Subjective Nature of Lower Limb Radicular Pain

Background

Lumbar pathologies may cause the perception of leg pain, but the character of this pain has not been described. Diagnosis is often based on dermatomal charts, but observations reveal that the pain is not typically perceived on the skin.

Objective

To document the incidence of superficial versus deep pain localization among patients with lumbar radicular pain.

Methods

Twenty-five patients with lower limb radicular pain were questioned to determine the specific localization of their pain. The investigator categorized the pain location into general areas (eg, posterior thigh or anterior leg). Patients were asked if their pain was perceived as being on the skin or deep, as a forced choice question. These data were gathered in 2 conditions: at rest (spontaneous pain) and during a straight leg raise test (mechanically evoked pain). Data were recorded using a standardized form for later analysis.

Results

In all cases, symptoms were reported to be in deep structures. Pain was typically reported at sites correlated with multiple spinal levels.

Conclusion

Because radicular pain symptoms are perceived in deep structures rather than on the skin, the diagnostic value of dermatomal charts is questioned. Clinicians are advised to be specific when questioning patients with radicular pain symptoms and to refer to myotomal and sclerotomal charts when making diagnoses.