Kidney stones cause severe pain. Patients with a stone lodged in the ureter (the tube that drains the bladder), require urgent treatment with a stent to relieve the blockage. This tube, or ureteral stent, gives the patient relief until they can have their stone treated. This study is to evaluate a new type of ureteral stent to relieve pain from kidney stones. This stent is designed to drain the kidney and unlike other ureteral stents, is also designed to widen the ureter to help the stone pass on its own.

This study is to evaluate a new type of ureteral stent to relieve kidney obstruction from a stone lodged in the ureter. This stent would be placed when a patient presents with pain in the Emergency Room or clinic in a patient that has no signs of infection. It is designed to continue drainage of the kidney and unlike other ureteral stents, is also designed to help dilate the ureter to facilitate spontaneous stone passage. This means the stent may also be therapeutic and the patient would be less likely to undergo another procedure to have the stone removed. Research performed at the Stone Centre at VGH shows that in ex vivo pig kidneys, this stent provides very good urinary drainage of the kidney. This has been published in a peer-reviewed journal (Lange D, Hoag NA, Poh BK, Chew BH. Drainage characteristics of the 3F MicroStent using a novel film occlusion anchoring mechanism. J Endourol. 2011 Jun;25(6):1051-6.).

Inclusion Criteria:

1. Perforation of the urinary tract;

2. Acute hemorrhage;

3. Tissue trauma;

4. Edema;

5. Submucosal tunneling of guidewire or device during advancement; and

6. Protein encrustation of the device.

   Exclusion Criteria:

7. Infection;

8. Hemorrhage;

9. Complications associated with the use of anesthesia,

10. Perforation of the urethra or bladder,

11. Scarring or stricture of the urethra; and

12. Urinary retention due to urethral edema.

Patients that present with a unilateral, mid- or distal, ureteral stone that require stent placement to relieve stone symptoms