Well its 9 years not 10 as those numbers don't include 2018.
2016 10k - Q3'17 all say over 28000.
Further context, 2015 10k:
More than 25,000 of our silicon nitride spine products have been implanted in patients.
So roughly 3000 units sold in 2016 with revenue of 15.7m and puts unit sales on par with 2015. What we don't know is how many of what sold in 2015 as Valeo C is significantly less than Valeo L
Over 20,000 of our silicon nitride spine products have been implanted in patients.
No, one report states "to date", while the other states "since 2008". The reference to "8 years" is relative to the "track record". If the referenced Valeo implant was cleared in 2008, the relevant time period is clearly the same in both statements.