identification markers for intraoperative assessment of the lateral surgical margin in segmentectomy.

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.

Application of Mimics Medical 21.0 software in thoracoscopic anatomical sublobectomy

BACKGROUND

The anatomical structure of pulmonary segments is complex, and there are many anatomical variations, making the operation more difficult, so we used Mimics Medical 21.0 software for three-dimensional computed tomography bronchography and angiography (3D-CTBA), carefully formulated the surgical plan and on this basis completed the video-assisted thoracoscopic anatomical sublobectomy.

METHODS

A total of 38 patients with pulmonary nodules were selected and received video-assisted thoracoscopic anatomical sublobectomy after using Mimics Medica 21.0 software for 3D-CTBA.

RESULTS

The mean operative duration was 158.42±20.21 minutes, and the operative hemorrhage was 97.66±22.37 mL. In pathological diagnoses, there were 5 benign cases (13.2%), 9 cases with atypical adenomatous hyperplasia (23.7%), 12 cases with adenocarcinoma in situ (31.6%), 11 cases with minimally invasive adenocarcinoma (28.9%) and 1 case with invasive adenocarcinoma (2.6%); 8.29±0.98 lymph nodes sampled had no metastasis. The chest tube drainage duration and postoperative hospitalstay were 2.47±0.73 days and 5.47±0.73 days, respectively.

CONCLUSIONS

Using Mimics Medical 21.0 software can quickly and accurately complete 3D-CTBA, which is beneficial to formulate a personalized anatomical sublobectomy surgical plan.

The role of three-dimensional reconstructions in understanding the intersegmental plane: an anatomical study of segment 6

OBJECTIVES

The identification of the intersegmental plane during lung segmentectomies remains a practical difficulty, notably with minimally invasive approaches. The intraoperative techniques are based on demarcating either the bronchial or the vascular territories. The goal of this study was to evaluate the use of 3-dimensional reconstructions in understanding the intersegmental plane of segment 6.

METHODS

Between March and September 2018, Synapse 3-dimensional programme was used to carry out bilateral venous, arterial and bronchial segmentations of segment 6. All computed tomography (CT) scans were contrast-enhanced and of a high resolution (0.6 mm slices). The patients had normal results on respiratory function tests. The volumes obtained from each of the 3 modalities were then compared. The results are presented as mean and standard deviation and as median and interquartile ranges for lung volume measurements.

RESULTS

During the aforementioned period, 15 high-resolution chest CT scans were selected (8 men and 7 women). The median age was 70 years. In all of the studied segments (N = 30, 15 right S6 and 15 left S6), the segmental volume of the vein was greater than the segmental volumes of the bronchus and the artery. A significant difference was found between the segmental volumes obtained from the 3 modalities (P = 0.001). The segmental volume of the vein was significantly higher than the segmental volume of the bronchus (P < 0.001) and the segmental volume of the artery (P < 0.001). On the other hand, the segmental volume of the artery was significantly higher than the segmental volume of the bronchus (P = 0.01).

CONCLUSIONS

Within the limits of this study, the segmental venous volume of S6 was greater than the volumes of the segmental bronchial and arterial volumes. Thus, depending solely on bronchial techniques might lead to leaving a border zone in venous congestion.

Review of Approaches to Developing Intersegmental Plane during Segmentectomy

In recent years, with the popularity of computed tomography (CT) scanning, early lung cancer has been found in a large number of patients, and segmentectomy has been widely used in clinical practice. The development of intersegmental plane is the most critical step in segmentectomy. At present, there are many methods to identify the intersegmental plane. Also, dissection of the intersegmental plane has been a challenge for thoracic surgeons for decades because of the complicated anatomic variations. This study focuses on the safety and efficacy of relevant methods in both identification and dissection of the intersegmental plane in segmentectomy.

Lung segmentectomy assisted by highly selective independent segmental ventilation: a series of three cases

BACKGROUND

The identification of targeted intersegmental planes and resection with adequate surgical margins are among the crucial steps in anatomical pulmonary segmentectomy, and technical improvements are still needed.

CASE PRESENTATION

We reported three cases of intersegmental plane identification using highly selective independent segmental ventilation during segmentectomy. All cases required cooperation with an anesthesiologist who was able to perform segmental ventilation and double confirmation of segmental bronchus branches by the surgeon. The surgical procedure provides a direct visualization of spare segment inflation and saves time in deflation over the conventional residual segment inflation method.

CONCLUSIONS

Highly selective independent segmental ventilation could be considered a suitable option for pulmonary intersegmental plane identification and could be universally used for lung segmentectomy.

