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Original Article Utility of underwater endoscopic mucosal resection combined with a protruding anchor by saline injection for superficial non-ampullary duodenal tumors: a retrospective study in Japan
Yoshie Nomoto1orcid, Satoshi Shinozaki1,2orcid, Yoshimasa Miura1,3orcid, Hiroyuki Osawa1orcid, Yuji Ino1orcid, Tomonori Yano1orcid, Nikolaos Lazaridis4orcid, Hironori Yamamoto1,orcid

DOI: https://doi.org/10.5946/ce.2024.181
Published online: March 12, 2025

1Division of Gastroenterology, Department of Medicine, Jichi Medical University, Shimotsuke, Japan

2Shinozaki Medical Clinic, Utsunomiya, Japan

3Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan

4Royal Free Unit for Endoscopy, The Royal Free Hospital and UCL Institute for Liver and Digestive Health, London, UK

Correspondence: Hironori Yamamoto Division of Gastroenterology, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan E-mail: ireef@jichi.ac.jp
• Received: July 4, 2024   • Revised: September 19, 2024   • Accepted: September 30, 2024

© 2025 Korean Society of Gastrointestinal Endoscopy

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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  • Background/Aims
    Underwater endoscopic mucosal resection (UEMR) is the standard resection method for superficial non-ampullary duodenal tumors (SNADETs). We developed a novel UEMR technique that creates an anchor by protruding the distal fold with a saline injection (UEMR-A). The aim of this study was to clarify the usefulness of UEMR-A compared to conventional UEMR (UEMR-C).
  • Methods
    This retrospective observational study included patients who underwent UEMR for SNADETs.
  • Results
    A total of 141 patients were included and divided into UEMR-A (n=54) and UEMR-C (n=87) groups. Lesion resection was performed significantly more frequently by an expert endoscopist in the UEMR-C group compared to the UEMR-A group (p<0.001). The procedure time for UEMR-A was significantly shorter than that for UEMR-C (p=0.02), despite the additional time required for submucosal injection. The R0 resection rate was significantly higher in the UEMR-A group than in the UEMR-C group (p=0.004). The horizontal margins were significantly clearer in the UEMR-A group than in the UEMR-C group (p=0.02). Multivariate analysis revealed that the use of UEMR-A was the only significant positive factor for R0 resection.
  • Conclusions
    The UEMR-A technique for SNADETs appears to improve R0 resection rates and reduce procedure times compared to the UEMR-C technique.
  • Keywords: Duodenal neoplasms; Endoscopic mucosal resection; Endoscopy; Patient outcome assessment
Superficial non-ampullary duodenal tumors (SNADETs) are rare; however, the endoscopic resection of SNADETs is increasing in Japan.1 This rise could be attributed to the early detection of SNADETs, which has been facilitated by the development and evolution of image-enhanced endoscopy and heightened endoscopist awareness. Despite these advancements, endoscopic submucosal dissection (ESD) of SNADETs is associated with high perforation rates (6%–50%) and moderate R0 resection rates (38%–100%).2 In contrast, endoscopic mucosal resection (EMR) does not have adequate R0 resection rates, and piecemeal resection undoubtedly elevates the rate of local recurrence. This is noteworthy because repeat resection becomes more challenging endoscopically due to scar formation and the inherently thin duodenal wall. Furthermore, underwater EMR (UEMR) for SNADETs was reported in 2013 as a novel strategy for endoscopic resection. During this procedure, the gastrointestinal lumen is filled with water, and snare resection is performed without submucosal injection.3 As a result, UEMR for SNADETs <20 mm in size has significantly higher en-bloc resection rates and shorter procedure times compared to EMR.4
Anatomically, unlike the colonic haustra, the duodenal wall forms a linear muscularis. Thus, the duodenal fold does not contain the muscularis. This anatomical variance allows the convoluted folds to flow into the water-filled duodenal lumen and facilitates the resection of the superficial lesion without muscularis involvement, which contributes to a decreased perforation risk even without submucosal injection. Therefore, UEMR has emerged as the first-line therapy for SNADETs, preferred over both EMR and ESD.5
Despite the development and widespread use of UEMR for SNADETs, R0 resection has not yet been achieved in all cases.6 To address this challenge and improve the R0 resection rate while minimizing local recurrence, we developed a new UEMR method, facilitated by a protruding anchor created by saline injection into the distal duodenal fold (UEMR-A).7 The aim of this study was to evaluate the usefulness and safety of UEMR-A for SNADET resection compared to conventional UEMR (UEMR-C).
Study population
