CPT code 61596: Skull base approach, transcochlear posterior fossa2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 61596 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 61596 covers

This approach reaches the posterior cranial fossa through the temporal bone and cochlear region. The exposure includes mastoid work, removal of petrous bone, and posterior transposition of the facial nerve. It is used by skull base teams, typically involving an otologist or neurotologist and a neurosurgeon, to access lesions near the clivus, petrous apex, or ventral brainstem. The route is selected when the required exposure calls for this specific transcochlear corridor rather than a transtemporal or transpetrosal route.

Report the approach based on the operative route and documented work, not just the lesion’s location. The approach includes its described exposure steps; document the facial nerve transposition and bony work performed. Report the definitive lesion procedure separately when supported by the applicable CPT instructions. CMS classifies this as major surgery with a 90-day global period, including the day-before preoperative visit and related postoperative care. When multiple procedures are performed in one session, the highest-valued is paid in full and others at 50%. For a bilateral procedure reported with modifier 50, CMS pays at 150%. Assistant-at-surgery payment may be available; 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 61596 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 61596 rate is calculated

Each of 61596’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 61596

61596 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

61596 compared with similar codes

How to choose

61595Skull base approachTranstemporal route

61595 represents a transtemporal approach to the posterior cranial fossa. Use 61596 when the operative route is transcochlear and includes its distinct exposure work.

61597Skull-base approachTranscondylar route

61597 uses a transcondylar route, typically involving access around the occipital condyle. It is not the transcochlear temporal-bone approach described by 61596.

61598Skull base approachTranspetrosal corridor

61598 represents a transpetrosal route. Choose between it and 61596 based on the approach actually performed and documented, not merely the target lesion.

61616Skull-base resectionIntradural lesion

61616 describes resection of an intradural posterior cranial fossa lesion; 61596 describes the transcochlear approach. The codes represent different parts of the operative service.

Codes related to 61596

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