Objective: To compare if the degenerative findings from MRI differ between the sciatica patients classified as centralizers (CEN) and non-centralizers (Non-CEN) according to the McKenzie Method of mechanical diagnosis and therapy.

Study design: A cross-sectional study.

Methods: Patients (N = 100) referred to a spine clinic of a single tertiary hospital for specialist consultation for sciatica. The McKenzie-based assessment was performed by the mechanical diagnosis and therapy-trained physiotherapists. Clinical data and prevalence of lumbar MRI findings were compared between the groups.

Results: There was no significant difference in leg pain intensity between the groups. The Non-CEN had significantly more intense back pain, mean 56 (SD 30) and were more disabled 44 (SD 15) compared to the CEN mean 41 (SD 25) and mean 31 (11), measured with a visual analogue scale (0-100), and the Oswestry Disability Index (0-100), respectively. The CEN had more severe degenerative findings on MRI than the Non-CEN: vertebral end-plate changes were 63% and 43%; mean Pfirrmann's disc degeneration lumbar summary score was 12.8, and 10.6; and severity score of total damage was 12.0 and 10.1, respectively. There were differences neither in disc contour changes nor nerve root stenosis on MRI.

Conclusions: Sciatica patients classified as non-centralizers had significantly more severe back pain, and were significantly more disabled than centralizers, who instead had more severe degenerative findings on MRI. Thus, classification to non-centralizers by the McKenzie method seems not predict higher incidence of degenerative findings on MRI compared to centralizers.