Hirohisa Kato

Anatomic thoracoscopic pulmonary segmentectomy under 3-dimensional multidetector computed tomography simulation: A report of 52 consecutive cases

OBJECTIVE The purpose of this retrospective study was to evaluate the efficacy of anatomic thoracoscopic pulmonary segmentectomy performed under the guidance of 3-dimensional multidetector computed tomography simulation. METHODS Between September 2004 and June 2009, 52 patients (median age, 68 years; range, 16-85 years) underwent thoracoscopic segmentectomy without mini-thoracotomy. Images were obtained by using 64-channel multidetector computed tomography and a contrast agent. The pulmonary arteriovenous structure was mainly determined using a 3-dimensional volume-rendering method. The preoperative simulation was performed at the initial stage of the study and the intraoperative at a later stage. The simulated images were used to identify the venous branches in the affected segment for division and the intersegmental veins to be preserved. Four 5- to 20-mm ports were used. Segmentectomy was performed by separating the pulmonary arteries and bronchi followed by dissection along the intersegmental plane. RESULTS Fifty-one patients underwent a complete thoracoscopic segmentectomy. A mini-thoracotomy was performed in 1 case because of arterial bleeding. The success rate of segmentectomies under complete thoracoscopy was 98%. The procedure was classified into 3 categories according to the degree of surgical difficulty. Before introducing the simulation, there were 4 easy cases and 1 fairly difficult case. After introducing preoperative simulation, 7 cases were classified as fairly difficult among 12 segmentectomy cases. Furthermore, 7 cases of difficult segmentectomy were performed using intraoperative simulation. No local recurrence or metastasis and no mortality were observed during the follow-up. CONCLUSIONS Thoracoscopic pulmonary segmentectomy under 3-dimensional multidetector computed tomography simulation is a safe technique.

Role of diffusion-weighted magnetic resonance imaging for predicting of tumor invasiveness for clinical stage IA non-small cell lung cancer

OBJECTIVES Recently, diffusion-weighted MR imaging (DWI) for the whole body has become available for clinical use, as has been previously used for the central nervous system. Favorable results have been reported using this imaging system to differentiate between benign and malignant lesions in some organs, and to correlate with the degree of cell differentiation in lung cancer. The purpose of this study was to assess the role of DWI for predicting tumor invasiveness of non-small cell lung cancers (NSCLC), especially for clinical stage IA patients. METHODS From January 2006 to September 2007, preoperative DWI and 18F-FDG-PET/CT were performed on 41 patients with clinical stage IA NSCLC who had undergone curative operations. Lung cancers that exhibited nodal, lymphovascular or pleural invasion were defined as invasive lung cancers. Nodules with strong dark signal, as observed by DWI in spinal cords, were defined as DWI-positive. We analyzed the associations between the pathological findings and the following preoperative clinical factors: age, gender, smoking history, preoperative CEA levels (<5.0 or >/=5.0ng/ml), preoperative tumor size, SUV max on PET/CT (<5.0 or >/=5.0) and DWI (positive or negative). RESULTS A total of 15 lesions (37%) were assessed as DWI-positive and 26 lesions (63%) were DWI-negative. Univariate analyses showed positive correlations for development of invasive cancer with the preoperative CEA level (p=0.049), SUV max (p=0.001) and DWI (p<0.001). Multivariate analysis showed that DWI (p=0.005) was an independent predictive factor for tumor invasiveness. CONCLUSION Our results suggest that DWI might be a useful method for predicting tumor invasiveness for clinical stage IA NSCLC.

Total thoracoscopic pulmonary segmentectomy

OBJECTIVE In lung resection, thoracoscopy has been mainly used for wedge resection and lobectomy. There have been very few reports on pulmonary segmentectomy, mainly because of its complex nature. The present report evaluates the safety and efficacy of thoracoscopic pulmonary segmentectomy for the treatment of benign lung diseases or small lung carcinomas. METHODS The study involved 30 patients who underwent thoracoscopic segmentectomy without a minithoracotomy from September 2004 to March 2008. The median age of the patients was 69 years (range, 16-81 years). Four 5-20 mm ports were used. The pulmonary vessels were ligated, and the bronchi were closed using a stapler. An electrocautery was used for intersegmental dissection. Chest tubes were inserted in all cases. RESULTS Twenty-eight patients underwent complete thoracoscopic segmentectomy. A minithoracotomy was created in one case because of arterial bleeding, and open lobectomy was performed in another case owing to the diagnosis of small cell carcinoma. The operative time ranged from 147 to 425 min (median time, 216 min). The inserted chest tubes were maintained in position for 1-7 days (median duration, 1 day). One patient developed subcutaneous emphysema that spontaneously resolved. No mortality was observed for 30 days after the surgery. Further, no local recurrence or metastases were observed during follow-up in cases of malignancy. CONCLUSIONS Thoracoscopic pulmonary segmentectomy is a feasible and safe technique. Reduced postoperative pain and an improved cosmetic outcome are considered advantages of this minimally invasive procedure.

Slip knot bronchial ligation method for thoracoscopic lung segmentectomy.

We report a novel monofilament slip knot technique for bronchial ligation and for visualization of the anatomic plane during lung segmentectomy. After threading the bronchus, a slip knot is made outside the thorax. During lung ventilation, one end of the string is pulled, and the knot slips to reach the bronchus without a knot-pusher. Bronchial ligation is then performed to block the outflow of segmental air while the segment remains expanded, whereas the other segments become collapsed. This technique allows identification of the anatomic intersegmental plane, facilitating thoracoscopic anatomic lung segmentectomy.

