Neurosurgery Coding Alert

Hint: If the aneurysm exceeds 1.5 cm, it's complex

When the neurosurgeon performs surgery on an intracranial aneurysm, CPT has very specific guidelines that separate simple and complex aneurysms. Coders must know the differences between the two, or they run the risk of miscoding their claims -- a quick road to denials or lost revenue.

But if you follow the experts- advice, you-ll choose the proper code for each claim every time. Check out this advice from the pros on differentiating simple and complex aneurysm surgeries.

Find Out Where the Aneurysm Occurred

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 Teresa Thomas, CPC, practice manager at St. John's Clinic Neurosurgery in Springfield, Mo. -These are both very important factors- when deciding on a code, she says.

The basics: 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.

Try this: You can find clues on aneurysm location by knowing the branches of the carotid circulation, which include the middle cerebral, anterior choroidal artery (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 arteryvia 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.

Observe These Rules When You Consider Complexity

Once you determine where the aneurysm occurred, you-ll need to verify whether it is simple or complex. In order to code for a complex aneurysm surgery, the aneurysm must meet at least one of the following criteria, says Lisa May, CPC, coder at Fletcher Allen Health Care in South Burlington, Vt.:

- 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,  May says. 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,- Thomas says. 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 temporary clipping was used, you would code this as a complex intracranial aneurysm,- Thomas says. On the claim, you should report 61697 for the encounter.