Dr. Theodore Schwartz and Dr. Mingrui Zhao have been awarded a $100,000 grant from the Weill Cornell Daedalus Fund for Innovation to explore a novel approach to curing epilepsy surgically. The award, effective September 2015, will allow Dr. Schwartz’s team to develop and use a new “laser scalpel” — tightly focused infrared pulses, only a femtosecond in duration, to sever neural connections around the focus of a seizure to prevent it from spreading.
Focal seizures are those that affect a limited area of the brain — they originate in a very specific location, or focus, then spread. If that seizure focus can be safely removed, patients whose seizures are not controllable with medication can be cured surgically. When the seizure focus is located in a functional part of the brain, however, surgical options are limited because removing the focus interferes with brain function in that area. In this new research, Dr. Schwartz’s team will test a surgical approach that can stop a seizure’s spread without causing neurological injury.
The new technique takes advantage of the fact that focal epileptic seizures spread laterally from the point of origin, but the brain’s information processing functions are organized vertically in the cortex. If the focus cannot be removed, leaving it in place but severing the connections that allow a seizure to spread offers a new potential for a surgical cure in those patients.
The cuts must be so small, and so precise, that they are beyond the ability of older surgical instruments to make. Dr. Schwartz’s team has been using laser scalpels in epilepsy surgery in patients where it’s possible to remove the seizure focus, but this is the first test of these laser pulses to sever lateral connections while leaving the focus in place.
In focal epilepsy, seizure activity spreads along horizontal neural connections (a), but normal brain activity is more vertically organized between layers (b). Subsurface, femtosecond laser cuts could block seizure with minimal collateral damage (c).
Each infrared laser pulse lasts only a femtosecond, which is 10 to the minus 15th of a second (that is one quadrillionth, or one millionth of one billionth, of a second). That pulse must not damage blood vessels on the brain surface, and it must sever horizontal connections in as few cortical layers as possible to disrupt seizures with minimal neurological impact.
The research team has already found that a single ring of cuts around a focus can reduce the spread of a seizure by 50 percent. This new research will now test multiple concentric rings and a grid of cuts that overlays the focus, investigating whether these more complex cut geometries can achieve even greater seizure control.
This new research requires a multi-disciplinary team with expertise in clinical neurological surgery for epilepsy, the neurophysiology of epilepsy in animal models, and femtosecond laser ablation of brain tissue. In this project, the expertise will be provided by Dr. Schwartz, Dr. Zhao, and a new fellow who will work under the mentorship of Dr. Chris Schaffer in Ithaca. It is hoped that the investigation will yield results that allow for an extremely precise, laser-based surgical solution for focal epilepsy.
The Weill Cornell Medical College Daedalus Fund for Innovation was designed to support early-stage research projects and to foster and expedite the development of discoveries that can benefit the public. The fund supports key experiments aimed at generating the proof-of-concept and validation data necessary make a new technology commercially viable.