No-waiting segmentectomy: an optimized approach for segmentectomy

Background

Currently, modified inflation–deflation is considered the easiest way to identify the intersegmental plane during pulmonary segmentectomy. However, this approach requires a wait of about 10–20 min during the operative procedure. Therefore, we optimized the procedure, which we call no-waiting segmentectomy. In this study, we compared no-waiting segmentectomy with the modified inflation–deflation method.

Methods

We studied 123 consecutive patients with pulmonary ground-glass nodules who underwent segmentectomy by uniportal video-assisted thoracoscopic surgery in a single medical group from January 2019 to April 2020. Forty-five patients underwent the modified inflation–deflation method and 78 patients underwent the no-waiting method. The no-waiting procedure involved severing of the target segmental pulmonary artery, inflating the lung with atmospheric air, dissecting the hilum, and dividing the target segmental bronchus. The entire procedure could be performed at a stretch and no pause was needed. We compared the two methods for surgery time, bleeding volume, drainage time, and postoperative hospital stay. Propensity-score matching was used to adjust the baseline characteristics.

Results

Thirty-three pairs of 123 patients were successfully matched. Before propensity-score matching, there was no difference between the two methods in terms of surgery time, bleeding volume, drainage time, and postoperative hospital stay. After propensity-score matching, the surgery time in the no-waiting group was significantly shorter than that in the modified inflation–deflation method group (80.12±35.53 vs. 102.97±48.07 min, P=0.03). There was no difference between the two methods in terms of bleeding volume, drainage time, and postoperative hospital stay.

Conclusions

No-waiting segmentectomy was associated with a reduced surgery time, compared to that associated with modified inflation–deflation segmentectomy. Furthermore, no-waiting segmentectomy did not increase bleeding volume, drainage time, and postoperative hospital stay. Thus, no-waiting segmentectomy is an optional optimized approach for segmentectomy.

Fluorescence navigation with indocyanine green for identification of intersegmental planes using a photodynamic eye camera

Background

Pulmonary segmentectomy is an important surgical option for complete resection in patients with poor lung function. However, correctly recognizing the intersegmental plane for accurate segmentectomy is sometimes difficult. We therefore developed a novel method that allows the detection of intersegmental planes using an indocyanine green (ICG) fluorescence imaging device, photodynamic eye (PDE) camera, PDE-neo.

Methods

As a prospective study, we performed bronchial ICG-guided segmentectomy using PDE-neo. The patients were placed in a lateral position under general anesthesia, and we performed a combined muscle-sparing minithoracotomy with video assistance. The pulmonary artery, pulmonary vein, and segmental bronchi were separated, and ICG mixed with autologous blood was introduced by spraying through the resected segment bronchi to enable visualization of the intersegmental surface with PDE-neo. This study protocol was approved by the Research Ethics Board of Hamamatsu University School of Medicine, Japan. Written informed consent was obtained from all patients.

Results

Overall, 10 lung malignancy patients, including 8 males and 2 females, participated in this study from March 2011 to October 2013. The median age was 69 years (range, 29-76 years). Pathologic diagnoses were 7 adenocarcinomas, 1 adenosquamous carcinoma, 1 carcinoid tumor, and 1 lung metastasis from the parotid gland cancer. The intersegmental planes of 8 cases could be identified by this method using a PDE-neo, whereas those of 2 cases did not show clear demarcations. The reason was that because of severe emphysema, air flowed from the resected segment to the surrounding segments, obliterating the demarcation between the two segmental planes. There were no recurrent cases and only two deaths due to other diseases were observed; and the 5-year cause-specific survival rate was 100%.

Conclusions

Intersegmental planes could be more easily identified using ICG fluorescence imaging during segmentectomy. This method is feasible and effective and has a good long-term prognosis.

Identification of the intersegmental plane during thoracoscopic segmentectomy: state of the art

During thoracoscopic segmentectomy, where direct palpation of the tumour is not always possible, achieving adequate margins from the cancer is of crucial importance. It is thus mandatory to accurately identify the intersegmental plane (ISP). Indeed, inadequate determination and division of the ISP can lead to unsatisfactory oncological results. Our systematic review focused on the effectiveness of the different techniques for identifying the ISP, highlighting the fact that a 1-size-fits-all method is not feasible. Based on the published evidence, 6 main methods were reported, each with its pros and cons: inflation-deflation technique, selective resected segmental inflation, systemic injection of indocyanine green, injection of endobronchial dye, 3-dimensional simulation using multidetector computed tomography and virtual-assisted lung mapping. In conclusion, ISP demarcation is mandatory to achieve a high rate of success of thoracoscopic segmentectomy, and it is very helpful in surgical planning, especially when preoperative multidetector computed tomography and 3-dimensional reconstructions are routinely performed.

