Pain Mechanisms in Low Back Pain: A Systematic Review With Meta-analysis of Mechanical Quantitative Sensory Testing Outcomes in People With Nonspecific Low Back Pain.
BACKGROUND
Mechanical quantitative sensory testing (QST) assesses sensory functioning and detects functional changes in (central) nociceptive processing. It has been hypothesized that these functional changes might be apparent in people with nonspecific low back pain (LBP), although the results are mixed.


OBJECTIVE
The aim of this systematic review was to examine whether sensory function, measured with QST, was altered in people with nonspecific LBP.


METHODS
This systematic review was conducted according to PRISMA guidelines. Six databases were searched for relevant literature. Studies comparing mechanical QST measures involving people with subacute and chronic LBP and healthy controls were included if (1) pressure pain thresholds (PPTs), (2) temporal summation, or (3) conditioned pain modulation were reported. Risk of bias was assessed using the Newcastle-Ottawa scale. When possible, the results from different studies were pooled.


RESULTS
Twenty-four studies were included. Scores on the Newcastle-Ottawa scale varied between 1 and 6 points. People with nonspecific LBP, compared to healthy controls, had significantly lower PPTs at remote sites and increased temporal summation at the lower back. The PPTs measured at the scapula were significantly lower in patients with nonspecific LBP than in healthy controls (pooled mean difference, 119.2 kPa; 95% confidence interval: 91.8, 146.6 kPa; P<.001).


CONCLUSION
The PPT measurements at remote body parts were significantly lower in people with nonspecific LBP compared with healthy controls. Temporal summation and conditioned pain modulation measurements had mixed outcomes.


LEVEL OF EVIDENCE
Therapy, level 3a. J Orthop Sports Phys Ther 2019;49(10):698-715. Epub 23 Aug 2019. doi:10.2519/jospt.2019.8876.
['den Bandt|Hester L|HL|', 'Paulis|Winifred D|WD|', 'Beckwée|David|D|', 'Ickmans|Kelly|K|', 'Nijs|Jo|J|', 'Voogt|Lennard|L|']
D059333:Central Nervous System Sensitization D006801:Humans D017116:Low Back Pain D058748:Pain Perception D017288:Pain Threshold
low back pain pressure pain threshold temporal summation conditioned pain modulation central sensitization