Goal of the Study?
In this case-controlled study from the Scandinavian Journal of Pain1 the authors’ goal was to investigate if patients diagnosed with only lumbar radicular pain have different pain experiences and somatosensory profiles from those diagnosed with combined lumbar radicular pain and radiculopathy.
Why are they doing this study?
The prevalence of “sciatica”, commonly known as pain radiating from the lower back into the leg, varies significantly between studies and investigated sample populations. Evidence for the benefit of conservative management is inconclusive with some cohorts responding to treatment and others not. Understanding clinical care pathways and treatment outcomes are muddied, with a variety of challenges to the interpretation of conditions and appropriate care. This study is an attempt to reduce one of these confounding challenges by comparing the differences of somatosensory profiles of two patient groups.
What was done?
Comprehensive Quantitative Sensory Testing (QST) using a series of tools were applied to 26 patients, eight of which had only radicular pain and the other 16 had radiculopathy co-morbidity. These measurement tools included;
- painDETECT questionnaire, which screens for the presence of neuropathic pain using pain intensity and pain descriptors
- Oswestry Disability Index, which measures low back pain functional index
- Hospital Anxiety and Depression scale which assesses mood disorder, anxiety and depression
- Tampa Scale for Kinesiophobia which assesses fear avoidance behaviour
- Pain Catastrophic Scale which measures how a patient experiences their pain by either ruminating, magnifying it or feeling helpless
A neurosurgeon, blinded to the patient’s clinical presentation reviewed lumbar MRI imaging and graded the degree of nerve root compression according to Pfirrmann’s system. Nerve root compression was found in 12 patients, nerve root displacement in six and contact of the nerve root with disc material in the remaining eight patients.
What did they find?
The results of this small cohort study indicate distinct differences in QST derived somatosensory profiles and pain experiences between patients with radicular pain only and those with radiculopathy co-morbidity. Patients with only radicular pain scored significantly lower on the painDETECT score and did not report any symptoms of numbness while 78% of the patients with radiculopathy did. Patients with only radicular pain were also less anxious, but these two groups had no statistically significant difference in their functional disabilities or in the frequency of Oswestry Disability Index classifications.
Why do these findings matter?
This study supports the notion that radicular pain and radiculopathy are discrete conditions and each condition has distinct differences in QST derived somatosensory profiles and pain experiences. The authors request that clinicians and researchers should be made aware of these differences and possible care implications. They should also be aware that the definition of “sciatica” requires much more clarity in its classification and operational guidance.
Distinguishing radicular pain from pathological pain, as in the case of neurological compromise with radiculopathy, can be an important distinction and should be shared with the patient. At Dynamic Disc Designs, we have developed models to help professionals explain the difference in a realistic way.