CENTRALIZATION IN PATIENTS WITH SCIATICA: ARE PAIN RESPONSES TO REPEATED MOVEMENT AND POSITIONING ASSOCIATED WITH OUTCOME OR TYPES OF DISC LESIONS?

Purpose

To describe the frequency of different patterns of pain response and their association with outcomes (prognosis) and MRI findings in patients experiencing sciatica.

Methods

176 consecutive consenting patients with radicular pain underwent an MRI and a clinical assessment at baseline using a standardized procedure of repeated lumbar movements and positioning guided. Based on their pain response, patients were divided into five groups: abolition centralization, reduction centralization, unstable centralization, peripheralization, and no effect on pain.

Results

Overall, 84.8 % of patients reported experiencing one of the three forms of centralization, 7.3 % reported peripheralization and 7.9 % reported “No effect”. The median reduction in RMQ scores across all three centralization groups was 9.5 points at 3-months and 12.0 points at 12-months. The peripheralization group improved by a similar amount (7.0 and 14.0 respectively). In contrast, the ‘no effect’ group improved by 3.0 at both time points and this was significantly different (p<0.001) from the other groups. These results were mimicked in relation to leg pain. In addition, there was no association between the reported pain responses (centralization, peripheralization or no effect) and the type of disc lesion observed on MRI.

Conclusion

In patients with sciatica, centralization was common. Centralization and peripheralization at baseline were equally associated with improvement in activity limitation and leg pain over time.

As there was no association between MRI findings and the pain response to movement, these results do not support the belief that centralization only occurs if the annulus is intact and the intra-discal hydrostatic mechanism is functional.