Multiple Code Assignment Key to Coding Strabismus
Multiple Code Assignment Key to Coding Strabismus
Operations to correct strabismus, an abnormal ocular condition in which the eyes are crossed, often involve several steps. Although multiple codes should be assigned in such cases, they often are not.
The information below will, hopefully, lead to more accurate, comprehensive code assignment for this complex procedure.
Strabismus may be either paralytic or nonparalytic. In paralytic strabismus, the eye muscle’s inability to move is caused by a neurologic or muscular dysfunction caused by a tumor, infection, or brain or eye injury.
With nonparalytic strabismus, an inherited defect, the patient can “fix” only one eye on an object straight ahead. Choices to correct this imbalance include a patch for the “fixing” eye, which forces the deviated eye into use, or surgery.
In the surgical procedure, the physician realigns the eyes so they both look in the same direction. This correction restores depth perception and single vision and expands the visual field.
Six muscles control the position of each eye—two horizontal muscles and four vertical muscles.
A physician may operate on one or more of these muscles in one or both eyes. To gain access to the muscle(s), the surgeon rolls the eyes into one position or another and places a speculum in the eye. Then, he or she makes an incision in the conjunctiva at the juncture of the sclera and cornea (the limbus) and isolates the operative muscle with a hook. (This either strengthens the muscle by resection or weakens it by recession.) The surgeon secures the muscles with sutures and closes the wound.
Before choosing codes for strabismus surgery, check the patient’s clinical history in the operative report and answer the following questions: Has the patient had previous strabismus surgery? Is there scarring around the eye muscle? Is the surgery being performed on the vertical, horizontal or oblique muscles? Which muscles were operated on in each eye?
When the surgeon operates on at least two and sometimes four muscles at the same time (very common), report multiple CPT codes. Since the CPT system does not differentiate between the right and left eye, make sure the operative report identifies the specific muscles (in each eye) on which surgery was performed.
The CPT codes for strabismus surgery (67311-67318) refer to each eye individually. If the same operation is performed on both eyes, assign the code twice for hospital outpatient services. For physician office services, assign modifier -50 to indicate bilateral procedures.
To report extensive operations performed on previously operated upon eyes, use “add-on” code 67331 or 67332. (Add-on codes do not stand alone. You also must assign another strabismus surgery code.)
Reoperations require more time and skill than initial surgery. To indicate additional work during the surgery, choose from add-on, unilateral codes 67320, 67335 or 67340. Physicians would not assign the modifier -51 (multiple procedures).
Assigning a unilateral code usually indicates that the patient’s eyes turn in (esotropia) or out (exotropia). Most likely, the surgeon previously operated on one or both of the horizontal or the vertical muscles.
For more difficult operations (such as those on the vertical and superior oblique muscles), report the main procedure codes separately.
In addition to the above, you may choose from other add-on codes, which are listed below.
- Code 67320 describes a transposition procedure performed on an eye muscle that has lost its ability to turn outward or inward. The goal is to replace some of the eye’s movement in the weakened direction. This often accompanies another operation in the same eye.
- Use 67331 to indicate that the current surgery is more difficult because the patient had previous eye surgery or injury.
- To report extraocular muscle scars, which indicates previous surgery or muscle abnormalities, use 67332.
- To report the placement of adjustable sutures, use 67335. The surgeon uses these to adjust the eye muscles before they heal into place. On the day of the surgery or the next day, the physician checks the muscle alignment, deciding whether to reposition the sutures to improve it.
- Although infrequently assigned, 67340 is the correct code for exploratory surgery where the surgery tries to recover a detached muscle.
- To restore mobility after multiple procedures, the surgeon may sever adhesions that form between the eye muscles and the orbital contents or cavity wall. Report this with 67343. Do not assign this code if the surgeon performs the procedure on the eye muscle with strabismus, since adhesion dissection is considered part of the operation.
Unlike the above, you cannot use 67334 as an add-on. This code describes strabismus surgery by posterior fixation technique, in which the surgeon places a suture through the muscle and partial thickness of the eye wall.
If performed at the same time as another eye operation, assign codes for that procedure and for the fixation muscle operation. (Note that the CPT manual does not identify which eye muscle has had the posterior fixation suture placed.)
* About the author: Kathleen A. Mundy is a senior health care consultant with Medical Learning Inc. (MedLearn®), St. Paul, MN.