Thalamotomy — CPB 0153 | AETNA Coverage Update

Aetna modified CPB 0153 for thalamotomy procedures, effective September 26, 2025. Here's what billing teams need to act on before that date.

Aetna, a CVS Health company, updated its thalamotomy coverage policy under CPB 0153 Aetna system, covering three distinct procedure types: conventional surgical thalamotomy (CPT 61720), focused ultrasound thalamotomy (CPT 61715 and HCPCS C9734), and gamma knife radiosurgery (CPT 61796–61799). The update refines medical necessity criteria across multiple indications—Parkinson's disease, essential tremor, dystonia, and malignant pain—and draws a sharp line between what's covered and what isn't. If your practice bills for any of these thalamotomy procedures, the September 26, 2025 effective date is your deadline to review charge capture, prior authorization workflows, and ICD-10 pairing.

---

Quick-Reference Table

Field	Detail Copy
Payer	Aetna
Policy	Thalamotomy — CPB 0153
Policy Code	CPB 0153
Change Type	Modified
Effective Date	September 26, 2025
Impact Level	High
Specialties Affected	Neurosurgery, Neurology, Radiosurgery, Movement Disorder Programs
Key Action	Audit active thalamotomy cases for all three selection criteria before September 26, 2025 and confirm ICD-10 coding matches the covered indication

---

Aetna Thalamotomy Coverage Criteria and Medical Necessity Requirements 2025

The real issue with CPB 0153 is that Aetna runs three parallel coverage tracks—conventional surgical thalamotomy, focused ultrasound thalamotomy, and gamma knife thalamotomy—and each track has its own medical necessity threshold. Billing as if these are interchangeable will get your claim denied.

Conventional Surgical Thalamotomy (CPT 61720)

Aetna covers unilateral thalamotomy for movement disorders including Parkinson's disease, dystonia, spasmodic torticollis, and tremor—but only when the member meets all three of the following criteria simultaneously:

#	Covered Indication Copy
1	Positive then refractory drug history. The member had an initial positive response to medication but has since become refractory. A member who never responded to medication does not satisfy this criterion.
2	Neurologist screening. A neurologist with movement disorder expertise must have screened the member and confirmed all appropriate non-surgical therapies were tried.
3	Severe, incapacitating tremors with failed medical therapy. Symptoms are worsening and/or the member has disabling medication side effects.

All three criteria must be met. One or two out of three is not sufficient. Document each criterion explicitly in your prior authorization submission—Aetna reviewers will be looking for all three, not a summary narrative.

Focused Ultrasound Thalamotomy (CPT 61715)

The coverage bar here is narrower: severe essential tremor (ET) that is inadequately responsive to medical therapy. Parkinson's disease is not a covered indication for focused ultrasound thalamotomy under this policy. This distinction matters when selecting ICD-10 codes—a G20-series Parkinson's diagnosis paired with CPT 61715 is a denial waiting to happen.

Gamma Knife Thalamotomy (CPT 61796, 61797, 61798, 61799)

Gamma knife thalamotomy has the broadest coverage of the three tracks. Aetna covers it for two movement disorder indications and one oncology indication:

#	Covered Indication Copy
1	Severe essential tremor inadequately responsive to medical therapy
2	Refractory disabling tremor and rigidity from Parkinson's disease — must also meet the conventional thalamotomy criteria above
3	Malignant pain — but only as a last resort, with five additional criteria all met (see Coverage Indications table below)

The malignant pain pathway is unusual. It requires advanced oncological disease with limited life expectancy, exhausted radiotherapy options, failed best medical treatment, failed targeted interventions like nerve blocks, and no technical contraindications. This is a five-gate prior authorization scenario. If you're billing for gamma knife thalamotomy with a pain diagnosis, document every one of those gates before submitting.

The HCPCS Wrinkle: C9734

HCPCS C9734 covers focused ultrasound ablation with MRI guidance for indications other than uterine leiomyomata. Under CPB 0153, this code sits in the "not covered when selection criteria are met" group. That's a specific designation—it means even when the clinical criteria for focused ultrasound thalamotomy are otherwise satisfied, C9734 does not get covered under this policy. Bill CPT 61715 for the covered focused ultrasound thalamotomy procedure. Do not substitute C9734 expecting reimbursement on Aetna claims.

---

Aetna Thalamotomy Exclusions and Non-Covered Indications

The clearest exclusion in CPB 0153 is C9734. Aetna does not cover HCPCS C9734 for focused ultrasound thalamotomy, even when the member meets the essential tremor criteria. This isn't a documentation problem you can fix—it's a code-level coverage exclusion.

Beyond the specific code exclusion, the policy structure creates effective exclusions by indication. Focused ultrasound thalamotomy (CPT 61715) for Parkinson's disease is not listed as a covered indication. Conventional thalamotomy for a member who never responded to medication—even one with severe tremor—doesn't meet the criteria. And gamma knife for malignant pain without all five supporting criteria fails medical necessity.

These aren't edge cases. They're the scenarios most likely to generate claim denials for practices that don't read the criteria carefully.

---

Coverage Indications at a Glance

---

Aetna Thalamotomy Billing Guidelines and Action Items 2025

Copy Action Items

---

CPT, HCPCS, and ICD-10 Codes for Thalamotomy Under CPB 0153

Covered CPT Codes (When Selection Criteria Are Met)

Not Covered Codes

Code	Type	Description	Reason Copy
C9734	HCPCS	Focused ultrasound ablation/therapeutic intervention, other than uterine leiomyomata, with magnetic resonance guidance	Excluded under CPB 0153 even when selection criteria are otherwise met

Key ICD-10-CM Diagnosis Codes

These are the primary diagnosis families covered under CPB 0153. The full policy references 283 ICD-10 codes—the categories below represent the core covered indication groups.

The complete ICD-10 list in CPB 0153 runs 283 codes across neurological, oncological, and other diagnostic categories. Verify your specific diagnosis codes against the full policy at CPB 0153 on PayerPolicy before the September 26, 2025 effective date.

---