The purpose of this trial is to collect clinical outcomes including radiographic and CT outcomes in patients who undergo interbody spinal fusion using the EVOS Lumbar Interbody System.

This prospective, non-comparative, multi-center, post-market trial will evaluate the safety and efficacy of the PEEK-OPTIMA™ HA Enhance Interbody Cages System - EVOS- HA in patients suffering from degenerative disc disease and spondylolisthesis in the lumbar spine. The trial will capture clinical outcomes, radiographic and CT outcomes over a 24 month period post operatively. Two centers will be involved in the recruitment of 30 patients. All patients will be drawn from clinics which focus on this type of treatment.

Inclusion Criteria:

• Is the subject aged 18 years of age or older and skeletally mature?
• Does the subject have a primary diagnosis of symptomatic degenerative disc disease (DDD) or symptomatic degenerative disc disease (DDD) with spondylolisthesis (Grade 1) at one or two contiguous levels from L2 to S1?
• Does the subject have discogenic back pain with degeneration of the disc confirmed by medical history, radiographic examination and MRI (MRI must be obtained within the 6 months prior to subject surgery and radiographs obtained within 3 months prior to subject surgery)?
• Is the subject judged by the Investigator to be suitable for transforaminal lumbar interbody fusion (TLIF) surgery based on their medical history?
• Is the subject indicated for surgical treatment with the EVOS Lumbar Interbody System with autologous bone graft?
• Has the subject completed at least 6 months of conservative non-operative treatment without obtaining adequate symptomatic relief?
• If the subject is female and of childbearing age, do they have a negative pregnancy test (by Beta HCG qualitative analysis), or do they have a history of a surgical sterilisation, or a history of no menses in the past twelve months?
• Is the subject, in the opinion of the Investigator, able to understand this clinical study, co-operate with the procedures and are they willing to return to the hospital for all the required post-operative follow-ups?
• Is the subject able to give voluntary, written informed consent to participate in this clinical study and from whom consent has been obtained?

Exclusion Criteria:

• Has the subject undergone previous spinal surgery at the affected disc level(s), excluding discectomy and laminectomy procedures?
• Does the subject have evidence of tumour and/or malignant disease with resultant life expectancy of less than two years?
• Does the subject have known osteoporosis or severe osteopenia as determined by the Investigator?
• Does the subject have rheumatoid arthritis, ankylosing spondylitis or are they immunocompromised?
• Does the subject have a known allergy to the material used in the instrumentation?
• Does the subject have evidence of an active infection and/or do they have any condition that would compromise their participation and follow-up in this clinical study?
• Is the subject receiving any drug treatment that may affect bone metabolism?
• If the subject is female, are they pregnant or lactating?
• Is the subject a current smoker, or have they stopped smoking less than 6 months ago?
• Is the subject a known drug or alcohol abuser or do they have a baseline opioid use greater than 30 mg of morphine equivalent/day or do they have psychological disorders that could affect follow-up care or treatment outcomes?
• Is the subject currently enrolled in a clinical study?