The University of Michigan — home to three hospitals, 125 clinics and home care operations serving more than 2.3 million people annually — will open an innovative $920 million medical center for patients needing the most complicated care. The Board of Regents approved plans Thursday for the 12-story, $920 million adult in-patient hospital that's expected to "transform inpatient and surgical care" and move UM's health care services into the future.