Neurosurgery Coding Alert

Hint: Code 61790 refers to the gasserion ganglion, and 61791 refers to the medullary tract.

When your neurosurgeon performs stereotactic radiosurgery, you must check the medical documentation for specific details such as the exact site of the stereotactic lesion and the number of lesions. You should also know the intent of the surgery to choose the appropriate CPT^® code for the procedure.

Read on to keep your stereotactic surgery claims in tip-top shape.

Identify Exact Site of Stereotactic Lesion

To choose the correct CPT^® code for the creation of a lesion by the stereotactic method, you must know the exact site of the lesion. Different sites correlate to different procedure codes.

Globus pallidus or thalamus: For example, for the creation of stereotactic lesions in the globus pallidus or thalamus, you should report code 61720 (Creation of lesion by stereotactic method, including burr hole(s) and localizing and recording techniques, single or multiple stages; globus pallidus or thalamus).

The globus pallidus regulates voluntary movements in the patient’s body.

On the other hand, the thalamus is a symmetrical near-midline structure in the brain that acts as a relay station for various sensory and motor signals to the higher centers in the brain. The thalamus also regulates sleep and alertness.

Brain structures anatomically located below cerebral cortex: When your neurosurgeon uses the stereotactic method to create a lesion on an area that is anatomically located below the patient’s cerebral cortex, but not the globus pallidus or thalamus, you should report code 61735 (Creation of lesion by stereotactic method, including burr hole(s) and localizing and recording techniques, single or multiple stages; subcortical structure(s) other than globus pallidus or thalamus). Brain structures that fall under this category include the hippocampus, amygdala, corpus callosum, and basal ganglia.

Codes 61720 and 61735 are inclusive of the burr holes your surgeon creates to facilitate the approach to the central structures, as well as the localization and recording techniques.

Caution: “It is important to note that all of the stand-alone stereotactic surgery codes by definition include the stereotactic 3-D guidance,” says Gregory Przybylski, MD, immediate past chairman of neuroscience and director of neurosurgery at the New Jersey Neuroscience Institute, JFK Medical Center in Edison, New Jersey. “Therefore, you should not report the add-on code for stereotactic navigation intradural procedure +61781 (Stereotactic computer-assisted (navigational) procedure; cranial, intradural (List separately in addition to code for primary procedure)). Parenthetical language is included in the CPT^® manual noting this preclusion.”

Pinpoint Different Intents of Stereotactic Surgery

When you read your neurosurgeon’s documentation, you must understand the intent of the stereotactic surgery. You will report different codes for different intents such as biopsy, implantation, and localization.

Stereotactic biopsy: If your neurosurgeon performs a stereotactic biopsy, you should report code 61750 (Stereotactic biopsy, aspiration, or excision, including burr hole(s), for intracranial lesion). However, if your surgeon uses imaging assistance such as computed tomography (CT) or magnetic resonance imaging (MRI) for the biopsy, you should report code 61751 (… with computed tomography and/or magnetic resonance guidance) instead.

Stereotactic implantation: When your neurosurgeon implants electrodes in the patient’s brain for mapping the location of seizures, you should report 61760 (Stereotactic implantation of depth electrodes into the cerebrum for long-term seizure monitoring).

Stereotactic localization: You should report 61770 (Stereotactic localization, including burr hole(s), with insertion of catheter(s) or probe(s) for placement of radiation source) when your neurosurgeon attempts stereotactic localization and places a probe or catheter to deliver radioactive seeds. Your neurosurgeon may work with a radiation oncologist who implants the seeds.

Know Anatomy to Choose Appropriate Code Between 61790 and 61791

The code descriptors for 61790 (Creation of lesion by stereotactic method, percutaneous, by neurolytic agent (eg, alcohol, thermal, electrical, radiofrequency); gasserian ganglion) and 61791 (... trigeminal medullary tract) are very similar. However, if you look carefully, you will see that these two codes actually point to different types of a patient’s anatomy.

Code 61790 refers to the gasserion ganglion, and code 61791 refers to the medullary tract. So, in the medical documentation, you must confirm the approach your neurosurgeon took to choose the correct code.

Coding example: The neurosurgeon diagnoses the patient with trigeminal neuralgia. The neurosurgeon uses a nerve destroying agent, which he percutaneously administers to make a lesion in the patient’s gasserion ganglion. The neurosurgeon uses the stereotactic method. You should report 61790 for the procedure since the surgeon’s documentation specifies the gasserian ganglion. You would report G50.0 (Trigeminal neuralgia) as the ICD-10-CM code on your claim.

Count Number of Lesions With Care

Two very important details you must check for in the stereotactic documentation are the number of lesions your neurosurgeon performed stereotactic radiosurgery on and whether the lesions were simple or complex.

Complex lesions include those that are adjacent (5 mm or less) to the optic nerve/optic chasm/optic tract or within the brain stem. Certain types of lesions are inherently considered complex. These include schwannomas, arterio-venous malformations, pituitary tumors, glomus tumors, pineal region tumors, and cavernous sinus/parasellar/petroclival tumors. Simple cranial lesions are less than 3.5 cm in maximum dimension that do not meet CPT^®’s definition of a complex lesion.

Coding example: According to the medical documentation, your neurosurgeon performed stereotactic radiosurgery on one simple cranial lesion using a gamma ray. You would report 61796 (Stereotactic radiosurgery [particle beam, gamma ray, or linear accelerator]; 1 simple cranial lesion) on your claim.

On the other hand, you would report 61798 (Stereotactic radiosurgery (particle beam, gamma ray, or linear accelerator); 1 complex cranial lesion) if your neurosurgeon had instead performed stereotactic radiosurgery on one complex cranial lesion.

Multiple lesions: If the neurosurgeon treats multiple lesions, you’ll add either +61797 (Stereotactic radiosurgery (particle beam, gamma ray, or linear accelerator); each additional cranial lesion, simple (List separately in addition to code for primary procedure)) or +61799 (Stereotactic radiosurgery (particle beam, gamma ray, or linear accelerator); each additional cranial lesion, complex (List separately in addition to code for primary procedure)) to your claim, based on whether the lesions are simple or complex. You can include either of these add-on codes for a maximum of five lesions treated during the session.