Port-access thoracoscopic anatomical lung subsegmentectomy

OBJECTIVES The diagnosis of small lung nodules has increased in recent years; limited resection and minimally invasive surgery are highly desirable in patients with these lesions. While wedge resection may be curative for small lung nodules, the technique is sometimes difficult to perform when the tumour nodule is near the pulmonary hilum. In such situations, either anatomical segmentectomy or subsegmentectomy can obtain an adequate surgical margin; port-access thoracoscopic surgery is the preferred type of minimally invasive surgery. Three-dimensional (3D) computed tomography (CT) simulations are reportedly useful in planning and performing thoracoscopic surgery. We use 3D CT simulation to aid thoracoscopic segmentectomy for small lung nodules and subsegmentectomy for even smaller nodules and conduct here a retrospective evaluation of the clinical results of subsegmentectomy. We present our technique for 3D CT simulation-assisted port-access thoracoscopic subsegmentectomy in the superior segment of the left lower lobe. METHODS Between July 2008 and June 2012, 15 patients underwent port-access thoracoscopic subsegmentectomy. We evaluated the pathological diagnoses, the tumour sizes, the indications, the operative times and the volumes of blood loss. RESULTS Seven patients were diagnosed with lung cancer (LC) and eight had metastatic lung tumours (MLT). The median tumour size was 12 mm. The indication for using this surgical technique was to secure surgical margins in 13 patients (LC, 6; MLT, 7) and because of poor surgical risk in two patients (LC, 1; MLT, 1). The mean surgical time was 166 min and the median blood loss was 19 ml. There were no recurrences. CONCLUSIONS Port-access thoracoscopic lung subsegmentectomy using 3D CT simulation can be safely performed and is able to secure adequate surgical margins.

Techniques to define segmental anatomy during segmentectomy

Pulmonary segmentectomy is generally acknowledged to be more technically complex than lobectomy. Three-dimensional computed tomography (3D CT) angiography is useful for understanding the pulmonary arterial and venous branching, as well as planning the surgery to secure adequate surgical margins. Comprehension of the intersegmental and intrasegmental veins makes the parenchymal dissection easier. To visualize the segmental border, creation of an inflation-deflation line by using a method of inflating the affected segment has become the standard in small-sized lung cancer surgery. Various modifications to create the segmental demarcation line have been devised to accurately perform the segmentectomy procedure.

Posterior approach to thoracoscopic pulmonary segmentectomy of the dorsal basal segment: A single-institute retrospective review

Objective: Anatomic resection of the dorsal area of the basal segment of the lower lobe is difficult because of the deep location of vessels and bronchi in the parenchyma. This study aimed to describe a novel technique for port‐access thoracoscopic segmentectomy of the dorsal (S10) and lateral dorsal segments (S9+10). Methods: This retrospective study analyzed 20 patients who underwent S10 and S9+10 thoracoscopic segmentectomy via a posterior approach between January 2004 and March 2016. In this approach, the lung parenchyma between S6 and S10 was divided along V6b,c from the dorsal side of the lower lobe, which exposed the targeted bronchus (B10, B9+10) and artery (A10, A9+10) and enabled anatomic S10 and S9+10 segmentectomy. Results: Of the 20 patients, 15 had lung cancer, 3 had metastases, and 2 had benign nodules. The number of segmentectomies of the right S10, right S9+10, left S10, and left S9+10 was 5, 5, 1, and 9, respectively. Median operative time was 165 minutes (range, 107‐276 minutes). The median duration of chest tube insertion was 1 day (range, 1‐2 days). One patient had atelectasis. Median hospital stay was 6 days (range, 3‐11 postoperative days). No recurrence or mortality was observed during the median follow‐up period of 46 months. Conclusions: The posterior approach for port‐access thoracoscopic segmentectomy at S10 or S9+10 is technically challenging, but in our hands it has been feasible. It exposes the targeted bronchus (B10, B9+10) and artery (A10, A9+10) and enables anatomic S10 and S9+10 segmentectomy while avoiding inessential parenchymal splitting from the major fissure.

Thoracoscopic anatomical lung segmentectomy using 3D computed tomography simulation without tumour markings for non-palpable and non-visualized small lung nodules

OBJECTIVES Although wedge resection can be curative for small lung tumours, tumour marking is sometimes required for resection of non-palpable or visually undetectable lung nodules as a method for identification of tumours. Tumour marking sometimes fails and occasionally causes serious complications. We have performed many thoracoscopic segmentectomies using 3D computed tomography simulation for undetectable small lung tumours without any tumour markings. The aim of this study was to investigate whether thoracoscopic segmentectomy planned with 3D computed tomography simulation could precisely remove non-palpable and visually undetectable tumours. METHODS Between January 2012 and March 2016, 58 patients underwent thoracoscopic segmentectomy using 3D computed tomography simulation for non-palpable, visually undetectable tumours. Surgical outcomes were evaluated. RESULTS A total of 35, 14 and 9 patients underwent segmentectomy, subsegmentectomy and segmentectomy combined with adjacent subsegmentectomy, respectively. All tumours were correctly resected without tumour marking. The median tumour size and distance from the visceral pleura was 14 ± 5.2 mm (range 5-27 mm) and 11.6 mm (range 1-38.8 mm), respectively. Median values related to the procedures were operative time, 176 min (range 83-370 min); blood loss, 43 ml (range 0-419 ml); duration of chest tube placement, 1 day (range 1-8 days); and postoperative hospital stay, 5 days (range 3-12 days). Two cases were converted to open thoracotomy due to bleeding. Three cases required pleurodesis for pleural fistula. No recurrences occurred during the mean follow-up period of 44.4 months (range 5-53 months). CONCLUSIONS Thoracoscopic segmentectomy using 3D computed tomography simulation was feasible and could be performed to resect undetectable tumours with no tumour markings.

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.