Article

CODING & COMPLIANCE

Strabismus Surgical Coding In The ASC

How to handle coding for both pediatric and adult patient cases

This article focuses on coding for strabismus surgery that may involve either pediatric or adult patients. Sometimes, in a pediatric patient, surgery actually is a covered procedure by Medicare due to the patient’s insurance being Medicare as a result of the presence of other medical problems. The adult population also may likewise be covered. The following case scenarios follow Medicare guidelines.

THE CPT CODES

Basic codes. The following list of CPT codes consists of the primary ones used for strabismus coding; the add-on codes and their usage are described further on in the paper.

Please note that CPT format is such that when a code is a sub-code (such as 67312, 67314, and 67316), the parent code (67311) is capitalized at the beginning of the descriptor, whereas the sub-codes are not, but rather are indented. Technically, all of the parent descriptor up to the semicolon (;) is included as part of the sub-code descriptor. The newer terminology refers to the main code as the parent code and the sub-code as the child code.

The CPT descriptions are:

67311 Strabismus surgery recession or resection procedure; one horizontal muscle
67312     two horizontal muscles
67314     one vertical muscle (excluding superior oblique)
67316     two or more vertical muscles (excluding superior oblique)
67318 Strabismus surgery, any procedure, superior oblique muscle

CPT Primary Code Choices (67311 vs. 67312 and 67314 vs. 67316). The selection of the proper code in these two code sets remains confusing. Use the code 67311 or 67314, “one horizontal muscle” or “one vertical muscle.” When a single muscle is operated upon in either one eye or one muscle in each eye CPT code 67311 would be used again, along with the proper location modifier (RT or LT) for ASC coding (only physician coding may use modifier 50). Example: recession of right lateral rectus and left lateral rectus.

When more than one rectus muscle is operated on in the same eye, procedure code 67312 (two horizontal muscles, i.e., recession and resection in the same eye) or 67314 (two or more vertical muscles [excluding superior oblique]) should be used respectively, depending upon whether the horizontal acting or vertical acting muscles are operated upon. Example: recession of right lateral rectus and resection of right medial rectus.

If a recession or resection of a muscle is performed in each eye concurrently, such as a bilateral lateral rectus recession, the proper coding then would be 67311-RT combined with 67311-51-LT. Physician coding only would be 67311-50. Modifier 50 is reserved for other uses in an ASC — it is used with diagnostic test coding. Some insurers still use modifier 51, although it is not very common anymore.

Add-on codes. This information is provided for those who perform both ASC and physician coding.

These codes, designated in CPT by a + sign that prefaces the numerical digits, by definition are procedure codes that cannot be billed alone and must be coded with another CPT code that is not an add-on code. In the CPT book under strabismus coding, the instruction mandates using them in conjunction with CPT codes 67311 – 67334. If the add-on code is not added to another designated regular code and is used alone, it will not be paid. Therefore, another procedure with it must be billed, such as a recession or resection, in order to be paid. Currently, the main difference between ASC coverage and physician coverage for Medicare is that the add-on codes are packaged (N1 indicator) with the main code in ASC coding.

Medicare reimburses add-on codes at 100% of the allowable for physician coding; however, they are not reimbursed for ASC coding as they involve only physician work.

Add-on CPT procedure codes +67332 (Strabismus surgery on patient with scarring of extraocular muscles [e.g., prior ocular injury, strabismus, or retinal detachment surgery] or restrictive myopathy [e.g., dysthyroid ophthalmopathy]) and +67331 (Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles) should not be used if the previous surgery or medical condition applies to the fellow eye and not the eye being operated on. These codes are reimbursed for more difficulty encountered physically, and in an eye that has not been previously traumatized, either by injury or surgery, or have pre-existing conditions, such as thyroid ophthalmopathy, use of the codes generally would not apply.

The following codes are add-on codes:

+67320 Transposition procedure (e.g., for paretic extraocular muscle), any extraocular muscle (specify)
+67331 Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles
+67332 Strabismus surgery on patient with scarring of extraocular muscles (e.g., prior ocular injury, strabismus, or retina detachment surgery or restrictive myopathy (e.g., dysthyroid ophthalmopathy)
+67334 Strabismus surgery by posterior fixation suture technique, with or without muscle recession
+67335 Placement of adjustable suture(s) during strabismus surgery, including postoperative adjustment of suture(s)
+67340 Strabismus surgery involving exploration and/or repair of detached extraocular muscle(s)

Transposition codes. CPT procedure code +67320 is only to be used for transposition of muscles for paretic muscles. It is an add-on code, thus, a regular surgery code must be used with it. Raising or lowering the insertions for correction of an A or V pattern when the primary procedure is a recession or resection for correction of a horizontal deviation, is incidental to the main procedure and should not be coded separately.

