Though aqueous shunts have been a staple of glaucoma therapy for decades, we still run into questions from our clients. Let’s review the more significant ones.

Q. Does Medicare cover implantation of aqueous shunts?

A. Yes, for medically necessary indications. A glaucoma shunt is intended to reduce IOP and to control the progression of disease in severe and complex cases where medical and more common surgical treatments have not been successful. These cases sometimes have complicating conditions that must be taken into account, as well.

Q. What CPT codes describe this procedure?

A. There are two codes that may pertain, depending on whether a patch graft is used:

• 66179. Aqueous shunt to extraocular equatorial plate reservoir, external approach; without graft
• 66180. Aqueous shunt to extraocular equatorial plate reservoir, external approach; with graft

Q. What is the surgeon’s reimbursement for these codes?

A. The final 2021 Medicare Physician Fee Schedule (MPFS) has not been released at the time of this writing, but the proposed rule allows $1,006 for 66179 and $1,060 for 66180. The specific allowed amount is adjusted by local wage indices. Other payers set their own rates, which may vary considerably from Medicare amounts.

Q. Does Medicare allow a facility fee in an ASC?

A. Yes. The expected 2021 national ASC allowable amount for 66179 is $1,860 and for 66180 is $2,525. Local rates vary.

Q. How is a hospital outpatient department (HOPD) paid for these procedures?

A. Under OPPS, both 66179 and 66180 are assigned to the Ambulatory Payment Classification (APC) 5492; the 2021 proposed national allowed amount is $3,958.

Q. Is there separate payment for the implant?

A. No. The implanted device is supplied by the facility and is included in the facility fee for both ASC and HOPD.

Q. If a patch graft is used, are there any coding changes depending on the type of graft material?

A. No, other than the use of the proper code (66180 instead of 66179). The surgeon may choose from donor cornea or scleral tissue, amniotic membrane tissue or another suitable material. The graft material used does not affect coding or alter the reimbursement. A graft procedure is not paid separately.

Q. If a revision procedure is needed, is it covered?

A. Yes; when medically necessary, Medicare will pay for revision of a previously implanted aqueous shunt. Again, two specific codes are available for use. Both are based on whether a graft is used at the revision; whether a graft was used at the initial implantation doesn’t change the coding.

• 66184. Revision of aqueous shunt to extraocular equatorial plate reservoir, external approach; without graft
• 66185. Revision of aqueous shunt to extraocular equatorial plate reservoir, external approach; with graft

In 2021, the proposed national MPFS allowed amount is $737 for 66184 and $791 for 66185.

The procedures are included in APC 5491. The proposed HOPD allowable is $2,109; for an ASC, it is $1,041.

Q. Do any bundles affect these codes?

A. Yes. A number of ophthalmic procedures may not be billed concurrently with any of these codes, particularly other glaucoma procedures, including MIGS. The codes are mutually exclusive with one another. Established patient eye exam codes are also bundled with these codes.

For a complete listing of National Correct Coding Initiative (NCCI) edits, see the CMS website (https://go.cms.gov/3owfxHB ) or ask us about a subscription to Corcoran’s Medicare Quick Reference Guide. OM

Suzanne L. Corcoran is vice president of Corcoran Consulting Group. She can be reached at (800) 399-6565 or www.corcoranccg.com .