TL;DR: The Centers for Medicare & Medicaid Services modified NCD 216 governing Medicare coverage of stereotaxic depth electrode implantation, effective March 7, 2026. This policy update reaffirms coverage criteria for this pre-surgical diagnostic procedure in focal epilepsy patients — and if your neurology or neurosurgery billing team hasn't reviewed documentation requirements against this updated standard, now is the time.
CMS's National Coverage Determination 216 covers stereotaxic depth electrode implantation as a diagnostic procedure for Medicare beneficiaries with intractable focal epilepsy. The policy does not list specific CPT or HCPCS codes — a detail that creates real documentation risk if your billing team isn't mapping claims carefully. Here's what changes and what your team needs to do before claims hit the queue.
| Field | Detail |
|---|---|
| Payer | CMS (Centers for Medicare & Medicaid Services) |
| Policy | Stereotaxic Depth Electrode Implantation |
| Policy Code | NCD 216 |
| Change Type | Modified |
| Effective Date | 2026-03-07 |
| Impact Level | Medium |
| Specialties Affected | Neurology, Neurosurgery, Epilepsy Centers, EEG/Neurophysiology |
| Key Action | Audit documentation for medical necessity against the updated NCD 216 criteria before submitting claims for this procedure |
CMS Stereotaxic Depth Electrode Implantation Coverage Criteria and Medical Necessity Requirements 2026
NCD 216 is the National Coverage Determination governing Medicare coverage of stereotaxic depth electrode implantation — a procedure where thin wire electrodes are surgically placed into the brain of a focal epilepsy patient for electroencephalograph (EEG) monitoring during seizure activity. The goal is to pinpoint the epileptic focus precisely enough to inform surgical resection decisions. This isn't a standalone treatment; it's a diagnostic step that gates access to surgery.
CMS has found this procedure both safe and effective for one specific population: patients with focal epilepsy who are unresponsive to anticonvulsant medications and who are being evaluated as candidates for surgical treatment. The coverage policy ties directly to that clinical context — pre-surgical diagnostic workup, not monitoring for any other purpose.
The medical necessity bar here is clear. The patient must have intractable seizures that haven't responded to anticonvulsant therapy, and the depth electrode implantation must be specifically aimed at identifying a resectable seizure focus that conventional scalp EEGs have failed to localize. If your documentation doesn't reflect both of those conditions, expect a claim denial. The coverage policy doesn't give CMS adjudicators much wiggle room, and your medical records need to close that loop before the claim goes out.
Prior authorization requirements are not explicitly addressed in the updated NCD 216. That said, Medicare Advantage plans operating under CMS rules frequently impose their own prior auth requirements on procedures covered by NCDs — so if your patient is in an MA plan, verify those plan-level requirements separately before the procedure date.
Reimbursement flows under the Diagnostic Tests benefit category, which matters for how the claim gets classified and adjudicated. Make sure your billing team isn't miscategorizing this as a surgical or therapeutic service at the claim level.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Focal epilepsy patients unresponsive to anticonvulsant medications, evaluated for surgical treatment | Covered | Not specified in NCD 216 | Must be pre-surgical; documentation must reflect seizure focus localization as the diagnostic purpose |
| Conventional scalp EEG insufficient to identify seizure focus | Covered (supporting criterion) | Not specified in NCD 216 | Scalp EEG inadequacy should be documented in the record before depth electrode placement |
| Use outside of pre-surgical evaluation for intractable focal epilepsy | Not established as covered | Not specified in NCD 216 | NCD 216 does not extend coverage beyond the defined indication |
CMS Stereotaxic Depth Electrode Implantation Billing Guidelines and Action Items 2026
The modified NCD 216 is effective March 7, 2026. Your billing team needs to move on several fronts now.
| # | Action Item |
|---|---|
| 1 | Audit your existing documentation templates against the updated NCD 216 criteria. Every claim for stereotaxic depth electrode implantation needs to show: intractable focal epilepsy, failure of anticonvulsant therapy, and a pre-surgical diagnostic purpose. If your operative and clinical notes don't explicitly address all three, fix the templates before March 7, 2026. |
| 2 | Confirm code mapping with your coding team, since NCD 216 does not list specific CPT or HCPCS codes. This is the biggest billing risk in this policy. The absence of listed codes means your team needs to identify the correct procedure codes through the AMA CPT codebook and CMS's own claims processing instructions — then document the link between those codes and NCD 216 coverage explicitly. Don't assume the MAC will make that connection for you. |
| 3 | Check with your Medicare Administrative Contractor (MAC) for any local coverage additions or billing instructions tied to NCD 216. NCDs set the national floor, but MACs can layer on additional documentation or coding requirements. Contact your MAC directly if you're unclear on which procedure codes they expect on claims for this service. |
| 4 | For patients in Medicare Advantage plans, verify plan-level prior authorization requirements separately. NCD 216 doesn't specify prior auth, but that doesn't mean your MA plan won't require it. Call the plan before the procedure for any patient where coverage is tied to an MA contract. |
| 5 | Flag any pending claims for this procedure that were submitted before March 7, 2026, under the prior version of NCD 216. If the modification introduced any substantive criteria changes, those claims may need to be reviewed for compliance with the updated standard. Loop in your compliance officer before assuming prior submissions are clean. |
| 6 | If you're billing under the Diagnostic Tests benefit category and your MAC pends or denies a claim, appeal on the NCD 216 coverage language directly. The policy language is specific enough that a well-documented appeal citing the exact CMS criteria has a real chance of overturning an incorrect denial. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Stereotaxic Depth Electrode Implantation Under NCD 216
This is where the policy gets genuinely frustrating for billing teams. NCD 216, as updated effective March 7, 2026, does not list specific CPT codes, HCPCS codes, or ICD-10 diagnosis codes. That's not a gap in this article — it's the actual state of the policy document.
That absence creates real exposure. When a coverage policy doesn't enumerate applicable codes, the burden of proof falls entirely on your billing team to map the claim correctly and defend that mapping if challenged. A claim denial isn't hypothetical in this scenario — it's likely if the code choice is ambiguous or if the MAC's claims processing system doesn't link the submitted code back to NCD 216 automatically.
Covered CPT Codes (When Medical Necessity Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| Not specified in NCD 216 | — | CMS did not enumerate specific CPT or HCPCS codes in this policy. Coordinate with your MAC and coding team to identify the correct procedure code(s) for stereotaxic depth electrode implantation. |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| Not specified in NCD 216 | — |
The right move here is to pull the AMA CPT codebook entries for depth electrode implantation, confirm the applicable code(s) with your MAC, and document that consultation. If you're uncertain about how to map this procedure for Medicare claims, talk to your billing consultant or compliance officer before the March 7, 2026 effective date.
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