Spineworks Medical, a Santa Clara, Calif. maker of medical devices, has raised about $7.6 million toward a total round of funding of $8.8 million, according to a regulatory filing acquired by VentureBeat. Spineworks is a stealth mode company, without a significant public presence. However, a patent filing made for the company suggests that it is working on a stabilization device that can be attached to cancellous bone like spinal vertebrae, with methods for cutting into the bone and expanding to secure itself. The investment appears to be an expansion on an earlier-disclosed round of $5.2 million. The financiers include Hatteras Fund, MedFocus Fund and private investors.