Table 2 Inclusion and exclusion criteria

Initial inclusion criteria

Age between 18 and 85 years

Clinical signs of low back pain and/or radiculopathy from vertebrae L1 to S1

MRI and CT confirmed: central canal stenosis, lateral recesses stenosis, or foraminal stenosis leading to:

- radiculopathy, defined as pain and/or motor weakness or paralysis and/or paraesthesia in at least one specific nerve root distribution from vertebrae L1 to S1 or

- neurogenic intermittent claudication, defined as pain and/or weakness and/or abnormal sensation in the legs during walking or prolonged standing or

- indicating decompressive surgery and instrumented mono-segmental, bi-segmental or tri-segmental spondylodesis with posterior instrumented fusion system and an intervertebral cage (TLIF)

Unresponsive to non-operative treatment for a minimum of 3 months including at least physiotherapy, pain medication and local infiltration therapy

Presence of progressive symptoms or signs of nerve root and/or spinal cord compression although performing conservative treatment

Psychosocial, mental and physical ability to understand and to perform with this protocol, especially visiting scheduled follow-up controls, observe treatment plan and all other study-related procedures

Personally signed and dated informed consent document prior to any study-related procedures indicating that the patient has been informed of all pertinent aspects of the trial

Initial exclusion criteria

Previous surgery: (a) any instrumented lumbar spinal surgery, (b) cervical and/or (c) thoracic spinal disease to the extent that surgical consideration is likely or anticipated within 6 months after the lumbar surgical treatment

Other degenerative joint diseases (i.e. shoulder, hip knee) to the extent that surgical consideration is likely or anticipated within 6 months after or before the lumbar surgical treatment

Any other physical diseases (e.g. neuromuscular disorders) before and/or within 6 months after lumbar surgical intervention, which are able to restrict study procedures (i.e. wheelchair bound) or preclude accurate clinical examination or outcome

Severe obesity (BMI >35 kg/m²)

Neoplasia as the source of symptoms

Fixed or permanent neurological deficit unrelated to the lumbar spine disease

Active or chronic infection, systemic or local, including HIV, AIDS, hepatitis

Active malignancy defined as a history of any invasive malignancy, except non-melanoma skin cancer, unless the patient has been treated with curative intent and there have been no clinical signs or symptoms of the malignancy for a minimum of 5 years

Autoimmune disorder that impacts the musculoskeletal system (i.e. lupus, rheumatoid arthritis, ankylosing spondylitis)

Acute episode or major mental illness (psychosis, major affective disorder or schizophrenia)

Physical symptoms without a diagnosable medical condition to account for the symptoms, which may indicate symptoms of psychological rather than physical origin

Recent or current history of substance abuse (drugs, alcohol, narcotics, recreational drugs)

Known allergy to titanium, carbon/PEEK and tantalum or intolerance to any device material

Radiological exclusion criteria

Three or more vertebral levels requiring surgical treatment in the lumbar spine

Clinically compromised vertebral bodies at the affected level due to current or past trauma, including osteoporotic fractures

Spondylolisthesis according to Meyerding grade III or higher

Various exclusion criteria

Patient is currently pursuing personal litigation

Pregnancy or the desire to become pregnant in the next year

Prisoner or ward of the state

Patient has used another investigational drug or device within the last 30 days prior to surgery