Sublobar anatomic resection or segmentectomy has been proposed for selected patients with early lung cancer . However, total thoracoscopic pulmonary segmentectomy or subsegmentectomy is not yet popular with thoracic surgeons. In recent years, the diagnosis of early lung cancers with ground-glass opacity has been increasing due to developments in computed tomography. Additionally, new electrosurgical devices  have been developed and the application of three-dimensional computed tomography (3DCT)?is gaining popularity in the simulation of the approach method and detection of the course of the vessels . In this situation, thoracoscopic segmentectomy of the lung has been gradually adapted for early lung cancer to secure an adequate surgical margin and to reduce surgical injury [4,5]. However, thoracoscopic segmentectomy and subsegmentectomy are more difficult than lobectomy because of the complexity of the procedure. In these procedures, precise detection of the pulmonary vessels and identification and division of intersegmental plane are very essential issues. There are few reports on thoracoscopic subsegmentectomy for early lung cancer . We describe our technique of two separate total thoracoscopic bi-segmentectomies by using preoperative three-dimensional computed tomography (3D-CT) and new electrosurgical devices.
A 63-year-old male with a gradually enlarging ground glass lesion (6 mm in size on CT: Figure 1) in right lung segment 2a was admitted to our institute for histological diagnosis and treatment. Preoperative 3D-CT showed the following (Figure 2) the tumor was localized in the intersegmental plane between S1 and S2, the pulmonary artery supplying segment 2 (A2) was composed of a descending A2 and an ascending A2, and the right upper lobe pulmonary vein (PV) was a central vein type. The bronchi B1 and B2 had 2 subsegmental branches each. The needle marker (Guiding Marker System; Hakko Medical Products, Tokyo, Japan) was put around the tumor under CT guidance on the day before surgery . Bisubsegmentectomy was subsequently scheduled.
Figure 1. Preoperative computed tomography showing a 6mm ground grass lesion in right lung segment 2a close to segment 1a.
Figure 2. A) The tumor was localized in the intersegmental plane between S1 and S2, the pulmonary artery supplying segment 2 (A2) was composed of a descending A2 and an ascending A2.
Figure 2B) The right upper lobe pulmonary vein (PV) was a central vein type. The V1b and V2b (intersubsegmental veins) were preserved with S1b and S2b respectively because of the main drainage veins
Figure 2C) The bronchi B1 and B2 had 2 subsegmental branches each.
Two thoracoports were placed in the sixth intercostal space (ICS) anterior axillary line and seventh ICS posterior axillary line. The anterolateral 30mm utility port was placed in the fourth ICS. The pulmonary arterial branches were dissected (descending A2 and A1a). To make the inflation-deflation demarcation line, the subsegmental bronchus (B1a, B2a) was ligated and divided after inflation of the right lung, and single ventilation of the left lung followed. Outer intersubsegmental division by electrocautery was performed with the use of the inflation–deflation demarcation line, and inner intersubsegmental division was done with the VSS?(LigaSure™ V, Covidien, Mansfield, USA) along the intersubsegmental pulmonary veins (V2b and V1a) as guides to confirm the intersubsegmental plane (Figure 3). After subsegmental division and pulmonary vessel division (V2a and V1a), the S1a+S2a were removed. The V1b and V2b were preserved with S1b and S2b respectively because of the main drainage veins. The #11s and #12u nodes were sampled during the procedures. The intersubsegmental planes were covered with fibrin sealant after pulmonary fistula was managed using the Vio Soft coagulation device system (VSCS?VIO 300D; ERBE Elektromedizin, Tübingen, Germany). The intraoperative frozen-section examination of a lesion in S2a revealed adenocarcinoma in situ without nodal involvement. Thoracoscopic bisubsegmentectomy was successfully completed with a total operative time of 236 min and blood loss of 60mL. The chest tube was removed on postoperative day 5, and the patient was uneventfully discharged.
Figure 3A. Intersubsegmental pulmonary veins (V2b) as guides to confirm the intersubsegmental plane RS2a-RS2b.
Figure 3B. Intersubsegmental pulmonary veins (V1a) as guides to confirm the intersubsegmental plane RS1a-RS1b.
An intentional pulmonary anatomical reduction surgery is an option to treat peripheral small-sized non-small cell lung carcinoma. Thoracoscopic segmentectomy has been increasingly employed with the advancement in surgical device and diagnostic equipment. Smaller lung resection may be able to secure sufficient surgical margin for a small tumor. The surgical margin greater than the size of the tumor can reduce locoregional recurrence [1,8]. If the tumor is located across the segmental range, a combination of subsegmentectomy can provide adequate surgical margin. The procedure is also useful for postoperative respiratory function preservation.
Visualization of the inflation-deflation lines is reportedly useful for intersegmental determination and dissection . This procedure allows air in the subsegmental branches to make effective inter-subsegmental inflation-deflation lines.
Obtaining adequate anatomical interpretation by the use of 3D-CT for preoperative or intraoperative simulation of the pulmonary vessels led to a safe and radical procedure of thoracoscopic segmentectomy . It also enables visualization of pulmonary vessels at subsegmental level because of increasingly clear image processing. However, the hilum side and subsegmental surface split along the pulmonary vein are not clearly divided. Some of the bronchioles and small blood vessels exist between the subsegmental surfaces. Using a VSS is a very safe and useful device for intersubsegmental division and pulmonary vessel division [2,10,11]. Furthermore, VSCS induces organization of protein denaturation at relatively low temperatures, which effectively closes a pulmonary fistula. Of course, pulmonary fistula at the level of the bronchioles needs direct closure, but small leakage can be repaired in the divided subsegmental surface with VSCS.
With the pre-operative 3D-CT for simulation of the complex vessel structure, VSS to expose and divide the pulmonary vascular vessels and VSCS to seal pulmonary fistula, total thoracoscopic bisubsegmentectomy of the right upper S1a+2a was safely performed.
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