Laparoscopic replacement of urinary tract segments using biodegradable materials in a large-animal model.
OBJECTIVE
We elected to evaluate laparoscopic segmental bladder and ureteral replacement with free biodegradable graft materials in a large-animal model.


METHODS
In 18 Yucatan minipigs, a 1.5- to 2.8-cm segment of the upper ureter was excised. In 15 study animals, the ureter was laparoscopically replaced: by a stinted (6F double-J stent) tube graft made of acellular matrix (AMX) prepared from minipig ureters (MUMX) in 6 animals, acellular matrix prepared from domestic pig ureters (DUMX) in 3, and small-intestinal submucosa (SIS) in 6. In 3 control animals, the ureteral gap was bridged only by an indwelling stent. The stent was removed at 6 weeks, and retrograde ureteropyelography was performed preoperatively and at 8 and 12 weeks postoperatively, when animals were sacrificed. In 18 Yucatan minipigs, 3 x 3-cm bladder dome segments were laparoscopically replaced: by acellular matrix prepared from minipig small bowel (MBMX) in 6 animals, and SIS in 6 animals. The bladder was closed primarily in 6 control animals. Bladder capacity was assessed preoperatively and at 6 and at 12 weeks, when the animals were sacrificed.


RESULTS
The average operating time for ureteral replacement was 187 (range 105-360) minutes. At 12 weeks, all animals had complete obstruction at the level of the replacement, with fibrosis +/- bone formation at the level of the stricture. For the bladder replacement groups, the average operating time was 147 (range 85-200) minutes. At 12 weeks, the bladder capacity was 60% of the preoperative capacity in the control group, 118% in the MBMX group, and 142% in the SIS group. Histologic examination showed regeneration of urothelium and some muscle with both MBMX and SIS.


CONCLUSIONS
We were able to develop a reliable laparoscopic technique for both segmental ureteral and partial bladder replacement in a porcine model. With AMX and SIS replacement, regeneration of urothelium occurred in both ureter and bladder. However, functional replacement was successful only in the bladder.
Shalhav
A L
AL
Division of Urologic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Elbahnasy
A M
AM
Bercowsky
E
E
Kovacs
G
G
Brewer
A
A
Maxwell
K L
KL
McDougall
E M
EM
Clayman
R V
RV
D020341:Absorbable Implants; D000818:Animals; D003558:Cystoscopy; D005109:Extracellular Matrix; D005500:Follow-Up Studies; D007421:Intestine, Small; D010535:Laparoscopy; D013552:Swine; D013556:Swine, Miniature; D014513:Ureter / Q000166:cytology / Q000601:surgery*; D001743:Urinary Bladder / Q000166:cytology / Q000601:surgery; D014567:Urography; D013520:Urologic Surgical Procedures / Q000379:methods*; D019459:Urothelium / Q000166:cytology