Anesthesia Coding Alert

Tip: Narrow anatomy options to simplify code selection.

When your pain management specialist treats trigeminal neuralgia, verifying the site and structure approached makes all the difference in your coding. Make coding -- and obtaining correct pay -- easier by following four simple steps.

1. Brush Up On Anatomy Basics

Knowing cranial nerve anatomy simplifies your code selection. The trigeminal nerve is the largest cranial nerve, and is a mixed nerve with a predominant sensory component. It mainly supplies innervations to the face through the three branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3). The three nerves converge on the trigeminal ganglion that contains cell bodies of the incoming sensory fibers.

Terminology: The trigeminal ganglion is also called the semilunar ganglion or the gasserian ganglion. Check your health professionals for these terms as well as "trigeminal ganglion."

"The gasserian ganglion is a bundle of nerve cells where the trigeminal nerve (CN V) divides into the V1, V2, and V3 nerves," explains Jennifer Schmutz, CPC, a health information coder with Neurosurgical Associates, LLC, in Salt Lake City, Utah. The foramen ovale (oval window) is one of the larger of several holes in the sphenoid bone at the skull base that is the passageway for the trigeminal nerve and the meningeal artery.

2. Evaluate Code Choices

A pain management specialist can treat trigeminal neuralgia via nerve destruction. If your provider destroys an individual nerve branch, report 64600 (Destruction by neurolytic agent, trigeminal nerve; supraorbital, infraorbital, mental, or inferior alveolar branch). For destruction of the V2/V3 divisions of the trigeminal nerve, choose between 64610 (Destruction by neurolytic agent, trigeminal nerve; second and third division branches at foramen ovale under radiologic monitoring) and 64605 (...second and third division branches at foramen ovale), depending on whether he uses radiologic monitoring.

Explanation: In this approach, the physician often uses fluoroscopic guidance to insert a trocar or needle lateral to the corner of the mouth into the corresponding foramen ovale. The neurolysis of the gasserian ganglion at this location is often performed with either radiofrequency or an injection of glycerol or alcohol, Remember, if the physician uses pulsed radiofrequency for the ablation, you are required to report 64999 (Unlisted procedure, nervous system) instead of one of the 64600 -- 64610 destruction codes.

A neurosurgeon, by contrast, often uses a stereotactic method to treat trigeminal neuralgia. Stereotactic surgery is a minimally invasive form of surgical intervention that uses a three-dimensional coordinates system to locate the trigeminal ganglion within the skull. The surgeon can use either a frame-based system in which a light-weight frame is attached to the head or a frame-less system which uses fiducial markers that are attached to the scalp. The head is then imaged by CT or MRI to identify the ganglion in relationship to the stereotactic frame or markers. When coding for this type of surgical approach, you would choose between two codes, i.e. 61790 (Creation of lesion by stereotactic method, percutaneous, by neurolytic agent [e.g., alcohol, thermal, electrical, radiofrequency]; gasserian ganglion) and 61791 (Creation of lesion by stereotactic method, percutaneous, by neurolytic agent [eg, alcohol, thermal, electrical, radiofrequency]; trigeminal medullary tract).

"If the lesion is created in the brainstem, then you are going to use 61791, and if it is done in the gasserian ganglion, you will use 61790," Schmutz says. "One location is the brainstem and the other isn't in the brainstem."

3. Pinpoint Procedure Location

Review your provider's notes for specific details regarding which trigeminal division or nerve branch he destroyed. You'll also need to verify what type of radiologic guidance your provider used, if any.

"You will decide by the description of the location in the physician's documentation," says Teresa Thomas, BBA, RHIT, CPC, practice manager II at St. John's Clinic (Neurosurgery) in Springfield, Missouri. "Without knowing the location, you would not know the correct code to bill."

4. Use Correct ICD Codes

Whether you report 61790 or 61791 or one of the codes from the 64600 -- 64610 code range, the correct diagnosis choice is 350.1 (Trigeminal neuralgia). When ICD-10 goes into effect in October 2013, you'll report code G50.0 (Disorders of trigeminal nerve; trigeminal neuralgia).