Advancements in the Diagnosis of Gastric Subepithelial Tumors

A diagnosis of subepithelial tumors (SETs) is sometimes difficult due to the existence of overlying mucosa on the lesions, which hampers optical diagnosis by conventional endoscopy and tissue sampling with standard biopsy forceps. Imaging modalities, by using computed tomography and endoscopic ultrasonography (EUS) are mandatory to noninvasively collect the target’s information and to opt candidates for further evaluation. Particularly, EUS is an indispensable diagnostic modality for assessing the lesions precisely and evaluating the possibility of malignancy. The diagnostic ability of EUS appears increased by the combined use of contrast-enhancement or elastography. Histology is the gold standard for obtaining the final diagnosis. Tissue sampling requires special techniques to break the mucosal barrier. Although EUS-guided fine-needle aspiration (EUS-FNA) is commonly applied, mucosal cutting biopsy and mucosal incision-assisted biopsy are comparable methods to definitively obtain tissues from the exposed surface of lesions and seem more useful than EUS-FNA for small SETs. Recent advancements in artificial intelligence (AI) have a potential to drastically change the diagnostic strategy for SETs. Development and establishment of noninvasive methods including AI-assisted diagnosis are expected to provide an alternative to invasive, histological diagnosis.

Three-Dimensional Flexible Endoscopy Can Facilitate Efficient and Reliable Endoscopic Hand Suturing: An ex-vivo Study

Background/Aims@#Three-dimensional (3D) flexible endoscopy, a new imaging modality that provides a stereoscopic view, can facilitate endoscopic hand suturing (EHS), a novel intraluminal suturing technique. This ex-vivo pilot study evaluated the usefulness of 3D endoscopy in EHS. @*Methods@#Four endoscopists (two certified, two non-certified) performed EHS in six sessions on a soft resin pad. Each session involved five stitches, under alternating 3D and two-dimensional (2D) conditions. Suturing time (sec/session), changes in suturing time, and accuracy of suturing were compared between 2D and 3D conditions. @*Results@#The mean suturing time was shorter in 3D than in 2D (9.8±3.4 min/session vs. 11.2±5.1 min/session) conditions and EHS was completed faster in 3D conditions, particularly by non-certified endoscopists. The suturing speed increased as the 3D sessions progressed. Error rates (failure to grasp the needle, failure to thread the needle, and puncture retrial) in the 3D condition were lower than those in the 2D condition, whereas there was no apparent difference in deviation distance. @*Conclusions@#3D endoscopy may contribute to increasing the speed and accuracy of EHS in a short time period. Stereoscopic viewing during 3D endoscopy may help in efficient skill acquisition for EHS, particularly among novice endoscopists.

The Efficacy of an Endoscopic Grasp-and-Traction Device for Gastric Endoscopic Submucosal Dissection: An Ex Vivo Comparative Study (with Video)

BACKGROUND/AIMS: To investigate whether the EndoLifter (Olympus), a counter-traction device facilitating submucosal dissection, can accelerate endoscopic submucosal dissection (ESD). METHODS: Two endoscopists (novice/expert in ESD) performed 64 ESDs (artificial 3-cm lesions) in 16 ex vivo pig stomachs: per stomach, two at the posterior wall (forward approach) and two at the lesser curvature (retroflex approach). Per approach, one lesion was dissected with (EL+) and one without (EL-) the EndoLifter. The submucosal dissection time (SDT), corrected for specimen size, and the influence of ESD experience on EndoLifter usefulness were assessed. RESULTS: En bloc resection rate was 98.4%. In the forward approach, the median SDT was shorter with the EndoLifter (0.56 min/cm2 vs. 0.91 min/cm2), although not significantly (p=0.09). The ESD-experienced endoscopist benefitted more from the EndoLifter (0.45 [EL+] min/cm2 vs. 0.68 [EL-] min/cm2, p=0.07) than the ESD-inexperienced endoscopist (0.77 [EL+] min/cm2 vs. 1.01 [EL-] min/cm2, p=0.48). In the retroflex approach, the median SDTs were 1.06 (EL+) and 0.48 (EL-) min/cm2 (p=0.16). The EndoLifter did not shorten the SDT for the ESD-experienced endoscopist (0.68 [EL+] min/cm2 vs. 0.68 [EL-] min/cm2, p=0.78), whereas the ESD-inexperienced endoscopist seemed hindered (1.65 [EL+] min/cm2 vs. 0.38 [EL-] min/cm2, p=0.03). CONCLUSIONS: In gastric ESD, the EndoLifter, in trend, shortens SDTs in the forward, but not in the retroflex approach. Given the low numbers in this study, a type II error cannot be excluded.

