Neurosurgery Coding Alert

CPT includes 15 codes to describe surgeries for intracranial aneurysms, arterio-venous malformations or vascular disease (61680-61711) and in some cases skull base surgery codes (61580-61598) might apply. With so many choices, appropriate coding for these procedures can seem daunting. A careful reading of CPT can provide the necessary answers.

CPT Groups Codes by Type

CPT divides codes 61680-61711 into four categories, depending on the reason for surgery. Note that each of these procedures includes craniotomy, when appropriate.

The first category, 61680-61692, specifies surgery of intracranial arteriovenous malformation. In this case, arteries and veins are abnormally fused in a tumor-like mass, bypassing the arterial capillaries that normally provide nourishment to the surrounding tissue. The malformation may be supratentorial (i.e., above the tentorium cerebelli, or the upper part of the brain), infratentorial (the lower part of the brain), or dural that is, within the dura (the thick membrane covering the brain). According to Eric Sandham, CPC, compliance educator for Central California Faculty Medical Group, a group practice and training facility associated with the University of California at San Francisco in Fresno, each of these procedures may be simple or complex, as determined by accessibility and difficulty of repair.

Note: Neither CPT nor CPT Assistant offers objective criteria to judge a simple versus complex procedure. The surgeon must determine this based on experience and clinical expertise.

For example, using angiography, the surgeon determines the presence of an arterio-venous malformation within the left temporal lobe. This qualifies as a complex repair because of the depth of the mass and the delicacy of the surrounding structures, Sandham says. Use 61686 ( infratentorial, complex) to report the procedure.

Simple or Complex Aneurysm?

The second category of codes (61697-61703) covers repair of intracranial (within the skull) aneurysms. An aneurysm is a bulge or abnormal dilation caused when the walls of a blood vessel weaken. With the addition of 61697 (Surgery of complex intracranial aneurysm, intracranial approach; carotid circulation) and 61698 ( vertebrobasilar circulation) in CPT 2001, these repairs are classified as either simple or complex. According to CPT, a repair is complex if the aneurysm(s) is larger than 15 mm, involves calcification of the aneurysm neck (the constricted portion at the "base" of the aneurysm), incorporates normal vessels into the aneurysm neck, or requires temporary vessel occlusion, trapping or cardiopulmonary bypass to complete the repair. Therefore, to bill successfully for a complex repair, you must make sure that supporting documentation specifically notes one of the above conditions.

These repair codes are further differentiated according to the location of the aneurysm. The carotid circulation supplies blood to the anterior (front) and middle portions of the brain (via the carotid artery), while the vertebrobasilar circulation supplies the cerebellum and brain stem via vessels coming up the vertebrae. Code 61703 (Surgery of intracranial aneurysm, cervical approach by application of occluding clamp to cervical carotid artery [Selverstone-Crutchfield type]) describes a unique procedure that involves an approach through the neck to clamp the carotid artery. The clamp reduces blood pressure in the affected vessel, possibly enabling the aneurysm to collapse and reducing the chance of rupture. It also allows for vascular control when combined with craniectomy and intracranial approach, as in 61705 (Surgery of aneurysm, vascular malformation or carotid-cavernous fistula; by intracranial and cervical occlusion of carotid artery).

For example, Sandham says, the surgeon locates and resects a 14-mm aneurysm in the frontal portion of the skull. Report 61700 (Surgery of simple intracranial aneurysm, intracranial approach; carotid circulation). If the same aneurysm measured 17 mm, however, the correct code is 61697.

Note: In some cases, a procedure may be complicated or require more time than usual, but not meet the CPT definition of "complex." In these cases, report 61700 or 61702 (... vertebrobasilar circulation) with modifier -22 (Unusual procedural services) to indicate the additional difficulty of the procedures. Be sure to include a detailed operative report with the claim and request additional reimbursement to reflect the extra time and/or effort required.

On occasion, the surgeon may use an anterior (61580-61586), middle (61590-61592) or posterior (61595-61598) fossa approach to access the aneurysm, says Vallo Benjamin, MD, professor of neurosurgery at New York University. Although these codes are normally associated with skull base surgeries to remove brain tumors, they are appropriate in these circumstances, and unlike a craniotomy may be reported separately. If, for instance, an anterior (frontal) fossa approach was used in the above example, report 6158x or 6159x (depending on the exact approach) in addition to the code for the definitive aneurysm procedure (61600-61616), he says. For those payers that recognize modifier -51 (Multiple procedures), attach the modifier to the lesser-valued code.

Anastomosis Is Easy to Recognize

Code 61711 (Anastomosis, arterial, extracranial-intracranial [e.g., middle cerebral/cortical] arteries) describes the joining of arteries to bypass an aneurysm or other defect. The surgeon clamps, ligates and attaches the "feeder" artery to the receiving artery, which has been dissected from the surrounding tissue. This is required when blood flow to a critical artery must be restored after excision or ligation of aneurysm. Because the procedure described by this "category of one" is unique, it is unlikely to be confused with other codes in this portion of CPT.

Miscellaneous Techniques

The final category of codes (61705-61710) describes other techniques and/or approaches for repairing intracranial abnormalities, including carotid-cavernous fistulae (abnormal passages from the cavernous sinus to the carotid artery). Code 61705 (Surgery of aneurysm, vascular malformation or carotid-cavernous fistula; by intracranial and cervical occlusion of carotid artery) describes a combined approach through the neck and skull in which the surgeon interrupts blood flow to the abnormality in both directions. Report 61708 for use of intracranial electrothrombosis (a type of cautery) to obliterate the lesion.

Code 61710 describes surgery by intra-arterial embolization, injection procedure, or balloon catheter. In this procedure, the surgeon injects tiny beads, or uses a coiled or balloon catheter, to seal the neck of the aneurysm and prevent blood flow, allowing the aneurysm to collapse and heal. The approach is via craniotomy rather than by percutaneous catheter placement (which would be reported 61624, Transcatheter occlusion or embolization [e.g., for tumor destruction, to achieve hemostasis, to occlude a vascular malformation], percutaneous, any method; central nervous system [intracranial, spinal cord]).

Report Operating Microscope Separately

Use of the operating microscope during any of the above procedures may be reported separately with +69990 (Microsurgical techniques, requiring use of operating microscope [list separately in addition to code for primary procedure]). This is an add-on procedure, and should be paid at its full value (5.90 relative value units, or about $214 for Medicare). Do not append modifier -51 (Multiple procedures) to +69990. Although payers have varying guidelines for this code, you should expect payment for the operating microscope with 61304-61711.