Neurosurgery Coding Alert

Question: When a patient receives treatment for a skull base lesion, how many different surgeries are required?

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Answer: Two primary procedures, and they need to be performed in sequence. Time and expertise are the essences of successful skull base lesion surgery. The procedure requires multiple surgeries, and multiple surgeons, who are “working together or in tandem during the operative session,” CPT^® states.

There are three distinct procedure categories for skull base lesion surgery — and they all contain multiple codes:

Approach procedure: The surgeon performs this procedure “to obtain adequate exposure to the lesion (pathologic entity),” according to CPT^®. Examples of approach procedures include 61580 (Craniofacial approach to anterior cranial fossa; extradural, including lateral rhinotomy, ethmoidectomy, sphenoidectomy, without maxillectomy or orbital exenteration) and 61595 (Transtemporal approach to posterior cranial fossa, jugular foramen or midline skull base, including mastoidectomy, decompression of sigmoid sinus and/or facial nerve, with or without mobilization).

Definitive procedure: The surgeon performs this procedure “to biopsy, excise, or otherwise treat the lesion,” per CPT^®. Examples of definitive procedures include 61600 (Resection or excision of neoplastic, vascular or infectious lesion of base of anterior cranial fossa; extradural) and 61605 (Resection or excision of neoplastic, vascular or infectious lesion of infratemporal fossa, parapharyngeal space, petrous apex; extradural).

Repair/reconstruction: The surgeon performs this procedure to fix “the defect present following the definitive procedures,” states CPT^®. The only two codes for repair/reconstruction procedures are 61618 (Secondary repair of dura for cerebrospinal fluid leak, anterior, middle or posterior cranial fossa following surgery of the skull base; by free tissue graft (eg, pericranium, fascia, tensor fascia 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)).

Your neurosurgeon may perform any of these procedures, so you should be familiar with all phases of skull base surgery coding. Further, skull base lesions require surgeons working together, so you need to be on the lookout for potential co-surgeries, surgical teams, etc. For example, the following modifiers might need to be applied to your surgery codes for these patients, depending on encounter specifics:

• 62 (Two surgeons)
• 66 (Surgical team)
• 80 (Assistant surgeon)
• 81 (Minimum assistant surgeon).

Remember this: The primary procedure always involves an approach and definitive procedure code pair. Add-on codes may also be applicable, such as microdissection (+69990 [Microsurgical techniques, requiring use of operating microscope (List separately in addition to code for primary procedure)]) and intracranial or extracranial computer-assisted navigation (+61782 [Stereotactic computer-assisted (navigational) procedure; cranial, extradural (List separately in addition to code for primary procedure)] and +61781 [Stereotactic computer-assisted (navigational) procedure; cranial, intradural (List separately in addition to code for primary procedure)). If a cerebrospinal fluid (CSF) leak is found postoperatively and requires re-exploration and repair in the operating room, the secondary repair codes (61618 [Secondary repair of dura for cerebrospinal fluid leak, anterior, middle or posterior cranial fossa following surgery of the skull base; by free tissue graft (eg, pericranium, fascia, tensor fascia lata, adipose tissue, homologous or synthetic grafts)] or 61619 [… by local or regionalized vascularized pedicle flap or myocutaneous flap (including galea, temporalis, frontalis or occipitalis muscle)]) would be reported for the subsequent treatment of a CSF leak.