Neurosurgery Coding Alert

Surgeon/coder communication and flawless documentation are a must for 61580-61598

To find the appropriate skull-base surgery approach code, look to the surgeon's documentation to determine the fossa he targeted and whether he cut into the dura.
 
When you've used this information to narrow your search, confer with the surgeon to verify the exact structures he moved or removed so you can select the code that best describes the procedure.

1. Identify the Location of the Lesion

 The first step in choosing a skull-base approach code is to determine the precise area of the skull base the surgeon wishes to access. In other words, you should ask, "What is the location of the lesion the surgeon needs to address?"

CPT divides the skull base into three constituent parts: the anterior (frontal) cranial fossa (61580-61586), middle (temporal) cranial fossa (61590-61592), and posterior (cerebellar) cranial fossa (61595-61598).
 
Don't Worry About the Point of Entry ... Yet

Although the initial access can become a factor in code selection, you should first narrow your code selection by the destination the surgeon wishes to reach, rather than the method he used to get there. This is because the surgeon can access any of the fossae via several entry points or approach techniques, says Richard D. Bucholz, MD, professor and associate director of the division of neurosurgery at St. Louis University in Missouri.

Example: The surgeon's op notes specify that he used an orbitocranial approach to access the anterior cranial fossa.

 If you focus first on the approach, you could mistakenly choose 61592 (Orbitocranial zygomatic approach to middle cranial fossa [cavernous sinus and carotid artery, clivus, basilar artery or petrous apex] including osteotomy of zygoma, craniotomy, extra- or intradural elevation of temporal lobe) as the correct code.

If you look more closely, however, you'll see that 61592 applies to the middle cranial fossa. In this case, you should narrow your code selection to the 61580-61586 category, which applies specifically to the anterior cranial fossa.2. Determine Intra- or Extradural

Next, determine whether the surgeon performs dissection intra- or extradurally. An intradural approach requires that the surgeon cut the dura, the tough elastic membrane that holds the brain in place, Bucholz says.

Tip: If the surgeon does not specify "intradural" or "extradural" in the operative report, you may look further in the documentation for evidence of a watertight closure (for instance, "The dura was repaired") following the eventual definitive procedure. If the surgeon repaired the dura, the dissection was intradural.

Example: The surgeon specifies approach to anterior cranial fossa with intradural dissection.

First, narrow your code selection by location (anterior fossa, 61580-61586).
 
Next, rule out all codes in this category that specify an extradural approach (because the surgeon, in this case, cut the dura), and you further narrow your code selection to 61583 (Craniofacial approach to anterior cranial fossa; intradural, including unilateral or bifrontal craniotomy, elevation or resection of frontal lobe, osteotomy of base of anterior cranial fossa) or 61586 (Bicoronal, transzygomatic and/or LeFort I osteotomy approach to anterior cranial fossa with or without internal fixation, without bone graft).
 
Not Every Code Will Specify Intra- or Extradural

 Some codes, such as 61586 or 61595 (Transtemporal approach to posterior cranial fossa, jugular foramen or midline skull base, including mastoidectomy, decompression of sigmoid sinus and/or facial nerve, with or without mobilization), do not specify intra or extradural, while others, such as 61592, may specify intra- or extradural.

Caution: You should not rule these codes out when narrowing your selection, no matter if the surgeon specifies that he cut the dura.

Why skull-base surgery? Surgeons perform skull- base surgery to remove a lesion - such as cancerous tissue, vascular malformation or aneurysm - from the undersurface of the brain. The skull base itself is a thick, complex structure on which the brain rests, and which separates the brain from the remainder of the head, face and neck. 

Skull-base surgery involves several steps, including the approach (61580-61598), a "definitive procedure" to remove or destroy the lesion (61600-61616 or, less frequently, 61680-61711 for intracranial aneurysms) and, occasionally, secondary closure or repair (61618-61619).

Because of the complexity and duration of skull-base surgery, surgeons of several specialties may work together or consecutively to approach the lesion, remove the lesion and close.

3. Find Out What the Surgeon Mobilized

Your final - and most difficult - task in choosing the appropriate skull-base approach code is to determine exactly which internal structures the surgeon exposed or mobilized. And, in this case, there's no substitute for surgeon/coder communication and cooperation.

Best strategy: If documentation isn't clear, ask. "The terminology [for skull-base approach codes] can be difficult," says Suzan Hvizdash, BSJ, CPC, physician education specialist for the department of surgery at UPMC Presbyterian-Shadyside in Pittsburgh.

A surgeon familiar with the CPT code descriptors may document his work so that you can simply pick out key terms and match a code to the procedure. But, more often, surgeons won't always use CPT terminology or reference the precise anatomic landmarks specified in the code descriptors. And, considering that the difference in reimbursement for the highest-paying approach code and the lowest-paying approach code is over $1,000, you shouldn't be afraid to ask the surgeon for guidance.

Example: The operative report specifies that the surgeon approached the anterior cranial fossa with extradural dissection. From this information, you narrow your code selection to 61580, 61581, 61582, 61584, 61585 or 61586. The op report further specifies incision along the nose and resection of the forehead, with approach via the anterior sinuses.

With the surgeon's guidance, you can determine that the op note describes a craniofacial approach with lateral rhinotomy ("... incision along the nose ..."), thereby narrowing the code selection further to 61580 and 61581.

Because the surgeon does not indicate upper-jaw (maxillectomy) resection or the removal of material from the area around the eye (orbital exenteration), you should select 61580 (Craniofacial approach to anterior cranial fossa; extradural, including lateral rhinotomy, ethmoidectomy, sphenoidectomy, without maxillectomy or orbital exenteration).