Difference Between Lumbosacral Radiculopathy and Sciatica
Sciatica is a symptom describing pain radiating down the leg, while lumbosacral radiculopathy is a specific diagnosis indicating nerve root compression or dysfunction at the spinal level. 1
Terminology and Clinical Distinction
The term "sciatica" is archaic and confusing because patients and many clinicians use it to describe any lower back pain radiating to the leg, regardless of whether true nerve root involvement exists. 1 In contrast, radiculopathy specifically refers to nerve root pathology, most commonly from disc herniation, that follows a single dermatome distribution pattern. 2
Key Distinguishing Features:
Radiculopathy follows a single dermatome distribution, meaning symptoms (pain, numbness, weakness) track along one specific nerve root pathway (L3, L4, L5, or S1). 3, 2
Sciatica as commonly used describes any leg pain, which may be either true radicular pain from nerve root compression OR referred pain from the lower back without actual nerve involvement. 1
True radicular pain from disc herniation requires both compression AND inflammation of the nerve root to become symptomatic, with tumor necrosis factor-alpha playing a key mediator role. 1
Clinical Implications
The distinction matters critically because:
Epidemiology, clinical course, and therapeutic interventions differ substantially between true radiculopathy and referred pain masquerading as "sciatica." 1
Radiculopathy produces specific neurological findings including dermatomal sensory loss, myotomal weakness, and reflex changes corresponding to the affected nerve root (L3, L4, L5, or S1). 4
Prevalence estimates for sciatic symptoms range from 1.6% to 43%, but when stricter definitions requiring specific pain distribution and duration are applied, rates are much lower. 1
Diagnostic Approach
MRI of the lumbar spine is typically performed first due to the higher prevalence of radiculopathy-related degenerative spine disease. 5
MRI of the lumbosacral plexus may be needed when clinical uncertainty exists between plexopathy and radiculopathy, as their clinical and electrodiagnostic features often overlap. 3, 5
Electrodiagnostic studies combined with MRI improve diagnostic accuracy for confirming true radiculopathy. 5
Common Pitfalls
Failing to differentiate radicular pain from referred pain leads to inappropriate treatment selection, as the two conditions require different management strategies. 1
Using "sciatica" as a diagnosis rather than a symptom description creates confusion and imprecision in clinical communication. 1
Not recognizing that lateral disc herniations may cause plexopathy that is not detected on standard lumbar spine MRI. 3