Digital and Mechanical Characterization of Ureteral Stent Luminal Reduction in Response to Extrinsic Compression Forces

Niall F. Davis, John J.E. Mulvihill, James J. Lynch, Eva Browne, Damien M. Bolton, Gregory S. Jack, Michael T. Walsh

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To investigate the principles that govern ureteral stent failure by digitally and mechanically characterizing their luminal reduction in response to various extrinsic compression forces. To explore the relationship between ureteral stent "material area," "luminal area," and "cross-sectional area (CSA)" for resisting extrinsic compression forces. Materials and Methods: We mechanically investigated 4.8F (n = 9), 6F (n = 9), and 7F (n = 9) ureteral stents to determine parameters that contribute to resisting radial compression forces. Digitalized images of luminal reduction values under incrementally increased reductions of stent outer diameters were obtained (0%, 25%, 50%, and 60% of original outer diameter). Forces (Newton [N]) and percentage luminal reduction that resulted in complete ureteral stent obstruction were determined. Results: Uniaxial incremental compression in the radial direction demonstrated complete luminal reduction (95%-100%) when 58% to 62% of the outer stent diameter was compressed. The 6F ureteral stents demonstrated the greatest resistance to extrinsic compression and the greatest "material area" relative to "CSA" (mm 2 ). The force (N) required for 50% compression of outer stent diameter was 10.44, 28.13, and 25.39 N for 4.8F, 6F, and 7F ureteral stents, respectively. The "material area"/"CSA" at 50% compression of the outer stent diameter was 76%, 86%, and 78% for 4.8F, 6F, and 7F ureteral stents, respectively. Conclusions: Maintenance of intraluminal stent diameter in the presence of extrinsic compressive forces is primarily dependent on the stent's ratio of "material area" to "CSA." Urologists should be aware of these findings to decrease the risk of ureteral stent failure when treating extrinsic ureteral obstruction.

Original languageEnglish
Pages (from-to)1148-1153
Number of pages6
JournalJournal of Endourology
Volume32
Issue number12
DOIs
Publication statusPublished - Dec 2018

Keywords

  • Extrinsic compression
  • Failed ureteral stent
  • Ureteral obstruction
  • Ureteral stent

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