This is a retrospective observational study involving 188 patients with SNADETs treated by UEMR at Jichi Medical University Hospital from August 2016 to January 2024. During the study period, most UEMR-C cases were performed until June 2021, after which UEMR-A was developed and used considerably more often. The medical record review included data collection from endoscopic reports and videos. We excluded 47 patients based on the following criteria: (1) use of the clip anchor method; (2) scheduled piecemeal resection; (3) en-bloc resection for multiple lesions; (4) use of gel immersion EMR; (5) patients with familial adenomatous polyposis; (6) lesions located just behind the pyloric ring; (7) resected specimens collapsed by aspiration into the working channel; and (8) recurrent lesions after EMR. We divided the remaining 141 patients into two groups based on the resection method used: UEMR-A (n=54) and UEMR-C (n=87).
The procedure time for UEMR-A was defined as the interval between the insertion of the injection needle via the working channel and the completion of snare resection. For UEMR-C, it was defined as the interval between the start of water infusion and the end of resection. En-bloc resection was defined as the resection of the entire lesion as a single piece, while R0 resection was defined as an en-bloc resection with negative margins. Intraprocedural bleeding was defined as bleeding requiring endoscopic hemostasis during the UEMR, and delayed bleeding was defined as melena or hematochezia, or the requirement for endoscopic hemostasis within 14 days after the UEMR. All patients attended an outpatient clinic follow-up appointment and received a detailed pathological diagnosis more than four weeks after discharge. An “expert” endoscopist was defined as one who had performed more than 100 upper gastrointestinal ESDs. In total, 24 endoscopists participated, including 7 experts and 17 non-experts.
Devices and conditions
Endoscopes with a water jet instrument (EG-L580RD/RD7, EG-L600ZW/ZW7, EG-840T, EG-840TP, EG-450RD; Fujifilm) were used in the procedures. The VIO300D (endoCUT I mode, effect 1, duration 4, interval 1) or VIO3 (endoCUT I mode, effect 1, duration 2, interval 1) electrosurgical unit (ERBE) was employed. UEMR-A was performed using a 15-mm RotaSnare (Medi-Globe). UEMR-C was performed using either a 10-mm Snare Master (Olympus), a 15-mm RotaSnare (Medi-Globe), a 30-mm Lariat snare (US Endoscopy), or an 11- or 13-mm Profile snare (Boston Scientific). All procedures were conducted under conscious sedation with pethidine hydrochloride and midazolam. A cylindrical hood (D-201-11804; Olympus) was utilized, and carbon dioxide insufflation was applied. Endoscopic clip closure was achieved using either an EZ Clip (Olympus) or a SureClip (Micro-Tech). An antispasmodic agent was administered when strong bowel contractions impeded the procedure.
UEMR-A procedure
Initially, a mucosal injection of 2 to 3 mL normal saline was performed into the anal side fold (not the flat area between folds) just after the target lesion. This injection was later used to anchor the tip of the snare and secure the anal side margin. Mucosal markings were not placed prior to the procedure. Afterward, all gas and air were aspirated from the duodenal lumen, which was then filled with water to create the underwater environment needed for resection. The snare tip, inserted through the accessory channel, was positioned on the protruded mucosa, serving as a cushion and enhancing stability. The rotatable snare was then opened and adjusted to cover the target lesion with sufficient margins on both the left and right sides. Even during snare closure, the protrusion enabled stable snare manipulation. Subsequently, snare resection was performed with electrocauterization. The deployment of endoscopic clips assisted in mucosal defect closure while remaining underwater (Fig. 1).
Statistical analysis
Differences in continuous variables between the two groups were compared using the Mann-Whitney U-test. Differences in categorical variables were assessed with the chi-square test, and the Fisher exact test was used when the expected value was <5. Logistic regression analysis was employed to identify factors associated with R0 resection. For the multivariate analysis, factors with a p-value <0.2 in the univariate analysis were selected. Statflex ver. 7.0 software (Artech Co. Ltd.) was used for these analyses, and differences were considered significant at p<0.05.
Ethics approval
This retrospective review was approved by the Institutional Review Board of Jichi Medical University (ID#20-103).
Baseline characteristics and outcomes
There were no differences between the UEMR-A and UEMR-C groups regarding lesion size, location, or involvement of a fold (Tables 1, 2). Notably, more procedures were performed by expert endoscopists in the UEMR-C group than in the UEMR-A group. Moreover, the procedure time for UEMR-A was significantly shorter than that for UEMR-C, despite the additional time needed for submucosal injection. Additionally, the R0 resection rate in the UEMR-A group was significantly higher than that in the UEMR-C group, despite most procedures in the UEMR-A group being performed by non-experts. Furthermore, the horizontal margins were significantly clearer in the UEMR-A group compared to the UEMR-C group.
