The purpose of this narrative review is to analyze the available literature concerning central sensitization and altered central pain processing in patients with chronic low back pain (LBP). Literature was screened using several electronic search databases. Additional literature was obtained by reference tracking and expert consultation. Studies evaluating central pain processing in conservatively treated patients with chronic LBP were included. Results of studies examining the responsiveness to various stimuli in patients with chronic LBP are conflicting. Some studies in patients with chronic LBP have demonstrated exaggerated pain responses after sensory stimulation of locations outside the painful region, while other studies report no differences between patients and healthy subjects. Studies examining the integrity of the endogenous pain inhibitory systems report unaltered activity of this descending inhibitory system. In contrast, studies analyzing brain structure and function in relation to (experimentally induced) pain provide preliminary evidence for altered central nociceptive processing in patients with chronic LBP. Finally, also psychosocial characteristics, such as inappropriate beliefs about pain, pain catastrophizing, and/or depression may contribute to the mechanisms of central sensitization. It tempting to speculate that ongoing nociception is associated with cortical and subcortical reorganization and may play an important role in the process of the chronification of LBP. Future prospective research should explore to what extent these changes are reversible and if this reversibility is associated with improved functioning of patients.

The aims of this study were to examine: (i) baseline pressure pain thresholds in patients with chronic fatigue syndrome and those with chronic low back pain compared with healthy subjects; (ii) the change in mean pain threshold in response to exercise; and (iii) associations with exercise-induced increase in nitric oxide. Twenty-six patients with chronic fatigue syndrome suffering of chronic pain, 21 patients with chronic low back pain and 31 healthy subjects. Participants underwent a submaximal aerobic exercise protocol on a bicycle ergometer, preceded and followed by venous blood sampling (nitric oxide) and algometry (hand, arm, calf, low back). Patients with chronic fatigue syndrome presented overall lower pain thresholds compared with healthy subjects and patients with chronic low back pain (p < 0.05). No significant differences were found between healthy subjects and patients with chronic low back pain. After submaximal aerobic exercise, mean pain thresholds decreased in patients with chronic fatigue syndrome, and increased in the others (p < 0.01). At baseline, nitric oxide levels were significantly higher in the chronic low back pain group. After controlling for body mass index, no significant differences were seen between the groups at baseline or in response to exercise. Nitric oxide was not related to pain thresholds in either group. The results suggest hyperalgesia and abnormal central pain processing during submaximal aerobic exercise in chronic fatigue syndrome, but not in chronic low back pain. Nitric oxide appeared to be unrelated to pain processing.

Chronic spinal pain (CSP) is a severely disabling disorder, including nontraumatic chronic low back and neck pain, failed back surgery, and chronic whiplash-associated disorders. Much of the current therapy is focused on input mechanisms (treating peripheral elements such as muscles and joints) and output mechanisms (addressing motor control), while there is less attention to processing (central) mechanisms. In addition to the compelling evidence for impaired motor control of spinal muscles in patients with CSP, there is increasing evidence that central mechanisms (ie, hyperexcitability of the central nervous system and brain abnormalities) play a role in CSP. Hence, treatments for CSP should address not only peripheral dysfunctions but also the brain. Therefore, a modern neuroscience approach, comprising therapeutic pain neuroscience education followed by cognition-targeted motor control training, is proposed. This perspective article explains why and how such an approach to CSP can be applied in physical therapist practice.