Sub-group Classification of Low Back Related Leg Pain: Is this the Catalyst Needed for Other Challenging Conditions?

Low back related leg pain (LBLP) or ra-dicular pain 1 exists in many variations and has been associated with poor prognosis in a number of studies 2-5. Evidence has shown that LBLP is predictive of progression to chronicity 6 , poor outcomes with conservative care 2 , as well as lower functional status, well being, and higher levels of disability 7. Why some patients with LBLP and not others progress toward disability is unknown 8. Often, the pain associated with LBLP is indistinct. To some degree, an explanation of symptom variation is associated with dissimilar lumbar segment origins (e.g., L4 versus L5) 9 , conditions that mimic radicular symptoms such as tumors , diabetic neuropathy, or methyl metacrylate neuropathy 1 , musculoskele-tal dysfunctions of the lower limbs (myo-fascial pain) 9 , or when injury is present to a non-localized region of the sciatic nerve 10. Another reason for variation is the multiplicity of potential neural and/ or musculoskeletal structures associated with LBLP, which is not limited to a disc herniation or lumbar stenosis. To further the complexity, radicular pain (radiating pain) is not exclusively associated with radiculopathy, which is a clinical condition associated with loss of sensation and/or motor function as a result of a conduction block 1. Diagnosis of LBLP involves a number of suspect clinical and imaging test methods. The straight leg raise is a sensitive test but lacks specificity 11. Tests associated with neurological examination (sensibility, reflex, manual muscle testing , etc.) have very low sensitivities indicating findings may be below the threshold needed for the tests to be positive 11,12. The crossed (or well) straight leg raise is a specific measure but also lacks sensitivity 13. Report of symptoms using terms such as " sharp " , " burning " and " aching " and pain that fails to subside immediately during position changes has been associated with radiculopathy 14. At present, there are no clinical decision rules to dictate diagnosis of a specific LBLP condition. Imaging methods fare slightly better. Diagnostic blocks appear best served when ascertaining the guilty level when multiple levels are examined 13. Magnetic resonance imaging (MRI) examining nerve root compression has demonstrated moderate reader reliability 15,16 and is sensitive during identification of nerve root compression 17. Further source differentiation may warrant the use of elec-trodiagnostic techniques for assessment of nerve conduction changes to truly isolate radiculopathy 18. Targeting the proper interventions …