[Advances in Identification of Intersegmental Plane during Pulmonary Segmentectomy]

With the popularity of computed tomography (CT) scan in recent years, early stage lung cancer has been discovered in large numbers of patients and pulmonary segmentectomy has been widely used clinically. Identification of the intersegmental plane is one of the key steps in pulmonary segmentectomy, and current methods for identifying the intersegmental plane are numerous and have their own advantages and disadvantages. We will review relevant methods to help the clinical practice.
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Constant-rate intravenous infusion of indocyanine green leading to high fluorescence intensity in infrared thoracoscopic segmentectomy

Objectives

The purpose of this study was to determine whether or not fluorescence could be increased by administering indocyanine green at a constant rate, thus stabilizing its blood concentration.

Methods

In 20 consecutive patients undergoing segmentectomy, the dominant pulmonary arteries were ligated, blocking blood in the target segment. Fluorescence intensity was then observed using different indocyanine green administration methods under infrared thoracoscopy. Intravenous administration of indocyanine green, via a syringe pump at a rate of 12.5 mg/min, was defined as the constant rate group. The bolus group was defined by a 5-mg indocyanine green rapid intravenous injection. The fluorescence intensity was compared at the time of maximum fluorescence and 2 minutes after fluorescence initiation.

Results

At maximum staining, the fluorescence intensity of the normal blood flow area was brighter in the constant rate group (median, 184.2; interquartile range, 170.2-200.1) compared with the bolus group (median, 122.3; interquartile range, 87.3-144.7; P = .0003). The fluorescence of the normal blood flow was retained even after 2 minutes. There was no difference in the fluorescence intensity of the ischemic segments.

Conclusions

The constant rate method showed brighter and better fluorescence than the bolus injection, without an increase in the dose. The contrast between adjacent segments was clear, facilitating the differentiation of the areas.

"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.

Novel technique for identification of the pulmonary intersegmental plane using manual jet ventilation during pulmonary segmentectomy

Introduction

For successful pulmonary segmentectomy, the identification of boundaries between segments is important. Previous measures include tracing the intersegmental vessels by staining with a dye via the affected pulmonary artery or bronchus and inflating with oxygen via a high frequency ventilator. However, problems with these methods have been reported.

Aim

We developed a novel method using a manual jet ventilator (MJV) and investigated its efficacy in identification of the pulmonary intersegmental plane.

Material and methods

Patients underwent MJV for pulmonary segmentectomy in the period from January 2013 to December 2017 at our institution. The patients’ characteristics, resected segments, availability of clear resection planes, and complications associated with MJV from medical records were investigated. A questionnaire survey was conducted with the surgeons on the effectiveness of lung segment identification using MJV.

Results

Of 199 cases of planned pulmonary segmentectomy, 171 cases with descriptions of identified intersegmental planes were analyzed. Of these, 152 (89%) cases showed a clear boundary. There were 19 cases where the exact boundaries were not clearly identified, but segmentectomy was still performed. Furthermore, we found that identification of the right upper lobes was difficult (p = 0.0028). A subjective questionnaire was answered by the 12 surgeons who performed the procedures. All 12 responded that MJV was very effective or effective regarding clarity, safety, shorter identification time, and shorter resection time.

Conclusions

MJV enabled surgeons to more easily and safely identify the pulmonary intersegmental plane, thereby suggesting that MJV has clinical significance during pulmonary segmentectomy.

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.

Postsurgical residual lung complications following left upper trisegmentectomy

OBJECTIVES

Segmentectomy has become an increasingly popular surgical procedure for small-sized lung lesions. Left upper trisegmentectomy (LUTS) is one of the most common segmentectomies performed because of its relative ease and simplicity; however, limited information is currently available on the specific postoperative complications associated with this procedure.

METHODS

Among 2060 surgically resected cases in our institute between 2009 and 2016, 129 (6.2%) underwent LUTS. Postoperative chest X-rays and/or thoracic computed tomography (CT) scans were retrospectively assessed for all cases to assess postsurgical residual lung complications following LUTS. We categorized cases into 4 groups: type A (atelectasis of the lingular segment), type B (lung torsion of the lingular segment), type C (necrosis of the 'isolated segment') and type D (haematoma along stapling lines).

