Neurosurgery Coding Alert

Submit 61618 or 61619 for secondary repair/reconstruction of surgical defects of the skull base.

Surgeons commonly perform skull base surgery to remove and/or treat a lesion, such as cancerous tissue, vascular malformation or aneurysm, from the undersurface of the brain. “A principle of skull base surgery is to remove bone in order to create an access pathway that reduces the need or extent of brain retraction to get to the target lesion,” explains Gregory Przybylski, MD, immediate past chairman of neuroscience and director of neurosurgery at the New Jersey Neuroscience Institute, JFK Medical Center in Edison, New Jersey.

Read on to learn all you need to know about skull-base coding.

Report Co-Surgeons With Care

Neurosurgeons often perform skull-base surgeries with the assistance of other surgeons. In these cases, the codes are billed according to who performed them and if the surgeon performed them with or without assistance.

CPT^® categorizes skull base surgeries into three categories — the approach procedure, the definitive procedure, and a secondary repair/reconstruction procedure.

“When one surgeon performs the approach procedure and another surgeon performs the definitive procedure, each surgeon reports only the code for the specific procedure performed,” according to CPT®. “If one surgeon performs more than one procedure (ie, approach procedure and definitive procedure), then both codes are reported, adding modifier 51 to the additional stand-alone procedure(s).”

Know Which Area of Cranial Fossa Impacted

Skull base surgeries include these three anatomical areas — the anterior, middle, and posterior cranial fossae. When you find the skull base surgery codes in the CPT® manual, you will see that the approach and definitive procedures are organized by these anatomical areas.

Anterior cranial fossa defined: The anterior cranial fossa is the portion of the skull base lying to the front of the cranium, approximately above the eyes.

Middle fossa defined: The middle fossa is an irregularly shaped area resembling a butterfly that centers on the pituitary gland and cradles the temporal lobes of the brain.

Posterior fossa defined: The posterior, or rearmost, fossa rests below the brainstem and cerebellum

Surgeon Performs Approach Procedure? Do This

The first category of procedure CPT^® identifies for skull base surgeries is the approach procedure, which is necessary to obtain adequate exposure to the lesion or pathologic entity.

Take a look at the different codes for the approach procedure:

• 61580 (Craniofacial approach to anterior cranial fossa; extradural, including lateral rhinotomy, ethmoidectomy, sphenoidectomy, without maxillectomy or orbital exenteration)-61586 (Bicoronal, transzygomatic and/or LeFort I osteotomy approach to anterior cranial fossa with or without internal fixation, without bone graft) for the anterior cranial fossa.
• 61590 (Infratemporal pre-auricular approach to middle cranial fossa (parapharyngeal space, infratemporal and midline skull base, nasopharynx), with or without disarticulation of the mandible, including parotidectomy, craniotomy, decompression and/or mobilization of the facial nerve and/or petrous carotid artery)-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) for the middle cranial fossa
• 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)-61598 (Transpetrosal approach to posterior cranial fossa, clivus or foramen magnum, including ligation of superior petrosal sinus and/or sigmoid sinus) for the posterior cranial fossa.

Dig Into Definitive Procedure Guidelines

Surgeon perform definitive procedures to “biopsy, excise, or otherwise treat the lesion,” according to CPT^®.

When you look at the code descriptors for the definitive procedures, you will see that they describe the repair, biopsy, resection, or excision of various skull base lesions. Also, if appropriate, some of these codes may include the primary closure of the dura, mucous membranes, and skin.

Codes for definitive procedures are as follows:

• 61600 (Resection or excision of neoplastic, vascular or infectious lesion of base of anterior cranial fossa; extradural) and 61601 (… intradural, including dural repair, with or without graft) for the base of the anterior cranial fossa.
• 61605 (Resection or excision of neoplastic, vascular or infectious lesion of infratemporal fossa, parapharyngeal space, petrous apex; extradural)-61613 (Obliteration of carotid aneurysm, arteriovenous malformation, or carotid-cavernous fistula by dissection within cavernous sinus) for the base of the middle cranial fossa.
• 61615 (Resection or excision of neoplastic, vascular or infectious lesion of base of posterior cranial fossa, jugular foramen, foramen magnum, or C1-C3 vertebral bodies; extradural) and 61616 (… intradural, including dural repair, with or without graft) for the base of the posterior cranial fossa.

Don’t miss: Code +61611 (Transection or ligation, carotid artery in petrous canal; without repair (List separately in addition to code for primary procedure)) is included in the 61605-61613 series.

You should report add-on code +61611 in addition to the code for the primary procedure — 61605-61608. You should report only one transection or ligation of carotid artery code per operative session, according to CPT^®.

Caution: When coding for skull-base surgeries, the approach and definitive procedure code must match anatomical locations. Therefore, an anterior approach, such as 61586, should accompany a code describing, for instance, removal of a lesion in the same portion of the skull (the anterior cranial fossa). Likewise, an intradural approach code, for example 61583, must accompany an intradural definitive procedure code, such as 61601, in the same anatomical fossa.

Don’t Miss These 2 Codes for Repair/Reconstruction

If it is necessary for the surgeon to perform re-exploration with dural grafting, cranioplasty, local or regional myocutaneous pedicle flaps, or extensive skin grafts for a subsequent cerebrospinal fluid (CSF) leak, then you would report the repair/reconstruction procedures for secondary repair, Przybylski says. As a delayed CSF leak typically occurs within the global period of the initial procedure, you would need to apply the appropriate modifier — typically modifier 78 (Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period).

You have two codes to choose from for codes for repair/reconstruction of surgical defects of the skull base. They are as follows:

• 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)
• 61619 (… by local or regionalized vascularized pedicle flap or myocutaneous flap (including galea, temporalis, frontalis or occipitalis muscle)).