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

Abstract

Anatomical segmentectomies play an important role in oncological lung resection, particularly for ground-glass types of primary lung cancers. This operation can also be applied to metastatic lung tumors deep in the lung. Virtual assisted lung mapping (VAL-MAP) is a novel technique that allows for bronchoscopic multi-spot dye markings to provide "geometric information" to the lung surface, using three-dimensional virtual images. In addition to wedge resections, VAL-MAP has been found to be useful in thoracoscopic segmentectomies, particularly complex segmentectomies, such as combined subsegmentectomies or extended segmentectomies. There are five steps in VAL-MAP-assisted segmentectomies: (I) "standing" stitches along the resection lines; (II) cleaning hilar anatomy; (III) confirming hilar anatomy; (IV) going 1 cm deeper; (V) step-by-step stapling technique. Depending on the anatomy, segmentectomies can be classified into linear (lingular, S6, S2), V-or U-shaped (right S1, left S3, S2b + S3a), and three dimensional (S7, S8, S9, S10) segmentectomies. Particularly three dimensional segmentectomies are challenging in the complexity of stapling techniques. This review focuses on how VAL-MAP can be utilized in segmentectomy, and how this technique can assist the stapling process in even the most challenging ones.

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

“…Technical details of stapler-based segmentectomy in general have been described previously (1). We usually use virtual-assisted lung mapping (VAL-MAP), a preoperative bronchoscopic multi-spot dye marking technique, to determine appropriate resection lines intraoperatively (3,4), although other methods such as conventional and applied inflation-deflation line (5), and intravenous or bronchoscopic indocyanine green (ICG) injection (6)(7)(8) are also usable.…”

“…The hilar anatomy should be carefully inspected in the light of preoperative 3D images, and intraoperative bronchoscopy. Removal of hilar lymph nodes is also important not only for lymph node sampling but for exposure of clean anatomy (1). And then the target bronchus and vessels are resected by a stapler, energy device, or simply after tying.…”

“…The hilar pulmonary parenchyma should be further resected along the intersegmental plane by approximately 1 cm. This maneuver creates space to allow for a stapler to be placed smoothly at the hilum (1).…”

“…Namely, stapling is started from the thing, peripheral, and easy parts of the lung and continued to reach the most difficult hilar stapling and/ or stapling of the thick lung tissue in a step-by-step manner. Especially in segmentectomies involving the basal segment of the lower lobe necessitating three-dimensional stapling, different peripheral stapling are done first and then the staple lines are connected together toward the center (1). Notably it is safe to place the cartilage side of the stapler to the hilum rather than the anvil side, which can easily damage the lung parenchyma or vessels (Figure 2).…”

“…Staplerbased segmentectomy provides better sealing of the lung parenchyma and thus expected to reduce post-operative airleakage and associated complications such as empyema (1). However, the application of stapler-based segmentectomy to S10 is challenging for multiple reasons: (I) similar to other basal segments [e.g., anterior basal segment (S8)], three-dimensional stapling to fold a cuboidal segment is necessary (1); (II) the belonging pulmonary artery is not directly facing the interlobar fissure or the hilum, which makes identification of target artery difficult; (III) the anatomy of S10 and adjacent segments is variable.…”