Neurosurgery Coding Alert

Skull base surgeries often require the skills of several surgeons of different specialties and are broken down into three kinds of procedures (approach, definitive and repair/reconstruction) creating complex coding issues for the neurosurgeon involved. By not documenting and coding correctly, you may not receive reimbursement for the procedure you have performed.

Skull base coding is even more involved because the approach procedures are broken down into the anterior cranial fossa, middle cranial fossa and posterior cranial fossa, depending on which of three different directions the neurosurgeon uses to approach the brain. The definitive procedures performed after the approach is made are broken down into the base of the anterior cranial fossa, base of the middle cranial fossa, and base of the posterior cranial fossa depending on precisely where the problem lies in the base of the brain. Precise documentation is essential for proper coding as the difference of only a few centimeters in the initial incision may affect the code range that should be employed.

Coding for Co-Surgeons

Skull base surgeries often are performed with the assistance of other surgeons including otolaryngologists and oral surgeons. In these cases, the codes are billed according to who performed them and if they were performed with or without assistance. According to CPT 2000, When one surgeon performs the approach procedure, another surgeon performs the definitive procedure, and another surgeon performs the repair/reconstruction procedure, each surgeon reports only the code for the specific procedure performed. If one surgeon performs more than one procedure (i.e., approach procedure and definitive procedure), then both codes are reported, adding modifier -51 (multiple procedures) to the secondary additional procedures.

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, and a coder who specializes in surgical and neurosurgical procedures, states that if the neurosurgeon performs the approach and the definitive procedure and then the otolaryngology surgeon performs the closure (closing the dura, putting the bone back in, sewing up the soft tissue), then they both should code the approach procedure and use the -62 modifier (two surgeons) to indicate that it was a co-surgical procedure between the neurosurgeon and the otolaryngology surgeon. The neurosurgeon also would code for the definitive procedure with the -51 modifier.

Coding the Approach Procedures

Arlene Liestman-Phillips, CPC, RHIT, professional services coder for neurosurgery and neurology at Oregon State University in Portland, reports that she runs into problems when the neurosurgeons document a modified approach in their operative notes. Liestman-Phillips cites a modified orbital zygomatic approach, which might be coded 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) or 61586 (bicoronal, transzygomatic and/or LeFort I osteotomy approach to anterior cranial fossa with or without internal fixation, without bone graft), depending on exactly how the surgeon modified the approach.

Patricia Boudreaux, CPC, CCS-P, data specialist for Tyler Neurosurgical Associates, PA, who has been coding for 12 years in Tyler, Texas, reports that because of the diversity and complexity of the potential approaches, choosing the correct approach code from CPT code range 61580-61598 can be very difficult. Often, the approaches will end up being mixed. In other words, the approach may have elements that can be found in the definitions of several seemingly conflicting codes. Or two different approaches may be required to reach a problem area.

Sometimes the approach will be modified only to a small extent, allowing the use of the code that fits it without the word modified attached, and at other times the approach may have been modified to the extent that a code from another range entirely might be more appropriate, Boudreaux reports. She recommends that when an approach is modified, the coder should begin by locating the approach code that best fits the operative report. If there is any confusion, the coder should verify the choice of approach code with the neurosurgeon prior to submitting the bill, she says.

Boudreaux states that many times an oral surgeon will perform one approach, and the neurosurgeon will perform another. In that case, the oral surgeon should bill for his or her approach, and the neurosurgeon should bill separately for his or her approach.

Coding for Definitive Procedures

According to CPT 2000, The definitive procedure(s) describes the repair, biopsy, resection, or excision of various lesions of the skull base and, when appropriate, primary closure of the dura, mucous membranes, and skin. Sandham reports that one of the problem areas with the definitive procedures is how to code clipping of an aneurysm.

Only one skull base code specifically includes aneurysm, which is 61613 (obliteration of carotid aneurysm, arteriovenous malformation, or carotid-cavernous fistula by dissection within cavernous sinus). Some coders use codes 61700-61702 with a skull base approach procedure. Sandham does not recommend this because the aneurysm codes were designed to reflect the approach and the clipping of the aneurysm. If the coder bills for a skull base approach above and beyond that, the coder is double-dipping or billing twice for one allowable procedure.

Sandham reports that some add-on procedure codes are occasionally forgotten by coders with skull base surgeries, and they should be billed without the -51 modifier. These include CPT codes:

61609 (transection or ligation, carotid artery in cavernous sinus; without repair)
61610 (transection or ligation, carotid artery in cavernous sinus; with repair by anastomosis or graft)
61611 (transection or ligation; carotid artery in petrous canal; without repair)
61612 (transection or ligation; carotid artery in petrous canal; with repair by anastomosis or graft)

Coding for Repair/Reconstruction Procedures

Sandham states that one of the key issues with skull base surgeries is that the repair and reconstruction codes really are designed to be used if a secondary repair and reconstruction (61618-61619) is needed. These codes would be used only for surgery performed during a later operative session. This usually will occur because a dural leak has developed and needs to be repaired.

According to CPT 2000, The repair/reconstruction procedure(s) is reported separately if extensive dural grafting, cranioplasty, local or regional myocutaneous pedicle flaps, or extensive skin grafts are required. If the secondary repair is done during the global surgical period and it was planned at the time of the original procedure, modifier -58 (staged or related procedure or service by the same physician during the postoperative period) should be used. If it was not planned then the -78 modifier (return to the operating room for a related procedure during the postoperative period) would be added to the reconstruction codes 61618-61619.

Coding for Additional Procedures

Sandham states that there are additional procedure codes that generally are overlooked by coders but can and should be billed in addition to the skull base codes when appropriate. These include:

69990 (use of operating microscope), an add-on code used for microdissection.
31600 (tracheostomy, planned [separate
procedure]), used when a tracheostomy is done to gain airway control during the surgery.
62272 (spinal puncture, therapeutic, for drainage of spinal fluid [by needle or catheter]), used when the neurosurgeon performs this procedure to maintain/control the pressure of the spinal fluid.
20926 (tissue grafts, other [e.g., paratenon, fat, dermis]), used for fat grafts that are done for the closure.
Note: This is a -51 modifier exempt code.
20920 (fascia lata graft; by stripper) or 20922 (fascia lata graft; by incision and area exposure, complex or sheet), used to get a water tight closure of the dura to prevent leaks that can cause infections.

Note: These codes are both -51 modifier exempt.

15732 (muscle, myocutaneous, or fasciocutaneous
flap; head and neck [e.g., temporalis, masseter,
sternocleidomastoid, levator scapulae]), for muscle flap repair.

Note: Occasionally, other flaps are required including microvascular flaps (codes 15740-15770).