Radiology Coding Alert

Lesion count supersedes session counts in radiosurgery.

Radiosurgery coding is complex because your physician may treat one lesion in multiple sessions and multiple lesions in a single session. Review these seven basic questions that help you clarify your approach to radiosurgery coding.

Options in stereotactic radiosurgery codes are the following:

• 61796 -- Stereotactic radiosurgery (particle beam, gamma ray, or linear accelerator); 1 simple cranial lesion
• +61797 -- …each additional cranial lesion, simple (List separately in addition to code for primary procedure)
• 61798 -- …1 complex cranial lesion
• +61799 -- …each additional cranial lesion, complex (List separately in addition to code for primary procedure)
• 63620 -- Stereotactic radiosurgery (particle beam, gamma ray, or linear accelerator); 1 spinal lesion 
• +63621-- …each additional spinal lesion (List separately in addition to code for primary procedure)

Question 1: What is a complex lesion?

You report codes for complex lesions when your physician treats a lesion that:

• Is more than 3.5 cm in size,
• Consists of a certain pathology including arteriovenous malformation, schwannoma, pituitary adenoma, and pineal and glomus tumors,
• Is located in the cavernous sinus, parasellar, or petroclival regions, or
• Is proximal to critical structures such as the optic nerve or brainstem.

Question 2: What is the best approach to select a radiosurgery code?

When submitting codes for stereotactic radiosurgery, you keep a count of lesions that your physician treats. Code 61796 describes stereotactic radiosurgery of a single lesion, with one or more isocenters. The procedure may be done in a single fraction or over several sessions.

61796 applies to one simple lesion: You may read that your physician performed stereotactic radiosurgery on five simple lesions. In this case, you should not report five units of 61796. Consider submitting the add-on code +61797 for additional lesions, to a maximum of five total lesions. 

Note: You may not report multiple units of 61796 for multiple treatments on the same lesion, as the code includes the course of treatment, even if performed over several sessions. Instead, you may report one unit of 61797 for each separate lesion the physician treats, up to five total lesions. “CPT^® 61796 MUE is 1 and 61797 MUE is 4, same as CPT^® 61798 MUE is 1 and 61799 MUE is 4.  Giving that total of five lesions,” says Dianne Nakvosas, ACS-RAD, Compubill, Inc., IL.

Do not append modifier 59 for multiple lesions: When reporting multiple lesions, you look at the more specific codes for additional lesions. Use the add-on codes to denote additional simple cranial (61797), complex cranial (61799), and spinal (63621) lesions. As with other add-on codes, you do not need modifier 59.

Question 3: What if the physician treats more than five lesions?

AMA instructions state directly that you should not report treatment of more than five lesions. Therefore, even if the physician treats more than five lesions per date of service, you should limit yourself to no more than one primary code and four units of the add-on code. In other words, you do not report +61797 more than four times for an entire course of treatment, regardless of the numbers your physician treats.

Question 4: Why is five a cut off in radiosurgery?

A target of five is justified based on the current available evidence and expertise in radiosurgery. Beyond the defined target, the radiation field begins to resemble whole brain radiation rather than targeted radiosurgery. Stereotactic radiosurgery is precise high power energy on a small area (tumor, lesion), where the radiologist provides imaging guidance and supervision,” Nakvosas says.

Question 5: What is the significance of number of sessions in radiosurgery procedures and how does it impact coding?

When you report stereotactic surgery codes, you do not count on the number of sessions the physician requires to treat the lesions. The codes’ descriptors reflect the work over the course of treatment.

Your physician may choose to treat the same lesion during more than one session over the course of treatment. This is because your physician tries to safely radiate the lesion. You’ll see this referred to as fractionated treatments. “Fractionated treatments are usually one to five fractions over 1-2 weeks.  This is unlike conventional radiation which is daily, i.e. 5 days a week over 5-9 weeks,” Nakvosas says.

In this case, you should report 63620 only once for the first lesion treated, regardless of how many sessions the physician requires to treat the lesion.

Example: You may read that your physician used the gamma knife to target and destroy four spinal lesions. During an initial session, your physician may have treated two of the lesions completely and planned to fractionate treatment for two others. During a later session, your physician may again treat the remaining two lesions. Because your physician treated four separate lesions, you do not report 63620 (Stereotactic radiosurgery [particle beam, gamma ray, or linear accelerator]; 1 spinal lesion) x 4. “The Gamma Knife surgery involves no knife but rather the precision of the radiation delivered,” Nakvosas says.

Note: For spinal radiosurgery, CPT^® limits the number of additional lesions to two.

Question 6: What are the modifiers that can be used in radiosurgery codes?

Complex lesions do not imply additional use of modifier 22 (Increased procedural services). Your physician may be treating a lesion with multiple isocenters and/or that requires more complex targeting. CPT^® offers two different sets of codes, distinguishing simple from complex. You should use the complex cranial lesion code 61798 and +61799.

You would be wrong to report 61796 and append modifier 22 for complex lesion radiosurgery. Therefore, you shouldn’t reach for modifier 22 automatically when your physician’s documentation describes a complicated surgery. Apply modifier 22 only in those truly difficult and unusual circumstances that call for significant additional physician work and/or time that is not accounted for in the complex lesion descriptor.

Do not append modifier 59 for multiple lesions. When reporting multiple lesions, you look at the more specific codes for additional lesions. Use the add-on codes to denote additional simple cranial (61797), complex cranial (61799), and spinal (63621) lesions. As with other add-on codes, you do not need modifier 59.

If the physician discovers and treats a new lesion during the 90-day global period of the original stereotactic radiosurgery treatment, you should once again report 61796, but you would append modifier 58 (Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period) to show that this is a related, “more extensive” procedure.

Question 7: Is there a code for the frame-based system?

 If your physician uses a frame-based system, then you should apply another add-on code, +61800 (Application of stereotactic head frame for stereotactic radiosurgery [List separately in addition to code for primary procedure]) with 61796.