Billing code 61304: Exploratory craniotomyMedicare rate & RVUs in Oregon
Reports an exploratory cranial opening above the tentorium when the surgeon investigates intracranial pathology without performing a separately defined therapeutic procedure.
CMS doesn’t publish an office rate for 61304 in Oregon.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 61304 covers
A neurosurgeon opens the skull over the cerebral hemispheres, above the tentorium, to inspect intracranial structures when exploration is the operative objective. The surgeon may create a temporary bone opening or remove bone as part of the approach. This is a facility-based cranial operation, typically performed in an operating room; Medicare recorded facility services for this code in 2024.
Select the code based on the supratentorial location and the exploratory purpose documented in the operative report. Record the approach, structures examined, findings, and any additional procedure performed so the reported service reflects the work actually done. The 90-day global period includes the day-before preoperative visit and 90 days of related postoperative care. For multiple procedures in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% reduction. Modifier 50 is not appropriate for this cranial service. An assistant at surgery may be paid; co-surgeon payment requires supporting documentation, and team surgery is not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 61304 pays more and less in Oregon
| Payment locality | Office | Facility |
|---|---|---|
| Portland | Unavailable | $1,598.28 |
| Rest Of Oregon | Unavailable | $1,512.27 |
How the 61304 rate is calculated
Each of 61304’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 61304
RVUs × geographic indexes × conversion factor
Swap in your local Medicare rate.
Work 22.82Practice expense 15.82Malpractice 9.53
All indexes start at 1.000 (the national rate). Enter a ZIP or drag a slider.
Payment rules and modifiers for 61304
61304 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 61304
Exploratory craniotomy
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.11/0.76/0.13 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 61304
Exploratory craniotomy
90-day global period ends
Dec 30, 2026
Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).
Visit on Oct 31, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
61304 without 51 · national facility
$1,608.92
Exploratory craniotomy
61304-51 · Second procedure: 50%
$804.46
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
61304 compared with similar codes
Compare codes
61304 vs 61305 vs 61312 vs 61313: national Medicare rates
Swap in your local Medicare rate.
How to choose
- 61305Cranial exploration
- Choose 61304 for exploration above the tentorium and 61305 for exploration below it, in the infratentorial region.
- 61312Hematoma evacuation
- 61312 identifies evacuation of a supratentorial extradural or subdural hematoma; 61304 describes exploration rather than that specified treatment.
- 61313Hematoma evacuation
- 61313 is for evacuation of an intracerebral hematoma. Use 61304 when the documented operation is exploratory rather than hematoma evacuation.
61304 billing questions
How is this code distinguished from 61305?
This code describes exploration above the tentorium, over the cerebral hemispheres. Code 61305 is for exploration below the tentorium in the infratentorial region.
Should this code be used when the surgeon evacuates a hematoma?
Choose a hematoma-specific code when evacuation is the procedure performed. For a supratentorial extradural or subdural hematoma, compare 61312; for an intracerebral hematoma, compare 61313.
What should the operative report establish?
Document the supratentorial operative location, the exploratory purpose, the approach, and the structures examined. Describe any therapeutic procedure performed so code selection reflects the actual operation.
Can modifier 50 be appended?
No. Modifier 50 is not appropriate for this cranial exploration; report the service once rather than as a bilateral procedure.
How are other same-session procedures paid?
Under the standard multiple procedure reduction, the highest-valued procedure is paid in full and other procedures performed in the same session are paid at 50%.
Can an assistant or co-surgeon be reported?
An assistant at surgery may be paid. Co-surgeon payment requires supporting documentation; team surgery is not permitted.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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