Related Experiment Video
Updated: Apr 23, 2026
Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats
Published on: April 4, 2012
Tactile allodynia in patients with lumbar radicular pain (sciatica)
Ruth Defrin1, Marshall Devor, Silviu Brill
1Department of Physical Therapy, School of Allied Health Professions, The Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel Department of Cell and Developmental Biology, Institute of Life Sciences, and Center for Research on Pain, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Institute of Pain Medicine, Department of Anesthesia and Critical Care Medicine, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv 69978, Israel.
Patients with low back pain (LBP) may experience allodynia, a novel symptom indicating central sensitization. This finding helps explain sciatica pain and validates leg allodynia as a biomarker for LBP research.
Area of Science:
- Neurology
- Pain Medicine
- Sensory Neuroscience
Background:
- Low back pain (LBP) is a prevalent condition with complex underlying mechanisms.
- Understanding the neurophysiological basis of LBP, particularly radicular pain (sciatica), is crucial for effective treatment.
- Current understanding of pain mechanisms in LBP may not fully explain all reported symptoms, such as shooting pain.
Purpose of the Study:
- To identify and characterize a novel symptom, cutaneous allodynia, in patients with LBP.
- To investigate the relationship between allodynia and the type of LBP (radicular vs. axial).
- To elucidate the pain mechanisms involved in LBP and sciatica, including central sensitization.
Main Methods:
- Quantitative sensory testing was employed to assess cutaneous allodynia.
- Patients with radicular LBP, axial LBP, and healthy controls were compared.
- Allodynia was tested in response to tactile and cooling stimuli on the leg and low back.
Main Results:
- ~60% of patients with radicular LBP reported tactile and cooling allodynia on the leg, sometimes extending to the foot.
- Allodynia was predominantly on the low back in patients with axial LBP.
- The degree of dynamic tactile allodynia correlated with background pain intensity, suggesting central sensitization.
Conclusions:
- The presence of allodynia in LBP patients suggests peripheral nerve sensitization leading to central sensitization.
- Distal allodynia indicates ectopic afferent activity in injured ventral ramus, not somatic referred pain.
- Findings support leg allodynia as a valid pain biomarker in LBP research and may have prognostic and therapeutic implications.
