Evaluation of a chronic indwelling prototype mesh ureteral stent in a porcine model.
OBJECTIVE
Ureteral stents all share one general goal, drainage, and one major drawback, irritative symptoms in the kidney and bladder. In an effort to preserve drainage while minimizing irritation, a lightweight, self-expanding mesh stent was designed. Herein, we compare the in vivo tissue reaction and flow characteristics of the mesh stent to a standard 7F double-pigtail polyurethane stent.


METHODS
Eight female Yucatan minipigs had bilateral stents placed: a mesh stent on one side and a standard 7F stent on the opposite side. Imaging and flow measurements were obtained in 4 pigs at 1 week and in another 4 pigs at 6 weeks. Following this procedure, the stents were removed, and the kidneys, ureters, and bladder were harvested en bloc for a blinded histopathologic analysis.


RESULTS
The degree of stent-related tissue reactivity was low for both stents and appeared similar for the ureter and bladder. Overall, the mesh stent resulted in a decrease in inflammation along the urinary tract at 1 week, but this result was statistically insignificant (P = 0.55). Flow rate through the mesh stent tended to be greater than for the polyurethane stent both at 1 week and at 6 weeks.


CONCLUSIONS
Overall, the mesh stent appeared to be well tolerated and provided for excellent flow.
Olweny
E O
EO
Department of Surgery (Division of Urologic Surgery), Washington University School of Medicine, St. Louis, Missouri, USA.
Portis
A J
AJ
Sundaram
C P
CP
Afane
J S
JS
Humphrey
P A
PA
Ewers
R
R
McDougall
E M
EM
Clayman
R V
RV
D000818:Animals; D001672:Biocompatible Materials; D003404:Creatinine / Q000097:blood; D004322:Drainage / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D007668:Kidney / Q000473:pathology; D007682:Kidney Pelvis / Q000000981:diagnostic imaging; D011140:Polyurethanes; D019736:Prostheses and Implants; D011859:Radiography; D015607:Stents; D013526:Surgical Mesh; D013556:Swine, Miniature; D014513:Ureter / Q000000981:diagnostic imaging / Q000473:pathology; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology; D014556:Urine
D001672:Biocompatible Materials; D011140:Polyurethanes; D003404:Creatinine