Mastering the rules of strabismus coding

Case studies illustrate the complexities of modifiers, code bundles and add-on codes.

Issue: December 1, 2005

ByRiva Lee Asbell

Strabismus coding runs the gamut from simple to complex. There are numerous rules that need to be mastered in order to code correctly and optimize reimbursement. This review provides some of the essential tools and then proceeds to case studies.

My articles apply to Medicare, and this one is no exception; however, there may be variations according to insurer. Nevertheless, all insurers usually adhere to CPT regulations and, for the most part, all insurers run a parallel course.

Modifiers

Most practices have competent billing personnel who are capable of attaching appropriate modifiers when indicated, such as those for location, multiple surgeries and bilateral procedures. However, mastery of modifiers 58, 78 and 79 by the physician is merited.

Modifier 58 — Staged or related procedure or service by the same physician

Modifier 58 has three distinct uses: procedures planned prospectively at the time of the original procedure (staged); procedures that are more extensive than the original procedure; and procedures performed for therapy after a diagnostic procedure.

Modifier 58 pays at 100% of the allowable, and a new global period starts. For Medicare, the global period is either 0, 10 or 90 days. Procedures are classified as minor or major based solely on the global period, with those procedures having a global period of 0 or 10 days being minor and those having a global period of 90 days being major. Complexity of the procedure is irrelevant in determining the global period; it is fixed by Medicare, and different carriers have different global periods.

Strabismus example: An adult strabismus patient with longstanding horizontal and vertical deviation. The surgeon plans to perform the horizontal muscle surgery first and within the global period to perform the vertical muscle surgery.

Modifier 78 — Return to operating room for a related procedure during the global period

Modifier 78 is defined as the related procedure and is to be used when a procedure performed in the global period is related to the original procedure. Be careful — Medicare’s concept of related is not necessarily a physician’s medical concept of related. Complications are generally considered related.

Medicare’s definition of an operating room includes a laser suite an endoscopy suite, and an operating room in a hospital or ambulatory surgery center. The physician is paid at the intraoperative value of the procedure, which for most cases is 70% of the allowable. No new global period starts.

Strabismus example: Surgery is performed for the correction of esotropia. Patient develops consecutive exotropia, and remedial surgery is performed during the global period.

Modifier 79 — Unrelated procedure or service by the same physician during the postoperative period

Modifier 79 is defined as the unrelated modifier and is to be used for services and procedures that are not related to the original procedure. They can be unrelated by virtue of a different location or a different diagnosis. Payment is made at 100% of allowable, and a new global period starts.

Strabismus example: Patient develops torsional diplopia during the global period of a macular translocation surgery. The strabismus surgery, in Medicare terms, would be considered unrelated because it was not what the original surgery was performed for.

National Correct Coding Initiative (NCCI)

The NCCI lists sets of code pairs, defined as either comprehensive or mutually exclusive, that cannot be used together for various reasons. Other insurers may use the infamous “Black Box” edits, which include most of the NCCI edits plus others.

Comprehensive bundles. Column 1 (formerly comprehensive) code sets are defined as code set pairs that include all related services, most of which are listed in column 2. When coding, one should not fragment one service into component parts in order to maximize reimbursement. Because this was being done in excess (ie, fraudulently), the NCCI was developed.

Mutually exclusive bundles. Mutually exclusive codes are those codes that cannot reasonably be done in the same session. This is based on the CPT definition of the medical impossibility or improbability that the procedures could be performed at the same session. Caution — the lowest paying code (code with lowest relative value units) is paid.

Here are some important edits:

CPT code 67343 (Release of extensive scar tissue without detaching extraocular muscle) is bundled with all the strabismus codes.

CPT code 67331 (Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles) is bundled mutually exclusively with CPT code 67332 (Strabismus surgery on patient with scarring of extraocular muscles (eg, prior ocular injury, strabismus or retinal detachment surgery) or restrictive myopathy (eg, dysthyroid ophthalmopathy)).

CPT code 67500 (Retrobulbar injection; medication) is bundled with all the strabismus codes (excluding add-on codes, to which there is no application).

Add-on codes

Add-on codes are special codes describing procedures or services that are performed in addition to the primary procedure. The add-on concept applies only to add-on procedures or services performed by the same physician. These codes may provide clarification of specific circumstances (see Table).

Here are some characteristics of add-on codes:

They do not stand alone – in other words, you cannot bill them alone. At the end of each add-on code there is the instruction “Use 673XX in conjunction with 67311-67334”.

They do not take modifier 51.

Payment is at 100% of the allowable for that code and not at 50%, which is customary for multiple surgery payment rules.

Next column:

See the January 1, 2006, issue for information on retina/vitreous medicare coding for pharmacologic therapies.

For Your Information:
Riva Lee Asbell can be reached at www.rivaleeasbell.com.

CPT codes, copyright 2005, American Medical Association.