Neurology & Neurosurgery Advances

NewYork-Presbyterian

Advances in Neurology & Neurosurgery

Neurosurgeons Advance Applications of Minimally Invasive Techniques for Epilepsy

NewYork-Presbyterian Hospital neurosurgeons are redefining therapies to control and cure seizures that defy the prevailing treatments.

In the Level 4 Epilepsy Centers at NewYork-Presbyterian/Columbia University Irving Medical Center and NewYork-Presbyterian/Weill Cornell Medical Center, patients with refractory epilepsy are finding help and hope for their uncontrollable seizures without needing to undergo invasive craniotomies. These include laser thermal ablation therapy and high-intensity focused ultrasound.

Laser Thermal Ablation Therapy

With the emergence of stereo-electroencephalography (SEEG) and advanced brain imaging, data on the origin of epileptic seizures can be captured as they occur, enabling neurosurgeons to determine the optimal treatment approach – laser ablation or open surgery. Laser ablation is particularly valuable for reaching seizures in the hippocampus.

Our neurosurgeons are using the newest ablation technique, MR-guided laser interstitial thermal ablation, to eradicate the seizure focus. The laser fiber is placed into the hippocampus through a very small opening in the skull and using an MRI scanner, they can see exactly what they are achieving with ablation in real time. The approach offers access to foci virtually anywhere in the brain with minimal disruption of the overlying cortex and white matter, resulting in fewer neurological side effects.

A study by faculty of Columbia University Vagelos College of Physicians and Surgeons evaluated the effectiveness of laser ablation for temporal lobe epilepsy in 30 patients – with and without mesial temporal sclerosis (MTS) – if hippocampal seizure onsets are localized by SEEG. Seizure freedom was achieved in 57 percent of patients overall, offering early evidence that by confirming mesial temporal onset with SEEG, patients without MTS can achieve rates of seizure freedom following laser ablation similar to those with MRI-diagnosed MTS. Read more at:

https://onlinelibrary.wiley.com/doi/full/10.1111/epi.14004

The researchers note that because laser ablation is a focal therapy, surgical resection of the epileptogenic zone still offers the best chance of seizure freedom. However, patients generally decide to undergo laser ablation first as it is much less invasive and some 60 percent of patients undergoing the procedure will become seizure-free. A comprehensive review of laser ablation for epilepsy was published by the Columbia team in the April 1, 2020 issue of Neurosurgery. https://academic.oup.com/neurosurgery/article-abstract/86/4/E366/5715752?redirectedFrom=fulltext

A prospective study of MR-guided stereotactic laser ablation for temporal lobe epilepsy is now underway at NewYork-Presbyterian and many other sites across the country. You can read about the new study at:

https://onlinelibrary.wiley.com/doi/full/10.1111/epi.16529

Focused Ultrasound

Our neurosurgeons also have been uncovering important applications for high-intensity focused ultrasound, including essential tremor and, more recently, tremors related to Parkinson’s disease. Applications of this novel therapeutic modality continue to be developed, including for the treatment of refractory epilepsy. Focused ultrasound is under study at other centers for its ability to directly ablate lesions that are responsible for epilepsy, or modulate the way that the temporal lobe functions to treat epilepsy. At Weill Cornell, neurosurgeons are evaluating a completely different approach that targets the outflow tracts of the temporal lobe, a small, deep white matter structure to disrupt the abnormal circuitry in temporal lobe epilepsy. This is a smaller and deeper target than those currently under investigation, which present treatment advantages for focused ultrasound. They then undertook a study to test the feasibility of magnetic resonance-guided focused ultrasound (MRgFUS) ablation of this structure in mesial temporal lobe epilepsy.

The Weill Cornell Medicine team retrospectively reviewed 3-T MRI scans obtained with diffusion tensor imaging. The study group included 10 patients with essential tremor who underwent pretreatment CT and MRI prior to MRgFUS, and two patients with mesial temporal sclerosis who underwent MRI. From the results of their study, which were published in the June 2019 issue of Journal of Neurosurgery, the team determined that MRgFUS can theoretically disconnect posterior mesial temporal structures to potentially create a novel, noninvasive treatment approach toward mesial temporal sclerosis, avoiding the morbidity associated with current open and minimally invasive treatment options.

The researchers believe that this method is reproducible in select patients, and the study paved the way for their development of a clinical study employing this novel strategy in a larger cohort of patients.

You can read more about the feasibility study at https://thejns.org/view/journals/j-neurosurg/133/1/article-p63.xml