IMPLICATIONS: Quantitative sensory testing has the potential to become an important tool in the selection of appropriate treatment for lumbar radiculopathy and to assist in identifying the mechanisms of pain generation in these patients.

Lumbar radiculopathy secondary to prolapsed disk is a relatively common medical condition. Nevertheless, the precise pathogenesis and the best treatment modality for sciatica have not been clearly defined. It has been believed for decades that nerve root compression by the protruded intervertebral disk is the main cause of sciatic pain (1). Yet, the frequent lack of correlation between the severity of symptoms and the size of the herniated disk has suggested the potential presence of additional underlying mechanisms (2). There is evidence that leakage of inflammatory substances from the nucleus pulposus can cause inflammation, nerve root excitation, and pain (3). However, it is difficult to say which of the two is the dominant mechanism in any given patient.