URETERAL SUBSTITUTION WITH A STAPLED NEOURETER: A SIMPLIFIED BOARI FLAP

Abstract

We evaluate a new technique that will quickly and easily replace a long segment of ureter by creating a tapered neoureter (Boari flap) with bladder wall and absorbable staples. A neoureter was created in 14 pigs with native bladder and 75 mm. Polysorb gastrointestinal anastomosis staplers (U. S. Surgical, Norwalk, Connecticut). Urine culture and serum creatinine were obtained before neoureter creation. Neoureter length and time to construct were recorded. At 6 weeks serum creatinine was repeated, and ureteral stent removed with evaluation of the staple lines for stones and residual staples. At 4 months intravenous pyelogram, cystogram and serum creatinine were obtained before necropsy. The bladder, neoureter and kidneys were examined grossly and histologically for hydronephrosis, staples, stones and stenosis. Mean neoureter length was 13.4 cm. and mean time to construct was 15 minutes. Laboratory results were unremarkable. Of the 14 pigs 2 died of pneumonia before stent removal, and at autopsy neither had evidence of hydronephrosis nor anastomotic stricture. In the remaining 12 pigs there was no evidence of residual staples or stone formation with mucosa covering the staple line at cystoscopy and necropsy. Successful neoureter substitution was performed in 9 pigs with no gross or histological changes. There were 3 pigs that had evidence of hydronephrosis with histological findings of chronic pyelonephritis and 2 of them appeared atrophic compared to the contralateral kidney. Our study demonstrates a new technique for ureteral substitution with bladder and absorbable staples that may be performed quickly and easily. Furthermore, we show that absorbable staples can be safely incorporated into the urinary tract with minimal worry about encrustation or calculus formation.