Safe and Efficient Procedures and Training System for Endoscopic Submucosal Dissection

Abstract

Recent improvements in endoscopists' skills and technological advances have allowed endoscopic submucosal dissection (ESD) to become a standard treatment in general hospitals. As this treatment entails a high risk of accidental perforation or hemorrhage, therapeutic procedures and training methods that enable ESD to be conducted more safely and efficiently are constantly being developed. This article reviews the therapeutic procedures and training methods used to improve the safety and efficiency of ESD and describes the ESD training system used in a Japanese university hospital at which the number of ESD procedures has gradually increased in a newly established Department of Digestive Endoscopy. During the establishment of this department, the ESD perforation rate was zero among all procedures, including those conducted by trainees.

Keywords: endoscopic submucosal dissection; hemorrhage; perforation.

Figure 1

ESD training steps in our facility. Every step is supervised by experts. Abbreviations: ESD: endoscopic submucosal dissection; CS: colonoscopy; EMR: endoscopic mucosal resection.

Figure 2

(a,b) G-Master; (c,d) training scenery using the G-Master.

Figure 3

Making a mucosal flap in G-Master training. (a) While there is sufficient localized fluid injected to the submucosal layer, a short distance mucosal incision and submucosal dissection (trimming) of the area should be repeated. (b) After trimming several times, the distal attachment can be used to burrow under the submucosal layer (success in making the mucosal flap). (c) While keeping the visual field, dissect the submucosal layer so that it is parallel to the muscular layer. (d) Description of the layers. (e) Schema diagram.

Figure 4

Incomplete mucosal flap in G-Master training. (a) If the mucosal incision is extended too wide with inadequate trimming, it is difficult to obtain sufficient submucosal swelling because the injected fluid is spread over a wide area. (b) Because no space can be created between the mucosal and submucosal layers, the distal attachment cannot burrow under the submucosal layer (failure to make the mucosal flap). (c) Schema diagram.

Figure 5

(a) A colorectal training model made from VTT, a basket, an accordion hose, and a tubular snack box. (b) The snack box contains a VTT with the electrode attached. Abbreviations: VTT: versatile training tissue.

Figure 6

Esophageal ESD training using an ex vivo porcine model. (a) An ex vivo porcine model; (b) a training scene showing the instruction of an expert. Abbreviations: ESD: endoscopic mucosal dissection.

Figure 7

(a) Normal position (the esophageal wall at the 6 o’clock position for submucosal dissection). In this case, the flap is more likely to enter the distal attachment when the device is approached toward the submucosal layer. Furthermore, the device that comes out from the underside, the 6 o’clock direction of the scope, is close to the muscular layer, so there is a risk of damaging the muscular layer. (b) The “upside-down” position (the esophageal wall at 12 o’clock for submucosal dissection). By rotating the scope 180°, the device that comes out from the underside, allows the dissection to be made away from the muscular layer. The risk of perforation can be minimized as much as possible by recognizing the safe direction of the esophageal lumen where the device should move and the dissection. (c) Schema diagram of the normal position. (d) Schema diagram of the “upside-down” position.