For tumors smaller than 15 mm, the R0 resection rate was significantly higher in the UEMR-A group than in the UEMR-C group. For tumors located on the anterior wall, the R0 resection rate was also higher in the UEMR-A group compared to the UEMR-C group. No tumors exhibited submucosal invasion. In the UEMR-A group, the R0 resection rate performed by an expert was 82.4% (14/17), which was comparable to that of non-expert endoscopists at 83.8% (31/37). No intraprocedural bleeding or perforation was observed; however, delayed bleeding occurred in one patient in the UEMR-C group.
Factors associated with R0 resection
Factors affecting the R0 resection rate were examined using multivariate analysis to control for extraneous variables (Table 3). The use of UEMR-A was identified as the only positive significant factor for R0 resection in both univariate and multivariate analyses. Tumor size, involvement of a fold, and resection performed by an expert did not appear to influence R0 resection rates.
This retrospective comparative study revealed that UEMR-A has a significantly higher R0 resection rate compared to UEMR-C. Anchoring with a mucosal protrusion facilitates precise snare placement by allowing the tip of the snare to be fixed in the duodenum. In the UEMR-C technique, the extent of the resection area is sometimes uncontrollable due to the influence of peristalsis and the fixed duodenum on the retroperitoneum. In contrast, UEMR-A creates an artificial protrusion on the anal side with a spring effect, allowing for adequate lateral margins through precise opening of the snare. This fixation of the snare tip by the protrusion prevents an excessive anal side margin and facilitates visualization of the oral and lateral side margins. Even in non-expert hands, the UEMR-A technique facilitated R0 resection rates similar to those performed by experts. This is the first original report demonstrating the superiority of UEMR-A over UEMR-C.
UEMR, developed by Binmoeller et al.,8 was disseminated worldwide over the last decade, a phenomenon referred to as the “underwater revolution”. In this context, endoscopic ultrasound studies have demonstrated that the underwater method can induce circumferential convolution of the mucosa. Nevertheless, convolution of the muscularis has not been identified, suggesting that UEMR is a relatively safe procedure. In contrast, ESD is considered an established strategy for resecting superficial esophageal, gastric, and colorectal tumors. However, duodenal ESD is considered a high-risk procedure for perforation and requires sophisticated techniques.9 Furthermore, although duodenal piecemeal EMR for SNADETs is a viable option, a thinner duodenal wall makes salvage ESD difficult and carries an extremely high risk of perforation in cases with local recurrence. Therefore, R0 resection on the first attempt is more important than resection in other parts of the gastrointestinal tract. Overall, considering the perforation risk and advanced endoscopic skills required for duodenal ESD, we believe that ESD should not be considered the standard treatment option for SNADETs by non-expert endoscopists. In light of these factors, UEMR-A is easier to perform than UEMR-C and can facilitate en-bloc resection regardless of the location of the lesion and the experience of the endoscopist, as long as the lesion size is less than 15 mm.
UEMR-C for SNADETs can be a challenging therapeutic procedure due to several factors, including the slippery duodenal mucosa, limited visual field, bowel peristalsis, and retroperitoneal fixation. As a result, these factors can prolong procedural times and potentially extend unnecessary margins. To address these difficulties, the UEMR-A technique has been developed specifically to tackle the issue of the slippery duodenal mucosa. Notably, there is an anatomical difference in the submucosal structure between the duodenal folds and the flat areas. This difference allows for solution injection to be dispersed in the thin submucosal layer between folds; however, injecting into the folds can create an appropriate protrusion.10 Thus, submucosal saline injection during UEMR-A should be performed on the “fold area” at the anal side of the SNADET to minimize the dispersion of the injected solution and to create a suitable soft protrusion with a spring effect.
To further enhance procedural efficacy, the protrusion created during UEMR-A is sufficiently soft that the tip of the snare can be moderately fixed, allowing push-and-pull movements in any direction. Moreover, the flexibility of the snare tip on the protruded mucosa facilitates the opening and maneuvering of the snare onto the duodenal mucosa to obtain adequate horizontal margins. Furthermore, since the snare tip is not solidly fixed, its location can be finely tuned and adjusted. This moderate fixation of the snare tip during UEMR-A helps shorten the procedure time compared to UEMR-C. This fixation also influences the curability of the endoscopic resection. Notably, this study revealed that there were no differences in R0 resection rates between UEMR-A and UEMR-C for lesions located on the papilla or the posterior wall, which align with the direction of the working channel. In contrast, lesions located on the opposite side of the papilla or the anterior wall require rotational maneuvers in the narrow lumen, making resection more difficult. In these latter cases, the R0 resection rate in the UEMR-A group was higher than that for in UEMR-C group. Therefore, UEMR-A can overcome the difficulties associated with lesion location, ultimately facilitating a high R0 resection rate.
