Kenta Nakahashi

Learning curve for port-access thoracoscopic anatomic lung segmentectomy

Objectives There have been few prospective randomized studies, but many retrospective studies strongly suggest the benefits of segmentectomy in properly selected patients. The indications for video‐assisted thoracic surgery segmentectomy are growing because of the effectiveness and minimal invasiveness of the procedure. The aim of the present study was to analyze the learning curve for video‐assisted thoracic surgery segmentectomy procedures in our institution. Methods We prospectively collected data from patients undergoing video‐assisted thoracic surgery segmentectomy and retrospectively reviewed 252 patients from 2004 to 2015. Operative time, bleeding, and complications were analyzed. The learning curve was evaluated using operative time and the cumulative sum value of operative time in all cases with regard to the leading surgeon and nonleading surgeon at our institution. Results Once we applied the cumulative sum method to all cases, we obtained a graph for the cumulative sum value of operative time that showed 3 well‐differentiated phases: phase 1 (n = 61), the initial learning phase; phase 2 (n = 23), the increased competence phase; and phase 3 (n = 168), the highest skill phase. As we compared phases 1 and 2 with phase 3, we observed significant differences in relation to operative time (P < .001) and bleeding (P < .001). Without level 3 segmentectomy, we observed a significant reduction in operative time after 32 cases for the leading surgeon and a significant reduction in operative time and bleeding after 38 cases for the nonleading surgeon. Conclusions The data suggest that the inflection point for the learning curve was achieved after 84 cases in our institution. Therefore, increased aptitude with video‐assisted thoracic surgery is achievable within a relatively short time.

Thoracoscopic wedge resection and segmentectomy for small-sized pulmonary nodules

With the recent increase in the detection of small-sized lung nodules because of the widespread use of computed tomography (CT), limited resection and minimally invasive surgery are preferred by patients with these lesions. In particular, the detection of nodules that show ground-glass opacity during high-resolution CT has increased. Although lobectomy and lymph node dissection were the standard procedures used for treating lung cancer, limited wedge resection and segmentectomy have become acceptable for treating small-sized lung cancers with nodules showing ground-glass opacity. These limited procedures are widely performed, especially because they can be accomplished thoracoscopically. Furthermore, not only simple segmentectomy but also complex segmentectomy and subsegmentectomy can be performed using three-dimensional (3D)-CT to achieve sufficient resection based on tumor size. There are, however, technical difficulties in thoracoscopic wedge resection and segmentectomy. While it may be curative for small-sized lung nodules, it is sometimes difficult to correctly perform wedge resection when the tumor is not identified intraoperatively. In such cases, we usually perform tumor marking before operating. However, serious complications, such as cerebral air embolism, have been reported. Further, although it can sufficiently resect small-sized lung nodules, segmentectomy is more technically complex than wedge resection. Therefore, we have developed methods to overcome these technical difficulties. By using a hookwire method in a hybrid operating room and 3D-CT simulation for each wedge resection and segmentectomy, we have obtained good outcomes. Limited resection individualized for each patient will continue to evolve with applications such as CT.

Thoracoscopic anatomical S10 segmentectomy: a posterior approach

Although previous reports have described thoracoscopic segmentectomies, an anatomical thoracoscopic posterior basal segmentectomy is difficult to perform because arteries and bronchi are located deep within the parenchyma in the vicinity of the major fissure and the presence of multiple dissection surfaces. In addition, separation of superior and anterior basal segments occurs to perform this resection from the interlobar fissure. We developed a posterior approach for the resection of the posterior (S10) or the lateral and posterior (S9+10) basal segments based on three-dimensional computed tomography (3D-CT) surgical simulation. To date, we have performed 28 port access anatomical lung segmentectomies using this posterior approach. The primary steps of the surgical procedure have been presented in this article.

What is the most appropriate procedure for intraoperative localization of small pulmonary nodules

Ciriaco and colleagues described some methods and advantages concerning the intraoperative localization for pulmonary nodules. The researchers previously reported the preoperative computed tomography (CT)-guided hookwire localization method of pulmonary nodules (1). We thank them for mentioning our manuscript as an alternative method of resection for small nodules that require intraoperative localization.

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.

