title: Numerical analysis of the effect of side holes of a double J stent on flow rate and pattern.
abstract: A double J stent has been used widely these days for patients with a ureteral stenosis or with renal stones and lithotripsy. The stent has multiple side holes in the shaft, which supply detours for urine flow. Even though medical companies produce various forms of double J stents that have different numbers and positions of side holes in the stent, the function of side holes in fluid dynamics has not been studied well. Here, the flow rate and pattern around the side holes of a double J stent were evaluated in curved models of a stented ureter based on the human anatomy and straight models for comparison. The total flow rate was higher in the stent with a greater number of side holes. The inflow and outflow to the stent through the side holes in the curved ureter was more active than in the straight ureter, which means the flow through side holes exists even in the ureter without ureteral stenosis or occlusion and even in the straight ureter. When the diameter of the ureter changed, the in-stent flow rate in the ureter did not change and the extraluminal flow rate was higher in the ureter with a greater diameter.
authors.affiliation: Department of Mechanical Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-gu, Seoul, 156-743, Korea.
authors.forename: Kyung-Wuk
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University Boramae Hospital, 425 Shindaebang-2-dong, Dongjak-gu, Seoul,156-707, Korea.
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Choi
authors.affiliation: Department of Urology, Seoul National University Boramae Hospital, 425 Shindaebang-2-dong, Dongjak-gu, Seoul,156-707, Korea.
authors.forename: Seung Bae
authors.initials: SB
authors.lastname: Lee
authors.affiliation: Department of Radiology, Ryokusenkai Yonemori Hospital, 1-7-1, Yojiro, Kagoshima-shi, Kagoshima, 890-0062, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Baba
authors.affiliation: Department of Mechanical Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-gu, Seoul, 156-743, Korea.
authors.forename: Hyoung-Ho
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-gu, Seoul, 156-743, Korea.
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Suh
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D019544:Equipment Failure Analysis; D006801:Humans; D008954:Models, Biological; D011474:Prosthesis Design; D012212:Rheology / Q000379:methods; D015607:Stents; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000503:physiopathology* / Q000628:therapy*; D014554:Urination; D014556:Urine / Q000502:physiology*
keywords: CFD; Ureter; flow; numerical analysis; stent