DC 8520STRONG evidenceLast verified: MAR 11, 2026

Bilateral Lower Extremity Radiculopathy Secondary to Lumbar Spine Injury / Degenerative Disc Disease

Bilateral Lower Extremity Radiculopathy can develop as a service-connected secondary condition to Lumbar Spine Injury / Degenerative Disc Disease when a medical nexus links the two under 38 CFR § 3.310. The strength of medical evidence for this specific pairing is strong. Lumbar disc herniation and degenerative disc disease cause radiculopathy through direct mechanical compression and inflammatory irritation of lumbosacral nerve roots.

How is Bilateral Lower Extremity Radiculopathy connected to Lumbar Spine Injury / Degenerative Disc Disease?

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.

“Disability which is proximately due to or the result of a service-connected disease or injury shall be service connected.”
— 38 CFR § 3.310(a), Disabilities that are proximately due to, or aggravated by, service-connected disease or injury

What evidence supports claiming Bilateral Lower Extremity Radiculopathy as secondary to Lumbar Spine Injury / Degenerative Disc Disease?

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).

How do I file a secondary claim for Bilateral Lower Extremity Radiculopathy?

Lumbar MRI showing disc herniation or stenosis with nerve root contact. EMG/NCS documenting radiculopathy in BOTH lower extremities. Consider 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.

How does the VA rate Bilateral Lower Extremity Radiculopathy?

Bilateral Lower Extremity Radiculopathy is rated under 38 CFR Part 4 using the diagnostic code assigned to that condition. The VA evaluates the severity of the secondary condition independently and assigns a rating from 0% to 100% in increments defined in the rating schedule. That rating is then combined with Lumbar Spine Injury / Degenerative Disc Disease and all other service-connected conditions using the combined ratings formula under § 4.25.

Bilateral Lower Extremity Radiculopathy is rated under DC 8520 in 38 CFR Part 4.

Common Questions — Bilateral Lower Extremity Radiculopathy Secondary to Lumbar Spine Injury / Degenerative Disc Disease

Can Bilateral Lower Extremity Radiculopathy be claimed as secondary to Lumbar Spine Injury / Degenerative Disc Disease?

Yes. Under 38 CFR § 3.310(a), any disability proximately caused or chronically worsened by a service-connected condition is itself service-connected. Bilateral Lower Extremity Radiculopathy is a documented secondary pairing for Lumbar Spine Injury / Degenerative Disc Disease with strong medical evidence. A nexus letter from a qualified physician linking the two conditions is the most reliable way to establish this connection.

What evidence proves Bilateral Lower Extremity Radiculopathy is caused by Lumbar Spine Injury / Degenerative Disc Disease?

The gold standard is a private nexus opinion stating — to at least a 50% probability ("at least as likely as not") — that the secondary condition was caused or aggravated by the primary service-connected condition. Peer-reviewed medical literature supporting the physiological mechanism strengthens the nexus. Treatment records documenting the onset or worsening of the secondary condition in temporal relation to the primary are supporting evidence.

Does the VA combine or separately rate Bilateral Lower Extremity Radiculopathy?

The VA rates Bilateral Lower Extremity Radiculopathy separately under its own 38 CFR Part 4 diagnostic code, then combines it with Lumbar Spine Injury / Degenerative Disc Disease and all other service-connected ratings using the combined ratings formula under § 4.25. The formula applies the whole-person concept: a 50% combined existing rating plus a new 30% rating yields 65% (rounded to 70%), not 80%.

What legal standard applies to secondary service connection?

38 CFR § 3.310(a) states: "Disability which is proximately due to or the result of a service-connected disease or injury shall be service connected." The aggravation variant under § 3.310(b) applies where the primary condition permanently worsens a pre-existing disability beyond its natural progression. Both standards require a showing of nexus — a medical or scientific link between the primary condition and the secondary.

How strong is the medical evidence for this pairing?

The medical evidence supporting Bilateral Lower Extremity Radiculopathy as secondary to Lumbar Spine Injury / Degenerative Disc Disease is rated strong. 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.

Do I need a nexus letter for a secondary claim?

The VA will not solicit nexus evidence on your behalf for secondary claims. In practice, a written nexus opinion from a private physician or independent medical examiner is essential — the VA's Compensation & Pension (C&P) examiner is not required to produce a favorable nexus opinion, and the VA has discretion to weigh competing opinions. Submitting a private nexus letter at the time of filing is the most reliable strategy.

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