This is related to the query which I raised in MSDN forum regarding the issue on Sprint name change (http://social.msdn.microsoft.com/Forums/en-US/tfsgeneral/thread/f6e634ea-aac4-42b8-b054-d94044209cea)

Currently TFS2012 does not scan all the queries whenever there is a change in Sprint name. So impact is, all the queries which are refering to the Sprint name will get error. So my suggestion here is, if TFS2012 allows user to change a Sprint name, this should be automatically taken care internally and all the queries should get updated automatically.
Please let me know , if you need any more clarity.