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Surgery with disc prosthesis versus rehabilitation in patients with low back pain and degenerative disc: two year follow-up of randomised study

BMJ 2011; 342 doi: (Published 19 May 2011) Cite this as: BMJ 2011;342:d2786
  1. Christian Hellum, orthopaedic surgeon1,
  2. Lars Gunnar Johnsen, orthopaedic surgeon23,
  3. Kjersti Storheim, physiotherapist456,
  4. Øystein P Nygaard, neurosurgeon2,
  5. Jens Ivar Brox, consultant1,
  6. Ivar Rossvoll, orthopaedic surgeon23,
  7. Magne Rø, consultant7,
  8. Leiv Sandvik, professor8,
  9. Oliver Grundnes, orthopaedic surgeon5
  10. and the Norwegian Spine Study Group
  1. 1Department of Orthopaedics, Oslo University Hospital and University of Oslo, Kirkevn 166, 0407 Oslo, Norway
  2. 2National Centre for Diseases of the Spine, University Hospital of Trondheim, 7030 Trondheim
  3. 3Orthopaedic Department, University Hospital of Trondheim, 7030 Trondheim
  4. 4Norwegian Research Centre for Active Rehabilitation (NAR), Department of Orthopaedics, Oslo University Hospital, Kirkevn 166, 0407 Oslo
  5. 5Hjelp24, Nimi, Oslo Sognsveien 75 D, 0855 Oslo
  6. 6Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Høgskoleringen 1, 7491 Trondheim (MR), FORMI, Oslo University Hospital, Kirkevn 166, 0407 Oslo
  7. 7Multidiscipline Spinal Unit, Department of Physical Medicine and Rehabilitation, University Hospital of Trondheim, 7030 Trondheim
  8. 8Section for Biostatistics and Epidemiology, Oslo University Hospital, Kirkevn 166, 0407 Oslo
  1. Correspondence to: C Hellum christian.hellum{at}
  • Accepted 25 March 2011


Objective To compare the efficacy of surgery with disc prosthesis versus non-surgical treatment for patients with chronic low back pain.

Design A prospective randomised multicentre study.

Setting Five university hospitals in Norway.

Participants 173 patients with a history of low back pain for at least one year, Oswestry disability index of at least 30 points, and degenerative changes in one or two lower lumbar spine levels (86 patients randomised to surgery). Patients were treated from April 2004 to September 2007.

Interventions Surgery with disc prosthesis or outpatient multidisciplinary rehabilitation for 12-15 days.

Main outcome measures The primary outcome measure was the score on the Oswestry disability index after two years. Secondary outcome measures were low back pain, satisfaction with life (SF-36 and EuroQol EQ-5D), Hopkins symptom check list (HSCL-25), fear avoidance beliefs (FABQ), self efficacy beliefs for pain, work status, and patients’ satisfaction and drug use. A blinded independent observer evaluated scores on the back performance scale and Prolo scale at two year follow-up.

Results The study was powered to detect a difference of 10 points on the Oswestry disability index between the groups at two years. At two years there was a mean difference of −8.4 points (95% confidence interval −13.2 to −3.6) in favour of surgery. In the analysis of prespecified secondary outcomes, there were significant differences in favour of surgery for low back pain (mean difference −12.2, −21.3 to −3.1), patients’ satisfaction (63% (n=46) v 39% (n=26)), SF-36 physical component score (mean difference 5.8, 2.5 to 9.1), self efficacy for pain (mean difference 1.0, 0.2 to 1.9), and the Prolo scale (mean difference 0.9, 0.1 to 1.6). There were no significant differences in return to work, SF-36 mental component score, EQ-5D, fear avoidance beliefs, Hopkins symptom check list, drug use, and the back performance scale. One serious complication of leg amputation occurred during surgical revision of a polyethylene dislodgement. The drop-out rate was 20% (34) and the crossover rate was 6% (5).

Conclusions Surgical intervention with disc prosthesis for chronic low back pain resulted in a significantly greater improvement in the Oswestry score compared with rehabilitation, but this improvement did not clearly exceed the prespecified minimally important clinical difference between groups of 10 points, and the data are consistent with a wide range of differences between the groups, including values well below 10 points. The potential risks of surgery and the substantial amount of improvement experienced by a sizeable proportion of the rehabilitation group also have to be incorporated into overall decision making.

Trial registration NCT 00394732.


  • We thank the patients participating in the study; Coast Hospital for Physical Medicine and Rehabilitation, Stavern, for videos and material for lectures for the rehabilitation intervention; Hege Andresen at St Olavs Hospital, Trondheim, for data coordination; Per Farup at St Olavs Hospital, Trondheim, for organising the web randomisation system; Astrid Woodhouse and Kirsti Vanvik from St Olavs Hospital for performing the two year control; and Lucy Hyatt for paid editorial assistance.

  • The Norwegian Spine Study Group

  • University Hospital North Norway, Tromso (eight patients): Odd-Inge Solem (department of orthopaedic surgery), Jens Munch-Ellingsen (department of neurosurgery), and Franz Hintringer, Anita Dimmen Johansen, Guro Kjos (department of physical medicine and rehabilitation).

  • Trondheim University Hospital, Trondheim (21 patients): Hege Andresen, Helge Rønningen, Kjell Arne Kvistad (national centre for spinal disorders, department of neurosurgery), Bjørn Skogstad, Janne Birgitte Børke, Erik Nordtvedt, Gunnar Leivseth (multidiscipline spinal unit, department of physical medicine and rehabilitation).

  • Haukeland University Hospital, Bergen (64 patients): Sjur Braaten, Turid Rognsvåg, Gunn Odil Hirth Moberg (Kysthospitalet in Hagevik, department of orthopaedic surgery), Jan Sture Skouen, Lars Geir Larsen, Vibeche Iversen, Ellen H Haldorsen, Elin Karin Johnsen, Kristin Hannestad (Outpatient Spine Clinic, department of physical medicine and rehabilitation).

  • Stavanger University Hospital, Stavanger (27 patients): Endre Refsdal (department of orthopaedic surgery).

  • Oslo University Hospital, Oslo (53 patients): Vegard Slettemoen, Kenneth Nilsen, Kjersti Sunde, Helenè E Skaara (department of orthopaedics), Anne Keller, Berit Johannessen, Anna Maria Eriksdotter (department of physical medicine and rehabilitation).

  • Contributors: All authors had full access to the data, were responsible for study concept and design, and critically revised the manuscript for important intellectual content. Acquisition of data: CH, LGJ, KS, OPN, MR, OG acquired the data, which were analysed and interpreted by HC , LGJ, KS, OPN, JIB, LS, IR, and OG. CH drafted the manuscript. CH and LS did the statistical analysis. CH, LJ, KS, OPN, JIB, MR, and OG provided administrative, technical, or material support. CH, KS, OPN, JIB, IR, LS, and OG supervised the study. CH is guarantor.

  • Funding: The study was funded by the South Eastern Norway Regional Health Authority and EXTRA funds from the Norwegian Foundation for Health and Rehabilitation, through the Norwegian Back Pain Association.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study was evaluated and approved by the regional committees for medical research ethics in east Norway and all participants gave written informed consent. We did not obtain participants’ informed consent for data but the presented data are anonymised and risk of identification is low.

  • Data sharing: Dataset available from the corresponding author at christian.hellum{at}

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