RESULTS

Postsurgical lung complications following LUTS were observed in 17 (13.1%) patients (type A: n = 7, type B: n = 1, type C: n = 4 and type D: n = 5). Three patients (2.3%) required surgical intervention because of type B (n = 1) and type C (n = 2), namely, decreased permeability and remaining ground glass opacities in the residual lung, showing an exacerbated systemic inflammatory response. In contrast, type A and D cases were successfully observed by chest CT without any surgical intervention, and patients recovered within a few months of surgery.

CONCLUSIONS

We identified several postoperative residual lung complications following LUTS. Lung torsion or necrosis of the residual segment may require intensive care, including reoperation. Potentially serious complications always need to be ruled out after LUTS when radiological consolidation is detected postoperatively.

A novel technique for identification of the segments based on pulmonary artery plane combined with oxygen diffusing discrepancy

Background

Segmentectomy has been widely accepted as a powerful tool to treat small lung nodules. Despite been commonly used, identify the intersegment plane precisely in visual during the operation still being a complex issue. We described a novel method in minimal invasive thoracic surgery utilizing arterial-navigation combined with oxygen diffusing discrepancy based on the variance of oxygen diffusion in target and reserved segments. We perspectively analyzed 24 cases with small lung nodules of T1N0M0 disease to examine the efficacy of the new method.

Methods

From June 2018 to September 2018, 24 patients with small primary lung cancers underwent segmentectomy at The Affiliated Hospital of Qingdao University. All the patients received minimally invasive procedures and standard anatomical segmentectomy. Ligation of the target segment artery followed by observation and the arterial-navigation line gradually appeared by color discrepancy in the visceral pleural surface. The plane was then testified by inflation-deflation method.

Results

The mean identification time of the intersegments plane was 8 minutes. The residual segments collapsed and stayed pink, meanwhile the target parts remained inflated and turned dark. It allowed a clear identification of the intersegments plane on the surface. All operations were successfully completed. There were no perioperative deaths or major complications. The coincidence rate of arterial-navigation and inflation-deflation technique was 22/24.

Conclusions

The arterial-navigation method is safe and feasible to identify the intersegmental plane in small lung tumor resection.

Discovery of lung surface intersegmental landmarks by three-dimensional reconstruction and morphological measurement

Background

The lack of anatomic landmarks between segments on the lung surface makes the identification of intersegmental planes one of the greatest challenges in anatomic segmentectomy. Therefore, with the aim to determine the landmarks of intersegmental planes on the lung surface, we used three-dimensional (3D) reconstruction and morphological measurement techniques to reconstruct stereoscopic models of all pulmonary segments, and measured the length of each segment on the lung surface along the lobe's anatomic landmark lines.

Methods

We downloaded the primary computed tomography (CT) scan data of 619 patients and imported them into a 3D reconstruction system, which could automatically reconstruct the 3D model of the trachea-bronchi system. We manually reconstructed the intersegmental veins to ensure the accuracy of segmental boundary. The 3D models of pulmonary segments could be reconstructed based on the bronchial tree and the pathways of the intersegmental veins. We then measured the length of each segment on the lung surface along the lobe's anatomic landmark lines and calculated the proportions between these lengths.

Results

Complete 3D segmental models were successfully reconstructed in 500 patients (241 male and 259 female), and the lengths of every segment on the lung surface along the lobe's anatomic landmark lines were measured. Our data revealed that the length of each segment on lung surface varied among individuals. However, the proportions between these lengths stayed constant, even when stratified by gender, age, height, and weight.

Conclusions

We discovered that the proportion between the lengths of adjacent segments on the lung surface stayed constant. The constant proportion reflected and uncovered the lung surface intersegmental landmarks, which could help direct surgeons to identify intersegmental planes during anatomic segmentectomy in an easy and safe way without additional cost.

Recent fluorescence imaging technology applications of indocyanine green in general thoracic surgery

Thoracic surgeons perform a wide variety of cancer operations, which are often associated with high morbidity and mortality. Thus, thoracic surgery involves many special challenges that require innovative solutions. The increased utilization of minimally invasive practices, poor overall cancer survival, and significant morbidity of critical operations remain key obstacles to overcome. Fluorescence imaging technology (FIT), involving the implementation of fluorescent dyes and imaging systems, is currently used as an adjunct for general thoracic surgery in many situations and includes sentinel lymph node mapping, pulmonary intersegmental plane identification, pulmonary nodule identification, pulmonary bullous lesion detection, evaluation of the anastomotic perfusion after tracheal surgery, and thoracic duct imaging for postoperative chylothorax. This technology enhances the surgeon's ability to perform operations, and has specific advantages. We review some of the key studies that demonstrate the applications of FIT in the field of general thoracic surgery, focusing on the use of indocyanine green.

