- Last Updated on 14 December 2016
Corpus callosotomy a neurosurgical procedure in which the principal connection between the left and right brain—the corpus callosum—is severed. In some types of seizures, and rarely in infantile spasms, the seizures are especially severe because electrical discharges associated with these seizures spread very rapidly to both sides of the brain. This rapid spread of electrical discharges, via the corpus callosum, can be responsible for falls or other injuries during seizures. The goal of corpus callosotomy is to prevent this rapid spread of seizures, and thus prevent falls and other injuries that result from these seizures.
In select cases of infantile spasms and other epilepsy syndromes, seizures spread so quickly within the brain that neurologists can't determine where seizures originate, and as a result, have difficulty treating the seizures. As corpus callosotomy destroys the main connection between the left and right brain, this procedure can be a method to determine "laterality", i.e. to figure out which side of the brain is the source of seizures. If a focal source of seizures is discovered, additional therapies could be indicated, especially focal surgical resection.
Like any treatment for infantile spasms, corpus callosotomy doesn't always work. Although the corpus callosum is the main connection between the left and right brain, there are other smaller connections which can't be easily cut with surgery. It is possible for seizures to spread from one side of the brain to the other, through these smaller connections.
You might ask why we have a corpus callosum, and what happens if you destroy it. This structure has many functions, and its key role is to facilitate most tasks that require the use of both sides of the brain. Damage to the corpus callosum can result in disrupted cognitive processing, incoordination, and potentially deleterious effects on language skills (especially reading). However, like many structures in the brain, if the injury (intentional or otherwise) occurs at an early age, substantial recovery and accommodation is possible. In patients who already exhibit well-developed language, a so-called "anterior two-thirds corpus callosotomy" (in which the rear one-third of the structure is preserved) can be undertaken to reduce to risk of linguistic side effects.
As is the case with other epilepsy surgeries, corpus callosotomy is not undertaken without careful consideration of the risks and benefits of the procedure. The decision making process is similar to that described for focal resections or hemispherectomy. Corpus callosotomy is rarely employed in the treatment of infantile spasms, and success is much more common in the treatment of atonic seizures or tonic seizures associated with Lennox-Gastaut syndrome.