Neurosurgery Coding Alert

Coding for a repair of dura for cerebral spinal fluid (CSF) leak (61618 or 61619) in the wake of skull base surgery (61592 and 61608) for a brain tumor removal can be tricky. This is because of the need to decide if the repair is technically related or unrelated to the initial surgery.

An incorrect determination can cost a neurosurgery practice considerable amounts of otherwise easily attainable reimbursement. With a proper understanding of when to use secondary repair codes, when a postoperative complication is related or unrelated, and tips for diagnosis coding and documentation, coders will be armed with the necessary reimbursement tools.

Normal Closure or Secondary Repair?

Some neurosurgery coders believe that the secondary repair codes should be used whenever a skull base surgery is performed. This is improper coding because the codes for the primary or definitive procedure do not specifically list closure. However, according to Medicare guidelines, a standard closure is included in the definitive procedure. A secondary repair code should only be used when the specific circumstances described in the definitions are met.

For example, a patient has skull base surgery. It consists of an infratemporal approach with a left frontotemporal craniotomy coded as 61592 (orbitocranial zygomatic approach to middle cranial fossa [cavernous sinus and carotid artery, clivus, basilar artery or petrous apex] including osteotomy of zygoma, craniotomy, extra- or intradural elevation of temporal lobe). The definitive procedure consists of an orbitotomy, the complete removal of the intradural portion of the tumor, and closure is coded as 61608 (resection or excision of neoplastic, vascular or infectious lesion of parasellar area, cavernous sinus, clivus or midline skull base; intradural, including dural repair, with or without graft). This is a standard skull base operation.

The repair and reconstruction codes for these surgeries, 61618-61619 (see definitions below) are designed to be used when the secondary repair of the dura occurs at a different operative session, says Eric Sandham, CPC, compliance educator for Central California Faculty Medical Group, a group practice and training facility associated with the University of California at San Francisco in Fresno.

These codes are not meant for a normal closure and will be denied.

Definitions: 61618 secondary repair of dura for CSF leak, anterior, middle or posterior cranial fossa following surgery of the skull base; by free tissue graft [e.g., pericranium, fascia, tensor fascior lata, adipose tissue, homologous or synthetic grafts]; and 61619 ... by local or regionalized vascularized pedicle flap or myocutaneous flap [including galea, temporalis, frontalis or occipitalis muscle].

Related or Unrelated?

If the patient needs to be returned to the operating room during the 90-day global period for secondary repairs to the dura, 61618 or 61619 should be used (the choice depends on the exact work done). The code needs to be appended with an appropriate modifier to avoid denials by ensuring that it is not bundled into the global surgical package. One of two modifiers may be used, either modifier -78 (return to the operating room for a related procedure during the postoperative period) or -79 (unrelated procedure or service by the same physician during the postoperative period). Chose a modifier based on whether the secondary repairs are related or unrelated to the original surgery, says Laurie Castillo, MA, CPC, president of Physician Coding and Compliance Consulting, a physician consulting firm in Manassas, Va., and a coding expert in neurosurgery.

In this particular circumstance, Medicare and third-party payers often use completely different criteria to judge if additional work is related or unrelated. So while it is technically correct, as stated above, that modifier -78 should be used if additional work is related and modifier -79 should be used if the additional work is unrelated, the situation is not that simple. You must first consider what kind of carrier is being billed and their criteria for related versus unrelated before choosing a modifier.

Sandham, a coder who specializes in surgical and neurosurgical procedures, says that with most third-party payers, modifier -78 should be used to identify services that have already had the postoperative part of the global surgical package paid (in the reimbursement for the original procedure), but were not planned as part of the original procedure. Because modifier -78 indicates a complication of the original surgery, reimbursement is discounted and the carrier will pay a partial surgical allowance that covers only the new procedure, not pre- and postoperative costs. Sandham also says some coders incorrectly believe that the secondary repair is related to the original surgery if the procedures are performed at the same location and use the -78 modifier inappropriately. It should only be used if the above criteria are met.

He also reports that a dural leak is considered beyond the scope of normal uncomplicated care (infection, bleeding and perforation) with third party-payers, and therefore, repair of this is not related to the original surgery so modifier -79 is appropriate.

However, Castillo says Medicare will not reimburse with the -79 modifier unless a service is completely unrelated to the original surgery, all postoperative follow-up care is included in the original surgery reimbursement (thus related), and that all surgeries related to the original, even for complications, should be appended with modifier -78.

Diagnosis Code and Documentation

Sandham states that coders should also be sure to note the different diagnosis code for the secondary repair, 997.09 (other nervous system complications). The operative report should reflect that the repair was performed to care for a complication that is beyond normal follow-up care and is unrelated.