Lumbar Disc Prosthesis Versus Multidisciplinary Rehabilitation; 8-year Follow-up
Condition: Chronic Low Back Pain
MeSH terms: Back Pain; Low Back Pain
Study type: Interventional

Summary: 
      During the past 25-30 years, surgery with total disc replacement (TDR) has become an option
      for a selection of patients with chronic low back pain (LBP) traditionally treated
      conservatively or operated on with spinal fusion. Randomized trials comparing TDR with fusion
      have found the clinical outcome of TDR at least equivalent to that of fusion, and the only
      study comparing TDR to non-surgical treatment (The Norwegian TDR study) concludes that TDR is
      significantly more effective than multidisciplinary rehabilitation (REHAB) after 2 years.
      However, the long-term effects of TDR in terms of clinical results, costs, reoperation- and
      revision rate, degenerative changes and prognostic factors have not been investigated in high
      quality prospective trials. This is very much required since TDR surgery is offered a great
      number of patients world wide, and is associated with high complexity and risk of serious
      complications and difficult revision. Hence, the overall aim of the present study is to
      evaluate the long term (eight years follow-up) effect of The Norwegian TDR study where TDR
      surgery were compared to modern multidisciplinary rehabilitation in patients with chronic low
      back pain and localized degenerative disc changes.
    

Detailed description: 
      Two-year results of the Norwegian TDR study were published in BMJ in May 2011 (Hellum et al).
      The current protocol is 8-year follow-up of patients included in the Norwegian TDR study.

      Hypothesis of the 8-year follow-up:

      Main hypothesis (H0): There are no differences in change between TDR and REHAB for pain and
      disability measured by Oswestry Disability Index (main outcome), back pain, quality of life,
      psychological variables, work status, patients satisfaction, drug use, urinary incontinence,
      and back surgeries after 8 years.

      Secondary Hypothesis:

        1. There are no differences in incidence and degree of disc degeneration at adjacent level
           or facet joint degeneration at index level between groups (radiological analysis).

        2. There is no association between baseline characteristics, pelvic anatomy / sagittal
           balance (defined by lumbar lordosis, pelvic tilt, pelvic incidence angle and sacral
           slope), and clinical outcome after TDR.

        3. There is no difference in cost effectiveness between surgery and REHAB 8 years after
           inclusion to the study.

      Statistical analysis:

      The investigators will use the same analysis as for 2-years results: two-way ANOVA, mixed
      model, regression analysis. p<0.05 will be considered statistically significant

      Additional analysis (not conducted at 2 years):

        1. cross-overs will receive last value before cross-over/fusion surgery

        2. survival analysis

        3. pelvic anatomy / sagittal balance (defined by lumbar lordosis, pelvic tilt, pelvic
           incidence angle and sacral slope) will be included in the predictor analysis

        4. Both CT scans and MRI are taken for the evaluation of index level facet arthropathy
    

Intervention name(s): Lumbar total disc replacement; Multidisciplinary rehabilitation
Intervention type(s): Procedure; Behavioral
Intervention description(s): The surgical intervention consisted of replacement of the degenerative intervertebral lumbar disc with a artificial lumbar disc device in one or two of the lover lumbal levels (L4/L5 or/and L5/S1). The ProDisc consists of three pieces, two metal endplates and a polyethylene core that is fixed to the inferior endplate when the device is implanted, and is implanted through a retroperitoneal (or transperitoneal) access.; The intervention is based on a treatment model described by Brox et al (Spine 2003;28:1913-1921) and is also described in details by Hellum et al (BMJ, May 2011). It consisted of a cognitive approach and supervised physical exercise and was delivered by a team of physiotherapists and specialists in physical medicine and rehabilitation. The rehabilitation programme lasted for about 60 hours over three to five weeks.
Other intervention name(s): ProDisc II, Synthes Spine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Chronic low back pain; Degenerated disc; Total disc replacement; Multidisciplinary rehabilitation; Long term results