Objectives: Perforation is the most serious complication associated with endoscopic mucosal resection (EMR). We propose a new classification for the appearance and integrity of the muscularis propria (MP) after EMR including various extents of deep mural injury (DMI). Risk factors for these injuries were analysed.
Design: Endoscopic images and histological specimens of consecutive patients undergoing EMR of colonic laterally spreading lesions ≥20 mm at a large Australian tertiary referral endoscopy unit were retrospectively analysed using our new DMI classification system. DMI was graded according to MP injury (I/II intact MP without/with fibrosis, III target sign, IV/V obvious transmural perforation without/with contamination). Histological specimens were examined for included MP and patient outcomes were recorded. All type III-V DMI signs were clipped if possible, types I and II DMI were clipped at the endoscopists' discretion.
Results: EMR was performed in 911 lesions (mean size 37 mm) in 802 patients (male sex 51.4%, mean age 67 years). DMI signs were identified in 83 patients (10.3%). Type III-V DMI was identified in 24 patients (3.0%); clipping was successfully performed in all patients. A clinically significant perforation occurred in two patients (0.2%). Only one of the 59 type I/II cases experienced a delayed perforation. 85.5% of patients with DMI were discharged on the same day, all without sequelae. On multivariable analysis, type III-V DMI was associated with transverse colon location (OR 3.55, p=0.028), en bloc resection (OR 3.84, p=0.005) and high-grade dysplasia or submucosal invasive cancer (OR 2.97, p 0.014).
Conclusions: In this retrospective analysis, use of the new classification and management with clips appeared to be a safe approach. Advanced DMI types (III-V) occurred in 3.0% of patients and were associated with identifiable risk factors. Further prospective clinical studies should use this new classification.
Trial registration number: NCT01368289; results.
Trial registration: ClinicalTrials.gov NCT01368289 NCT02000141.
Keywords: COLONIC NEOPLASMS; COLONIC POLYPS; COLONOSCOPY; ENDOSCOPIC POLYPECTOMY; ENDOSCOPIC PROCEDURES.
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