CPT code 61590: Skull base approach, infratemporal, extradural2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 61590 in California.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 61590 covers

This code represents an extradural infratemporal approach to the middle cranial fossa, used to reach lesions at the skull base through the temporal bone region. The operation may involve substantial bone work and exposure around the petrous temporal bone. Neurosurgeons and otolaryngologists with skull base expertise commonly perform this type of approach in a hospital operating room for complex skull base lesions when the infratemporal route is required.

Report the approach when the operative note supports an infratemporal route and an extradural surgical plane; distinguish it from an intradural approach or a different skull base corridor. Documentation should identify the target, route, extent of exposure and relevant bone work. CMS assigns a 90-day global period, including the day-before preoperative visit and related postoperative care. When multiple procedures occur in the same session, the highest-valued is paid in full and other procedures are reduced to 50%. Bilateral reporting with modifier 50 is paid at 150%. Assistant-at-surgery payment may be made; co-surgeon payment requires supporting documentation, and team surgery is 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 61590 pays more and less in California

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

29 of 29 payment localities

How the 61590 rate is calculated

Each of 61590’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.

Payment rules and modifiers for 61590

61590 has a 90-day global period: related visits in that window are included in the surgery payment.

What modifiers do to the payment

When to use modifier 50

61590 compared with similar codes

How to choose

61591Skull-base approachPostauricular infratemporal route

Both describe an infratemporal route to the middle cranial fossa; 61590 is extradural, while 61591 is intradural.

61595Skull base approachTranstemporal route

61595 uses a transtemporal corridor. Choose 61590 when the documented route is infratemporal and extradural.

61596Skull base approachTranscochlear posterior fossa

61596 identifies a transcochlear approach. It is distinct from the infratemporal extradural route represented by 61590.

61598Skull base approachTranspetrosal corridor

61598 represents a transpetrosal approach; 61590 is selected for the documented infratemporal extradural corridor.

Codes related to 61590

Related codes aren’t interchangeable: bill the code that matches the service performed.

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

Open CMS sourceHow we calculate rates