It is common practice in hospitals for patients to sign a form giving the doctor their consent, or approval, to perform surgery. In the form, the patient usually consents to the specific surgery as well as to any other procedures that might become necessary. Before you sign it, your doctor should give you a full description of the surgery and the risks involved, and the ramifications of not getting such treatment. If you can prove that your physician misrepresented or failed to adequately inform you of the risks and benefits before surgery, your consent may be invalid.