G83.81
BillableBrown-Séquard syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G83.81 an HCC code?
Yes. G83.81 maps to Monoplegia, Other Paralytic Syndromes under the CMS-HCC V28 risk adjustment model (and Monoplegia, Other Paralytic Syndromes under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for G83.81
For G83.81 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed G83.81 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G83.81 is the ICD-10-CM diagnosis code for brown-séquard syndrome. A spinal cord injury pattern causing weakness or paralysis on one side of the body and loss of pain/temperature sensation on the opposite side. G83.81 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering cerebral palsy and other paralytic syndromes (g80-g83).
Under the CMS-HCC V28 risk adjustment model, G83.81 maps to Monoplegia, Other Paralytic Syndromes (HCC 254) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, G83.81 mapped to the same category but with a base RAF weight of 0.304 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Document the level of spinal cord involvement and which side is affected for complete coding. Because G83.81 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G83.81 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the level of spinal cord involvement and which side is affected for complete coding
- •Identify the underlying cause (trauma, tumor, infection) as it may require additional coding
Clinical Significance
Brown-Sequard syndrome is a distinctive spinal cord injury pattern resulting from hemisection of the spinal cord, producing ipsilateral motor paralysis and loss of proprioception with contralateral loss of pain and temperature sensation. This characteristic crossed pattern is clinically important for localizing the lesion and planning rehabilitation. Among incomplete spinal cord injuries, Brown-Sequard syndrome generally has the best prognosis for recovery of ambulation.
Documentation Requirements
- ✓Explicit documentation of Brown-Sequard syndrome
- ✓Description of the characteristic crossed neurological findings
- ✓Spinal cord level of the lesion
- ✓Underlying etiology (trauma, tumor, disc herniation, demyelination, vascular)
- ✓Motor and sensory examination findings on both sides
- ✓Functional status and ambulatory potential
- ✓Active treatment and rehabilitation plan
Commonly Confused Codes
- •G83.82 Anterior cord syndrome — different spinal cord injury pattern (bilateral motor loss with bilateral pain/temperature loss)
- •G83.83 Posterior cord syndrome — different pattern (proprioceptive loss with preserved motor function)
- •G81.00-G81.94 Hemiplegia codes — brain-level lesion, not spinal cord hemisection
- •G83.89 Other specified paralytic syndromes — less specific; use G83.81 when Brown-Sequard is documented
- •S14-S34 Spinal cord injury codes — use for the acute traumatic injury itself