Sciatica VA Rating: Diagnostic Code 8520 Explained

Sciatica is the pain that travels from the lower back or buttock down the back of the thigh, sometimes into the calf and foot. It is not a diagnosis of its own so much as a description of what an irritated lumbar nerve root feels like, and the VA rates it under the sciatic nerve code, Diagnostic Code 8520 in 38 CFR 4.124a.

Two things decide the percentage: how much of the nerve's function is lost, and whether the findings are sensory only.

The percentages under Diagnostic Code 8520

Each leg carries its own evaluation. A veteran with moderate sciatic involvement in both legs has two 20 percent ratings, which combine under 38 CFR 4.25 and may attract the bilateral factor, rather than a single 40 percent rating.

• 10 percent - mild incomplete paralysis
• 20 percent - moderate incomplete paralysis
• 40 percent - moderately severe incomplete paralysis
• 60 percent - severe incomplete paralysis with marked muscular atrophy
• 80 percent - complete paralysis, where the foot dangles and drops, there is no active movement of the muscles below the knee, and knee flexion is weakened or lost

What separates mild from moderate

The schedule does not define these words numerically, so raters rely on the clinical picture. In practice, intermittent numbness or tingling in a dermatomal pattern with normal strength and reflexes reads as mild. Persistent symptoms with a diminished reflex or mildly reduced strength read as moderate. Consistent weakness, a lost reflex, and reduced muscle bulk move toward moderately severe.

The note in 38 CFR 4.124a sets a hard ceiling on the sensory-only picture: where involvement is wholly sensory, the rating should be for the mild, or at most the moderate, degree. If your leg gives out, if you have dropped things or caught your toe on a step, or if one calf has become visibly smaller, those facts need to be documented, because they are the difference between 20 and 40 percent.

Sciatica is rated in addition to the spine

Note (1) to the General Rating Formula for spine disabilities in 38 CFR 4.71a directs that associated objective neurologic abnormalities be evaluated separately. A service-connected lumbar disc condition rated on limited motion and a sciatic nerve rating for each affected leg are separate evaluations.

This is the most commonly missed piece of a back claim. If your decision letter granted a spine percentage and said nothing about the leg, read our back pain and VA disability guide and the radiculopathy secondary guide for how the claim is usually structured.

Neuritis and neuralgia of the sciatic nerve

When the record describes inflammation with objective findings, the claim may be rated under Diagnostic Code 8620 for sciatic neuritis. When the picture is a dull, intermittent pain along the nerve without objective loss, Diagnostic Code 8720 for neuralgia applies. Under 38 CFR 4.123 and 4.124, both carry a ceiling equal to moderate incomplete paralysis unless the neuritis shows loss of reflexes, atrophy, sensory disturbances, and constant pain.

Piriformis syndrome and other causes

Not all sciatic pain starts at the spine. The sciatic nerve can be irritated where it passes near the piriformis muscle in the buttock, and hip pathology can produce overlapping pain. The rating code is the same, but the medical reasoning connecting the condition to service is different, so the diagnosis in the record matters. Our hip and lower leg series covers the joint conditions that often sit alongside these claims.

What the exam needs to record

The peripheral nerves examination worksheet asks for sensory testing by dermatome, deep tendon reflexes at the knee and ankle, manual muscle strength testing, muscle atrophy measurements, and trophic changes. Answer for your worst days as well as your best, and say plainly what you cannot do.

Our nerve C&P exam guide walks through that appointment, and the evidence guide lists what belongs in the file before the exam is scheduled.

Filing an increased rating when sciatica worsens

Sciatica is not always static. A disc that continues to degenerate, a fall, or years of altered gait can move the clinical picture from mild to moderate, or from moderate to moderately severe, over time. When that happens, an increased rating claim is the correct route rather than waiting for a routine VA review, and it is supported the same way the original claim was: current treatment records showing the change, and, where useful, an updated examination.

The evidence that supports an increase is the same evidence that supports the initial grant, just measured again. Diminished strength that used to be normal, a reflex that has become absent, or a measurable loss of muscle bulk in the calf or thigh are the findings that move the percentage, not simply a report that the pain has gotten worse.

Because Diagnostic Code 8520 is graded on a five-step scale from 10 to 80 percent, even a documented step up in severity can represent a meaningful increase in the monthly rating, which is why keeping current treatment notes accurate matters well after the original decision.

Sciatica and the ability to work

Sciatic nerve involvement that reaches the moderately severe or severe levels often affects standing, walking, and the ability to safely operate machinery or drive for long periods, particularly when foot drop or significant weakness is present. When nerve symptoms, combined with other service-connected conditions, prevent a veteran from sustaining substantially gainful employment, Total Disability based on Individual Unemployability may apply even where no single condition reaches 100 percent.

The nerve rating and a TDIU claim are evaluated separately. The rating under Diagnostic Code 8520 measures the neurologic loss itself, while TDIU measures the functional and occupational impact of the service-connected conditions taken together. Veterans whose sciatica limits standing or walking for a full workday should review whether that impact is documented anywhere in the file, since occupational limitations are not always captured by a C&P exam focused on reflexes and strength.