Artificial spinal disc producer SpinalMotion, just tacked $500,000 onto its $20 million third round of funding through a patent licensing agreement with an unnamed corporation. Based in Mountain View, Calif., the company makes both cervical and lumbar artificial discs that are still undergoing clinical trials. It plans to request product approval from the Food and Drug Administration by the middle of the year, reports VentureWire. At that point, it will probably seek out a fourth round of funding to support commercialization. The discs are tailored to patients suffering from degenerative diseases.

The recent investment round came from Skyline Ventures, MedVentures Associates, Thomas Weisel Healthcare Ventures and Three Arch Partners. Beforehand, SpinalMotion raised $14 million in late 2007 from GE Healthcare Financial Services.