Asked by user in Indiana. Answered by Enjuris Editors.
Thank you for your question.
Indiana law requires veterinarians to obtain informed consent from a pet owner before performing an operation on the pet. The veterinarian doesn't need to obtain written approval. Generally, it's sufficient if the veterinarian explains the risks and the owner of the pet verbally agrees to proceed with the procedure.
There are some exceptions to this general rule, including cases where emergency treatment is necessary.
Its important to recognize, however, that unless the procedure harmed the pet, your sister is unlikely to recover much in the way of damages.