Spinal manipulative therapy (SMT) is commonly used as a treatment modality for those suffering from low back pain (LBP) in an attempt to relieve pain and dysfunction. The exact mechanisms by which SMT may exert an analgesic effect, specifically in the spine, remain under study. One theory suggests that manipulation-induced hypoalgesia may occur via a reduction in pain sensitivity. Two commonly employed research methods through which sensitivity can be studied in the context of SMT are pressure pain threshold (PPT) and temporal summation (TS). PPT is the threshold at which gradually increasing pressure causes pain and has been shown to be decreased in a variety of musculoskeletal conditions, meaning it requires less pressure for the patient to feel pain. PPT is normally tested with a pressure algometer. TS is a measure of how subjective pain severity changes over a series of painful stimuli repeated at intervals of 3s or less. The severity typically increases (‘summation’), and this increase appears to be heightened in multiple chronic pain conditions. TS in this study was tested using a pinprick stimulus (there are other methods as well).
 
The central purpose of this study was to perform a high-quality, double blinded, randomized controlled trial on a low back pain (LBP) population to investigate short-term changes in PPT and TS after lumbar SMT compared to a credible sham intervention. The two main research questions the authors looked to answer were: 1) Do PPT (measured at the lumbar spine, calf, and shoulder) and TS (measured at the feet and hands) change in the 30 minutes following true lumbar SMT compared to sham manipulation, in people with LBP? and 2) Do PPT and TS change from baseline to post-intervention in each group, and if so, which testing sites are affected?
 
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THIS WEEK'S RESEARCH REVIEW: “Pressure Pain Threshold & Temporal Summation After Lumbar SMT – Sham Comparison”
 
This paper was published in Musculoskeletal Science and Practice (2019) and this Review is posted in Recent Reviews, Lumbar Spine - Manipulation/Mobilization, Spinal Manipulation - Mechanisms of Action and the 2020 Archive.
 
ppt lower limb