Oral Surgery Coding & Reimbursement Alert

Hint: Watch the need for modifiers to overcome edit bundles.

Whenever your oral surgeon performs procedures to excise or biopsy a lesion(s) in the mouth, you will have to know which code(s) to report for the procedure(s). You would lose out on deserved reimbursement if you are not reporting all the different procedures that your clinician performed and in the right order.

Below is a case report to test your diagnosis and procedure coding skills. Review the op note, decide how to report it, and then match your responses to our coding experts.

Examine Multiple Lesions, Graft Reconstruction

Pre- and post-operative diagnoses: (1) Verruciform leukoplakia with moderate dysplasia of the left buccal mucosa, R/O (rule out) SCCA (squamous cell carcinoma) and (2) leukoplakia of the right buccal mucosa.

Indication: The patient is a 68-year-old male with a seven-month history of a left buccal lesion that was biopsied and confirmed as moderate dysplasia, which could not rule out well-differentiated SCCA. The lesion appears within a patch of verruciform appearing leukoplakia. Additionally, he has an area of benign appearing leukoplakia on the right gingivobuccal sulcus.

Procedures: After the patient was anesthetized and prepped, your oral surgeon delineated a margin of buccal mucosa centered over the dysplastic-appearing verruciform leukoplakia of the left buccal mucosa and then incised the mucosa down to the level of the buccinator muscle along the delineated margins. Your surgeon then removed and labeled the specimen, a single short stitch at twelve o’clock and a single long stitch at three o’clock.

Your surgeon then noted that an area of heaped-up keratinized mucosa remained at the superior border of the defect; thus, your surgeon excised and labeled an additional 3 mm superior margin, a short stitch posterior.

Next, your clinician noted an area of benign-appearing leukoplakia along the gingivobuccal sulcus of the right buccal mucosa. He performed an incisional biopsy 3 mm by 3 mm wide to send to pathology and closed the site.

Then, your surgeon harvested the dermal graft, using a Zimmer dermatome (set at 0.12-inch thickness) to elevate an inferiorly based split-thickness skin graft. Next, he harvested a 5.5 by 4.5 cm dermal graft over the same site and laid the split-thickness skin graft down over the dermal graft harvest site and tacked it back to the skin.

Next, your surgeon tailored the dermal graft to fit the size of the left buccal mucosal defect, tacked stitches along the periphery to inset the dermal graft, and then applied central tacking before securing a bolster in place. Finally, your surgeon placed a Dobhoff tube in the left nasal cavity, sutured it to the septum, and used a Dedo laryngoscope to confirm postcricoid placement.

1: Look to Pathology for Diagnosis Codes

You may think of two neoplasm-related diagnoses for this case, namely 145.9 (Malignant neoplasm of mouth, unspecified) to represent the excision site and 145.0 (Malignant neoplasm of cheek mucosa) to represent the biopsy site. You’d be right if the pathology had come back malignant for the two sites. 

Unless pathology is available, avoid using a specific neoplasm code.  “One should use the appropriate code for a biopsy and after pathological identification use the CA description,” says Barry Shipman, DMD, clinical professor, University of Florida School of Dentistry, Hialeah Dental Center. The pre- and post-operative diagnoses state “R/O (rule out) squamous cell carcinoma.”

The best ICD-9 codes to choose without a confirmed pathology report would be:

• 528.6--Leukoplakia of oral mucosa including tongue, for the first lesion excision
• 528.72--Excessive keratinized residual ridge mucosa, for the excision of the additional margin, and
• 239.--Neoplasm of unspecified nature of respiratory system, for the biopsy taken on the right side.

ICD-10:  When you switch to using ICD-10 codes, 528.6 will crosswalk to K13.21 (Leukoplakia of oral mucosa, including tongue); K13.23 (Excessive keratinized residual ridge mucosa) in lieu of 528.72 and you will use D49.1 (Neoplasm of unspecified behavior of respiratory system) instead of 239.1.

2: Compare RVUs to Find Primary Procedure

You will need to report the procedure that carries the most relative value units (RVUs) first on the claim form with no modifiers. In this case, the first procedure that you will report first is the dermal autograft (15135,Dermal autograft, face, scalp, eyelids, mouth, neck, ears, orbits, genitalia, hands, feet, and/or multiple digits; first 100 sq cm or less, or 1% of body area of infants and children) as it carries a total RVU of 23.97.

Although the op note mentions a “split-thickness” graft, which you might consider coding as 15120 (Split-thickness autograft, face,...first 100 sq cm or less ...), stick with 15135 since the surgeon used the split-thickness graft to close the defect created from the harvest of the dermal autograft. This closure is inclusive in the work described by 15135.

3: Mention Muscle Excision for Best 40816 Odds

Next, you will need to report the excision on the left side with 40816 (Excision of lesion of mucosa and submucosa, vestibule of mouth; complex, with excision of underlying muscle, 11.74 RVUs). 

Since the op note describes excision of the mass down to the depth of the muscle, it’s reasonable to presume that a slim portion of muscle is captured with the excision. Therefore, you will be justified in choosing to report 40816. Your surgeon could make the op note clearer, however, by adding a brief mention of submitting a slim portion of fascia and muscle with the specimen to avoid an adverse decision on payment approval.

If your surgeon did not excise to the level of the muscle, you can choose to report 40814 (Excision of lesion of mucosa and submucosa, vestibule of mouth; with complex repair, 11.27 RVUs).

Follow up: To be precise, check the pathology report to see if muscle tissue was examined, and then go back to the surgeon and question the verbiage in the op report.

4: Weigh the Case for 40810

Consider whether to report the second, additional excised margin with 40810 (Excision of lesion of mucosa and submucosa, vestibule of mouth; without repair, 6.01 RVUs). Since Correct Coding Initiative (CCI) edits are in place when you report 40810 with 40816, you will have to append modifier 59 (Distinct procedural service) to 40810.

Rule: According to CPT® language, excision code selection is determined by measuring the greatest clinical diameter of the apparent lesion plus that most narrow margin required for complete excision. Some find this confusing and have debated whether this would include several more added resection margins.

This case shows, however, that there was cause, after further observation, for an additional excisional effort beyond the excision of the first lesion [and] the initial margins. Furthermore, the extra margins also represent additional keratinized mucosa separate from the leukoplakia, which helps justify your use of modifier 59 for the separate site. 

5: Append 59 to Biopsy

Finally, don’t forget to report 40808 (Biopsy vestibule of mouth, 5.44 RVUs) for the biopsy that your clinician took on the right side.

Modifier: Again, you will need to append modifier 59 to 40808. The CPT® codes 40808 and 40816 are distinct procedures in this instance because your surgeon performed the excision on the left side while he performed the biopsy on the right.

By using modifier 59 you can communicate to the payer that your surgeon performed a separate and distinct procedure that is normally bundled with another reported code. Without adding 59, the payer would bundle the biopsy into the excision code.

Conclusion: Bring it All Together

The final summary of coding is:

• 15135, for the dermal autograft
• 40816-51 (or 40814-51, depending on your interpretation or confirmation on whether there was excised muscle), for the lesion excision
• 528.6, for the above
• 40810-59 (potentially, depending on your interpretation), for the excision of the additional margin
• 528.72, for the above
• 40808-59, for the biopsy
• 239.1, for the above.