Several cross-sectional studies have demonstrated that patients with chronic low back pain have higher levels of pain sensitivity (local and widespread) when compared to controls. It is unclear however, if improvements in pain and function are reflected in a decrease in the sensitivity of pain mechanisms. This study compares the pain sensory profile in patients with chronic low back pain before and after a period of physiotherapy treatment. To account for natural fluctuations in pain sensitivity, healthy age matched controls are also measured twice
The sensitivity of pain mechanisms has consistently been shown to be increased in people suffering from chronic low back pain. This includes both sensitivity in the painful region but also in areas distant indicating widespread pain sensitivity. It is less clear whether this is normalized following a successful treatment intervention. This study is recruiting people with low back pain and healthy, age matched controls. At baseline, the following measurements are made: * the sensitivity to pressure (at the low back and at the shoulder) * the pain detection threshold and pain tolerance threshold at the lower legs * the temporal summation of pain * conditioned pain modulation * Fear-avoidance beliefs * Disability (Roland-Morris Disability Questionnaire) * The Orebro musculoskeletal pain questionnaire During their enrollment, the patients report their weekly pain electronically All quantitative sensory testing (QST) and questionnaire data are blind to the principal investigator until data collection has been finished After the baseline measurements, the patients are offered physiotherapy treatment. The treatment protocol (dosage and type of intervention) is designed based on individual needs following an assessment by a musculoskeletal physiotherapist. The number of sessions and time between treatment sessions depend on how the patients respond to the chosen intervention. Patients are discharged from treatment when: 1. they have made sufficient recovery (their back pain is no longer a problem) 2. the chosen intervention(s) have failed to affect their condition 3. no more recovery is expected The quantitative sensory testing measurements are performed again after discharge
Study Type
OBSERVATIONAL
Enrollment
40
Department of Health Science and Technology
Aalborg, North Denmark, Denmark
Change in cuff-pressure mechanical sensitivity, measured with a computer-controlled pressure cuff
The pressure needed to evoke first onset of pain (pain detection threshold, PDT) and the most pressure tolerable (pain tolerance threshold, PTT) are measured with a computer controlled pressure cuff. The cuff is placed on the lower leg and is gradually inflated (1kPa/sec). The first onset of pain (VAS 1, measured on an electronic VAS scale: 0=no pain, 10=worst pain imaginable) is indicated when the sensation of pressure around the leg changes to pain. The pressure continues to rise until the PTT is reached. PTT is defined as the point where the subject cannot endure more increase in pressure.
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)
Sensitivity to mechanical point pressure measured with a handheld pressure algometer
Change in sensitivity to mechanical point pressure back (L5 and L1) and shoulder (infraspinatus) between baseline and discharge from rehabilitation. Mechanical point pressure is measured with a handheld pressure algometer (Somedic, Sweden). The average from dominant and non-dominant sides will be used for analysis
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)
Temporal summation of pain (increase in pain from repeated nociceptive stimuli at the same intensity) measured with a computer-controlled pressure cuff
Change in temporal summation of pain between baseline and follow-up. Temporal summation of pain is assessed by using a computer controlled pressure cuff which is mounted on the lower leg on the dominant side. The participant receives 10 stimuli with a 1sec break between stimuli. Immediately following each stimuli, the participants rates the pain intensity using an electronic VAS scale (0-10, where 0=no pain and 10=worst pain imaginable)
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)
Conditioned pain modulation (change in pain sensitivity following the onset of a competing, nociceptive stimulus) measured with a computer-controlled pressure cuff
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Change in conditioned pain modulation between baseline and follow-up. Conditioned pain modulation is assessed by using two computer controlled pressure cuffs which are mounted on the lower legs, one on each side. On the non-dominant side, the cuff is inflated rapidly up to 80% of the pain tolerance threshold and kept there steady. In the meanwhile, the pain detection threshold and pain tolerance thresholds are assessed on the dominant side. Changes in PDT and PTT compared with baseline are defined as a CPM response.
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)
Pain (measured on a numeric rating scale)
Change in pain between baseline and follow-up measured on a numeric rating scale (0 = no pain and 10 = worst pain imaginable)
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)
Disability measured on the Roland-Morris Disability Questionnaire
Change in disability between baseline and follow-up will be found by comparing baseline measurements with measurements at discharge
Time frame: At baseline and after discharge from treatment (patients) or after 6-8 weeks (controls)