Inclusion Criteria:

1. stone disease

2. localized tumor disease

3. hydronephrosis of unknown ethiology

4. patients who receive a prophylactic stent before a planned operation.

Exclusion Criteria:

1. Patients being septic and in a life-threatening condition before or after
stent-insertion

2. patients with tumors in a progressive state that affect the retroperitoneum
(contralateral ureter might be affected and can not serve as a control for the
stented side)

3. patients with Morbus Ormond (same reason as above)

4. patients requiring ureteral stents bilaterally (same reason as above)

5. long-term stented patients will be excluded as we are interested in evaluating the
onset of changes in peristalsis rate which are expected to be most significant in an
acute setting.

6. patients with preexisting abnormalities/pathologies of the urinary tract e.g. reflux
disease, megaureter or bladder dysfunctions as these will likely affect our results

7. non English-speaking patients will be excluded as they will not be able to understand
the letter of consents.

Exclusion criteria for control group:

1. known preexisting pathology in the urinary tract (see above)

2. volunteers who underwent previous surgical procedures on kidney, ureter or bladder
within the past 5 years as this may change the starting position of our study

3. patients currently taking an α-blocker (alfuzosin, terazosin, doxazosin, tamsulosin,
prazosin) because these medications are known to affect peristalsis

4. patients currently taking calcium channel blocker (verapamil, diltiazem, nifedipine,
nicardipine, bepridil, mibefradil) because these medications are known to affect
peristalsis