Patient Registration. You may pre-register for surgery, tests or treatment at Oviedo Medical Center by phone: Pre-Registration: 1-888-454-7975. Pre-Admission Testing: (407) 890-2185. Surgery Scheduling: (407) 890-2700. Outpatient Test & Treatment Scheduling: 1-888-454-7974. To register online at Oviedo Medical Center, sign in using your ....