Ureteral double pigtail stenting in dogs and cats. Preliminary clinical results

Introduction: Indications for ureteral stents include: ureteral obstruction by calculi, palliation of inoperable ureteral neoplasia, end-to-end ureteral anastomosis and adjuvant application after ureter transplant. There are few reports on the use of ureteral double pig-tail stent in dogs and cats. The aim of this study was to investigate the use of stents for ureteral obstruction by calculi and to review their effectiveness in preventing recurrence of obstruction. Material and Methods: Patients considered eligible for the study were dogs and cats with ureteral stones and stone(s) in the ipsilateral renal pelvis. Work-up included laboratory evaluation, plain and contrast radiography and abdominal ultrasound. Immediately after ureteral stone removal and stent placement, radiographs were taken to evaluate the position of the stent. An ultrasonographic examination was performed 3 days later. Clinical, radiographic and/or ultrasound examinations were performed every 6–8 weeks. Efficacy of the stent was evaluated at follow-up by visualization of the renal calculi seen previously or their migration along the ureter without any ureter or pelvic dilation. Results: Between 2006 and 2008, 14 stents were placed in 7 dogs and 5 cats. The age ranged between 5 and 132 months (mean 65.8, median 75) the body weight ranged between 2.2 and 20Kg (mean 7.81; median 6.2). Two patients had a bilateral ureteral stenting; 2 modified stents (distal end cutted) were used in one of these. In 11 animals a polypropylene double pig tail openends stent (Optisoft, OptiMed, Germany, diameter 3 to 6 Fr; length 14 to 24cm) was used. Follow up varied from 6 to 32 months (mean 19.1, median 21); ureteral stone without dilation were relieved in 100% of cases. All animals had signs of ureteral inflammation but no sign of infection (urinalysis). Major complications were observed in 2 animals: 2 migrations (modified stents) and 1 encrustation. No upper urinary tract dilation was recorded. No lower urinary tract infection or inflammation/pain were observed. Conclusion: In our study, the presence of ureteroliths after stent positioning did not cause any upper urinary tract dilation. These preliminary results indicate that double j stents may safely be applied to relieve ureteral obstruction caused by ureteral calculi.