Near-Infrared-Guided Pulmonary Segmentectomy After Endobronchial Indocyanine Green Injection

BACKGROUND

The aim of this study is to prospectively determine the feasibility and safety of near-infrared fluorescence-guided pulmonary segmentectomy after endobronchial indocyanine green (ICG) injection using virtual bronchoscopy.

METHODS

Fifteen patients who underwent pulmonary segmentectomy were prospectively enrolled. Using preoperative computed tomography datasets a bronchial road map was created to determine the bronchus for ICG injection. Immediately after intubation ICG was injected into the target bronchi using an ultrathin bronchoscope. During the operation a near-infrared thoracoscope was used to detect ICG fluorescence and determine the intersegmental plane. The assessment points were (1) whether the ICG demarcation lines corresponded to the intersegmental lines expected from the pulmonary veins, (2) whether it was possible for the planned segmentectomy to be completed by electrocautery and 1 or fewer uses of an automated suturing device according to the demarcation plane, (3) whether any surgical complications occurred intraoperatively or (4) in the 1 month after surgery, and (5) whether the target lesion was removed completely with sufficient surgical margin to evaluate the feasibility and safety of this procedure.

RESULTS

In 13 cases (87%) a segmentectomy was completed in the planned way with sufficient surgical margins. The failure in 2 cases was due to a technical issue in the bronchial injection. No complications developed intraoperatively. Recurrent air leakage occurred in 1 case. No procedure-related adverse event was noted postoperatively.

CONCLUSIONS

Near-infrared-guided pulmonary segmentectomy with endobronchial ICG injection using virtual bronchoscopy was safe and feasible, and minor technical revision can make this procedure more reliable.

Is the near-infrared fluorescence imaging with intravenous indocyanine green method for identifying the intersegmental plane concordant with the modified inflation-deflation method in lung segmentectomy?

OBJECTIVES

At present, the modified inflation-deflation method is accepted and widely used in the clinic, but the near-infrared (NIR) fluorescence imaging with intravenous indocyanine green (ICG) method can also delineate the intersegmental demarcation. However, whether the two methods identify that the intersegmental plane is concordant with each other and match the real intersegmental demarcation is still unknown.

METHODS

Between March 2019 to July 2019, 19 consecutive segmentectomies were performed, using both methods to delineate the intersegmental plane, in order to evaluate and verify whether the intersegmental plane results created by the two methods were concordant and matched the real intersegmental demarcation.

RESULTS

Segmentectomies were carried out using uniportal video-assisted thoracic surgery (UVATS) successfully with no intraoperative conversions or ICG-related complications and only three cases (15.8%) with postoperative complications related to the operation. The intersegmental plane generated by the NIR fluorescence imaging with intravenous ICG method was found to be totally concordant with the modified inflation-deflation method that was approaching the real intersegmental demarcation in all 19 cases.

CONCLUSIONS

Both methods revealed the intersegmental plane clearly, and the NIR fluorescence imaging with intravenous ICG method was found to be totally concordant with the modified inflation-deflation method, which is highly concordant with the real intersegmental demarcation. NIR fluorescence imaging with intravenous ICG method may be more popular because of its safety, efficiency, and less complicated restrictions, especially in patients with pulmonary emphysema. Low doses of ICG do not affect the rate of identification of the intersegmental plane and is safer from drug toxicology.

Indocyanine green fluorescence-guided thoracoscopic pulmonary resection for intralobar pulmonary sequestration: a case report

Background

The potential complications of pulmonary sequestration are serious and may include recurrent pulmonary infection, hemoptysis, and tumorigenesis. Therefore, the gold standard of treatment has been surgery. Although an adequate boundary between the nonfunctional lung and normal lung is required for the resection of pulmonary sequestration, the boundaries have been conventionally identified intraoperatively with inflation/deflation of the target segment by clamping and unclamping the relevant bronchus. The technique of visualizing the demarcation line based on near-infrared fluorescence imaging with indocyanine green was recently developed.

Case presentation

A 42-year-old Japanese woman with right Pryce III intralobar sequestration was admitted to our hospital. We planned video-assisted thoracoscopic wedge resection of the right sequestration using near-infrared fluorescence imaging with indocyanine green because of the small volume of the nonfunctional region. The aberrant artery was recognized in the pulmonary ligament; the artery was cut off after ligation. Indocyanine green at 5 mg/body was rapidly injected into the peripheral vein, and the boundary of the sequestration was clearly identified under near-infrared fluorescence imaging.

Conclusion

Near-infrared fluorescence imaging with indocyanine green is safe and useful for the identification of the boundary of a pulmonary sequestration.

