“Rule of Five” in Ureteral Dilatation and its Role in Ureteral Access Sheath Placement during Retrograde Intrarenal Surgery

Purpose: Sequential ureteral dilatation facilitates placement of ureteral access sheath during retrograde intrarenal surgery. The authors adopted some improvisations in conventional sequential ureteral dilatation methods to achieve improved ureteral accommodation and prefer to call the sequential ureteral dilatation performed with these improvisations as “Rule of five” (ROF) ureteral dilatation. The objective of the article was to describe the “ROF” ureteral dilatation technique and share the preliminary experience with the technique. Materials and Methods: “ROF” ureteral dilatation involves repetitive dilatation of ureter for five times by 10 Fr ureteral dilator, with each dilatation lasting for 5 s. The technique was used in patients who underwent retrograde intrarenal surgery for renal calculi and in whom 12 Fr ureteral dilator passage and 9.5/11.5 Fr ureteral access sheath placement was not possible by conventional sequential ureteral dilatation methods. Preliminary efficacy and safety outcomes were reported. Results: “ROF” ureteral dilatation was performed in 14 renal units. Ureteral access sheath placement was successful in 10 renal units (71.4%) and unsuccessful in 4 renal units (28.6%). Ureteral access sheath associated low-grade ureteral wall injury was noted in 2 renal units (14.3%). None had new onset hydroureteronephrosis in follow-up ultrasonography and all patients were asymptomatic in the follow-up period. Conclusion: “ROF” ureteral dilatation is an improvisation of conventional sequential ureteral dilatation. It facilitates successful and safe ureteral access sheath placement in a proportion of patients undergoing sequential ureteral dilatation.