Page 103 - IJB-8-2

RESEARCH ARTICLE

3D-Printing-Assisted Extraluminal Anti-Reflux Diodes

for Preventing Vesicoureteral Reflux through Double-J

Stents

Jihun Lee , Jaebum Sung , Jung Ki Jo *, Hongyun So *
2
1,3
1
1
1 Department of Mechanical Engineering, Hanyang University, Seoul 04763, South Korea
2 Department of Urology, College of Medicine, Hanyang University, Seoul 04763, South Korea
3 Institute of Nano Science and Technology, Hanyang University, Seoul 04763, South Korea
Abstract: This paper presents novel umbrella-shaped flexible devices to prevent vesicoureteral reflux along double-J stents,
which is a backward flow of urine from the bladder to the kidney and is a critical issue in patients with urinary stones. The
anti-reflux devices were designed to mechanically attach to the stent and were manufactured using three-dimensional (3D)
printing and polymer casting methods. Based on the umbrella shapes, four different devices were manufactured, and the anti-
reflux efficiency was demonstrated through in vitro experiments using a urination model. Consequently, penta-shaped devices
exhibited the best anti-reflux performance (44% decrease in reflux compared to the stent without the device), and maximum
efficiency occurred when the device was attached near the bladder-ureter junction. In addition, a disadvantage of 3D printing
(i.e., unwanted rough surface) helped the device strongly adhere to the surface of the stent during the insertion operation.
Finally, long-term soaking experiments revealed that the fabricated devices were mechanically robust and chemically stable
(safe) even being soaked in urine for 4 weeks. The findings of this study support the use of additive manufacturing to make
various flexible and biocompatible urological devices to mitigate critical issues in patients with urinary stones.

Keywords: Vesicoureteral reflux; Double-J stent; 3D printing; Anti-reflux diode; Urology

*Correspondence to: Jung Ki Jo, Department of Urology, College of Medicine, Hanyang University, Seoul 04763, South Korea; victorjo38@
hanyang.ac.kr; Hongyun So, Department of Mechanical Engineering, Hanyang University, Seoul 04763, South Korea; hyso@hanyang.ac.kr

Received: December 21, 2021; Accepted: February 7, 2022; Published Online: February 7, 2022
Citation: Lee J, Sung J, Jo JK, et al., 2022, 3D-Printing-Assisted Extraluminal Anti-Reflux Diodes for Preventing Vesicoureteral Reflux
Through Double-J Stents. Int J Bioprint, 8(2):549. http://doi.org/10.18063/ijb.v8i2.549
1. Introduction medical tools for urologists during various urological
procedures and treatments . Despite the advantages
[10]
Most urological procedures and treatments, such of using DJ stents, the inserted DJ stents can cause side
as lithotripsy, ureteroscopic procedures, prevention
of ureteral stenosis, relief of hydronephrosis, and effects in patients. For example, hematuria, dysuria,
reduction in urological complications, require double-J irritative urination, and urinary tract infection can result
[4-7,9-13]
(DJ) stents [1-7] . In general, these DJ stents are thin and from inserted DJ stents . In addition, vesicoureteral
hollow tubes with side holes composed of polyurethane reflux (VUR) is a side effect that frequently occurs
material, and both ends are rolled up to hold the stent because the stents preclude the complete closure of the
in the ureter . The DJ stents are located in the ureter to bladder-ureter junction (vesicoureteric junction [VUJ])
[8]
enable urine drainage from the kidney into the bladder during urination [14-16] . VUR is a significant problem that
and to prevent contraction of the ureter after the removal leads to flank pain, pyelonephritis, renal scar formation,
of urinary stones [5,9] . In addition, ureteral stents are and renal failure [15,17-20] . In particular, VUR induced by
used during renal transplantation to reduce urological inserted stent can cause severe flank pain during urination
complications, such as anastomotic stricture or urine or upper urinary tract infection, which has a potential
leakage after operation [6,7] . Thus, DJ stents are necessary hazard of pyelonephritis [15,19-21] . In addition, occurrence of
© 2022 Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
95