Choosing the correct length of ureteric stent: a formula based on the patient's height compared with direct ureteric...

To evaluate a formula based on the patient's height for choosing the correct length of ureteric stent and to compare its accuracy with that of direct ureteric length measurement.

Thirty-five patients (41 ureters) with ureteric obstruction were prospectively studied. All received Percuflex 8F double pigtail ureteric stents. Stent lengths were chosen according to patient height: < 5 ft 10 in (<178 cm) = 22 cm; 5 ft 10 in to 6 ft 4 in (178-193 cm) = 24 cm; > 6 ft 4 in (>193 cm) = 26 cm. The final stent position was graded using a 5-point scale (0 representing ideal length, with -2 and +2 being too short and too long respectively). Stent length acceptability using direct ureteric measurement was then estimated using the same 5-point scale; and the results compared.

Patient's height correctly predicted stent length in the majority of ureters (grade 0 = 61%), with no stent being too short. In comparison, direct ureteric measurement oversized the stent in 83%, correctly predicting stent length in only 17%.

Patient's height is a more reliable guide to ureteric stent length than direct ureteric measurement, particularly in the dilated and tortuous ureter. This may be because the redundant ureter is capable of significant shortening under the influence of the ureteric stent.