Surgical coding for complex retina procedures can pose a formidable challenge. To help, the American Academy of Ophthalmology (AAO) and its practice management affiliate, the American Academy of Ophthalmic Executives (AAOE), have developed a 10-step process to guide practices and help ensure maximum reimbursement.

Here’s an example of how this 10-step process can be applied to a specific retina case, involving a 65-year-old male with type 2 diabetic who presents with diabetic macular edema in the left eye, treated with focal macular laser grid (CPT 67210) 1 month previously, and has proliferative diabetic retinopathy without edema in the right eye. A pars plana vitrectomy (PPV) is recommended for the right eye and performed with endolaser panretinal photocoagulation (PRP) and a membrane peel.

STEP 1: IDENTIFY ALL POSSIBLE CPT CODES AND REVIEW THEIR FULL CPT DESCRIPTORS

There are several possible codes to consider for vitrectomy surgeries:

• 67036: Vitrectomy, mechanical, pars plana approach.
• 67039: Vitrectomy, mechanical, pars plana approach; with focal endolaser photocoagulation.
• 67040: Vitrectomy, mechanical, pars plana approach; with endolaser panretinal photocoagulation.
• 67041: Vitrectomy, mechanical, pars plana approach; with removal of preretinal cellular membrane (macular pucker).
• 67042: Vitrectomy, mechanical, pars plana approach; with removal of internal limiting membrane of retina (for repair of MH, diabetic macular edema), includes, if performed, intraocular tamponade (air, gas, or silicone oil).
• 67043: Vitrectomy, mechanical, pars plana approach; with removal of subretinal membrane (choroidal neovascularization), includes, if performed, intraocular tamponade (air, gas, or silicone oil) and laser photocoagulation.

It is important to read the full CPT descriptors before selecting the code, as these descriptors provide crucial details about the procedures involved and the specific approach or devices used. Understanding these details is essential to accurately select the appropriate CPT code. After reviewing the operation report, the coder determines that 67040 and 67041 are the relevant codes for this case.

STEP 2: OBTAIN PRIOR AUTHORIZATION IF REQUIRED

The requirement for prior authorization may vary among payers and by procedure, so it is crucial to check their policies. Prior authorization helps ensure that a claim will not be denied for lack of approval.

In this case, prior authorization was required for the PPV PRP procedure. Any time there is uncertainty about which procedures will be performed, it is a good idea to receive prior authorization for the entire family of codes.

STEP 3: MEET THE PAYER’S DOCUMENTATION REQUIREMENTS

Payers may have specific documentation requirements for retinal surgery. It is important to review their guidelines and to document relevant information, such as the extent of the recommended surgery and any associated complications.

In the example case, the indications were documented in the clinic note to establish the medical necessity for the vitrectomy surgery, and the exact procedure was recorded in the operative report to help determine the appropriate CPT codes.

STEP 4: UNDERSTAND AND IDENTIFY GLOBAL PERIODS

If a surgical session occurs during the global period for a previous surgery, it is important to indicate whether it is unrelated to the initial procedure by appending the appropriate modifier. Other procedures may be related yet staged or considered lesser to greater.

As outlined in the scenario above, a major surgery (CPT 67210) was previously performed in the fellow (left) eye for diabetic macular edema. The subsequent surgery is within the 90-day global period for that surgery; therefore, the applicable modifiers will need to be appended to the surgical CPT code to ensure proper reimbursement (see Step 8).

STEP 5: ORDER CPT CODES BASED ON RELATIVE VALUE UNITS

When listing CPT codes for retinal surgeries, consider the relative value units (RVUs) assigned to each code. Codes with higher RVUs typically have higher reimbursement rates. When multiple procedures are performed during the same surgical session on the same eye, most payers pay 100% of the allowable for the primary procedure, listed first, and 50% for subsequent procedures. This information is also especially helpful when procedures are bundled (see Step 7).

Below are the RVUs for the relevant retinal detachment repair codes listed in order:

STEP 6: CONSIDER SITE OF SERVICE DIFFERENTIAL

Reimbursement for retinal surgeries may vary depending on the place where the surgery or procedure is performed. Different reimbursement rates may apply if the surgery is performed in a facility such as an ambulatory surgery center (ASC) or in an office setting. It’s necessary to be familiar with the specific policies of the Centers for Medicare and Medicaid Services (CMS) as well as the local Medicare Administrative Contractor (MAC) or commercial payer that has jurisdiction.

In the scenario above, there are no assigned RVUs for the office for the two procedures; payers expect them to be performed in the facility setting. The operation was performed in the ASC.

STEP 7: REVIEW NCCI EDITS

Be aware of National Correct Coding Initiative (NCCI) edits that bundle certain codes together for retinal surgery. The use of modifiers can unbundle some codes when it is appropriate to do so.

There are multiple bundling edits for all vitrectomy surgeries, including CPT 67040 bundled with CPT 67041. It would not be appropriate to bill both codes. Due to the vitrectomy and membrane peel described in the operative report, CPT 67041 is the appropriate code, based on the higher RVU.

STEP 8: APPEND APPROPRIATE MODIFIER(S)

The most common surgical modifiers not only have different definitions but impact reimbursement in different ways as well. The three most common surgical modifiers are:

• -58: Staged or related surgical procedures done during the postoperative period of the first procedure.
• -78: Unplanned return to OR/procedure room for related procedure by the same physician during the postoperative period.
• -79: Unrelated procedure or service by the same physician during the postoperative period.

Procedures with modifiers -58 and -79 are reimbursed at 100% of the allowable, while procedures with modifier -78 are reimbursed at 70% of the allowable. The reduction in reimbursement for modifier -78 is due to the related nature of the procedure to the initial surgery.

In this case, the procedure occurred during the global period for a prior surgery, which was performed in the fellow eye. Therefore, the appropriate modifier is modifier -79. Don’t forget to also indicate the laterality:

• -RT for right eye
• -LT for left eye
• -50 for both eyes

STEP 9: LINK THE CORRECT ICD-10 DIAGNOSIS CODES

Accurate coding requires linking the appropriate ICD-10 diagnosis code(s) to the corresponding CPT code for retinal surgeries. Be specific and avoid using unspecified codes to support medical necessity and facilitate proper reimbursement.

The diagnosis for the vitrectomy procedure is a crucial key factor in CPT selection, as outlined in the detailed diagnosis flow charts found in AAO’s 2023 Retina Coding: Complete Reference Guide.¹ For this example, the patient has proliferative diabetic retinopathy without edema in the right eye, E11.3591.

STEP 10: REVIEW, THEN SUBMIT THE CLAIM AND CONFIRM REIMBURSEMENT

To ensure proper payment, before the claim is submitted, review to ensure that the appropriate CPT codes are documented, modifiers applied, and ICD-10 diagnosis code linked.

For the example case, E11.3591 linked with CPT 67041 with modifiers -79 and -RT (anatomical modifiers are appended last). In Step 4, the coder confirmed that this surgery took place during the global period of an earlier surgery, and in step 8 the coder determined the need to use modifier -79 to indicate that this later procedure is unrelated to the initial one.

After submitting the claim for retinal surgeries, coders should carefully review the remittance advice to verify that proper payment has been made. Double-check the reimbursement percentage, especially in the case of bilateral procedures, to ensure accurate payment. Reimbursement should be 100% of the allowable with the use of modifier -79.

By following these 10 steps, coders can confidently navigate the reporting and reimbursement process for retinal surgery, maximizing the financial health of their practice. RP

REFERENCE

1. American Academy of Ophthalmic Executives. 2023 Retina Coding: Complete Reference Guide. American Academy of Ophthalmology; 2023.