CMS MIG Changes: Updates for ASC Medical Coders

CMS MIG Changes: Updates for ASC Medical Coders

By Paul Cadorette, CPC, COC, CPC-P, COSC, CASCC, Director, Training and Education, Coding, nimble solutions

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Effective November 17, 2024, significant updates to Local Coverage Determination (LCD) policies have reshaped the landscape for Micro-Invasive Glaucoma Surgery (MIGs). While five Medicare Administrative Contractors (MACs) have revised their policies, First Coast Service Options and Novitas have not made similar changes. Coders must carefully review the LCD information specific to their states to ensure compliance and accuracy.

Read about the LCD policy changes and new coding distinctions for Canaloplasty and Goniotomy. I've outlined the most critical changes and their implications for coding accuracy and potential impacts on revenue cycle performance.

Key Changes in MIGs LCD Policies

1. Cataract Extraction with IOL Placement and Single MIGs Procedure: Physicians can perform cataract extraction with insertion of an intraocular lens (IOL) and a single MIGs procedure, which, in the case of CPT codes 66989 and 66991, involves the placement of an aqueous drainage device without an external reservoir utilizing an internal approach. However, if a canaloplasty or goniotomy is also performed, it would constitute a second MIGs procedure, potentially resulting in the denial of the entire claim.
2. Limitations on Aqueous Drainage Devices: Revised LCDs now allow the placement of up to three aqueous drainage devices per eye. Conversely, the two MACs that did not update their policies restrict coverage to one or two devices. Placement of three devices would exceed policy limitations in these jurisdictions, leading to claim denials.
3. Refined Definitions for Canaloplasty and Goniotomy:
   • Canaloplasty: Defined as "Cannulation of Schlemm's canal with a catheter or stent with either an internal or external approach for at least three clock hours with an injection of viscoelastic while removing the stent to dilate the canal or via three or more punctures of the trabecular meshwork spanning at least three clock hours (90 degrees) to dilate Schlemm's canal."
     • Two Techniques: The first involves cannulating Schlemm's canal for 180 degrees and injecting viscoelastic material while withdrawing the cannula. This process is then repeated in the opposite direction. The second involves puncturing the trabecular meshwork three or more times and injecting viscoelastic material to achieve sufficient canal dilation over 90 degrees (three clock hours).
     • Note: Some carriers may require 360-degree dilation for reporting a canaloplasty, underscoring the importance of verifying specific carrier policies.
   • Goniotomy: Defined as "Incision and/or excision with blade or surgical instrument for at least 3 clock hours of trabecular meshwork to create an opening into Schlemm's canal from the anterior chamber, via an internal approach."
     • Procedures involving devices that perform microgoniotomies (e.g., trephination of trabecular meshwork) do not meet this definition and should be reported with unlisted CPT 66999.

Key Considerations for Compliance

1. Continuous Education: Coders should remain informed about carrier-specific policies to avoid compliance pitfalls, especially for nuanced procedures such as canaloplasty and goniotomy.
2. Policy-Specific Details: For example, while some policies accept the placement of three aqueous drainage devices, others may restrict coverage to fewer devices. Familiarity with these differences is crucial to ensure accurate coding and revenue capture.

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