He performed the surgery on pediatric patients with infantile hemiplegia, specifically as a treatment for their seizures and cognitive impairment.
As a result of the complication risk and the introduction of new anti-seizure medications, the popularity of the procedure began to decline in the 1950s.
Although this modification seemed to solve this issue, patients undergoing the modified hemispherectomy continued to have seizures, which was problematic.
[4] This surgery, the functional hemispherectomy, has been further modified over the years by several different neurosurgeons, and to this day there is not a consensus as to which exact technique should be used.
Hemispherotomy refers to some of the more recently developed approaches to disconnect the epileptic hemisphere while minimizing brain removal and the risk for complications.
[7] However, they do carry a risk of incomplete disconnection, which refers to when the surgeon inadvertently leaves remnants of fibers that continue to connect the hemisphere to the brain and body.
Another term that falls under the hemispherectomy umbrella includes hemidecortication, which is the removal of the cortex from one half of the cerebrum, while attempting to preserve the ventricular system by maintaining the surrounding white matter.
[7] The typical candidates for hemispherectomy are pediatric patients who have intractable epilepsy due to extensive cerebral unilateral hemispheric injuries.
Most patients also undergo other studies including functional MRI (fMRI), positron emission tomography (PET) or magnetoencephalography (MEG).
[9] The most common underlying etiologies include malformations of cortical development (MCD), perinatal stroke and Rasmussen’s encephalitis.
[6] MCD is an umbrella term for a wide variety of developmental brain anomalies, including hemimegalencephaly and cortical dysplasia.
There are several blood vessels that have connections with both sides of the brain, and these are carefully identified and clipped in such a way that spares the healthy hemisphere.
Portions of the cerebral lobes from the damaged side of the brain are removed, depending on the specific procedure being performed.
[7] Additional epilepsy surgery following hemispherectomy is rare (4.5%),[7] but may be recommended if there is a residual connection between the two hemispheres that is causing frequent seizures.
[6] Other possible complications include infection, aseptic meningitis, hearing loss, endocrine problems and transient neurologic deficits such as limb weakness.
[12] In terms of postoperative motor function, some patients may have improvement or no change of their weaker extremity,[10] and many can walk independently.