Contribution of centralization phenomenon to the diagnosis, prognosis, and treatment of diskogenic low back pain.

The centralization phenomenon is the migration of low back and/or radiating pain to the spinal midline in response to specific positions or movements, for instance during a McKenzie mechanical assessment. However, differences in the definition of the centralization phenomenon occur across studies, most notably regarding the smallest required change in pain location and the time to centralization. Standardized criteria would be useful. Available data fail to establish that centralization is sufficiently specific of diskogenic pain as to obviate the need for investigations, particularly in patients considered for surgical treatment (e.g., fusion or implant). Although centralization correlates strongly with a positive diskography, the value of this last finding as a sign of diskogenic pain or an indicator that surgery is needed remains highly controversial. Nevertheless, centralization may indicate a high likelihood of diskogenic pain and may provide therapeutic guidance. Because centralization is associated with better outcomes after nonsurgical treatment, even in patients with nerve root pain, its presence may constitute an argument against surgical treatment. Finally, the McKenzie assessment may induce pain relief, albeit to a modest extent and for no longer than 3 months.