Ophthalmology and Optometry Coding Alert

How many muscles?  Horizontal or vertical?  The answers will keep your coding from getting crossed up

When an ophthalmologist performs strabismus surgery, it can involve any combination of 12 extraocular muscles. Incorrectly identifying just one of those muscles can lead you to the wrong code--and take more than $700 in reimbursement out of your practice's pocket.

But you don't need a PhD in anatomy to keep the eye mucles straight--all you need are the answers to these frequently asked questions to guide you toward choosing the right code to report your practice's strabismus treatments.

Question 1: How do I pick the appropriate strabismus surgery code based on the ophthalmologist's operative notes?

Answer: A little knowledge of the eye's anatomy goes a long way toward understanding strabismus-correcting procedures. Which codes you report depends on the extraocular muscle or muscles the ophthalmologist operated on.

Each eye has six extraocular muscles that control the eyeball's movement and determine the eyeball's alignment, or in some cases misalignment. Strabismus surgery is the correction of misalignment with the potential restoration of quality visual activity.

CPT distinguishes the strabismus surgery codes (67311-67318) by whether the procedure involves horizontal, vertical or superior oblique muscles, says Nancy Cockrell, CPC, insurance manager at Jackson Eye Associates in Jackson, Miss.

Horizontal: The eye's two horizontal muscles are the lateral rectus (LR) and medial rectus (MR) muscles. (The MR muscle in either eye is the one closest to the nose.) If the ophthalmologist recesses (weakens) or resects (strengthens) these muscles, report 67311 (Strabismus surgery, recession or resection procedure; one horizontal muscle) or 67312 (... two horizontal muscles), depending on the number of muscles.

Vertical: The vertical muscles are the superior rectus (SR) and inferior rectus (IR) muscles. (The SR muscle is closer to the top of the head.) If the ophthalmologist recesses or resects these muscles, report 67314 (...one vertical muscle [excluding superior oblique]) or 67316 (...two or more vertical muscles [excluding superior oblique]), depending on the number of muscles.

CPT also considers the inferior oblique (IO) muscle--but not the superior oblique (SO) muscle--a vertical muscle, says Christina Hollis, OCS, coder and surgery scheduler at Pediatric Ophthalmology Associates in Columbus, Ohio. Report 67314-67316 for recession or resection of the inferior oblique muscles.

Superior oblique: The SO muscle wraps around the top of the eyeball. Report 67318 (Strabismus surgery, any procedure, superior oblique muscle) for procedures performed on the SO muscle.

Question 2: Is strabismus surgery considered unilateral or bilateral?

Answer: The strabismus surgery codes (67311-67318) are inherently unilateral, describing procedures performed in one eye only. When codes mention more than one muscle (e.g., 67312, Strabismus surgery, recession or resection procedures; two horizontal muscles), CPT is implying that those muscles are in the same eye, Cockrell says. Therefore, if the surgeon resects one horizontal muscle in each eye, 67312 would not be correct. In that scenario, report 67311 (Strabismus surgery, recession or resection procedure; one horizontal muscle) bilaterally--most Medicare carriers want you to report the entire session on one line with modifier 50 (Bilateral procedure) and a "1" in the units field.

Medicare usually reimburses for 67311-50 based on 150 percent of the fee schedule amount for a single code. The 2006 fee schedule assigns 13.05 national unadjusted facility RVUs to 67311, which yields $472.11 when multiplied by the 36.1770 conversion factor. Code 67311-50 should reimburse $708.16, 150 percent of $472.11.

However, if the ophthalmologist recesses both the lateral rectus and medial rectus muscles of the left eye, you are not coding a bilateral procedure. This is a case in which 67312 would be appropriate. CMS would reimburse this at $569.06 (15.73 facility RVUs x 36.177, unadjusted for geographic location).

Hidden trap: The same rules apply to the vertical muscle codes, although the wording "two or more vertical muscles" in the definition of 67316 may lead you to think it's a bilateral code, since there are technically only two vertical muscles in one eye.

Remember, however, that CPT considers the inferior oblique muscle a vertical muscle for coding purposes, Hollis says--so the ophthalmologist could resect "two or more vertical muscles" in one eye if he operates on the SR, IR and IO muscles.

Watch out: The bilateral status is different for the six strabismus add-on codes. Last year, CMS changed their bilateral status from "1" to "0," meaning that the 150 percent payment adjustment for bilateral procedures no longer applies. You can no longer use modifiers LT/RT (Left side/Right side) or 50 with these codes:

• +67320--Transposition procedure (e.g., for paretic  extraocular muscle), any extraocular muscle (specify) (list separately in addition to code for primary procedure)

• +67331--Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles (list separately in addition to code for primary procedure)

• +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) (list separately in addition to code for primary procedure)

• +67334--Strabismus surgery by posterior fixation suture technique, with or without muscle recession (list separately in addition to code for primary procedure)

• +67335--Placement of adjustable suture(s) during  strabismus surgery, including postoperative adjustment(s) of suture(s) (list separately in addition to code for primary procedure)

• +67340--Strabismus surgery involving exploration  and/or repair of detached extraocular muscle(s) (list
separately in addition to code for primary procedure).

For more information, see "Reporting Adjustable Sutures Bilaterally? Not Anymore" in the October 2005 Ophthalmology Coding Alert.

Question 3: Are MRIs covered for strabismus diagnoses?

Answer: Carriers' policies vary on coverage for magnetic resonance imaging (MRI). Most Medicare carriers are of the opinion that not all patients with the diagnosis of strabismus (378.50-378.63) require an MRI. Paralytic strabismus (378.50-378.56), mechanical strabismus (378.60-378.63), and Duane's syndrome (378.71) are three conditions by which many payers cover MRIs.

Pay close attention to the MRI code definitions when choosing the MRI code to correspond to the diagnosis of strabismus. MRI codes are organized according to the area of the body examined. The strabismus-related MRI codes for the orbit, face and neck include:

• 70540--Magnetic resonance (e.g., proton) imaging, orbit, face, and neck; without contrast material(s)

• 70542--... with contrast material(s)

 • 70543--... without contrast material(s), followed by contrast material(s) and further sequences.

Question 4: How should I code for Botox injections to treat strabismus?

Answer: Report 67345 (Chemodenervation of extraocular muscle), Hollis says. That code describes the injection of botulinum toxin (trade name Botox) into the affected muscle, preventing it from contracting and allowing the opposing muscle to bring the eye into the correct position. Remember to use J0585 for the drug (Botox) and indicate the number of units used, including any wastage.