Consensus on the digestive endoscopic tunnel technique

Figure 1 Mechanism of digestive endoscopic tunnel technique, demonstrating a tunnel that is created between the mucosal and muscularis propria layers.

Figure 2 Three methods of tunnel incision and closure. A and B: Longitudinal incision; C and D: Longitudinal incision closed with titanium clips; E: Transverse incision; F: “Anchoring” of a titanium clip in the middle of the transverse incision; G and H: Longitudinal closure using titanium clips successively; I: Inverted T incision; J-L: Longitudinal closure using titanium clips successively.

Figure 3 Schema chart of endoscopic submucosal tunnel dissection, demonstrating a tunnel that is created to resect mucosal lesions.

Figure 4 Simulated diagram of endoscopic observations in Ling IIb and Ling IIc. A: Ling IIb. The arrows indicate 1/3 of the oesophageal cavity, and the semi-annular structure’s midpoint remains within this range; B: Ling IIc. The arrows indicate 1/3 of the oesophageal cavity, and the crescent-like structure's midpoint goes beyond this range.

Figure 5 Endoscopic images of the Ling classification of achalasia cardia. A: Ling I; B: Ling IIa; C: Ling IIb; D: Ling IIc, E: Ling III1; F: Ling IIIr; G: Ling IIIlr.

Figure 6 Correlation between grade A or grade B mucosal inflammation and mild oesophageal submucosal adhesion. A: Grade A mucosal inflammation; B: Grade B mucosal inflammation; C: Mild oesophageal submucosal adhesion: The fibre filaments are distributed in bundles.

Figure 7 Correlation between Grade C mucosal inflammation and moderate oesophageal submucosal adhesion. A: Grade C mucosal inflammation; B: Moderate oesophageal submucosal adhesion. The fibres are arranged in disorder, with fusion and decreased transparency.

Figure 8 Correlation between Grade D, Grade E, or Grade F mucosal inflammation and severe oesophageal submucosal adhesion. A: Grade D mucosal inflammation; B: Grade E mucosal inflammation; C: Grade F mucosal inflammation; D: Severe oesophageal submucosal adhesion. The submucosa and muscularis propria are completely adherent.

Figure 9 Anatomical landmark in the tunnel from the lower oesophagus to the cardia. A: Grid-like blood vessels in the cardia; B: Crescent-like structure visible at the proximal cardia; C: Ampulla-like structure appearing after entering the crescent-like structure; D: Branching vessels with bulky vascular roots in the ampulla-like structure; E: Tunnel below the cardia, showing a steep downward form; F: Stubby and multi-branched vessels below the cardia; G: Beadlike vessels below the cardia.

Figure 10 Schema chart of per-oral endoscopic myotomy, demonstrating a tunnel that is created to incise the muscularis propria.

Figure 11 Endoscope crosses the “ridge” via short-tunnel per-oral endoscopic myotomy. A: Type Ling IIc oesophagus. The arrow indicates a “ridge” structure formed by the crescent-like structure; B: The short-tunnel entry incision established on a relatively flat oesophageal wall at the oral side of the “ridge”; C: It is easy to cross the “ridge” within the tunnel.

Figure 12 Inner circular muscle myotomy. The arrow shows the well-retained longitudinal muscle.

Figure 13 Full-thickness myotomy. The arrow shows the tunica adventitia of the oesophagus.

Figure 14 Glasses-style myotomy. The arrow shows the muscles remaining at the cardia.

Figure 15 Circular muscle myotomy + balloon plasty. A: The width of the incision should be 1/3 of the circumferential oesophagus; B: Balloon-dilation in the oesophagus; C: The width of the incision after expansion should be 2/3 of the circumferential oesophagus.

Figure 16 Progressive full-thickness myotomy. The yellow arrow shows the incision into the inner circular muscles from superficial to deep; the blue arrow shows the full incision into the muscularis propria.

Figure 17 Schema chart of per-oral endoscopic myotomy, demonstrating a tunnel that is created to resect the lesion from the muscularis propria.

Figure 18 Key steps of submucosal tunnelling endoscopic resection for a cardial submucosal tumour. A: Injection of methylene blue into the lesion incision site for marking and positioning; B: Establishment of a tunnel; C: Finding of the marking and positioning with methylene blue in the tunnel; D: Exposure of the lesion; E: Resection of the lesion; F: Wound following the resection of the tumour; G: Closure of the mucosal incision; H: The resected specimen.

Figure 19 Schema chart of digestive endoscopic tunnel technique on the external digestive tract wall, demonstrating a tunnel that is created to resect a node outside the digestive tract.