Adjustable sutures. Procedure code +67335 is used for placement of adjustable suture(s). Although there may be instances when multiple adjustable sutures are placed on the same side, physicians can only bill the add-on code once for each side.

MODIFIERS

Please note: ASC Modifier information for ASCs is included in the column “5 Top Ophthalmic Surgery Coding Errors in ASCs” in the May 2019 issue of The Ophthalmic ASC.

DIFFICULT CASE SCENARIOS IN ASC CODING

CASE 1. Patient is a 66-year-old female with a history of long standing esotropia. The patient had previous surgery that consisted of left lateral rectus muscle resection and left medial rectus muscle recession. A consecutive exotropia was present. Current surgery consisted of: (1) recession of both the left and right lateral rectus muscles (RLR, LLR); (2) placement of adjustable sutures on the right side. Code all procedure(s).

DIAGNOSES: 1) H50.15 Alternating Exotropia
                       2) Z98.890 Personal History Of Surgery Not Elsewhere Classified
Surgery: Diagnosis Procedure Code(s) Modifier(s)
1) 1, 2 67311 Recession RLR -RT
2) 1, 2 67311 Recession LLR -LT
NOTE: For Physician Coding CPT, add-on codes 67332 and 67335 also would be used.

CASE 2. Patient had thyroid ophthalmopathy with restriction of extraocular movement. Extraocular muscle surgery consisted of: (1) recession of right lateral rectus muscle; (2) recession of left lateral rectus muscle; (3) freeing of bilateral scar tissue from previous extraocular muscle surgery. Code all procedure(s).

DIAGNOSES: 1) H50.18 Alternating exotropia with other noncomitancies
                       2) H50.89 Other specified strabismus
                       3) Z98.890 Personal history of surgery not elsewhere classified
Surgery: Diagnosis Procedure Code(s) Modifier(s)
1) 1, 2, 3 67311 Recession left lateral rectus muscle -LT
2) 1, 2, 3 67311 Recession right lateral rectus muscle -RT
NOTES:
1. 2019 ICD-10-CM uses the word comitant. Concomitant is another word used with the same meaning.
2. For Physician Coding CPT, add-on code 67332 also would be used.

CASE 3. Patient was an 18-year-old young man who had previously undergone bilateral inferior oblique myectomies and bilateral medial rectus recessions at age 2 years. A subsequent right medial rectus recession was then performed 2 years prior to the current surgery. He then developed a consecutive exotropia. Current surgery consisted of: (1) right medial rectus resection with advancement of the muscle to its original insertion; (2) right lateral rectus recession; (3) placement of an adjustable suture on right lateral rectus. Code all procedure(s).

DIAGNOSES: 1) Monocular exotropia, right eye
                       2) Z98.890 Personal history of surgery not elsewhere classified
Surgery: Diagnosis Procedure Code(s) Modifier(s)
1) 1, 2 67312 Strabismus surgery, recession or resection procedure; two horizontal muscles -RT
NOTE: For Physician Coding CPT add-on codes 67332 and 67335 also would be used.

CASE 4. Patient sustained blunt head trauma in a motor vehicle accident with a resulting left superior oblique palsy with cyclotropia and torsional diplopia. Surgery consisted of: (1) dividing the left superior oblique tendon into an anterior and posterior portion and suturing the anterior portion of the superior oblique tendon to the superior border of the left lateral rectus muscle. (2) placement of an adjustable suture. Code all procedure(s).

DIAGNOSES: 1) H49.12 Fourth (trochlear) nerve palsy, left eye
                       2) H50.412 cyclotropia, left eye
                       3) H53.2 Diplopia
Surgery: Diagnosis Procedure Code(s) Modifier(s)
1) 1, 2, 3 67318 Advancement and division of anterior portion of superior oblique tendon -LT
NOTE: For Physician Coding CPT add-on codes 67332 and 67335 also would be used.

CONCLUSION

Currently, the main difference between ASC coverage and physician coverage for Medicare is that the add-on codes are not covered in ASC coding for Medicare.

It is often difficult to perform strabismus surgical coding without some basic clinical background in the subject. Perhaps an orthoptist, local ophthalmic technician society, or pediatric ophthalmologist would be willing to formulate a course for coders in your area.

Coders and physicians may find strabismus coding is more complicated than other ophthalmic subspecialties, and there is less information available. The more clinical background one can obtain, the clearer — and easier —strabismus coding will become. I wish you well! ■

CPT codes copyrighted 2018 by the American Medical Association