The Efficacy of an Endoscopic Grasp-and-Traction Device for Gastric Endoscopic Submucosal Dissection: An Ex Vivo Comparative Study (with Video)

BACKGROUND/AIMS: To investigate whether the EndoLifter (Olympus), a counter-traction device facilitating submucosal dissection, can accelerate endoscopic submucosal dissection (ESD). METHODS: Two endoscopists (novice/expert in ESD) performed 64 ESDs (artificial 3-cm lesions) in 16 ex vivo pig stomachs: per stomach, two at the posterior wall (forward approach) and two at the lesser curvature (retroflex approach). Per approach, one lesion was dissected with (EL+) and one without (EL-) the EndoLifter. The submucosal dissection time (SDT), corrected for specimen size, and the influence of ESD experience on EndoLifter usefulness were assessed. RESULTS: En bloc resection rate was 98.4%. In the forward approach, the median SDT was shorter with the EndoLifter (0.56 min/cm2 vs. 0.91 min/cm2), although not significantly (p=0.09). The ESD-experienced endoscopist benefitted more from the EndoLifter (0.45 [EL+] min/cm2 vs. 0.68 [EL-] min/cm2, p=0.07) than the ESD-inexperienced endoscopist (0.77 [EL+] min/cm2 vs. 1.01 [EL-] min/cm2, p=0.48). In the retroflex approach, the median SDTs were 1.06 (EL+) and 0.48 (EL-) min/cm2 (p=0.16). The EndoLifter did not shorten the SDT for the ESD-experienced endoscopist (0.68 [EL+] min/cm2 vs. 0.68 [EL-] min/cm2, p=0.78), whereas the ESD-inexperienced endoscopist seemed hindered (1.65 [EL+] min/cm2 vs. 0.38 [EL-] min/cm2, p=0.03). CONCLUSIONS: In gastric ESD, the EndoLifter, in trend, shortens SDTs in the forward, but not in the retroflex approach. Given the low numbers in this study, a type II error cannot be excluded.

The "Two-Sword Fencing" Technique in Endoscopic Submucosal Dissection

No abstract available.

Short-Term Healing Process of Artificial Ulcers after Gastric Endoscopic Submucosal Dissection

BACKGROUND/AIMS: The relationship between the appearance of an ulcer and postoperative bleeding after gastric endoscopic submucosal dissection (ESD) is not well understood. To explore this potential relationship, we retrospectively analyzed the short-term healing process of ESD. METHODS: A total of 520 consecutive lesions in 434 patients seen between January 2004 and December 2009 were retrospectively investigated. At the second-look endoscopy, which occurred between 1 and 8 days after ESD, artificial ulcers were categorized into 6 patterns according to Forrest's classification: spurting bleeding, oozing bleeding, non-bleeding visible vessel, adherent clot, black base/spot, and clean base. From these data, a short-term healing model of the artificial ulcer was generated. RESULTS: Ulcer base changed gradually from a bloody to a clean one. The bleeding or non-bleeding visible vessel categories, which occurred in approximately one quarter of the ulcers within 3 days of ESD, were rarely observed 4 days after ESD. CONCLUSIONS: Ulcers that occur after gastric ESD heal in line with a specific time course, and it appears that most healing occurs without massive bleeding.

Submucosal Injection of Normal Saline can Prevent Unexpected Deep Thermal Injury of Argon Plasma Coagulation in the in vivo Porcine Stomach

BACKGROUND/AIMS: There have been several reports of thermal injury induced by argon plasma coagulation (APC) in animal models, but no follow-up studies have revealed the actual thermal injury. METHODS: APC was performed on the stomachs of two living minipigs with and without prior submucosal injection of normal saline. The power and argon gas flow were set to 60 watts and 2 L/min, respectively, and pulse durations of 5, 10, and 20 seconds were used. One of the minipigs was killed immediately thereafter and the other was killed 1 week later. RESULTS: The minipig killed immediately showed only subtle differences between noninjected and injected injuries under all the conditions, and the usefulness of prior submucosal injection was not obvious. However, the minipig killed 1 week later had a deep ulcer extending to the deeper muscle layer at the noninjected site where APC had been applied for 20 seconds, whereas tissue injury of the injected site was limited to the submucosal layer. CONCLUSIONS: Unexpected tissue damage can occur even using a short-duration APC. Prior submucosal injection for APC might be a safer alternative technique, especially in a thinner and narrower gut wall.

Submerging Endoscopic Submucosal Dissection Leads to Successful En Bloc Resection of Colonic Laterally Spreading Tumor with Submucosal Fat

A 72-year-old female with a colonic laterally spreading tumor (LST) was referred to our department. A total colonoscopy revealed a large nongranular LST, 30 mm in diameter, in the ascending colon. Detailed examination with chromoendoscopy confirmed that the lesion was an intramucosal tumor, and endoscopic submucosal dissection (ESD) was performed. After a circumferential incision around the lifted lesion with a submucosal fluid cushion, diffuse adipose tissue was observed in the submucosal layer beneath the lesion. The endoscopic view was blurred when dissecting the submucosal layer due to fat adhering to the lens. Since this made it difficult to continue the procedures, we infused water into the lumen and kept the endoscope tip immersed in the collected water. The resulting improved view made it possible to complete all procedures without withdrawing the endoscope to wipe the lens. The lesion was successfully resected en bloc without complications. The pathological examination indicated the curative resection of a tubulovillous adenoma. We propose that a submerged ESD could also be an effective procedure for colonic neoplasms with submucosal fat by avoiding blurring of the endoscopic view.