PHILADELPHIA — A medical device company near Philadelphia pleaded guilty to dozens of crimes today for conducting unauthorized tests of its bone cement on about 200 spinal surgery patients, three of whom died on the operating table.

Synthes Inc. and its subsidiary, Norian Corp., performed the tests from 2002 to 2004.

The product was approved for use in the arm, but not in the weight-bearing spine. Synthes, though, had trained surgeons to use it “off-label” so the company could gather data to support its expanded use. Doctors are allowed to use drugs and medical products for “off-label” uses, but companies cannot promote them that way.

Synthes executives put profits over patient safety as they bypassed the long, expensive process of getting U.S. Food and Drug Administration approval for the clinical trial, the 2009 indictment charged.

Norian pleaded guilty today to a single felony, conspiring to impede FDA functions, along with 110 misdemeanor counts of shipping a mislabeled product. Synthes pleaded guilty to the shipping misdemeanor.

The West Chester-based companies will also pay the maximum $23 million in fines.