A Randomized, Blinded Comparison of Surgical Intervention with the Coflex® Interspinous Implant versus Surgical Decompression for Patients with Intermittent Neurogenic Claudication caused by Lumbar Stenosis

In this investigation, it will be investigated whether the effectiveness of surgical intervention with Coflex® is equivalent to surgical decompression after 12 months in people with intermittent claudication. The main advantage of coflex® might be a faster recovery after surgery, but after long term follow-up it is unknown if this treatment effect remains. Therefore in addition, it will be investigated whether surgical intervention with coflex® is more effective than surgical decompression on short-term follow-up (8 weeks to 6 months) and whether surgical intervention with coflex® is more cost-effective after 12 months than surgical decompression.

Inclusion Criteria:

• signed informed consent
• is 40 to 85 years old at time of surgery
• has INC, as noted by leg/buttock/groin pain with or without back pain. Leg/buttock/groin pain needs to be strongly relieved when flexed such as when sitting in a chair
• has received at least three months of conservative care therapy which may have included, but is not limited to, physical therapy, bracing, systemic and/or injected medications
• has a regular indication for surgical intervention of INC
• has a narrowed lumbar spinal canal, nerve root canal or intervertebral foramen at one or two levels confirmed by MRI
• is physically and mentally willing and able to comply with, or has a caregiver who is willing and able to comply with, the post-operative evaluations.

Exclusion Criteria:

• has cauda equina syndrome defined as neural compression causing neurogenic bowel (rectal incontinence) or bladder dysfunction (bladder retention or incontinence)
• has Paget's disease, severe osteoporosis or metastasis to the vertebrae
• has significant scoliosis (Cobb angle > 25 degrees)
• has a Body Mass Index (BMI) > 40 kg/m2
• has had any surgery of the lumbar spine
• has degenerative spondylolisthesis > grade 1 (on a scale 1 to 4) at the affected level
• has significant instability of the lumbar spine
• has severe comorbid conditions that will increase the risk to the patient or interfere with the evaluability of this study
• has a fused segment at the indicated level.
• has a herniated disk on the level of interest