Neurosurgeons continue to explore the less invasive Gamma Knife radiosurgery for elimination of temporal lobe abnormalities and brain lesions.
The Gamma Knife itself has been around for quite a while, so there’s a history of its use. But its application specifically for this form of epilepsy hasn’t really been done before. Therefore, the purpose of recent research was to see if the advantages of this minimally invasive tool could provide an alternative to standard surgery.
In one clinical Gamma Knife surgery trial, researchers found the number of seizures was dramatically decreased from a media of 92 seizures per month pre-operatively to 6 seizures per month after the procedure. And another smaller study showed, 66% of patients to be seizure-free following 18 months of treatment.
The term “Gamma Knife” connotes that it delivers radiation treatment as though it were an actual knife, offering the kind of precision and targeting as actual surgery. Indeed, it uses radiation in much the same way as a surgeon uses a knife.
The Gamma Knife “blades” are actually 201 beams of gamma radiation, with the precision of less than 1 mm, tightly focused to target the brain lesions. The aim is to impair the lesion and inhibit it from causing further seizures. Computer software guides the surgeon to the correct vantage points during the process and the lesion is carefully damaged.
Over time (several months to one year), most lesions slowly decrease in size and dissolve. The radiation exposure is brief and only the tissue being treated receives a significant dose, while the surrounding tissue remains unharmed.
When the entire lesion can be targeted, radiosurgery more than reduces the seizures, plus there are encouraging effects on cognition and quality of life. And although at this point, the procedure has shown to be ineffective for large lesions, Gamma Knife surgery could be a first-line surgical therapy to “blast” small tumors such as hamartomas — associated with partial gelastic (“laughing”) seizures.
Published reports indicate that the Gamma Knife may be used as an alternative to standard neurosurgical operations or as an adjunct therapy in the treatment of residual or recurrent lesions left unresected by conventional surgery. And the fact that it is a single treatment, usually done as an out-patient procedure, makes it especially appealing for those who are qualified.
“Epilepsy surgery probably is underutilized, and an alternate method may bring the benefits of surgery to a wider group of patients.” — Mark S. Quigg, M.D., Neurologist at University of Virginia School of Medicine
Let’s hope so.