The purpose of this combination retrospective and prospective post market study is to examine the short term safety and efficacy of the ROI-A® interbody fusion device with VerteBRIDGE® plates to treat single and two-level degenerative disc disease between L2 and S1, with a focus on fusion rates and patient outcomes.

Inclusion Criteria:

• Subjects must have degenerative disc disease (DDD) of the lumbar spine between L2 and S1
• Subjects may have up to a Grade 1 spondylolisthesis at the involved level(s)
• Subject must have the ROI-A® device at one level or at two contiguous levels between L2 and S1 only
• Subject should have had a minimum of 6 months non-surgical treatment prior to receiving the ROI-A® device
• Subject may have had NO MORE THAN two previous non-fusion surgeries to the lumbar spine at the same levels as the ROI-A®
• Subject must be at least 21 years of age at the time of surgery
• Subject must be willing to signed an informed consent document and return for a 12 month visit

Exclusion Criteria:

• Subject had more than Grade 1 spondylolisthesis at the operated level
• Subject is a prisoner.
• Subject was pregnant at the time of surgery.
• Subject had an active infection or sepsis at the time of surgery.

Subjects will be drawn from community surgeon practices in which the subjects have already received the device and who meet the Inclusion/Exclusion criteria.

From enrollment through final follow up (12 month) visit

An adverse event is defined as any change from baseline in a subject's condition during the clinical study. This includes events that are related to the device as well as events that are not related to the device.