During endoscopic procedures, the closing of the snare can be complicated by the slippery duodenal mucosa and excessively convoluted lumen, leading to the resection of a larger portion of normal mucosa at the anal side margin, which may elevate the risk of intraprocedural or delayed bleeding and perforation. However, these risks can be mitigated using UEMR-A. In addition, to secure appropriate lateral margins, attempts at snare closing can be repeated using UEMR-A, as the moderately fixed tip of the rotatable snare on the artificial protrusion allows for push-and-pull maneuvering. By applying a slight push during the closing of the snare, the shape of the snare can expand laterally, enabling repeated adjustments to secure negative horizontal margins, even in the slippery duodenal mucosa between the folds. Consequently, UEMR-A provides reliably negative horizontal margins for tumors larger than 10 mm in size that extend over two folds.
Any SNADETs <20 mm are generally indicated for UEMR.11,12 However, the R0 resection rate for this procedure has been found to be unsatisfactory, as indicated by the results of a large Japanese multicenter study (56%),6 which is notably lower than the rate observed in the current UEMR-A group (83%). Notably, Takatori et al.13 reported the usefulness of UEMR combined with partial submucosal injection, achieving a 96% en-bloc resection rate. This technique lifts wide-range mucosa with a submucosal injection into the anal side of the lesion, which facilitates careful observation and resection while viewing the anal side. In contrast, our method creates an anal-side artificial protrusion with a spring effect, allowing for an appropriate lateral margin by precisely opening the snare when it is pushed against the protrusion. This fixation of the snare tip by the protrusion prevents excessive resection of the anal side margin and aids in visualizing the oral and lateral side margins, resulting in a suitably sized resected specimen. However, as described in Table 2, the R0 resection rate for tumors ≥15 mm was not satisfactory, even in the UEMR-A group (57%); therefore, duodenal ESD should be considered for tumors of this size.
The strengths of this study include the following: first, this is a novel procedure that requires a simple step involving a single submucosal saline injection. Second, the fixation of the snare tip is adjustable, allowing for changes in its location as needed. The snare tip is moderately fixed and does not move easily due to the spring effect, even when the snare is pushed or pulled. Third, this method does not require any dedicated devices, making it cost-effective. However, our study has some limitations. Initially, this was a single-center retrospective observational study and not a prospective one. Additionally, the two groups did not run completely in parallel; the majority of the UEMR-C procedures were performed chronologically earlier than the UEMR-A procedures. Lastly, the level of experience among endoscopists was not the same in the two groups.
In conclusion, UEMR-A could improve the R0 resection rate compared to UEMR-C. Interestingly, despite the need for additional time for the injection, the overall procedural time was significantly shorter than that for UEMR-C. UEMR-A also minimized excessively large lateral margins. Therefore, we recommend UEMR-A for the resection of SNADETs <15 mm.
Fig. 1.
Procedure of underwater endoscopic mucosal resection aided by a protruding anchor created by saline injection into the distal duodenal fold (UEMR-A). (A) A superficial non-ampullary duodenal lesion measuring 7 mm in diameter. (B) A protrusion is created by injecting 2 to 3 mL of normal saline into the anal side fold. (C) A submucosal protrusion serves as an anchor for the snare tip and secures the anal side margin. (D) The snare tip is attached to the protrusion after water immersion, ensuring it does not easily miss the target even after the snare is opened. (E) The snare tip is moderately fixed, facilitating movement at various angles. Snaring can be performed under clear visualization. UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold.
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Table 1.
Baseline characteristics
Characteristic UEMR-A (n=54) UEMR-C (n=87) p-value
Age (yr) 68 (59–74) 69 (62–73) 0.59
Male 43 (79.6) 72 (82.8) 0.66
Location (portion)
 First 8 (14.8) 23 (26.4) 0.10
 Second 44 (81.5) 58 (66.7) 0.06
 Third 2 (3.7) 6 (6.9) 0.41
Relationship with papilla of Vater
 Upper part 31 (57.4) 44 (50.6) 0.43
 Lower part 23 (42.6) 43 (49.4)
Location (part)
 Papilla side 8 (14.8) 16 (18.4) 0.58
 Opposite side of papilla 21 (38.9) 29 (33.3) 0.49
 Anterior wall side 11 (20.4) 17 (19.5) 0.90
 Posterior wall side 14 (25.9) 25 (28.7) 0.28
Macroscopic type
 Elevated 34 (63.0) 56 (64.4) 0.86
 Depressed 20 (37.0) 31 (35.6)
Involvement of fold
 Yes 52 (96.3) 77 (88.5) 0.11
 No 2 (3.7) 10 (11.5)
Preoperative biopsy 36 (66.7) 53 (60.9) 0.50
Endoscopist
 Non-expert 37 (68.5) 27 (31.0) <0.001
 Expert 17 (31.5) 60 (69.0)

