Anatomy and approach lead to correct brain surgery coding
Have you ever heard someone say, “It’s not brain surgery” when referring to some task or action? In coding, sometimes it really is brain surgery and coders need a strong understanding of the anatomy of the skull and brain in order to correctly report diagnoses and procedures.
“To me, anatomy is extremely important when coding,” said Cynthia Stewart, CPC, CPMA, CPC-H, CPC-I, Revenue Cycle Systems Manager for St. Vincent Health in Indianapolis and president of the AAPC National Advisory Board, who discussed neuro anatomy and procedures during the April 2012 AAPC National Conference in Las Vegas. “If you don’t know the bones of the skull, you will be completely lost.”
Bones of the skull
The bones of the cranium meet along joints called sutures. As a person ages, the sutures gradually fuse together. Let's look at the specific bones of the cranium.
The frontal bone comprises the forehead (squama frontalis) and the upper orbit of the eye (pars orbitalis). It joins the parietal bones at the coronal suture.
Two temporal bones, located at the sides and base of the skull, are the hardest bones in the body. They include the ears, which comprise the auditory ossicles—the three smallest bones in the body.
The two parietal bones form most of the roof and sides of the skull. Each parietal bone consists of four borders (sagittal, squamous, frontal, and occipital) and four angles (frontal, sphenodial, occipital, and mastoid).
The ethmoid bone is located at the top of the nose and in between the two eye sockets. It differs from the other bones in the cranium because it's spongy instead of hard. It divides the nasal cavity from the brain.
The sphenoid bone is located behind the eyes at the base of the skull. Because of its shape, the sphenoid bone touches all the other cranial bones. It’s especially important that coders know where the ethnoid and sphenoid bones are when coding skull base surgeries, Stewart said.
The occipital bone forms the lower part of the back of the skull and the base of the cranium. The spinal cord exits the brain through a large oval hole, called the foramen magnum, in the occipital bone.
Other structures of the skull
The skull also includes three meninges, which are the protective membranes that cover the brain and spinal cord. The dura mater, the outermost membrane, surrounds the brain and the spinal cord and is responsible for retaining the cerebrospinal fluid. It also carries blood from the brain toward the heart.
The dura mater has two layers referred to as lamellae: the superficial layer, which serves as the skull's inner periosteum (i.e., the endocranium), and a deep layer, which is the actual dura mater.
The arachnoid mater, the middle membrane, helps separate the hemispheres of the brain.
The pia mater is the deepest of the membranes and acts like protective Saran Wrap covering the brain. The subarachnoid space lies between the pia mater and the arachnoid mater and contains the cerebrospinal fluid.
If a physician documents an arachnoid hemorrhage, he or she likely found cerebrospinal fluid between the pia mater and the arachnoid mater, Stewart said.
The holes in the skull that allow blood vessels and nerves to pass through are known as foramen. The spinal cord exits the skull through the foramen magnum.
Lobes of the brain
Coders also need to know where the different lobes of the brain are located in order to code for neurosurgery.
The frontal lobe is the largest lobe of the brain and is prone to injury because it sits in the front of the head, Stewart said.
The parietal lobe sits posterior to the frontal lobe and integrates sensory input. “It tells us which way is up,” Stewart said. When patients suffer an injury to the parietal lobe, they may be unable to recognize or locate their own body parts.
The temporal lobe is located at approximately the level of the ear on the side of the head. It processes speech and sound and is essential for long-term memory formation.
The occipital lobe is located at the lower back part of the head. It contains the visual cortex.
The brain stem is located at the base of the brain and is composed of the midbrain, pons, and medulla. It controls involuntary functions.
The cerebellum resembles a stalk of cauliflower and is located at the bottom of the brain, below the cerebral cortex and behind the pons. It plays an important role in motor control.
The pituitary is located in the sella turcica, which is a saddle-shaped depression in the sphenoid bone. When a physician removes a patient's pituitary gland, he or she breaks through the sella turcica to reach the pituitary.
The brain also includes four ventricles, a communicating network of cavities filled with cerebrospinal fluid (CSF): the right lateral ventricle, the left lateral ventricle the third ventricle, and the fourth ventricle. The body produces CSF in the third and fourth ventricles. CSF cushions the brain, reduces its weight, and decreases the pressure of the brain on the skull base, Stewart said.
Surgeons can use a variety of approaches when performing brain surgery. For an open approach, a surgeon can use a twist drill, burr hole, or trephine, depending on the procedure. For example, surgeons commonly use burr holes for the following procedures:
Surgeons can also perform a craniectomy or craniotomy. In a craniectomy, the surgeon removes a flap of bone, but does not replace it. In a craniotomy, the surgeon removes a flap of the skull and returns the piece of bone to its original place either immediately or at a later time. Most of the CPT® codes include craniectomy or craniotomy, so for coding purposes, it often doesn’t matter which procedure the surgeon performs, Stewart said.
Coders should report add-on CPT code 61316 (incision and subcutaneous placement of cranial bone graft) if the surgeon takes the flap out and replaces it later.
Surgeons may use one of two types of neuroendoscopic approaches instead of an open approach. If the surgeon uses a transnasal (through the nose) approach, the patient will not have any scarring. The surgeon may use a transcranial approach instead. The approach depends on the site and what structures the surgeon must pass through to access it, Stewart said.
Surgeons will often use a neuroendoscopic approach to remove tumors of the anterior skull base or anterior brainstem, Stewart said. Coders should note that CPT includes very few codes for transnasal procedures. Coders will find codes for neuroendoscopic procedures in 61548 and 62161–62165.
Procedures involving the brain
Coders will need their strong foundation in anatomy in order to code the actual procedures performed on the brain.
A patient may suffer a hematoma in the brain. The physician will locate the specific site of the bleed using a separately reportable CT scan. Coders will select the appropriate procedure code based on the location of the bleed and how the surgeon approaches and treats it, Stewart said.
For example, a patient has a subdural hematoma and the surgeon plans to evacuate and drain the hematoma. If the surgeon uses a twist drill, coders report 61108. However, if the surgeon uses a burr hole, report 61154, Stewart said.
If the surgeon performs a craniectomy or craniotomy to remove the hematoma, coders would look to codes 61312–61315. The codes are broken down by the site of the hematoma, according to Stewart.
One way coders can tell if the surgeon performed a subdural procedure is to look for documentation that the surgeon sutured the dura. That tells coders the surgeon is in the subdural space, Stewart explained.
Surgeons also perform a variety of procedures involving the ventricles. A surgeon may need to make a ventricular puncture. If the surgeon performs a ventricular puncture through previous burr hole, fontanelle, suture, or implanted ventricular catheter/reservoir and does not inject any substance or drug, coders would report 61020. If the physician performs the same procedure, but does inject a drug, coders would report 61026, as well as the HCPCS Level II code for the actual drug, Stewart said.
If a patient’s CSF is not draining properly, a surgeon may insert a shunt, which is a more complex procedure. The shunt may remain in place for a patient’s lifetime or the physician may remove it at some point.
Coders select the appropriate code based on the distal end of the catheter that removes the excess CSF, not on where the catheter starts, Stewart said. If the shunt ends up in the peritoneal cavity, the most common type of shunt, coders would report 62223. In addition, the surgeon may use endoscopy to help place the shunt. That work is not included in the shunt placement CPT code, Stewart said. So coders may report it separately provided the physician adequately documented the use of endoscopy.
If the surgeon removes the shunt completely, coders will choose a code based on whether the surgeon replaced the shunt. Report code 62256 for a removal without replacement and 62258 when the surgeon removes the shunt and replaces it with the same or similar shunt.
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