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.

Low-dose indocyanine green fluorescence-navigated segmentectomy: prospective analysis of 20 cases and review of previous reports

Background

A technique of visualizing the demarcation line based with indocyanine green (ICG) was recently developed, and its utility was reported. We demonstrated the safety and utility of low-dose (5 mg/body) ICG fluorescence-navigated video-assisted thoracic surgery (VATS) segmentectomy.

Methods

Patients who had undergone lung segmentectomy for early-stage non-small cell lung cancer (NSCLC) or small pulmonary metastasis were included in this study. ICG at 5 mg/body was rapidly injected into the peripheral vein, and the lung was observed using near-infrared (NIR) fluorescence thoracoscopy. We evaluated the identification rate of the demarcation line based on NIR fluorescence imaging with ICG and the perioperative outcomes.

Results

Lung segmentectomy NIR fluorescence imaging with ICG was performed in 20 patients. The identification of the target segmental line was possible in 18 (90%) of the 20 patients. The median duration of chest tube placement was one day, and the median length of postoperative stay was 8 days. Complications occurred in 5 (25%) of the 20 patients. All cases were prolonged air leak that required pleurodesis. There were no complications resulting from NIR fluorescence imaging with ICG.

Conclusions

NIR fluorescence imaging with ICG is safe and useful for the identification of the demarcation line for lung segmentectomy. Low-dose ICG might achieve a sufficient rate of identification of the segmental line.

Segmentectomia pulmonar anatômica robótica: aspectos técnicos e desfechos

RESUMO Objetivo: relatar nossa experiência inicial com a segmentectomia robótica, descrevendo a técnica operatória, a colocação preferencial dos portais, os resultados iniciais e desfechos. Métodos: dados clínicos de pacientes submetidos à segmentectomia robótica, entre janeiro de 2017 e dezembro de 2018, foram obtidos de um banco de dados prospectivo de cirurgia robótica. Todos os pacientes tinham câncer de pulmão, primário ou secundário, ou doenças benignas, e foram operados usando o sistema Da Vinci com a técnica de três portais mais uma incisão utilitária de 3cm. As estruturas hilares foram dissecadas individualmente e as ligaduras dos ramos arteriais e venosos, dos brônquios segmentares, assim como, a transecção do parênquima, realizadas com grampeadores endoscópicos. Dissecção sistemática dos linfonodos mediastinais foi realizada para os casos de câncer de pulmão não de pequenas células (CPNPC). Resultados: quarenta e nove pacientes, dos quais 33 mulheres, foram submetidos à segmentectomia robótica. A média de idade foi de 68 anos. A maioria dos pacientes tinha CPNPC (n=34), seguido de doença metastática (n=11) e doenças benignas (n=4). Não houve conversão para cirurgia aberta ou vídeo, ou conversão para lobectomia. A mediana do tempo operatório total foi de 160 minutos e do tempo de console foi de 117 minutos. Complicações pós-operatórias ocorreram em nove pacientes (18,3%), dos quais sete (14,2%) tiveram internação prolongada (>7 dias) devido à fístula aérea persistente (n=4; 8,1%) ou complicações abdominais (n=2; 4%). Conclusão: a segmentectomia robótica é um procedimento seguro e viável, oferecendo curto período de internação e baixa morbidade.

The role of indocyanine green fluorescence for intersegmental plane identification during video-assisted thoracoscopic surgery segmentectomies

Background

According to recent studies, thoracoscopic segmentectomy is an acceptable alternative to lobectomy for treating different lung diseases. This approach appears to have equivalent rates of postoperative morbidity with potentially similar long-term results even in selected lung cancer patients. At the same time, surgical success is highly dependent on intraoperative interpretation of segmental anatomy. We aimed to analyze our lung segmentectomy experience and identify the role of indocyanine green (ICG)-fluorescence for intersegmental plane detection.

Methods

A total of 86 consecutive patients who underwent 90 thoracoscopic segmentectomies with near-infrared-indocyanine green (NIR-ICG) method between September 2015 and December 2017 were investigated. According to the preoperative 3D lung hilar model, vascular and bronchial branches of the target segment were divided. ICG was thereafter injected into the central or peripheral vein. The boundary lines between the areas with and without fluorescence was marked on the visceral pleura by electrocautery.

Results

The fluorescence was detected immediately after bolus ICG injection in the central vein in all patients but had a time delay of 10-25 seconds in cases of peripheral vein administration. The median duration of intensive ICG staining was 90 seconds, regardless of the injection method. Well-defined fluorescence borders were observed in 86 of 90 (95.6%) segmentectomies due to technical reasons in three cases and severe emphysema in one. Chronic obstructive pulmonary disease (COPD) in other patients did not impair the boundary line identification, but reduced the duration of intensive ICG staining. No ICG-related complications were observed.