Values are presented as median (interquartile range) or number (%).

UEMR, underwater endoscopic mucosal resection; UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold; UEMR-C, conventional UEMR.

Table 2.
Endoscopic resection and histopathology
UEMR with an anchor for SNADET UEMR-A (n=54) UEMR-C (n=87) p-value
Procedure time (min) 4 (3–6) 6 (3–10) 0.02
Use of antispasmodic agent 19 (35.2) 42 (48.3) 0.12
En-bloc resection 53 (98.1) 81 (93.1) 0.18
R0 resection 45 (83.3) 53 (60.9) 0.004
 VM0 51/53 (96.2) 74/81 (91.4) 0.26
 HM0 46/53 (86.8) 56/81 (69.1) 0.02
R0 resection rate (location)
 Papilla side 5/8 (62.5) 8/16 (50.0) 0.54
 Opposite side of papilla 18/21 (85.7) 18/29 (62.1) 0.06
 Anterior wall side 11/11 (100.0) 10/17 (58.8) 0.01
 Posterior wall side 11/14 (78.6) 17/25 (68.0) 0.50
R0 resection rate (size)
 ＜15 mm 41/47 (87.2) 48/76 (63.2) 0.004
 ≥15 mm 4/7 (57.1) 5/11 (45.5) 0.63
Histological diagnosis
 Adenoma 51 (94.4) 74 (85.1) 0.09
 Adenocarcinoma 2 (3.7) 12 (13.8) 0.049
 Serrated lesion 1 (1.9) 1 (1.1) 0.77
Resected specimen (mm)
 Size of tumor 8.5 (6–12) 8.0 (6–12) 0.98
 Size of specimen 18.5 (15–23) 15.0 (11–17.5) <0.001
Perforation 0 (0) 0 (0) >0.99a)
Delayed bleeding 0 (0) 1 (1.1) >0.99a)

Values are presented as median (interquartile range) or number (%).

UEMR, underwater endoscopic mucosal resection; SNADET, superficial non-ampullary duodenal tumor; UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold, UEMR-C: conventional UEMR, IQR: interquartile range, VM: vertical margin, HM: horizontal margin.

a)Fisher exact test.

Table 3.
Factors associated with an R0 resection
Factor Univariate analysis
 Multivariate analysis
OR (95% CI) p-value OR (95% CI) p-value
Use of UEMR-A 3.208 (1.391–7.395) 0.006 3.083 (1.252–7.591) 0.01
Size 10 mm or over 0.579 (0.281–1.194) 0.139 0.630 (0.278–1.426) 0.27
Lower part of papilla of Vater 0.778 (0.379–1.595) 0.492
Depressed type 1.084 (0.512–2.294) 0.833
Involvement of folds 2.173 (0.992–4.761) 0.052 1.643 (0.684–3.948) 0.27
Preoperative biopsy 1.355 (0.650–2.826) 0.417
Performed by non-expert 1.620 (0.777–3.376) 0.197 1.118 (0.495–2.521) 0.79

OR, odds ratio; CI, confidence interval; UEMR-A, underwater endoscopic mucosal resection aided by a protruding anchor created by saline injection into the distal duodenal fold.

