Alternative to Epilepsy Surgery Offered by MRI-Guided Laser Treatment

For patients with mesial temporal lobe epilepsy (MTLE) that cannot be controlled by drugs, a minimally invasive laser procedure performed under magnetic resonance imaging (MRI) guidance provides a safe and effective alternative to surgery, according to new research.

The study’s findings were published in the June 2014 issue of Neurosurgery, the official journal of the Congress of Neurological Surgeons. “Real-time magnetic resonance-guided stereotactic laser amygdalohippocampotomy [SLAH] is a technically novel, safe, and effective alternative to open surgery,” according to the new research by Dr. Robert E. Gross, from the Emory University School of Medicine (Atlanta, GA, USA) and colleagues.

The researchers report their experience with MRI-guided SLAH in 13 adult patients with epilepsy mapped to an area of the brain called the mesial temporal lobe. The patients, median age 24 years, had “intractable” seizures in spite of treatment with antiepileptic drugs.

In the SLAH procedure, a saline-cooled fiberoptic laser probe was precisely targeted to the brain region—the amygdalohippocampal complex. Using real-time MRI guidance, the neurosurgeon was able to target the area of the brain responsible for seizure activity and ablate by computer-controlled laser energy, without injuring the surrounding brain tissue.

The technical features of the procedure were effectively carried out in all patients. Using thermal imaging and MRI guidance, the surgeons were able to see the area of laser ablation as treatment proceeded. The average laser exposure time was just under 10 minutes. On average, 60% of the amygdalohippocampal complex was destroyed in the SLAH procedure; the average length of the ablated area was 2.5 cm. Median time spent in the hospital was only one day compared to a typical two to five-day stay after standard temporal lobe surgery, and SLAH patients did not have to be admitted to the intensive care unit.

Most significantly, the procedure was effective in lessening or eliminating seizures in patients with MTLE. At a median of 14 months after SLAH, 10 out of 13 patients achieved meaningful seizure reductions, while seven were free of disabling seizures. This included six out of nine patients whose epilepsy was caused by a defect called mesial temporal sclerosis. Although some complications occurred, none were directly caused by laser application. Two patients had an additional SLAH procedure to control seizures, and another patient underwent standard open surgery.

Open brain surgery is the standard treatment for patients with intractable MTLE. Surgery has a high success rate, but carries a significant risk of neurological and cognitive (intellectual) impairment. Minimally invasive approaches like the new MRI-guided laser ablation technique might produce similar seizure control with lower risks than surgery.

The new findings shows “technical feasibility and encouraging results” with the minimally invasive MRI-guided SLAH technique for patients with MTLE. Effectiveness in relieving or eliminating seizures approaches that of surgery—possibly in particular among patients whose seizures are caused by mesial temporal sclerosis. “These are promising results considering that this reflects our initial experience, and results may improve with greater experience with this novel technique,” noted Dr. Gross. “Such minimally invasive techniques may be more desirable to patients and result in increased use of epilepsy surgery among the large number of medically intractable epilepsy patients,” Dr. Gross and colleagues concluded. They stressed that a larger, longer-term study of SLAH is underway, including assessment of the effects on cognitive function as well as seizures.

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Emory University School of Medicine