Minimally invasive glaucoma surgery (MIGS) has grown rapidly due in part to its improved safety profile when compared to traditional incisional glaucoma surgery such as trabeculectomy.¹ However, a variety of complications can occur with MIGS (Sidebar).

In most cases, medical treatment for these complications suffices; however, for a small percentage of cases, another surgery is required. What are the Medicare rules for reimbursement to treat complications and adverse events?

Conceptual Framework

Billing for the treatment of complications starts with answers to these questions:

1. Treatment: Did it require medications, minor procedure, or major surgery?
2. Timing: Was it during or after the postoperative period?
3. Place of service: Was it performed in-office, in a minor procedure room, or in an operating room?
4. Physician: Did the original surgeon or another physician provide the treatment?

Possible therapeutic remedies are listed along with applicable CPT codes in Table 1.

In the early 1990s, when Medicare established the global surgery package concept, it defined elements of the package for major surgery and other items and services as not part of the package.² Included in the global surgery package for major surgery are: care for complications that can be handled in-office, intraoperative services and supplies, 90 days of postoperative care that is related to the surgery, anesthesia that is administered by the surgeon, incidental services and supplies, and care by another physician within the same group practice. The Medicare Claims Processing Manual states, “When different physicians in a group practice participate in the patient’s care, the group bills for the entire global package if the physicians reassign benefits to the group. The physician who performs the surgery is shown as the performing physician.”³

The Medicare regulations excluded an exam to identify the need for surgery (modifier 57), most diagnostic tests within the global surgery period, care by another physician outside of the surgeon’s group, unrelated care such as for the fellow eye (modifiers 24 and 79), prosthetic devices, and some supplies such as injected medications, complications involving a reoperation (modifiers 58 and 78), and staged procedures (modifier 58).² A staged procedure is any operation undertaken in 2 or more separate parts, with a lull between the 2 stages to facilitate tissue healing or clearance of infection. A staged surgery may significantly increase the operation’s success rate, reducing postoperative complications. For example, a shunt procedure may be staged. In the first stage, the plate is attached to the globe and the tube is left in the subconjunctival space without entering the eye. Four to 6 weeks later, after a capsule has formed around the implant, the conjunctiva is opened and the tube is inserted into the anterior chamber to complete the procedure.⁴

Re-operations may be in-office or require a return to the operating room. In the Medicare regulations, an operating room is defined as, “a place of service specifically equipped and staffed for the sole purpose of performing procedures. The term includes a cardiac catheterization suite, a laser suite, and an endoscopy suite. It does not include a patient’s room, a minor treatment room, a recovery room, an intensive care unit.”⁵ A minor procedure such as paracentesis or intraocular injection that does not require a return to the operating room is not separately reimbursed, whereas a major procedure such as explantation of a wayward stent is reimbursed for the surgeon and the facility. Below are a few case examples to illustrate these rules.

Elevated Intraocular Pressure

Following a combined cataract and MIGS procedure, the patient returns to the clinic for postop care. The IOP initially dropped to 9 mmHg and then rose to 30 mmHg over a few weeks. The surgeon took the patient back to the operating room to reposition the stent in the eye 10 weeks after the initial procedure. This reoperation qualifies for separate reimbursement. Modifier 78 applies.

Hypotony

Following a MIGS procedure, the patient returns to the clinic for postoperative care. The surgeon finds IOP of 3 mmHg due to hypotony. Viscoelastic is injected in the eye in a minor procedure room. Topical medications are prescribed. This minor procedure does not qualify for separate reimbursement. The supply of viscoelastic is eligible for reimbursement.

Retained Viscoelastic

Following a combined cataract and MIGS procedure, the patient returns to the clinic for postoperative care. The surgeon finds IOP of 40 mmHg due to retained viscoelastic. Paracentesis is performed at the slit lamp. Topical medications are prescribed. This minor procedure does not qualify for separate reimbursement.

Explant

Several stents are implanted in the trabecular meshwork. At the first postop exam, the surgeon observes 1 stent floating freely in the anterior chamber and the patient is experiencing an adverse event. The surgeon takes the patient back to the OR to remove the wayward stent. This reoperation qualifies for separate reimbursement. Modifier 58 applies.

Conclusion

Billing, coding, and reimbursement for the treatment of complications of MIGS depend on many factors. Familiarity with CMS regulations can help determine when you are eligible for separate reimbursement. GP

Kevin J. Corcoran, COE, CPC, CPMA, FNAO, is president of Corcoran Consulting Group in San Bernardino, California.

Brandy H. Sperry, COMT, COE, OCS is an associate consultant with Corcoran Consulting Group.

References

1. Yook E, Vinod K, Panarelli JF. Complications of micro-invasive glaucoma surgery. Curr Opin Ophthalmol. 2018;29(2):147-154. doi:10.1097/ICU.0000000000000457
2. MCPM Chapter 12 §40.1A. Accessed October 11, 2022. https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c12.pdf
3. MCPM Chapter 12 §40.2A2. Accessed October 11, 2022. https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c12.pdf
4. AAO EyeWiki. Ahmed ClearPath Glaucoma Drainage Device. Accessed October 11, 2022. https://eyewiki.aao.org/Ahmed_ClearPath_Glaucoma_Drainage_Device
5. MCPM, Chapter 12, §40.1B. Accessed October 11, 2022. https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c12.pdf