  • 1. Goda K, Kikuchi D, Yamamoto Y, et al. Endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors in Japan: multicenter case series. Dig Endosc 2014;26 Suppl 2:23–29.ArticlePubMed
  • 2. Shibagaki K, Ishimura N, Kinoshita Y. Endoscopic submucosal dissection for duodenal tumors. Ann Transl Med 2017;5:188.ArticlePubMedPMC
  • 3. Binmoeller KF, Shah JN, Bhat YM, et al. "Underwater" EMR of sporadic laterally spreading nonampullary duodenal adenomas (with video). Gastrointest Endosc 2013;78:496–502.ArticlePubMed
  • 4. Lv XH, Luo R, Lu Q, et al. Underwater versus conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumors ≤20mm: a systematic review and meta-analysis. Dig Liver Dis 2023;55:714–720.ArticlePubMed
  • 5. Kato M, Kanai T, Yahagi N. Endoscopic resection of superficial non-ampullary duodenal epithelial tumor. DEN Open 2021;2:e54.ArticlePubMedPMCPDF
  • 6. Kato M, Takeuchi Y, Hoteya S, et al. Outcomes of endoscopic resection for superficial duodenal tumors: 10 years' experience in 18 Japanese high volume centers. Endoscopy 2022;54:663–670.ArticlePubMed
  • 7. Nomoto Y, Miura Y, Osawa H, et al. Underwater endoscopic mucosal resection aided by a protruding anchor created by saline injection into the distal duodenal fold. Endoscopy 2023;55(S 01):E442–E443.ArticlePubMedPMC
  • 8. Binmoeller KF, Weilert F, Shah J, et al. "Underwater" EMR without submucosal injection for large sessile colorectal polyps (with video). Gastrointest Endosc 2012;75:1086–1091.ArticlePubMed
  • 9. Miura Y, Shinozaki S, Hayashi Y, et al. Duodenal endoscopic submucosal dissection is feasible using the pocket-creation method. Endoscopy 2017;49:8–14.ArticlePubMed
  • 10. Miura Y, Osawa H, Nomoto Y, et al. Anatomical features of duodenal folds: a key feature to consider during endoscopic resection of duodenal neoplasms. VideoGIE 2021;6:529–532.ArticlePubMedPMC
  • 11. Suwa T, Takizawa K, Kawata N, et al. Current treatment strategy for superficial nonampullary duodenal epithelial tumors. Clin Endosc 2022;55:15–21.ArticlePubMed
  • 12. Jeon HK, Kim GH. Endoscopic resection for superficial non-ampullary duodenal epithelial tumors. Gut Liver 2025;19:19–30.ArticlePubMedPMC
  • 13. Takatori Y, Kato M, Masunaga T, et al. Efficacy of partial injection underwater endoscopic mucosal resection for superficial duodenal epithelial tumor: propensity score-matched study (with video). Dig Endosc 2022;34:535–542.ArticlePubMedPDF

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      Utility of underwater endoscopic mucosal resection combined with a protruding anchor by saline injection for superficial non-ampullary duodenal tumors: a retrospective study in Japan
      Image Image
      Fig. 1. Procedure of underwater endoscopic mucosal resection aided by a protruding anchor created by saline injection into the distal duodenal fold (UEMR-A). (A) A superficial non-ampullary duodenal lesion measuring 7 mm in diameter. (B) A protrusion is created by injecting 2 to 3 mL of normal saline into the anal side fold. (C) A submucosal protrusion serves as an anchor for the snare tip and secures the anal side margin. (D) The snare tip is attached to the protrusion after water immersion, ensuring it does not easily miss the target even after the snare is opened. (E) The snare tip is moderately fixed, facilitating movement at various angles. Snaring can be performed under clear visualization. UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold.
      Graphical abstract

      Fig. 1.

