Van Oosterwijck J.1,2, Hodges P.3, Parlevliet T.4, Goubert D.2, Cnudde J.2, Bleyaert K.2, Danneels L.2
1Research Foundation - Flanders (FWO), Brussels, Belgium, 2Ghent University, Department of Rehabiliation Sciences and Physiotherapy, Ghent, Belgium, 3The University of Queensland, Centre for Clinical Research Excellence in Spinal Pain, Injury and Health, Brisbane, Australia, 4Ghent University Hospital, Department of Physical Medicine and Orthopedic Surgery, Ghent, Belgium
Background: Changes in motor behavior of the lumbar spine have been established in patients with non-specific recurrent low back pain (RLBP) and do not spontaneously resolve when LBP dissipates as they are observed during remission. Sophisticated laboratory tests are widely used to identify these changes, but are extensive and expensive making them relatively inaccessible and unpractical for clinical practice. Therefore, a reliable clinical test which assesses the ability to dissociate lumbopelvic movement from that of the thoracolumbar junction indicating poor motor control was developed.
Purpose: To examine 1) if the clinical test of thoracolumbar dissociation can discriminate between healthy controls and RLBP patients in remission, 2) whether the movement pattern identified using this clinical test corresponds with activation and recruitment patterns of trunk muscles evaluated using electromyography (EMG).
Methods: Healthy people (n=18) and patients with non-specific RLBP in remission (n=15) performed the clinical test of thoracolumbar dissociation. The test performance was clinically evaluated by an assessor. Muscle activation was evaluated using surface EMG over the lumbar and thoracic parts of the erector spinae, the sacral multifidus and the abdominals, while fine-wire EMG was applied to the superficial and deep fibers of the lumbar multifidus. The test its discriminative capability was examined with ROC curve analysis and the calculation of odds and likelihood ratios (OR, LR) and diagnostic accuracy (DA). Correlation analysis was used to examine associations between test scores and muscle recruitment.
Results: An area under the curve of 0.715 and cut off score of 7.25/10 were established. Scores above/below this cut-off resp. indicate that subjects pass/fail the test (i.e. have a good/poor thoracolumbar dissociation) and are less likely to have a history of RLBP. Probability calculations revealed an OR of 3.438, a +LR of 2.082, and a -LR of 0.606. The DA indicates that 63.64% of the subjects can be correctly classified as healthy/RLBP in remission based on the test scores. Those who passed the test showed a greater activation the sacral multifidus and higher ratings on the quality of the motion, the control of adjacent regions and the overall performance. Several correlations were found between clinical test scores and muscle activation patterns, mainly indicating that better clinical performance scores were associated with higher activity of the deep and sacral multifidus.
Conclusion(s): The clinical test of thoracolumbar dissociation has a fair ability to discriminate between RLBP patients in remission and healthy people. A better ability to dissociate lumbopelvic movement from that of the thoracolumbar junction is related to higher activity of the sacral and deep multifidi in relation to the thoracic erector spinae, which indicates that the clinical observations and reasoning of this test are supported by the observations made using EMG.
Implications: Physiotherapists can add this clinical test to their arsenal of evaluation techniques to determine the capability of RLBP patients (even when in remission) to dissociate movements from the lumbar spine of that of the thoracic spine and adapt their treatment accordingly. Therefore training the activation of the deep lumbosacral muscles such as the multifidus seems to be one of the key components.
Funding acknowledgements: Jessica Van Oosterwijck is a post-doctoral research fellow
funded by the Research Foundation - Flanders (FWO), Belgium.
funded by the Research Foundation - Flanders (FWO), Belgium.
Topic: Musculoskeletal: spine
Ethics approval: The study was approved by the Ethics Committee of the University Hospital Ghent/Ghent University.
All authors, affiliations and abstracts have been published as submitted.
