Ally,
I first saw Isobar at the Medica congress 4 years ago. To my knowledge, it was approved in the US as a fusion device, but is not approved as a motion preservation device. It operates in a similar fashion as Dynesys, having pedicle screws (like a posterior fusion) joined by a flexible spacer. In Dynesys the spacer is a plastic tube with a stiff cord running through it providing tension. In Isobar, the pedicle screws are joined by a system of metal rods with a joint in the middle.
Besides Isobar and Dynesys there are several other systems that provide posterior stabilization with less invasive surgeries. I implore you to discover your options. There is no such thing as a 'freebie' spine surgery. No such thing as "try this, if it doesn't work, you haven't burned any bridges." Yes, there are less invasive surgeries that seem that way, but it is up to you do discover all your options before you submit to spine surgery.
Isobar, from
www.scientxusa.com
Dynesys, from various websites.
Mark