Normal saline solution versus other viscous solutions for submucosal injection during endoscopic mucosal resection: a systematic review and meta-analysis

Background and Aims: EMR is being increasingly practiced for the removal of large colorectal polyps. A variety of solutions such as normal saline solution (NS) and other viscous and hypertonic solutions (VS) have been used as submucosal injections for EMR. A systematic review and meta-analysis is presented comparing the efficacy and adverse events of EMR performed using NS versus VS. Methods: Two independent reviewers conducted a search of all databases for human, randomized controlled trials that compared NS with VS for EMR of colorectal polyps. Data on complete en bloc resection, presence of residual lesions, and adverse events were extracted using a standardized protocol. Pooled odds ratio (OR) estimates along with 95% confidence intervals (CI) were calculated using fixed effect or random effects models. Results: Five prospective, randomized controlled trials (504 patients) met the inclusion criteria. The mean polyp sizes were 20.84 mm with NS and 21.44 mm with VS. On pooled analysis, a significant increase in en bloc resection (OR, 1.91; 95% CI, 1.11-3.29; P = .02; I-2 = 0%) and decrease in residual lesions (OR, 0.54; 95% CI, 0.32-0.91; P = .02; I-2 = 0%) were noted in VS compared with NS. There was no significant difference in the rate of overall adverse events between the 2 groups. Conclusions: Use of VS during EMR leads to higher rates of en bloc resection and lower rates of residual lesions compared with NS, without any significant difference in adverse events. Endoscopists could consider using VS for EMR of large colorectal polyps and NS for smaller polyps because there is no significant difference in the outcomes with lesions <2 cm.