Associate Editor John R. Saltzman, MD, highlights this article from the February issue, “Non-adherence to the rule of 3 does not increase the risk of adverse events in esophageal dilation” by Karina V. Grooteman, Louis M. Wong Kee Song, Frank P. Vleggaar, Peter D. Siersema, and Todd H. Baron.

This study challenges the prevailing wisdom known as the “rule of 3.” The rule of 3 states that no more than 3 dilators of progressively increasing diameter (of about 1 mm) should be passed in one session after moderate resistance is encountered in order to prevent complications, especially perforation. This rule is only applicable to bougienage as resistance is not measured with through-the-scope dilators. As true for many things in medicine, this rule is derived from common sense and is not actually evidence based. These authors challenge this rule and report on their experience performing  more than 3 dilations in a session.

This is a large single center retrospective experience from the Mayo Clinic in Rochester Minnesota. The authors reviewed the charts of patients who underwent esophageal dilation between 1991 and 2013. There were 297 patients who underwent 2216 esophageal dilation procedures with major adverse events occurring in 22 dilation sessions (1%), including perforation in 11 cases (0.5%).  Overall, malignant strictures were associated with an increased risk of adverse events. Non-adherence to the rule of 3 occurred in 190 dilations (13%) with bougie dilators. Interestingly, non-adherence was not associated with an increased rate of major adverse events including perforation (none in this group).

The authors report that it is safe to exceed the rule of 3, and actually propose a new “rule of 6.” Although it may be safe to extend our range of dilation in selected patients,  endoscopists should still proceed with caution and have safety as the primary goal. As pointed out in the excellent accompanying editorial by Dr. Joel Richter, we need to individualize our approach. In most patients, there is no rush to dilate a stricture fully in 1 or 2 sessions. There are certain types of patients with strictures that may be more likely to experience adverse events, including malignant strictures and benign strictures due to caustic ingestion and eosiniphilic esophagitis. Both this study and the accompanying  editorial are highly recommended to be read in full as all endoscopists need to be able to effectively and safely dilate esophageal strictures.

Read the article abstract here.