Our novel procedure for thoracoscopic anatomical segmentectomy

Since 2004, over 300 patients have undergone thoracoscopic segmentectomy without mini-thoracotomy. Thoracoscopic segmentectomy is one of the most complicated surgeries. To perform the complex segmentectomies, pre-operative simulation and 3-dimensional multi-detector computed tomography( 3DCT) are both essential for safely performing operations and for securing adequate surgical margins. Comprehension of the intersegmental and intrasegmental veins to visualize the segmental border facilitates an easier parenchymal dissection. We describe our method and knack for creating an inflation-deflation line for lung segmentectomy that could especially be useful in thoracoscopic procedures for seg-mentectomy. The 5-year over overall survival, cancer specific survival and recurrence free survival rates were 91.8%( curative intent 98.1% versus compromised 74.6%), 100% and 98.1%( curative intent 100% versus compromised 93.3%). According to these technical aspects, our method of thoracoscopic segmentectomy is acceptable for selective patient.

Video-assisted thoracoscopic subsegmentectomy for small-sized pulmonary nodules

Segmentectomy has been widely performed as one of the types of limited resections that are performed for the resection of small-sized lung nodules. Video-assisted thoracoscopic surgery has also been in demand as a minimally invasive surgery. Subsegmentectomy is a much more limited resection than segmentectomy, but the technique is complex because it requires keen anatomical identification of small pulmonary structures. Therefore, there has been little reported about subsegmentectomy in medical literature. The recent development of computed tomography is remarkable, and some reports describe three-dimensional computed tomography as providing useful information because it assists surgeons in the performance of thoracoscopic anatomical subsegmentectomy. The creation of an intersubsegmental line is a key process in subsegmentectomy, therefore, some methods have been reported. We have safely and accurately performed some video-assisted thoracoscopic subsegmentectomies for small-sized lung tumors, using the three-dimensional computed tomography simulation and creating the intersubsegmental line with the inflation-deflation technique. In this article, we describe the recent techniques and roles of video-assisted thoracoscopic subsegmentectomy, and offer prospects for this procedure with our clinical data.

Swine model for training surgeons in minimally invasive anatomic lung segmentectomy

BACKGROUND Despite the increasing demand for thoracoscopic lung segmentectomy, the appropriate training method is not well established. Therefore, we developed a swine model for anatomical thoracoscopic lung segmentectomy training. METHODS Three-month-old pigs, weighing 40 to 45 kg, were used in this model. Anterior segmentectomy of the left cranial lobe and segmentectomy of the most anterior left caudal lobe were performed under general anesthesia and differential ventilation. Participants from several institutions participated in this program, which included training lectures and surgical skill drills. RESULTS From 2010 to 2015, 33 pigs were used for the lung segmentectomy training with 51 trainees. Eight pigs were operated on using the hybrid approach, and 25 pigs were operated on using the complete thoracoscopic approach. Among 25 pigs in which the complete thoracoscopic approach was used, conversion to thoracotomy was required in 3 pigs, owing to hemorrhage in two and failure of differential ventilation in one. The no-touch method in supine position provided sufficient intersegmental delineation of 20 (76%) planes among 26 left anterior segmentectomies in the cranial lobe. CONCLUSIONS Our live swine model of anatomical thoracoscopic lung segmentectomy is considered a good choice for training surgeons on how to perform minimally invasive lung segmentectomy in humans.

Port-access thoracoscopic bisubsegmentectomy of right upper lobe posterior and anterior segments

A 64-year-old woman was admitted to our hospital with a 16-mm non-solid tumor with pure ground-glass nodule (GGN) contents in the posterior segment near the anterior segment of her right upper lung lobe that was suspicious of adenocarcinoma in situ (AIS). Three-dimensional computed tomography (3DCT) simulation was performed to identify the subsegmental artery and vein pre- or intra-operatively. Port-access thoracoscopic bisubsegmentectomy of the right upper lobe was performed. A frozen section revealed AIS. The tumor size was 13 mm and the surgical margin from the tumor edge to cutting line was more than 20 mm. The surgical time was 191 minutes and bleeding was 101 mL. The chest tube duration was 3 days and the post-operative hospital stay was 6 days.