Use of Peppermint Oil During Screening Colonoscopy to Improve Visibility

Abstract

Introduction: Colonoscopy is the fundamental screening tool used to detect colorectal polyps and colorectal cancer. Many techniques are being developed to increase visualization and improve adenoma detection rate (ADR). Antispasmodic agents are used in intravenous form to inhibit peristalsis during colonoscopy. Limited data suggest beneficial effects of topical administration of peppermint oil, containing L-menthol, including diminished smooth muscle contraction, decreased endoscopic procedural time and improved ADR. We aimed to assess whether use of peppermint oil during screening colonoscopy improves visualization and increases patient satisfaction, as well as ADR. Methods: This was a randomized, double-blind, placebo-controlled study. Patients scheduled for screening colonoscopy were randomly assigned to either receive peppermint oil or placebo. Insertion of the colonoscope to the cecum was performed as standard practice and, once in the cecum, 50ml of peppermint oil solution or placebo containing normal saline was gently sprayed into the lumen. During withdrawal, the endoscopist graded colonic peristalsis, spasticity, and visibility while assessing for colon lesions. Quality measures including bowel preparation, withdrawal time and number of polyps removed were recorded. Additional data on demographics and procedural details were documented and analyzed. Statistical analysis was performed using Wilcoxon rank sum and Chi-square tests. Results: Preliminary data from 28 patients were analyzed. Thirteen patients were randomized to receive peppermint oil. Age, gender, and BMI were comparable between the two groups. Average Boston Bowel Preparation Score was overall excellent (mean 7.9 ±1.2 for drug vs 8.3 ±1.0 for placebo). Withdrawal time tended to be less in the group that received the drug (9.8 min vs. 10.9 min) with shorter overall procedure time (18.3 min vs 21.7 min, p= 0.56). With use of peppermint oil, ADR was 32.1% compared with 37.5% in controls (p=0.37). Assessment of spasticity, peristalsis and visualization did not differ in the two groups. Patient satisfaction evaluated by perception of pain and willingness to repeat the procedure was equally high in both groups. Conclusion: Our initial data on the use of peppermint oil in screening colonoscopy suggests no significant impact on peristalsis, patient satisfaction, or ADR. Decrease in procedure time may be a surrogate marker for improved visibility with additional patients currently being recruited to further explore our hypothesis.