In the search for the next big thing in spinal implants, I'll readily admit that I really knew nothing about spinal spheres. One day I was deep in the world of researching plates, screws, discs, interbody cages and the like and everything was normal, but increasingly my email inbox was filled with tidbits about spinal spheres. Were these going to suddenly be catapulted into spinal implant superstardom from relative obscurity. To my surprise after some deeper digging, the first incarnation of spinal spheres were used since 1957 to stabilize intervertebral disc space and augment interbody fusion. Well look at that. Not as new as I thought.
The Food and Drug Administration (FDA), on their website, describes spinal spheres as being solid, metallic or polymeric, and between 9.5 and 19 mm in diameter. They are designed as permanent implants for use in the intervertebral disc space following a discectomy to maintain disc height and provide postoperative stabilization during arthrodesis procedures. They are not, however, designed for use in motion-sparing nonfusion procedures.
They first achieved clearance through 510(k) and since then there have been six clearances from four manufacturers. The issue is that clinical evidence is terribly limited; up until August 2013 there were only five articles that discussed the use of spinal sphere devices. The devices earned a bit more albeit negative buzz later in the year, when the FDA's Orthopedic and Rehabilitation Devices advisory panel recommended the most stringent review process be implemented for these devices: Class III category assessment, requiring premarket (PMA) approval. This recommendation was given due to the lack of information on their effectiveness and the unreasonable risks for illness or injury. Anna Mazzuco, PhD, senior fellow, National Research Center for Women and Families was quoted on Medscape.com as saying. Holding these implants to the higher standard, the PMA, will help reassure patients that these devices are proven to be beneficial.
When it comes down to it, according to the FDA, spinal spheres have been generally abandoned for use in fusion procedures. I guess with all that said, I shouldn't hold my breath on spinal sphere devices and should keep my eyes open for the next big thing in spinal implants.