This is a prospective, non-randomized, multi-center (up to 30 sites) controlled clinical study enrolling 100 subjects following a pre-specified protocol with no site enrolling more than 30 subjects. All eligible subjects providing written informed consent and meeting study eligibility criteria will receive a facet preserving decompression using the FDA cleared iO-Flex® system on label. Treatment success using the iO-Flex® System will be analyzed using a precision estimate assuming a 55% positive response rate.