The ureter connects the kidneys with the urinary bladder. If , for example, they are narrowed or clogged by small stones, ureteral stents can be used for therapeutic purposes. In this case we are referring to permanent catheters that are placed in the ureter to restore the urine flow from the kidney to the urinary bladder. Often the urine flow is so extensively restricted by ureteral stones that the kidneys on both sides gradually lose their function. In larger dogs ereteral stents can be inserted entirely endoscopically, while in smaller dogs and cats surgical intervention is required. Compared to traditional surgical interventions, this method is associated with a significantly smaller potential for complications and thereby significantly improves the prognosis for the patient.
An alternative treatment option for cats is the so-called SUB.
The insertion of an urethral stent may be appropriate if the lumen is constricted as a result of tumor growth or scarred healing after a deeper urethral injury, for example as a result of stones. These implants, which mostly consist of a metal mesh (nitinol), are positioned without the necessity of an operation under fluoroscopy at the correct place in the urethra and they widen the narrow passage from the inside. Thereby the urine flow is immediately restored.