Implantação de sistema de derivação ureteral subcutânea (sidus) em cão com hidronefrose secundária à ureterolitíase: relato de caso

Abstract

Introduction: Ureteral obstruction is a critical condition of the upper urinary tract that requires immediate diagnosis and intervention to mitigate irreversible renal damage. In dogs, especially small-breed elderly females, obstructive ureterolithiasis is a frequent cause of hydronephrosis and azotemia, demanding therapeutic strategies

that restore urinary patency. Objectives: The present study reports the clinical- surgical management of an 11-year-old female Lhasa Apso with hydronephrosis

secondary to ureterolithiasis, discussing the transition between different ureteral decompression modalities. Methodology: Diagnosis was based on laboratory findings and imaging techniques, including ultrasonography and computed tomography (CT). The initial protocol consisted of multiple microureterotomies associated with the placement of a "double-J" ureteral stent. Due to early obstructive recurrence (25 days), the patient underwent surgical revision to replace the stent with a Subcutaneous Ureteral Bypass (SUB) system. Results and Discussion: CT scans evidenced moderate hydronephrosis and segmental hydroureter caused by multiple calculi. Although the "double-J" stent is widely indicated for the canine species, this case demonstrated short-term functional failure. The implementation of the SUB system, adapted with ultrasonographic and radiographic monitoring instead of fluoroscopy,proved effective in resolving the condition. Postoperative maintenance with a tetra- EDTA solution was essential to prevent biofilm formation and secondary

mineralization. Conclusion: Obstructive ureterolithiasis presents rapid evolution and a prognosis dependent on interventional agility. The failure of the "double-J" stent reinforces the need for individualized therapy, consolidating the SUB system as a superior and technically viable rescue alternative to ensure renal homeostasis and the patient's quality of life.