About Annular Closure

Dozens of bones called vertebrae make up the spine. The vertebrae are stacked on top of one another, from the neck down to the tailbone. Between each vertebra is a spongy disk that serves as a shock absorber and helps the spine remain flexible.

The disc itself includes a core and an outer ring. Disc herniation occurs when the core breaks open and extends beyond the outer ring. Most herniated discs occur in the lumbar vertebrae, which are in the lower back. A disc herniation leaves an annular defect (a tear or hole in the outer part of the disc) that does not typically fully heal, leaving some patients with large defects at higher risk of reherniation.

Limited discectomy is a procedure to remove the disc’s ruptured portion, while preserving much of the patient’s natural disc. But limited discectomy leaves behind the defect or hole that the herniation came through in the disc annulus, which is the outer ring of the disc. The annual defect makes the disc vulnerable to reherniation.

Spine surgeons use annular closure to repair holes the size of a pencil eraser (6 mm) or larger created during surgery. The goal of annular closure is to strengthen the disc tissue and help prevent reherniation. Surgeons at Stanford Health Care use an annular closure device that reduces disc reherniation by 52% and repeat surgeries by 61%.