Conclusions

The ICG-fluorescence technology is safe and effective for verification of anatomic segment borders for video-assisted thoracoscopic surgery (VATS). The perfusion-based ICG fluorescence technique has advantages for thoracoscopic surgeries compared to other methods. Doubling the dose of ICG allows clear detection of the intersegmental plane, even in certain suboptimal conditions.

Prolonged intravenous indocyanine green visualization by temporary pulmonary vein clamping: real-time intraoperative fluorescence image guide for thoracoscopic anatomical segmentectomy

The real-time endoscopic colour and fluorescence-merged imaging system, using intravenous injection of indocyanine green (ICG), allows a clear surgical view, which facilitates identification of the pulmonary inter-segmental plane in thoracoscopic surgery. However, the staining time is too short to mark and cut the intersegmental plane, because the mean washout time of ICG is only a few minutes in the clinical setting. To overcome this limitation, we have developed a new technique for prolongation of ICG staining time. The technique consists of 2 simple steps. First, we cut the targeted segmental artery, vein and bronchus. Second, ICG is injected intravenously, followed by temporary clamping of the pulmonary vein of entire lobe, including the segments. Our technique may not only offer prolonged washout time for marking the surface of the lung but also facilitate identification of precise intersegmental plane to be cut.

Uniportal video-assisted thoracoscopic S8 segmentectomy and S1a subsegmentectomy for synchronous multiple primary lung cancers

With the increasing incidence of synchronous multiple primary lung cancers (SMPLC), difficulties in diagnosis and decision making for treating patients with SMPLC can result in clinical dilemmas for clinicians. To simplify the diagnostic and treatment course, the less-invasive technique of video-assisted thoracic surgery (VATS) segmentectomy and subsegmentectomy can be selected preferentially. However, segmentectomy and subsegmentectomy are technically more sophisticated compared to lobectomy, and they involve the identification of the nodule locations, confirmation of the targeted structures and ensuring the surgical margin. Here, we describe the performance of uniportal VATS segmentectomy and subsegmentectomy technique in a patient with SMPLC in the right upper lobe with the assistance of three-dimensional (3D) navigation. We detected the intersegmental planes using infrared thoracoscopy with an intravenous injection of indocyanine green (ICG). The patient was discharged with no complication. We think that uniportal VATS segmentectomy is a feasible alternative and technically safe for treating patients with SMPLC.

Image-guided video-assisted thoracoscopic small lung tumor resection using near-infrared marking

BACKGROUND

Localization of non-visible, non-palpable small pulmonary nodules during video-assisted thoracoscopic surgery (VATS) remains challenging. We sought to investigate the feasibility and safety of image-guided video-assisted thoracoscopic surgery (iVATS) with near-infrared (NIR) marking in a hybrid operating room (OR).

METHODS

Both localization and surgery were performed by a single team of thoracic surgeons. Diluted indocyanine green (ICG; quantity: 0.3-0.5 mL; dye concentration: 0.125 mg/mL) was injected percutaneously to pinpoint the tumor's location under cone beam computed tomography (CBCT) guidance using a laser-guided navigation system. Real-time fluorescence images were intraoperatively obtained using a NIR thoracoscopic camera to guide subsequent resection.

RESULTS

Between March and December 2017, 26 patients underwent NIR marking of small pulmonary nodules for iVATS. The median tumor size was 7 mm (interquartile range [IQR] 5.3-10.8 mm), whereas their median distance from the pleural surface was 5 mm (IQR 0.3-10.5 mm). Seven nodules (35%) were solid, whereas 17 (65%) were ground-glass opacities. All lesions were identifiable on intraoperative CBCT. The median time required for NIR localization was 13 min. An NIR(+) "tattoo" was identified in all cases, and no intraoperative conversion to thoracotomy occurred. The final pathological diagnoses were primary lung cancer (n = 11), metastatic cancer (n = 6), and benign lung tumor (n = 9). Adverse events were not observed, and the median length of post-operative stay was 4 days (IQR 3-4 days).

CONCLUSIONS

Our data show that iVATS with NIR marking is useful, has no adverse effects, and can successfully localize difficult-to-identify small pulmonary nodules.

Determination of the intersegmental plane using the slip-knot method

Background

Visualization of intersegmental planes in the lung is desirable for precise anatomical lung segmentectomy. We developed the slip-knot method for creating inflation-deflation lines. This study aimed to assess relevant data for thoracoscopic segmentectomy performed using this method.

