Biocompatibility properties of a new braided biodegradable urethral stent: a comparison with a biodegradable spiral and a braided metallic stent in the rabbit urethra.
OBJECTIVE
To compare the biocompatibility properties of a new braided biodegradable self-reinforced poly-L-lactic acid (SR-PLLA) urethral stent to the former spiral biodegradable SR-PLLA stent and the stainless steel stent in a rabbit model.


METHODS
In all, 54 male New Zealand White rabbits were anaesthetized and stents inserted into the prostatic urethra, three of each kind for each sample time. The rabbits were killed after 1, 3, 6, 9, 12 or 15 months and light microscopy and scanning electron microscopy used to analyse the effects.


RESULTS
The disintegration of the braided SR-PLLA stent was more closely controlled than that of the spiral SR-PLLA stent. The metallic stent induced epithelial hyperplasia and polyposis earlier than the biodegradable stents, and in these rabbits the polyposis disappeared after the disintegration process. There were no differences in the histological analyses between the biodegradable stents, whereas the metallic stents caused the strongest inflammatory reactions.


CONCLUSIONS
The braided SR-PLLA urethral stent functioned well in the rabbit urethra and clinical studies are already planned.
Dept. of Surgery, Päijät-Häme Central Hospital, Keskussairaalankatu 7, 15850 Lahti, Finland. taina.isotalo@phks.fi
Taina M
TM
Isotalo
Juha-Pekka
JP
Nuutine
Anu
A
Vaajanen
Paula M
PM
Martikainen
Marita
M
Laurila
Pertti
P
Törmälä
Martti
M
Talja
Teuvo L
TL
Tammela
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use; D006965:Hyperplasia / Q000209:etiology; D007249:Inflammation / Q000209:etiology; D008297:Male; D013677:Medical Laboratory Science; D008670:Metals / Q000009:adverse effects; D011817:Rabbits; D015607:Stents / Q000009:adverse effects; D014521:Urethra; D014525:Urethral Stricture / Q000628:therapy*; D016055:Urinary Retention / Q000628:therapy*
D001672:Biocompatible Materials; D008670:Metals