Silicon Nitride Bioceramic, Biomaterials Wunderkind

“Silicon nitride, as a biomaterial, has so many different iterations and applications that we are just beginning to scratch the surface of its potential applications,” says Sonny Bal, M.D., J.D., MBA, president and CEO of Amedica Corporation. “Use of silicon nitride bearings led to improved reliability of the engines in the space shuttle; it’s used in the aerospace industry; in internal combustion engines, and other extreme industrial environments that are much more demanding than the human body. I see it helping solve real clinical problems and providing pain relief to a whole generation of patients, and that’s wonderful.”

This wonder-material that can be found in both space shuttles and the bones of orthopedic patients is silicon nitride, an alternative to PEEK (polyetheretherketone) and titanium for bone fusion. The reason for its presence in the NASA space shuttle is because the material, which is harder than metal, demonstrates 80 percent less friction, three to 10 times longer lifetime, 80 percent higher speed, 60 percent less weight, the ability to operate with lubrication starvation, higher corrosion resistance and higher operation temperatures than traditional metals used for bearings. If that made you think about joint replacements, you wouldn’t be the first. The material presents an exciting new frontier to those in the orthopedic biomaterials space for its mechanical and chemical properties.

“Innovations in biomaterials have historically been very important,” Bal said to Orthopedic Design & Technology. “If you look at hip replacements, it was the development of biomaterials that truly pushed hip replacements from a five-year success operation to a 10-year success operation, which led to its being adopted as a viable treatment for painful arthritis. The same is true for knee replacements. That paradigm still applies to innovative biomaterial technologies today that will give us a lifetime hip or knee replacement, which aren’t possible today. Innovative biomaterials will also address clinical problems like infection, which are very difficult to treat today.”

Silicon nitride is the core competency of Amedica, which newly-minted CEO Bal has been involved with from its inception. The company’s main line of products is the Valeo interbody fusion devices, all made from silicon nitride. The material promotes bone growth, is anti-infective, and may result in faster bone fusion. In fact, Amedica is the only company worldwide that currently has U.S. Food and Drug Administration clearance to manufacture and distribute silicon nitride implants.

“Our bread and butter today is our intervertebral body spacers for spinal fusion,” said Bal.  “We have clinical data from a prospective, randomized clinical trial in Europe that validates what we’ve believed and seen empirically all along, which is that bone has an affinity for this material. The material we used in Europe was a cancellous variation, and our hope was that the bone would grow into it. Not only did that happen, but it happened at rates equivalent to bone autograft which is very exciting, and unprecedented for any biomaterial.”

The Cascade study enrolled 104 patients in a prospective clinical trial that independently scored fusion rates and clinical outcomes at 12 months follow-up. Neck Disability Index scores decreased similarly in both patient groups. Importantly, the incidence of cervical spine fusion was statistically identical between study groups, and was consistent with figures reported in other studies. The study demonstrated that silicon nitride provides equivalent fusion to PEEK spacers with bone autograft.

Silicon nitride has only recently found its way into the medical space, and therefore presents a wide scope of opportunity for creative applications. Amedica has made it a point to vigorously foster innovation at home. Bal’s trifecta of professional graduate degrees in medicine, law and business were not sought on a whim. Bal said he sought expertise along the way as he found “deficiencies” within himself, like when he found executive friends seeking his advice on medical liability questions (that’s when he pursued the law degree), or when he had a private practice as an orthopedic surgeon and found that he needed to learn some business acumen (then came the MBA). But he does not see himself as the company’s “great leader;” rather, he is the “great enabler,” encouraging engineers, researchers, etc. to collaborate and innovate fearlessly.

“There are a limited number of scientists around the world that are experts in this field, and my vision has been to connect them all, fostering an affinity with the company so that we own this space in a very strong way,” Bal said. “The employees at Amedica are motivated, strong people with very powerful visions and very unique talents. You’ve got to get other people into leadership positions and let them make mistakes, be innovative, be creative. That’s what a startup company is. We create a climate in which everybody’s creativity is maximized. That will take us into the future and I believe very strongly in that. So far every day’s been better than the last.”