Corpus callosotomy

Overview

Corpus callosotomy, also known as callosal sectioning or brain-splitting, is a surgical procedure that involves cutting the corpus callosum to stop seizure signals from spreading from one brain hemisphere to the other. Corpus callosotomy is a surgical procedure used to address epilepsy seizures that remain uncontrolled despite the use of antiseizure medications.

The corpus callosum, located deep within the brain, is a band of nerve fibers that establishes a connection and exchange of information between the two cerebral hemispheres. However, it also plays a role in transmitting seizure impulses from one side of the brain to the other. With corpus callosotomy, cutting them lessens the severity and frequency of seizures and may possibly bring a stop to them.

Reasons for undergoing the procedure

Corpus callosotomy might be suggested for individuals experiencing severe and unmanageable forms of epilepsy. Individuals eligible for corpus callosotomy are usually those who have frequent atonic seizures and show little to no response to antiseizure medications.

A person having an atonic seizure, also known as drop attacks, collapses or drops to the ground when their muscles suddenly lose strength. Broken bones and concussions are among the injuries that are more likely to occur during an atonic seizure.

Corpus callosotomy is not a viable solution for individuals facing partial or focal seizures, which arise in a limited region or focal point of the brain.

Risk

Serious complications following a corpus callosotomy are uncommon. The prevalent problem post-surgery is disconnection syndrome. When performing basic tasks with closed eyes, the two brain hemispheres do not coordinate, leading to conflicting movements of the right and left sides of the body.

Other risks include:

• Surgical risks include bleeding, infection, and anesthesia-related allergic response
• Brain swelling
• Dysfunction in balance or coordination
• Apraxia, or difficulty producing speech
• Aphasia, or difficulty understanding and speaking
• Stroke
• Increase in partial seizures, occurring on one side of the brain
• Lack of awareness of one side of the body

Procedure

Corpus callosotomy makes seizures become less intense as they are confined to affecting only one hemisphere of the brain. When the corpus callosum is severed, it prevents the transmission of seizure signals between the two brain hemispheres. Seizures generally do not completely stop after this procedure but only manifest on one side.

Before the procedure

A comprehensive evaluation is required in determining the suitability of corpus callosotomy as a potential treatment. Various tests can in identifying the origin of seizures and their patterns of propagation in the brain. These tests include:

• Magnetic resonance imaging (MRI): MRI scan to assess any structural changes in the brain that might be the source of seizures. This test utilizes a powerful magnet, radio waves, and a computer to generate precise and detailed images.
• Electroencephalogram (EEG): The procedure is to record and measure the electrical signals in the brain. This test requires placing electrodes on the scalp to monitor brain activity.
• Positron emission tomography (PET): PET scan to determine which parts of the brain are responsible for the onset of seizures.

During the procedure

In a corpus callosotomy, craniotomy or opening the skull to access the brain is done. The surgery proceeds with removing a piece of the skull and lifting a part of the protective dura membrane.

This establishes a “window” to disconnect the corpus callosum. Surgical microscopes is used to help see brain structures more clearly as the healthcare provider gently separate the hemispheres to access the corpus callosum.

After cutting the corpus callosum, the dura will be replaced. Finally, the skull bone is secured back in place with stitches or staples. The entire procedure is done under general anesthesia.

A corpus callosotomy technique may occasionally occur in two phases. In the initial stage, the healthcare provider only cuts the front portion of the corpus callosum, enabling the ongoing sharing of visual information between the two brain sections. If the severe seizures persist, the healthcare provider may suggest a second surgery to sever the corpus callosum entirely.

After the procedure

During the recovery period, patients may feel fatigue, feelings of depression, and headaches. Some may experience:

• Memory issues
• Speech issues
• Nausea
• Numbness at the incision site

Patients typically spend two to four days in the hospital after a corpus callosotomy. The hair near the incision site will gradually regrow, concealing the surgical scar over time. Although recovery may take longer for some people, most patients can resume their usual activities, including work or school, within six to eight weeks post-surgery.

Outcome

Corpus callosotomy effectively halts drop attacks or atonic seizures, in approximately 50% to 75% of instances. This reduction in such seizures can lower the risk of injury and enhance the individual’s overall quality of life. After surgery, about one in five patients no longer experiences seizures.

Although uncommon, it is important to be on the lookout for signs and symptoms of complications. Seek immediate medical attention if any of the signs and symptoms are experienced:

• Stroke symptoms, such as speech impediments, blurred vision, or sudden paralysis, frequently affecting one side of the body
• Frequent or more severe seizures
• Excruciating Nausea or headaches
• Speech issues
• Fever or other infection-related symptoms, such as tenderness, redness, or yellow discharge near the location of the incision