Redwood City-based Relievant MedSystems, a developer of medical devices being targeted at treating low back pain, said today that it has raised $30M in a Series D funding round. The round was led by New Enterprise Associates, and also included prior investors Canaan Partners, Emergent Medical Partners, Morgenthaler Ventures, and ONSET Ventures. The firm said the funding will go towards expanding its worldwide clinical development programs. Relievant is developing a medical device for a minimally invasive procedure that uses radiofrequency energy delivered via percutaneous access into the vertebral body of the spine to ablate the basivertebral nerve. That nerve is often the source of chronic low back pain.