Endoscopic intermuscular disection (EID) is an evolving method allowing resection of submucosal invasive rectal neoplasms. In this unicenter prospective register study from a tertiary endoscopy centre we examined the oncological outcomes, procedure associated data also regarding safety under nurse administered sedation and assesed structural requirements for this procedure.

All patients treated with EID for rectal lesions from November 2024 to November 2025 at Evangelisches Krankenhaus Düsseldorf, Germany were included. The primary endpoints were en-bloc-, R0- and curative resection rate. Secondary endpoints were, periprocedural complications and sedation related complications as well as resection speed and duration of hospital stay.

A total of 8 patients with an average age of 64,9 years were included in this analysis (male/female 6/2). 3 lesions were previously treated by EMR. All lesions were resected en-bloc. Histopathologically the resected lesions were 5 adenocarcinoma- 3 pT1 with submucosal invasion (1 sm1, 2 sm3 ) and 2 pT2, 1 high grade dysplasia, 1 low grade dysplasia (with severe submucosal fibrosis) and 1 non- neoplastic lesion (secondary resection after pmEMR of an adenocarcinoma).The R0 resection rate was 83,3% whereas the curative resection rate was 50%. Not curatively resected patients underwent surgery in 2/3 cases. In one case there were no vital tumorcells in the specimen and the other one resulted to be a pT3 lesion.The procedures were performed under nurse administered sedation with propofol and midazolam. There were no intraprocedural or sedation associated complications. 1 post procedural bleeding occured that required endoscopic treatment. The average procedure time was 136 minutes. The average specimen size was 1350mm² and the resectionspeed 9,9mm²/min. Patients stayed in the hospital for an average of 3,25 nights. Compared to our prospective ESD data (17,8mm²/min for rectal lesions) the dissection speed  was slower among these first EID cases and there was no difference in length of hospital stay.

EID appears to be a feasable method, easy to establish in ESD experienced endoscopy centers to treat possibly submucosa invasive rectal lesions or lesions with submucosal firbosis. The method does not require additional measures and can be performed under nurse administered sedation. Continous prospective assesment of the method is necessary to further evaluate its safety profile and long term oncologic outcomes.