Microsphere Embolization Technology Treats Knee Osteoarthritis

Novel microspheres can alleviate symptomatic knee osteoarthritis (OA) by reducing blood flow to the periarticular tissue of the joints, limiting the inflammatory process.

The Varian Medical Systems (Varian; Palo Alto, CA, USA) Embozene spheres are biocompatible hydrogel microspheres coated with a proprietary polymer (Polyzene-F). The minute spheres are color-coded by size to allow for easy identification, and are delivered pre-compressed to enable smooth delivery via catheter. Embozene microspheres are intended for embolization of arteriovenous malformations and hypervascular tumors, such as uterine fibroids and hepatoma, benign prostatic hyperplasia (BPH), and now for genicular artery embolization (GAE).


GAE is performed under moderate sedation as an outpatient procedure, generally taking one to two hours. The delivery catheter is inserted in a percutaneous procedure under fluoroscopic guidance, with the microspheres conveyed to arteries supplying the inflamed synovium (lining of the knee). By blocking the genicular arteries, there is a reduction in the amount of inflammation associated with OA, which can diminish or eliminate the associated knee pain. Embozene microspheres are packaged in 20 ml syringes, with an approximate 7 ml fill volume across the range.

“GAE holds great promise in providing clinicians with a new, non-invasive treatment option, which may not only ameliorate pain, but reduce the economic burden of this common disease,” said Frank Facchini, MD, president of Varian Interventional Solutions. “Varian's investigational program for GAE exemplifies our commitment to investing in our core technologies to determine their potential to treat the world's most debilitating diseases.”

“GAE is the first minimally invasive procedure that has demonstrated significant symptom improvement for a prolonged duration,” said Siddharth Padia, MD, director of interventional radiology at UCLA Santa Monica (CA, USA). “In a 40-patient, prospective study, the procedure resulted in a marked improvement in pain and function, and adverse events were uncommon and mild. I remain excited about the possibilities of this technology and its benefit to patients.”

OA is a group of abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion. A variety of causes--hereditary, developmental, metabolic, and mechanical deficits--may initiate processes leading to loss of cartilage. As a result of decreased movement secondary to pain, regional muscles may atrophy, and ligaments may become more lax. OA of the knee affects about 250 million people worldwide (3.6% of the population).

Related Links:
Varian Medical Systems