Brain Surgery

By Denae M. Merrill, CPC, with assistance from Frank Schinco, MD

Have you ever felt like the wording in the CPT® codebook was written in a foreign language? It seems even more true in the Nervous System: Skull, Meninges, and Brain section. In order to better understand this section, we will break down the wording from CPT® into four categories: the how, the where, the why, and the what.

The How

There are four common approaches to brain surgery. How do you know which one your doctor performed? Here are some easy explanations to each type:

Twist drill [codes 61105-61108]: This wording started some 40 or more years ago, and has limited use in this day and age. The surgeon uses a hand drill with a drill bit to make a small hole in the skull for access to the brain.

Burr hole [codes 61120-61210, 61250-61253, and 61531]: A small power hand drill is the ‘new’ way to make a hole in the skull, and results in a bigger hole than the twist drill.

Craniectomy [codes 61304-61315, 61320-61334, 61343, 61450-61480, 61500-61516, 61518-61530, 61550-61552, 61558-61559, 61570-61571]: During this procedure, the surgeon takes out a piece of the skull to make a larger opening than in the above procedures. The skull piece is not put back when the procedure is finished.

Craniotomy [codes 61304-61315, 61320-61323, 61440, 61490, 61533-61546, 61556-61557, 61566-61571]: This procedure also takes out a piece of the skull, to make a larger opening than the twist drill or burr hole, and then replaces the bone when the procedure is finished.

The Where

There are 12 words to describe the location where the surgery is performed. This is when your anatomy and terminology knowledge come into play. But even then, it can be difficult to picture where this will take place. That’s where images are helpful.

The Why

Breaking this category down into the most basic terms, there are 18 different reasons why a doctor might go poking around in the brain.

Implantation, puncture, evacuation, drainage, biopsy, aspiration, exploration, treatment, decompression, removal, section, lobectomy, excision, transection, hemispherectomy, hypophysectomy, craniosynostosis, and amygdalohippocampectomy are the key words to look for. Many of these are self-explanatory, however, there are some that could use more explanation:

Section and Transection [codes 61440-61450, 61541, 61567]: Both of these terms mean “to cut;” however the ‘trans-‘ implies a deeper or fuller cut, although in reality there is not much of a difference.

Hemispherectomy [codes 61542-61543]: Hemisphere is half of the cerebrum, or brain, so this means to remove the whole portion of the hemisphere.

Hypophysectomy [codes 61546-61548]: This is removal of the pituitary gland.

Craniosynostosis [codes 61550-61559]: When the skull bone fuses together too early in children, a malformed head results. During this procedure, the doctor breaks the skull bone so it can regrow appropriately.

Amygdalohippocampectomy [code 61566]: The amygdale and hippocampus are medial temporal lobe structures, and during this procedure they are removed, most often to stop seizure activity.

The What

Last, but not least, what are we doing in here? We have to go back to “The Why” section and further explore it to include the “what.” For instance, the “why” is implanting, but implanting what? Or removal, but removal of what? There are many “whats” that might require the doctor to operate on the brain: catheter, pressure recording device or other monitoring device; hematoma; lesion; abscess; cyst; reservoir; EEG electrode(s); intracranial hypertension; foreign body; tentorium cerebelli; sensory root of gasserian ganglion; cranial nerve; medullary tractotomy; mesencephalic tractotomy or pedunculotomy; tumor or other bone lesion; osteomyelitis; meningioma; fenestration of cyst; cerebellopontine angle tumor; electrode array; epileptogenic focus; corpus callosum; choroids plexus; craniopharyngioma; pituitary tumor; and penetrating wound. Like the ‘whys,’ many are self-explanatory, while others could use additional explanation, such as:

Tentorium cerebelli: Formed by the dura mater, separates the cerebrum from the cerebellum.

Sensory root of gasserian ganglion: The gasserian (trigeminal or 5th cranial nerve) ganglion is a swelling of the sensory root and contains the cell bodies of most sensory neurons and occupies a cavity in the dura matter. The trigeminal nerve has three branches (ophthalmic, maxillary, and mandibular branch), which are responsible for the sensations in the face.

Medullary tractotomy: Surgical severing or incising of one or more ascending or descending tracts of the medulla oblongata (truncated cone of nerve tissue located near the brain stem), which deals with vital functions, such as respiration, circulation and special senses.

Mesencephalic tractotomy/pedunculotomy: Creation of lesion(s) in the midbrain for intractable pain relief.

Fenestration of cyst: Opening the cyst and releasing the fluid inside.

Cerebellopontine angle tumor: The myelin creates a coating on the 8th cranial nerve, which results in this benign tumor.

Corpus callosum: The hemispheres of the brain communicate with each other through this thick band of 200-250 million nerve fibers.

Choroids plexus: Found in all four ventricles (walls or roof) of the brain, this is where the cerebrospinal fluid is made.

Craniopharyngioma: A primary brain tumor, often benign, rare, congenital, and cystic, that develops in the pituitary gland.

A little note on the medullary tractotomy and mesencephalic tractotomy/pedunculotomy: These procedures are rarely done nowadays. They are quite dangerous, not always effective and other treatments are available that work successfully for pain management.

Take these four categories and utilize the knowledge you’ve gained on them to code your next brain surgery.


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