Neurosurgery Coding Alert

Neurosurgeons may select from several treatment options for trigeminal neuralgia (350.1) depending on the severity of the condition and the patient's preference. Coding requirements are unique to each treatment, however, and require that coders distinguish the various procedures or services.

Defining Trigeminal Neuralgia

Trigeminal neuralgia (TN), also known as tic douloureux, is a painful disorder characterized by intermittent, shooting pains in the face. TN can occur at any age, but it usually occurs in individuals over 50 years old and is more common among women. Symptoms are usually caused by touching a "trigger zone" near the mouth or nose. Drinking, eating or even talking may stimulate the trigger zone. The most common cause is an enlarged looping artery or vein pressing on the trigeminal nerve, which carries sensation from the face to the brain. Other less frequent causes include multiple sclerosis or brain tumor. Any of these can be diagnosed by magnetic resonance imaging, or MRI (70544-70546, depending on the use of contrast materials).
 
Medications such as carbamazepine or gabapentin usually control the pain. In severe cases, or when medication does not work or produces unacceptable side effects (e.g., nausea, ataxia or mental dulling), surgical treatment is required. These treatments may be classified as either destructive or nondestructive.
 
Note: Carriers may require that certain conditions be met before surgical treatment is covered. For instance, Aetna U.S. Healthcare (a private payer) requires that the TN "has persisted for at least six months despite conservative treatment with pharmacotherapies (carbamazepine, phenytoin and baclofen) or the patient is unable to tolerate the side effects of the medications and there is documentation that the pain can be abolished by local anesthetic injection, but not by placebo injection." Medicare carriers are likely to specify similar guidelines.

Nondestructive Procedures

Treatment for TN is always individualized and includes consideration of the patient's expected life span and other factors.
 
Note: For further explanation of the factors determining treatment options for TN, visit the University of California, San Diego Web site: http://neurosurgery.ucsd.edu/ cnd/trigeminal_neuralgia.htm.
 
Microvascular decompression (MVD) is the only nondestructive procedure typically successful for relieving the symptoms of TN, says Peter J. Jannetta, MD, chairman of the Trigeminal Neuralgia Association medical advisory board and a member of the department of neurosurgery at Allegheny General Hospital in Pittsburgh. A small incision is made behind the ear and, under visualization provided by an operating microscope, the blood vessels compressing the trigeminal nerve at the base of the brain are moved. The vessels are supported by a Teflon bridge or other padding to prevent further compression on the nerve.
 
MVD may be coded 61450 (craniectomy, subtemporal, for section, compression, or decompression of sensory root of gasserian ganglion) or 61458 ( suboccipital; for exploration or decompression of cranial nerves) depending on the approach used to access the nerve, Jannetta says. If the approach is through the brain stem (a more complex procedure), report 61458. Otherwise, report 61450. Use 69990 (use of operating microscope) for the microdissection. Because this is an add-on code, do not append modifier -51 (multiple procedures), or reimbursement may be inappropriately reduced.
 
Individual insurers may allow the surgeon to report additional codes for this procedure. For example, Excellus Health Plan Inc., a private payer, also allows payment for 64999 (unlisted procedure, nervous system) and 64716 (neuroplasty and/or transposition; cranial nerve [specify]) for MVD. To be sure that all applicable codes have been reported, check with the insurer or www.lmrp.net for the specific medical review policy on this procedure prior to submitting the claim.
 
If the pain recurs after an MVD (which happens in 10-15 percent of patients), it can usually be controlled with medication. Continued pain may require a repeat MVD or one of the destructive procedures listed below. In either case, if the repeat MVD or alternative procedure occurs within the 90-day global period of the first MVD, the second procedure should be reported with modifier -78 (return to the operating room for a related procedure during the postoperative period) appended.

Destructive Procedures

The most common destructive procedures that help in the treatment of TN are glycerol injections, radiofrequency rhizotomy, gamma knife radiation, balloon compression and dorsal root entry zone. These percutaneous procedures (MVD is an open procedure) interrupt the pain by partial damage to trigeminal nerve fibers.
 
Glycerol injections involve rhizotomy (section of the nerve root) by insertion of a needle into the patient's cheek. Glyceral is injected into the trigeminal cistern, which damages and desensitizes the nerve. This procedure should be reported with 61790 (creation of lesion by stereotactic method, percutaneous, by neurolytic agent [e.g., alcohol, thermal, electrical, radiofrequency]; gasserian ganglion). As with 64610 (see below), this code should be used when the lesion or injection is behind the foramen ovale.
 
Radiofrequency rhizotomy, like glyceral injections, is coded 61790. This procedure also uses a needle inserted in the cheek, although here it is guided to the site of the trigeminal nerve at the base of the skull using x-ray. Electric current is used to find the site of the pain, at which time the patient is anesthetized, and heat (generated by radio waves) is used to damage the nerve. 
 
Gamma Knife radiation is a noninvasive procedure that uses radiation to desensitize the trigeminal nerve. When a destructive procedure is required, gamma knife stereotactic radiosurgery is the procedure of choice because it is least invasive and has the lowest risk of numbness or other side effects while producing excellent pain relief in most patients with a low incidence of recurrence. This outpatient surgery creates a lesion on the nerve, and is coded 61793 (stereotactic radiosurgery [particle beam, gamma ray or linear accelerator], one or more sessions). According to the national Correct Coding Initiative, 61793 includes placing of the head frame, so 20660 (application of cranial tongs, caliper, or stereotactic frame, including removal [separate procedure]) should not be billed separately. Both Medicare and private carriers are likely to follow this edit.
 
Add-on code 61795 (stereotactic computer-assisted volumetric [navigational] procedure, intracranial, extracranial, or spinal) describes computer assistance to map and locate the nerve and lesion site during this procedure.
 
If Gamma Knife radiation is used in more than one location, coders may choose to report multiple units of 61793, with modifier -59 (distinct procedural service) on the second, third, etc., codes, or list 61793 once with modifier -22 (unusual procedural services) appended, depending on payer preference. (Most payers want the latter option, and some specifically prohibit billing multiple lesions as separate procedures. Check with your payer before billing.)
 
Balloon compression uses a tiny balloon inserted through a tube (which is itself inserted into the skull via a puncture in the cheek) and inflated to create a lesion by compressing the trigeminal nerve. Report either 64600 (destruction by neurolytic agent, trigeminal nerve; supraorbital, infraorbital, mental, or inferior alveolar branch), 64605 (... second and third division branches at foramen ovale) or 64610 ( second and third division branches at foramen ovale under radiologic monitoring), depending on the site where the lesion is created and if radiologic monitoring is used, says Rhonda Petruziello, CPC, reimbursement specialist for neurosurgery at Cleveland Clinic Foundation in Cleveland.
 
Dorsal root entry zone (DREZ), like radiofrequency, uses a current (here, electric) to damage the nerve. This procedure is a "last resort" because it can have serious side effects, including localized weakness (e.g., hemiparesis), coordination problems (ataxia) and possible damage to hearing. This procedure is also reported with 61790, Petruziello says.