In many cases of low back pain a ‘sciatic’ or ‘radiculopathy’ is present. This is generally described as pins and needles, tingling, numbness, ants, electricity or shooting pain down the leg (or around the hip). Centralization is the idea that the pain moves up toward the lower back (sight of the initial injury) as it heals, localizing as it goes. This may cause back pain to increase however that indicates that the treatment as prescribed is working. As long as leg pain and symptoms are decreasing, then centralization is occurring. In most cases, back pain does not increase significantly by self-reported VAS. Centralization is a core concept in the McKenzie method of assessment and treatment and a confirmation of this hypothesis would lend credibility to this method.

Werneke et al 2008 wanted to test if patient reported symptoms of centralization were a predictor of a good outcome.

Patients with lumbar and cervical syndromes were treated with various modalities, not McKenzie only. Overall, only 17% of patients displayed symptoms of centralization. This may be due to the type of treatments which were applied, the type of injury the patient had or the time period they had had it. Centralization was higher among patients who were younger, had a more acute symptoms and a better general health status.  For those with lumbar symptoms, non-centralization was associated with higher pain ratings and lower ability on functional task testing. For those with cervical pain, it was associated with higher pain ratings but no other loss. Interestingly, it did not seem to effect the number of visits. Thus we can say that centralization does help predict overall pain status and for those with lumbar pain, functional status. A follow-up using a McKenzie method of assessment and treatment would be interesting.