Medical Rationale
Lumbar disc herniation and degenerative disc disease cause radiculopathy through direct mechanical compression and inflammatory irritation of lumbosacral nerve roots. Herniated disc material (nucleus pulposus) contains phospholipase A2 and inflammatory cytokines that cause chemical radiculitis even without significant mechanical compression. The L4-L5 and L5-S1 levels are most commonly affected, producing sciatic nerve distribution symptoms (posterior thigh, lateral calf, foot). When bilateral disc disease or central stenosis is present, both lower extremities are affected. Each extremity's radiculopathy is rated separately — bilateral radiculopathy can significantly increase the combined rating. The bilateral factor (38 CFR § 4.26) adds approximately 10% to the combined bilateral rating.
Key Studies
Olmarker K et al. (1993) Spine (nucleus pulposus inflammatory radiculitis); Weinstein JN et al. (2006) JAMA (lumbar disc herniation outcomes — SPORT trial); Manchikanti L et al. (2014) Pain Physician (lumbar radiculopathy epidemiology).
Filing Tips
Lumbar MRI showing disc herniation or stenosis with nerve root contact. EMG/NCS documenting radiculopathy in BOTH lower extremities. File each leg as a separate secondary condition — left lower extremity radiculopathy AND right lower extremity radiculopathy. Each is rated independently under DC 8520 (sciatic nerve). Neurology nexus letter is ideal. The bilateral factor increases your combined rating by ~10%. This is one of the most impactful secondary claims for veterans with back conditions — bilateral moderate radiculopathy (20% each) with bilateral factor can add ~35% to combined rating.