This is a prospective, multicentric, comparative, randomised-controlled study to evaluate the safety and efficacy of the Facet Fixation implant.

The main objective is to evaluate the effectiveness of spinal decompression associated with FFX® implants compared to spinal decompression alone in treating lumbar spinal stenosis after 2 years of treatment.

Inclusion Criteria:

• Age ≥ 50 years.
• Radiographic confirmation of clinical symptoms of at least moderate degenerative spinal stenosis, of 1 to 3 adjacent segments in the L1-S1 region with the need for surgical decompression.
• Radiographic confirmation of no translational instability in main segment as well as in adjacent segments (dynamic translational instability ≤3 mm);
• Visual analogue scale (VAS) back pain score ≥ 50 mm (on a 100-mm scale).
• Minimum of 3 months of conservative therapy without improvement of symptoms.
• Mental & physical ability of the subject to follow the protocol (i.e., compliance with time schedule & treatment plan, able to fill in questionnaire & to undergo further study procedures).
• Personally signed and dated informed consent document prior to any study-related procedures indicating that the subject has been informed of all pertinent aspects of the clinical investigation.

Exclusion Criteria:

• Prior lumbar spine surgery.
• Radiographically confirmed damage of a vertebral body (e.g., osteoporotic compression fracture or because of tumours), at any lumbar level.
• Isthmic or degenerative spondylolisthesis (anterolisthesis; retrolisthesis ≥ grade II) or spondylolysis (pars fracture).
• Degenerative lumbar scoliosis (Cobb angle > 25°).
• Adipositas (obesity); defined as a body mass index (BMI) >40.
• Pregnancy, or wish to get pregnant during the course of the study, or breastfeeding.
• Known allergy or sensitivity to titanium, titanium alloys, or MRI contrast agents.
• Active or chronic infection-systemic or local.
• History of significant peripheral neuropathy.
• Significant peripheral vascular disease (e.g., with diminished dorsalis pedis or posterior tibial pulses).
• Paget disease, osteomalacia or other metabolic bone disorders.
• Cauda equina syndrome.
• Known or documented history of transmissible disease, including AIDS, HIV and active hepatitis.
• More than 3 vertebral levels requiring surgery.
• Disc herniation at any lumbar level requiring surgical intervention.
• Known osteoporosis (bone mineral density, BMD < 120 mg/cm3).
• Chronically taking medications or any drug known to potentially interfere with bone/soft tissue healing (e.g., steroids), not including a Medrol (methylprednisolone) dose pack.
• Fixed and complete motor, sensory, or reflex deficit.
• Rheumatoid arthritis or other autoimmune diseases.
• Active malignancy: a subject with a history of any invasive malignancy (except non-melanoma skin cancer) unless he/she has been treated with curative intent and there has been no clinical signs or symptoms of the malignancy for at least 5 years. Subjects with a primary bony tumour are excluded as well.
• Subject with a history of substance abuse (e.g., recreational drugs, narcotics, or alcohol).
• Bone destruction, demineralisation or any affection potentially affecting fixation of an implant.
• Spondylodiscitis or spine tumour.
• Currently seeking or receiving workman's compensation.
• In active spinal litigation.
• Subjects who participate(d) in another clinical trial (within the last 4 weeks) that might influence the safety & effectiveness assessment of this trial.
• Subjects who are lawfully kept in an institution.
• Subject who, in the opinion of the investigator, will be inappropriate for inclusion in this clinical trial or who will not comply with requirements of the study.
• Subject under supervision or legal guardianship, or judicial protection.
• Subject deprived of liberty by judicial or administrative decision.
• Subject not covered by a social security scheme.