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Scandinavian Journal of Pain

Official Journal of the Scandinavian Association for the Study of Pain

Editor-in-Chief: Breivik, Harald

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Superior outcomes following cervical fusion vs. multimodal rehabilitation in a subgroup of randomized Whiplash-Associated-Disorders (WAD) patients indicating somatic pain origin. Comparison of outcome assessments made by four examiners from different disciplines

Elisabeth Svensson / Bo Nyström / Ian Goldie / Nils Inge Landrø
  • Centre for the Study of Human Cognition, Department of Psychology, University of Oslo, NO-0373 Oslo, Norway
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Åke Sidén / Peer Staff
  • Department of Physical Medicine and Rehabilitation, Oslo University Hospital, NO-0405 Oslo, Norway
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Birgitta Schillberg / Adam Taube
Published Online: 2018-02-22 | DOI: https://doi.org/10.1515/sjpain-2017-0180


Background and aims:

Whiplash-Associated Disorders (WAD) are characterized by great variability in long-term symptoms. Patients with central neck and movement-induced stabbing pain participated in a randomized study comparing cervical fusion and multimodal rehabilitation. As reported in our previous paper, more patients treated by cervical fusion than by rehabilitation experienced pain relief. Although patient reported outcome measures are a core component of outcome evaluation, independent examiner has been recommended. Because of the heterogeneity of WAD complaints the patients in our study were examined at baseline and follow-up by four experts representing neurology, orthopedics, psychology and physical medicine. The aim was to compare the professional assessments of change both regarding the possible impact of the different examiners’ perspectives on individual patient’s outcome, and also on the analysis of possible outcome differences between the treatment groups.


WAD patients with long-term neck pain as the predominant symptom after a traffic accident were eligible. The neck pain origin should be in the midline and perceived as dull and aching, with sudden movement inducing midline stabbing pain. Of the 1,052 patients in contact with our team, 49 were eligible. The overall treatment effect was evaluated on a global outcome transitional scale. The criteria for the scale categories were defined by each expert’s professional perspective on change in the whiplash complaints. Statistical methods that take account of the non-metric properties of ordered categorical data were used. Observed inter-expert disagreement was evaluated by the Svensson method that identifies and measures systematic group-related disagreement separately from disagreement caused by individual variation. Possible differences in the distributions of assessments on the expert-specific outcome scales between the treatment groups were analyzed by the Kruskal-Wallis test.


The per-protocol evaluation showed that a majority of the 18 patients who underwent fusion surgery were assessed as somewhat or much better, ranging from 67% to 78% depending on the expert. Corresponding proportions of improvement in the 17 patients treated by multimodal rehabilitation ranged from 29% to 53%. The statistical analyses confirmed better outcomes in the patients treated by fusion surgery, with p-values ranging from 0.003 to 0.04. The experts’ assessments of intra-patient change disagreed more or less for all patients. The analyses of the paired comparisons confirmed that these disagreements could most probably be explained by the different profession-specific operational definitions of the outcome scales rather than by individual variations in data.


The multi-dimensional complexity of WAD-related complaints was comprehensively demonstrated by the inter-disciplinary disagreements in assessing intra-patient outcomes. The superiority of positive treatment effects in patients who underwent cervical fusion compared with multimodal rehabilitation was evident to all experts.


The results strengthen our previous opinion that neck pain in this subgroup of WAD patients has a somatic origin. More than one examiner is recommended for multi-dimensional outcome assessments.

Keywords: global scale of change; ordinal data; inter-rater agreement; fusion surgery; randomized study; symptoms of whiplash-associated disorders (WAD)


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About the article

aPresent address: Sländvägen 6, SE-38634 Färjestaden, Sweden.

bPresent address: Department of Neuroscience, Section of Neurosurgery, University Hospital, SE-75185 Uppsala, Sweden.


dPresent address: Clinical Neuroscience Research Group, Department of Psychology, University of Oslo, NO-0373 Oslo, Norway.

ePresent address: Tråkka 1, NO-0774 Oslo, Norway.

Received: 2017-12-11

Accepted: 2018-02-01

Published Online: 2018-02-22

Authors’ statements

Research funding: We gratefully acknowledge the financial support from the Marianne and Marcus Wallenberg Foundation, the Axel and Margaret Ax:son Johnson Foundation, Volvo and Vägverket.

Conflict of interest: The authors have no conflict of interest.

Informed consent: All patients were given both oral and written information on all parts of the study and gave their written informed consent.

Ethical approval: The study was approved by the Medical Ethics Committee, Örebro, Sweden, no. 368/96. The study is registered in ClinicalTrials.gov (registration no. NCT01994044).

Citation Information: Scandinavian Journal of Pain, 20170180, ISSN (Online) 1877-8879, ISSN (Print) 1877-8860, DOI: https://doi.org/10.1515/sjpain-2017-0180.

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©2018 Scandinavian Association for the Study of Pain. Published by Walter de Gruyter GmbH, Berlin/Boston. All rights reserved.. Copyright Clearance Center

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