• Inclusion of data on all consecutive patients treated during a one-year period.

• Study initiated from each site once the first patient is enrolled. Each centre will close its participation exactly one year after inclusion of the first patient.

• There is no minimum or maximum of number of sites participating in this study, however, all sites must receive prior approval of the CROES council.

• Subject to the approval of the CROES council, the lead investigator at study sites must be a member of the Endourological Society and in good standing. Subject to the approval of the CROES council, study sites may be proposed by the members from the Steering committee or on recommendation from a third party.

• Electronic database will be maintained at the central data collection site selected by the CROES council and shall be updated on a regular basis as determined by the CROES council. A manager, selected by the CROES council, at the central data collection site will maintain and coordinate the data collection.  

• Prior to approval of the site by the CROES council, for quality assurance, either an IRB approval or a letter from the principal investigator of the study site assuring the quality and ethical standards of data collection will be provided.

• The members of the study group will receive feedback on the data collected on a regular basis, as determined by the CROES council. 

• The data analysis shall be the responsibility of the Steering committee for the study group.

• The Steering committee shall be comprised of 6-8 international members and a chairman. A good balance among the different treatment specialists is desirable. Representatives of the CROES council may be joining during the Steering committee meetings.

• Representatives from the supporter of the study will join the Steering Committee.