Pain Sensory Profile Changes Following Treatment of Chronic Low Back Pain

Is the Subjective Experience of Recovery From Low Back Pain Related a Decrease in the Sensitivity of Pain Mechanisms?

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

Inclusion Criteria:

Patient group

• Pain located in the low back region, defined as the area lying between the posterior superior iliac spine below and the thoracolumbar junction above
• The pain has lasted between 3 and 60 months

Exclusion Criteria:

• Pain related to a specific pathology such as spinal stenosis, metastasis, fracture etc.
• Leg pain related to nerve root compression/irritation.
• Multiple painful sites/areas unrelated to the back pain
• Operation to the spine
• Any neurological or systemic diseases which can affect the outcome measures
• Pregnancy
• Lack of ability to cooperate

Control group Inclusion Criteria

• Are healthy and free from any pain specific to the low back and/or in general

Exclusion Criteria

• No current or previous history of on-going pain, defined as pain lasting more than 3 months, in the lumbopelvic region and/or elsewhere
• Have participated in studies using a similar experimental pain model