Classification of low back-related leg pain: do subgroups differ in disability and psychosocial factors?

It has been proposed that patients with low back-related leg pain can be classified according to pain mechanisms into four distinct subgroups: Central Sensitization (CS), Denervation (D), Peripheral Nerve Sensitization (PNS), and Musculoskeletal (M). The purpose of this study was to determine whether there were any differences in terms of disability and psychosocial factors between these four subgroups. Forty-five subjects with low back-related leg pain completed the Oswestry Disability Index, the hospital Anxiety and Depression Scale, and the Fear Avoidance Beliefs Questionnaire. Subsequently, an examiner blinded to the questionnaire results classified the subjects into one of the four subgroups, according to the findings of the self-administered Leeds Assessment of Neuropathic Signs and Symptoms questionnaire and a physical examination. It was found that the PNS subgroup had significantly greater disability compared to all other subgroups and significantly greater fear avoidance beliefs about physical activity compared to the CS and D subgroups. This highlights the importance of sub-classification but also the need to take into account disability and psychosocial factors in the management of low back-related leg pain.