Efficacy and Safety of Robot-assisted Endoscopic Submucosal Dissection for Colorectal Neoplasm

Procedure time is the time from the beginning of injection to the completion of dissection.

Dissection time is the time from the beginning of dissection to the completion of dissection.

Dissection speed is defined as the lesion area divided by the dissection time.

En bloc dissection refers to the complete removal of the entire lesion in a single piece.

R0 resection is defined as en bloc resection with negative vertical and horizontal margins.

Perforation were defined as: endoscopic visualization of mural transection during ESD, or postoperative clinical signs combined with radiologically confirmed pneumoperitoneum.

Post-ESD hemorrhage was strictly defined as meeting ≥1 of: hematemesis or melena with dizziness, hemoglobin decline >20 g/L, SBP drop >20 mmHg or HR elevation >20 bpm, presence of bloody fluid in nasogastric tube drainage, or active bleeding confirmed by repeat endoscopy.

Intraoperative hemorrhage is divided into four grades: Grade 0 means no significant bleeding is observed during the procedure. Grade 1 means minimal bleeding, which could stop spontaneously or be easily controlled by cauterization with a dual knife. Grade 2 refers to minor hemorrhage that requires multiple cauterizations with a dual knife or hemostatic forceps. Grade 3 indicates massive hemorrhage that requires multiple cauterizations with hemostatic forceps.

Hemostasis time referred to the time from the detection of submucosal bleeding until hemostasis was completed.

Muscular injury is described as visible damage to the muscularis propria.

Direct-vision dissection time is the time that the endoscopist can directly observe the tip of the dual knife and the submucosal layer at the same time. By dividing the direct-vision dissection time by the total dissection duration, the direct-vision dissection rate is calculated.

Postoperative pain score was assessed via the 11-point Numerical Rating Scale (NRS: 0=no pain, 10=worst imaginable pain). Patients independently rated their pain intensity on postoperative day 3, with scores categorized as mild (1-3), moderate (4-6), or severe (7-10).*

Supplemental injection refers to injections performed after the beginning of the dissection.

The time of supplementary injection is from the insertion of the injection needle into the submucosal layer until the injection is completed and the needle is withdrawn.