What is the correct CPT code for bilateral strabismus surgery of the superior oblique muscle?

Correct CPT Code for Bilateral Strabismus Surgery of the Superior Oblique Muscle

The correct CPT code for bilateral strabismus surgery of the superior oblique muscle is 67318-50. 1

Understanding the CPT Code Selection

When coding for strabismus surgery involving the superior oblique muscle bilaterally, the following considerations apply:

• 67318: This is the base code for "strabismus surgery, any procedure, superior oblique muscle"
• -50 modifier: This indicates a bilateral procedure (performed on both eyes)

Why 67318-50 is the Correct Choice:

1. Muscle-Specific Code: CPT code 67318 specifically addresses procedures on the superior oblique muscle, which is the exact muscle being operated on in this case 1

2. Bilateral Procedure: The -50 modifier is required because the surgery is being performed on both eyes 1

3. Alternative Codes Are Incorrect:

   • 67311: This code is for horizontal muscle procedures (not appropriate for superior oblique)
   • 67345: This code is for chemodenervation of extraocular muscle (injection procedure, not surgery)

Clinical Context for Superior Oblique Muscle Surgery

Superior oblique muscle surgery is typically performed for:

• Superior oblique palsy (SOP), which can be congenital or acquired
• Bilateral cases often require surgical strengthening procedures
• Common procedures include superior oblique tuck, advancement, or Harada-Ito procedure 1

Surgical Approaches for Superior Oblique:

• Superior oblique strengthening (ipsilateral) for bilateral cases, especially when torsion is a barrier to fusion 1
• Superior oblique tuck is recommended for lax tendons in presumed congenital SOP 1
• Advancement procedures for vertical and torsional deviations 1

Coding Pitfalls to Avoid

1. Don't use horizontal muscle codes (67311) for vertical/oblique muscle procedures

2. Don't omit the -50 modifier when the procedure is bilateral

3. Don't use multiple unilateral codes (reporting 67318 twice) instead of using the bilateral modifier

4. Don't use injection codes (67345) for surgical procedures

Documentation Requirements

For proper coding of bilateral superior oblique muscle surgery:

• Document the specific surgical technique used (tuck, advancement, etc.)
• Clearly indicate that the procedure was performed on both eyes
• Document the medical necessity (diplopia, compensatory head tilt, etc.)
• Include preoperative measurements of vertical deviation and torsion

Remember that proper coding ensures appropriate reimbursement and accurate medical records for this specialized strabismus procedure.