Methods

In the slip-knot method, the objective segmental bronchus is looped with a monofilament thread. One end of the thread is then pulled during temporary bilateral ventilation, causing the knot to slip toward the bronchus. Thereafter, bronchial ligation is tightened to block the outflow of segmental air, ensuring that the segment remains expanded while the other reserved segments collapse on resumption of unilateral ventilation. Data from 221 patients who underwent thoracoscopic pulmonary segmentectomy between 2010 and 2016 were analyzed.

Results

A total of 147 patients (67%) were indicated for the slip-knot method, and 74 cases (33%) were non-adaptive cases. Ninety six percent of 147 cases were well adapted to the slip-knot method, which allowed us to obtain good inflation-deflation line images to determine the intersegmental plane. The mean operative time was 171±51 min (range, 71-367 min). The mean duration of chest tube insertion was 1.5±1.2 days (range, 1-7 days). Three cases (2.0%) had prolonged air-leakage and one (0.7%) case had readmission for late air-leakage.

Conclusions

Our method enables determination of anatomical intersegmental planes using only one monofilament thread, thus facilitating thoracoscopic pulmonary anatomical segmentectomy.

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/).

Uniportal video-assisted thoracic lung segmentectomy with near infrared/indocyanine green intersegmental plane identification

In the era of lung cancer screening and early detection of lung lesions, pulmonary segmentectomy has gained wide acceptance between thoracic community reducing the need of lobectomy for diagnostic purpose and treatment in case of centrally located benign, multiple or undetermined lesions. In rigorously selected patients with stage I non-small cell lung cancer (NSCLC), segmentectomies seem to offer similar survival outcomes rather than lobectomies, but associated with a better conservation of lung function. However, segmentectomy is a more challenging procedure to be performed compared to lobectomy, especially by video-assisted thoracic surgery (VATS). Many difficulties could arise during video-assisted segmentectomy, making the procedure more demanding and stressful. Following the introduction of the near infrared (NIR)/indocyanine imaging system on standard endoscopic module, we decided to adopt peripheral intravenous injection of indocyanine green (ICG) to identify intersegmental plain during uniportal VATS lung segmentectomy. Our technique herein is widely illustrated.

How to demarcate intersegmental plane with resected-segments inflation method using the slip knot technique in thoracoscopic anatomic segmentectomy

Intersegmental demarcation line on the surface of the visceral pleura could not be found at thoracoscopic findings. The resected segments inflation (RSI) method has been reported as a useful technique for visualizing the intersegmental demarcation line during segmentectomy. Thoracoscopic anatomic segmentectomy is performed as follows: firstly, the pulmonary vein and artery of the segment planned for resection are dissected from the hilum in order to isolate the segmental bronchus located behind the pulmonary artery. Secondly, a monofilament non-absorbable suture is passed through the segmental bronchus, and a slip-knot is made outside the thorax. Thirdly, bilateral lung ventilation with pure oxygen is conducted. When the affected segment has inflated sufficiently, the slip knot suture is pulled and the segmental bronchus is ligated and collapse of the lung is made on reserved segments. Fourthly, as inflation of the affected segment and collapse of the reserved segments could be found, resection of intersegmental plane could be easily performed with the inflation-deflation line and the intersegmental pulmonary vein. If resected segmental bronchus could be identified, thoracoscopic segmentectomy with the slip-knot technique would be applicable. This slip-knot procedure is economical and is not need special instrument.

3D-CT anatomy for VATS segmentectomy

Segmentectomy has become a widely adopted surgical procedure, with recent reports describing the use of video-assisted thoracoscopic surgery (VATS) and robotic surgery. A major feature of segmentectomy is that it requires a three-dimensional (3D) understanding of the patient's pulmonary structure and a thorough preoperative analysis of the patient's individual anatomy. Here, we present our method for VATS segmentectomy based on 3D-computed tomography (3D-CT), with a review of the literature. We focus on techniques for 3D-CT reconstruction, analyses of the individual anatomy and anomalies, preoperative simulations of the procedure and surgical margin, and intraoperative navigation with 3D-CT images. We also reference the roles of members of our multi-disciplinary surgical team.

A segmental labeling technique for non-intubated thoracoscopic anatomical segmentectomy

Herein we present a method of pulmonary segmental labeling for non-intubated thoracoscopic segmentectomy assisted with artificial pneumothorax, which is assumed to obtain a significant colored inflation-deflation line between target segment and adjacent normal tissues for precise resection.