Records of several surgeries performed three years ago at the University of Toledo Medical Center will show those operations were completed without problems, but identifying the doctor who performed the operations could be more difficult. A nonprofit firm that conducts medical billing for UTMC doctors also investigates mistakes among the 100,000 or so bills sent annually to government and private insurance companies. In 2009, the University of Toledo Physicians Clinical Faculty Inc. investigated the billing of surgeries for at least two doctors and ultimately issued some refunds, according to a confidential document obtained by The Blade.