      Graphical abstract

      Utility of underwater endoscopic mucosal resection combined with a protruding anchor by saline injection for superficial non-ampullary duodenal tumors: a retrospective study in Japan
      Characteristic UEMR-A (n=54) UEMR-C (n=87) p-value
      Age (yr) 68 (59–74) 69 (62–73) 0.59
      Male 43 (79.6) 72 (82.8) 0.66
      Location (portion)
       First 8 (14.8) 23 (26.4) 0.10
       Second 44 (81.5) 58 (66.7) 0.06
       Third 2 (3.7) 6 (6.9) 0.41
      Relationship with papilla of Vater
       Upper part 31 (57.4) 44 (50.6) 0.43
       Lower part 23 (42.6) 43 (49.4)
      Location (part)
       Papilla side 8 (14.8) 16 (18.4) 0.58
       Opposite side of papilla 21 (38.9) 29 (33.3) 0.49
       Anterior wall side 11 (20.4) 17 (19.5) 0.90
       Posterior wall side 14 (25.9) 25 (28.7) 0.28
      Macroscopic type
       Elevated 34 (63.0) 56 (64.4) 0.86
       Depressed 20 (37.0) 31 (35.6)
      Involvement of fold
       Yes 52 (96.3) 77 (88.5) 0.11
       No 2 (3.7) 10 (11.5)
      Preoperative biopsy 36 (66.7) 53 (60.9) 0.50
      Endoscopist
       Non-expert 37 (68.5) 27 (31.0) <0.001
       Expert 17 (31.5) 60 (69.0)
      UEMR with an anchor for SNADET UEMR-A (n=54) UEMR-C (n=87) p-value
      Procedure time (min) 4 (3–6) 6 (3–10) 0.02
      Use of antispasmodic agent 19 (35.2) 42 (48.3) 0.12
      En-bloc resection 53 (98.1) 81 (93.1) 0.18
      R0 resection 45 (83.3) 53 (60.9) 0.004
       VM0 51/53 (96.2) 74/81 (91.4) 0.26
       HM0 46/53 (86.8) 56/81 (69.1) 0.02
      R0 resection rate (location)
       Papilla side 5/8 (62.5) 8/16 (50.0) 0.54
       Opposite side of papilla 18/21 (85.7) 18/29 (62.1) 0.06
       Anterior wall side 11/11 (100.0) 10/17 (58.8) 0.01
       Posterior wall side 11/14 (78.6) 17/25 (68.0) 0.50
      R0 resection rate (size)
       ＜15 mm 41/47 (87.2) 48/76 (63.2) 0.004
       ≥15 mm 4/7 (57.1) 5/11 (45.5) 0.63
      Histological diagnosis
       Adenoma 51 (94.4) 74 (85.1) 0.09
       Adenocarcinoma 2 (3.7) 12 (13.8) 0.049
       Serrated lesion 1 (1.9) 1 (1.1) 0.77
      Resected specimen (mm)
       Size of tumor 8.5 (6–12) 8.0 (6–12) 0.98
       Size of specimen 18.5 (15–23) 15.0 (11–17.5) <0.001
      Perforation 0 (0) 0 (0) >0.99a)
      Delayed bleeding 0 (0) 1 (1.1) >0.99a)
      Factor Univariate analysis
      		 Multivariate analysis
      OR (95% CI) p-value OR (95% CI) p-value
      Use of UEMR-A 3.208 (1.391–7.395) 0.006 3.083 (1.252–7.591) 0.01
      Size 10 mm or over 0.579 (0.281–1.194) 0.139 0.630 (0.278–1.426) 0.27
      Lower part of papilla of Vater 0.778 (0.379–1.595) 0.492
      Depressed type 1.084 (0.512–2.294) 0.833
      Involvement of folds 2.173 (0.992–4.761) 0.052 1.643 (0.684–3.948) 0.27
      Preoperative biopsy 1.355 (0.650–2.826) 0.417
      Performed by non-expert 1.620 (0.777–3.376) 0.197 1.118 (0.495–2.521) 0.79
      Table 1. Baseline characteristics

      Values are presented as median (interquartile range) or number (%).

      UEMR, underwater endoscopic mucosal resection; UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold; UEMR-C, conventional UEMR.

      Table 2. Endoscopic resection and histopathology

      Values are presented as median (interquartile range) or number (%).

      UEMR, underwater endoscopic mucosal resection; SNADET, superficial non-ampullary duodenal tumor; UEMR-A, UEMR aided by a protruding anchor created by saline injection into the distal duodenal fold, UEMR-C: conventional UEMR, IQR: interquartile range, VM: vertical margin, HM: horizontal margin.

      Fisher exact test.

      Table 3. Factors associated with an R0 resection

      OR, odds ratio; CI, confidence interval; UEMR-A, underwater endoscopic mucosal resection aided by a protruding anchor created by saline injection into the distal duodenal fold.

      Table 1.

      Table 2.

      Table 3.

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