The FDA posted a warning letter against California-based Spinal Elements, saying that the company failed to obtain regulatory clearance for design changes to certain of its intervertebral body fusion devices.

Agents inspected Spinal Elements’ Carlsbad facility early this year, dubbing the company’s Lucent and Lucent Ti-Bond devices "adulterated" under FDA law. The FDA further chided the company for "unsubstantiated claims" made about the Ti-Bond device that the agency never approved.

Spinal Elements won FDA clearance with straight and curved designed, but a new "bulleted" design was never reviewed, according to the warning letter.

"Your addition of the bulleted design is a major design change from your original premarket clearance submission that can significantly affect the safety and effectiveness of the device, and thus requires a new 510(k)," the FDA said.

Inspectors also knocked the company for performance claims regarding the Ti-Bond device in particular, including claims that the implant’s coating "recruits pluri-potential osteogenic cells," that it helps "minimize implant migration" and that it is "bioactive."

The FDA gave Spinal Elements 15 days to respond to the letter, which is dated June 12, 2014, and was published online this week.