STUDY PROCEDURES AND SPECIFIC TESTINGS In this observational study, the MOST RECENT DREAM questionnaire, a standard validated instrument(2) represents the only study specific testing outside of standard care. The questionnaire is handed out to patients to record the most recent dreams five times pre- and post-operatively. The length of each dream summary lies in between 50 and 300 words. Study participation and the questionnaires will not affect standard patient care in any way and carries no additional risks.