Study design and ethical statements
This retrospective cohort study was conducted at Saitama Medical University International Medical Center in Japan. It was approved by the Institutional Review Board of the medical center (institutional ID: 20–249) and performed in accordance with the principles of the Declaration of Helsinki. Informed consent was obtained from all patients.
Patients
Endoscopic resection was performed for 133 superficial duodenal epithelial tumors at our institution from April 2017 to February 2022. Among them, 7 ampullary tumors, 2 tumors observed during laparoscopy and endoscopy cooperative surgery, and 33 tumors observed during endoscopic mucosal resection were excluded. We also excluded 9 tumors in the duodenal bulb. Finally, 82 tumors for which complete mucosal defect closure after duodenal ESD was attempted were included in the analysis. The cases were divided into two groups: the OTSC group consisted of 55 cases and the control group (for which conventional clips only were used) consisted of 27 cases (Fig. 1).
Preparation For Duodenal Esd
In general, duodenal endoscopic mucosal resection was performed under intravenous anesthesia in the endoscopy room, and duodenal ESD was performed under general anesthesia in the operating room. However, the procedure was performed under intravenous anesthesia when the risk of performing duodenal ESD under general anesthesia was estimated to be high based on the patient’s general condition. Under intravenous anesthesia, our endoscopists adjusted the dosage of midazolam, pethidine, and dexmedetomidine according to the patient’s condition. The antispasmodic drugs used were scopolamine for patients who had no cardiac disease or benign prostatic hyperplasia, and glucagon for patients who had these conditions. All duodenal ESDs were performed by a single endoscopist (T.T.) who had experience performing more than 1,500 ESD procedures, including at least 300 each in the esophagus, stomach, and colon. All ESD procedures were performed using a therapeutic endoscope (GIF-H290T or GIF-Q260J; Olympus, Medical Systems Co., Tokyo, Japan) with a transparent cap (D-201-11804; Olympus). Regarding endoscopic devices, we used a 1.5-mm DualKnife J (KD655Q; Olympus) to perform mucosal incision or submucosal dissection. Depending on the circumstances of each case, a 3.5-mm Clutch Cutter (Fujifilm Co, Tokyo, Japan) was used as an adjunct. The endoCUT I (effect 1, duration 4, interval 1), forced coagulation (effect 2, 45 W), and soft coagulation (effect 4, 60 W) modes of an electrosurgical generator (VIO 300D; ERBE Elektromedizin, Tübingen, Germany) were used for mucosal incision, submucosal dissection, and hemostatic procedure, respectively. A local injection of 0.4% sodium hyaluronate (MucoUp®ฎ; Boston Scientific, Tokyo, Japan) combined with a small amount of indigo carmine was administered into the submucosa to firmly elevate it and ensure optimal visualization.
Details Of Both Groups And Definitions Of Outcomes
This study included 82 cases for which complete closure of mucosal defects after duodenal ESD was attempted. Of these, 55 cases were in the OTSC group and 27 were in the control group. Complete closure of mucosal defects was successfully achieved for 81 cases; however, it was unsuccessful for one case in the OTSC group.
OTSC group
At least one OTSC was used in each case. Depending on the size of the mucosal defect, conventional clips (EZ Clip, HX-610-135, HX-610-090L; Olympus) and PolyLoop ligating device sutures (HX21L1, MAJ339; Olympus) were used with OTSCs (Fig. 2).
Control group
Only conventional clips were used (Fig. 3).
Definitions
En bloc resection: a one-piece resection that included the entire tumor
Procedure time: the time from the initial mucosal incision to tumor resection
Resected specimen area: This was calculated using the following equation: the largest diameter of the resected specimen (mm)/2 × the smallest diameter of the specimen (mm)/2 × 3.14.
Intraoperative perforation: perforation that occurred during duodenal ESD
Delayed perforation: perforation diagnosed using computed tomography after duodenal ESD
Delayed bleeding: hemorrhage that required additional endoscopic hemostasis after duodenal ESD
Resectability: This was classified into three categories based on the final pathological diagnosis, as follows: R0, both the horizontal and vertical margins were negative; RX, either the horizontal or the vertical margin was unclear; and R1, either the horizontal or the vertical margin was positive.
Surgery due to adverse events: cases that required surgery because of duodenal ESD-related complications
Closing time: the time from re-insertion of the endoscope after specimen retrieval until the end of the closure procedure
Additional treatment: a case that required endoscopic treatment or surgery due to adverse events associated with OTSC application
Statistical analysis
The primary objective of this study was to estimate the area of possible complete closure of mucosal defects after duodenal ESD in the OTSC and control groups. First, we compared patient characteristics and duodenal ESD outcomes of the two groups in order to identify case bias, if any. Thereafter, we focused on the preoperatively estimated tumor size and resected specimen area, and calculated their median values for each closure method. Binary variables of the two groups were compared using Pearson’s chi-square test, and continuous variables were compared using Mann–Whitney U test or Student’s t-test. All analyses in this study were performed using STATA® version 17 (StataCorp, College Station, TX, USA). P < 0.05 was considered statistically significant.