Neurosurgery Coding Alert

You may know to refer to codes 61697-61703 when your neurosurgeon performs surgery on an intracranial aneurysm, but does your physician's documentation specify carotid circulation, vertebrobasilar circulation, or fixing the aneurysm via a neck approach?

The answer matters because CPT has very definite guidelines that not only specify circulation and access but the difference between simple and complex aneurysms. It's up to you to know these subtle differences, or you'll run the risk of miscoding your claims -- a quick road to denials or lost revenue.

Heed the following expert advice and choose the proper code for each claim every time.

Start here: Before filing the claim, you'll need to check the operative notes to see where the aneurysm occurred, because you should code the surgery based on the aneurysm's location and complexity, says Gloria Mendoza, business office assistant manager at Barrow Neurosurgical Associates LTC in Phoenix, Ariz. These are both very important factors when deciding on a code.

There are two possible aneurysm locations -- carotid or vertebrobasilar circulation.

For carotid circulation aneurysms, you'd report:

• 61697 (Surgery of complex intracranial aneurysm, intracranial approach; carotid circulation) if the aneurysm is complex

• 61700 (Surgery of simple intracranial aneurysm, intracranial approach; carotid circulation) if the aneurysm is simple.

For vertebrobasilar circulation aneurysms, you'd report:

• 61698 (Surgery of complex intracranial aneurysm, intracranial approach; vertebrobasilar circulation) if the aneurysm is complex

• 61702 (Surgery of simple intracranial aneurysm, intracranial approach; vertebrobasilar circulation) if the aneurysm is simple.

Hint: You can find clues on aneurysm location by knowing the branches of the carotid circulation, which include the anterior communicating, posterior communicating, middle cerebral, anterior choroidal (AC), and ophthalmic arteries. Conversely, branches of the vertebrobasilar circulation include the posterior cerebral and cerebellar arteries.

Exception: If your neurosurgeon fixes an aneurysm by clamping the carotid artery via an approach through the neck, you'd report 61703 (Surgery of intracranial aneurysm, cervical approach by application of occluding clamp to cervical carotid artery [Selverstone-Crutchfield type]) instead of either 61697 or 61700.

Once you determine where the aneurysm occurred, you'll need to verify whether it is simple or complex, says Rena Hall, CPC, coder/auditor for Kansas City Neurosurgery Group in Kansas City, Mo.

In order to code for a complex aneurysm surgery, the aneurysm must meet at least one of the following criteria, experts say:

• The aneurysm is larger than 1.5 cm (15 mm);

• The aneurysm involved calcification at the neck of the aneurysm;

• The aneurysm incorporates normal vessels into the neck of the aneurysm; or

• The aneurysm surgery requires one of the following: vessel occlusion, trapping, or cardiopulmonary bypass.

If the aneurysm does not meet at least one of those requirements, then you must code the surgery as simple.

Consider the following examples -- one describes a simple aneurysm surgery, and the other a complex fix:

Example 1: The surgeon discovers that a patient has a right carotid aneurysm. She performs visualization of the right posterior communicator as well as the neck of the aneurysm, which was extending laterally in view but in fact was projecting directly inferior.

The surgeon finds that the third cranial nerve is associated with and slightly superior to the dome of the aneurysm. She then clips the aneurysm with an 11-mm straight clip across the aneurysm neck with good occlusion. This does not meet the criteria to be coded as a complex aneurysm. On the claim, report 61700 for the encounter.

Example 2: A patient reports complaining of the worst headache of his life; he also says he has intractable nausea and vomiting. The neurosurgeon orders a CT scan, which shows diffuse basal subarachnoid hemorrhage. There is a large clot in the interhemispheric fissure in the region of the anterior communicating artery.

The physician performs a left pterional craniotomy for clipping of the anterior communicating aneurysm. He then opens ventriculostomy for brain relaxation. Further dissection into the optic cistern allows more removal of spinal fluid and a preoperative subarachnoid hemorrhage clot. The contralateral A1 and A2 are exposed, and the surgeon applies temporary clipping at the left A1 segment.

Because the physician used temporary clipping, you would code this as a complex intracranial aneurysm. On the claim, you should report 61697 for the encounter.