Becker's Spine Review

20 Executive Briefing Sponsored by: M ore than 1.2 million spinal surgeries are performed in the U.S. each year, including spinal fusion, decompression and discectomy procedures, according to the National Center for Health Statistics. And the volume of elective lumbar fusions is rising across the U.S., research published in Spine indicates. As spine fusion volumes increase, so do the numbers of patients who will develop pseudarthrosis, a related complication. A number of surgeons are turning to advanced techniques to help reduce non-union rates and the resulting expenditures. For instance, bone grafts are used in 59 percent of lumbar spinal fusion procedures and 91 percent of cervical spinal fusion procedures, according to GlobalData published in 2017. "There's a ton of biologics everywhere, and companies are continually approaching surgeons trying to get them to use or switch to their 'better' or 'improved' biologic," said Pierce Nunley, MD, director of the Shreveport-based Spine Institute of Louisiana. Because of all this noise, Dr. Nunley paid little mind at first when a Netherlands-based company called Kuros Biosciences came knocking. But then he saw Kuros' work on a novel fibrin parathyroid hormone-based bone graft product candidate, which recently received Investigational New Drug approval from the FDA. This product made him realize the company wasn't approaching biologics like the other vendors; it was taking a much more scientific approach. That's when he learned about MagnetOs bone graft. "[Kuros] showed me some real data," Dr. Nunley said. "And I thought, 'Wow. That's pretty compelling.' So, quite frankly, that's why I started using MagnetOs." Research examining how MagnetOs facilitated bone formation through cell differentiation is what convinced Dr. Nunley that the product was worth its salt for use in spinal fusions. In animal models, MagnetOs formed a bone fusion mass that was comparable — if not better — than other calcium phosphates, he said. A strong foundation What Dr. Nunley found even more compelling was why, physiologically and biologically, the product works. Essentially, MagnetOs' advanced submicron surface technology is configured in such a way that it "turns on" the M2 macrophage phenotype, which promotes bone formation, as opposed to the M1 macrophage phenotype that lead to problematic inflammation and fibrous tissue formation. This technology is based on a strong understanding of osteoimmunology and the benefits of 3D-implant porosity, according to Richard Todd Allen, MD, PhD, chief of spine surgery at UC San Diego (Calif.) Health System. MagnetOs' unique surface features are what enables the product to alter cellular reactivity to draw appropriate cells into the area and drive bone formation, he said. "This has been one of the most exciting fields of study over the past 15 years or so in terms of bone healing," Dr. Allen said. "Rather than identifying what affect an inflammatory response has to bone healing and fusion, our understanding of the specific cell types and integrated mechanisms involved in coordinating bone formation has improved, versus those cells generating a fibrous non-union." While this osteoimmunologic research behind MagnetOs looked promising, Dr. Nunley was cautious about introducing it into his practice, having tried seemingly effective products in the past that ended up causing severe inflammation and pain for patients. He performed a few cases with MagnetOs and followed the patients closely to see if there were any issues. No issues were discovered and it appeared to work well, so he decided the bone graft technology was worth continuing to use. "I've not had any — to my knowledge — negative events from the use of MagnetOs," he said. "I've only been using it a year or so, but I've not had a single non-union or concern currently about any of my MagnetOs patients having a non-union." Not your average white, powdery crystal While other companies offer beta tricalcium phosphate products — white, powdery crystals that are similar in appearance to MagnetOs bone graft — no other product facilitates the M1 to M2 macrophage response that the Kuros product does, according to Kornelis Poelstra, MD, PhD, director of The Robotic Spine Institute of Silicon Valley in Los Gatos, Calif. "There are a lot of papers now that directly compare, in very strong animal models, the class-leading (by sale) beta tricalcium phosphate products to MagnetOs," Dr. Poelstra said. "And the data is extremely strong for the surface modification and the direct bone formation with MagnetOs." Other products lead to fibrous bridging bone, which looks like good, bony fusion on X-rays and CT scans, according to Dr. Poelstra. The problem, however, is that the mass actually contains small particles of remaining bone graft material surrounded by fibrous tissue. In contrast, MagnetOs creates a solid block of bone, he said. This data-backed graft promotes bone formation, lowers costs in spinal fusion

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