Safety and Efficacy of Dynamic Submucosal Injection Technique for the Mucosal Resection of Large Colorectal Neoplasia

Abstract

Introduction: Endoscopic mucosal resection (EMR) of large colorectal polyps is efficacious and safe with the selection of the appropriate polyp and resection technique. Several studies have demonstrated the short and long term efficacy of EMR. Several techniques have been used to improve the efficacy and to minimize complications. Submucosal injection has been conventionally used to create a submucosal bleb that facilitates snaring the lesion off. Dynamic submucosal injection (DSI) technique employs several steps including adjusting the angle of the injecting needle, moving the needle while injecting in a path that is envisioned by the endoscopist, applying suction, and rapidly injecting the solution. We present our experience with the use of DSI technique in resecting large colorectal polyps. Results: We have performed 101 EMRs on 82 patients with a mean age of 65 years (60% males) between August 2013 and November 2014. The mean polyp size was 29mm (range 15-60mm). The mean procedure time was 57 minutes. 64% of the lesions were in the right colon. Histopathology showed tubular adenoma with low grade dysplasia (TA-LGD) (n=50), sessile serrated adenoma (n=26), tubulovillous adenoma (n=9), tubulovillous adenoma with focal high-grade dysplasia (n=6), tubular adenoma with focal high-grade dysplasia (n=4), intramucosal adenocarcinoma (n=2), invasive submucosal adenocarcinoma (n=3), and Maltoma (n=1). Complete removal was achieved in all cases and lesions were removed en bloc 30% of the time. A mean of 38ml of normal saline (with indigo carmine) was injected. Argon plasma coagulation was used in 73% of the resections with mucosal defect closure with endoclips performed in all. Complications included bleeding (n=1), postpolypectomy syndrome (n=1), and postprocedure emesis (n=1). In the twenty five patients that have undergone follow up colonoscopies so far, we have found 2-3mm residual polyp tissue (TA-LGD), only in 3 patients (10%). One of the intramucosal adenocarcinoma lesions underwent surgical resection as margins were involved. The other intramucosal lesion was removed en bloc with unremarkable computed tomography scan and rectal ultrasound and no recurrence on follow up. Of the three patients with invasive submucosal adenocarcinoma, two had subsequent colectomy with no residual cancer and negative lymph nodes. Discussion: DSI technique for endoscopic mucosal resection of large colorectal lesions is efficacious and safe.