Chronic low back pain: Relevance of a new classification based on the injury pattern.

BACKGROUND: The objectives of this study were to define the role for surgery in the treatment of chronic low back pain (cLBP) and to develop a new classification of cLBP based on the pattern of injury.

HYPOTHESIS: Surgery may benefit patients with cLBP, and a new classification based on the injury pattern may be of interest.

METHOD: A systematic literature review was performed by searching Medline, the Cochrane Library, the French public health database (Banque de Données en Santé Publique), Science Direct, and the National Guideline Clearinghouse. The main search terms were "back pain" OR "lumbar" OR "intervertebral disc replacement" OR "vertebrae" OR "spinal" AND "surgery" OR "surgical" OR "fusion" OR "laminectomy" OR "discectomy".

RESULTS: Surgical techniques available for treating cLBP consist of fusion, disc replacement, dynamic stabilisation, and inter-spinous posterior devices. Compared to non-operative management including intensive rehabilitation therapy and cognitive behavioural therapy, fusion is not better in terms of either function (evaluated using the Oswestry Disability Index [ODI]) or pain (level 2). Fusion is better than non-operative management without intensive rehabilitation therapy (level 2). There is no evidence to date that one fusion technique is superior over the others regarding the clinical outcomes (assessed using the ODI). Compared to fusion or multidisciplinary rehabilitation therapy, disc replacement can produce better function and less pain, although the differences are not clinically significant (level 2). The available evidence does not support the use of dynamic stabilisation or interspinous posterior devices to treat cLBP due to degenerative disease (professional consensus within the French Society for Spinal Surgery). The following recommendations can be made: non-operative treatment must be provided for at least 1 year before considering surgery in patients with cLBP due to degenerative disease; patients must be fully informed about alternative treatment options and the risks associated with surgery; standing radiographs must be obtained to assess sagittal spinal alignment and a magnetic resonance imaging scan to determine the mechanism of injury; and, if fusion is performed, the lumbar lordotic curvature must be restored.

DISCUSSION: This work establishes the need for a new classification of cLBP based on the presumptive mechanism responsible for the pain. Three categories should be distinguished: non-degenerative cLBP (previously known as symptomatic cLBP), in which the cause of pain is a trauma, spondylolysis, a tumour, an infection, or an inflammatory process; degenerative cLBP (previously known as non-specific cLBP) characterised by variable combinations of degenerative alterations in one or more discs, facet joints, and/or ligaments, with or without regional and/or global alterations in spinal alignment (which must be assessed using specific parameters); and cLBP of unknown mechanism, in which the pain seems to bear no relation to the anatomical abnormalities (and the Fear-Avoidance Beliefs Questionnaire and Hospital Anxiety and Depression Scale may be helpful in this situation). This classification should prove useful in the future for constituting well-defined patient groups, thereby improving the assessment of treatment options.

LEVEL OF EVIDENCE: II, systematic review of level II studies.