Laser ablation rivaled open surgery for epileptogenic lesions

Craniotomies and open resections may soon no longer be necessary to remove focal, well-circumscribed refractory epileptogenic lesions from the brain, two small studies have shown.

Two research teams reported positive, early results for laser ablation, an alternative approach in which a narrow probe is inserted through a small hole in the skull to kill epileptogenic neurons with heat under real-time MRI and EEG guidance.

At the Sutter Neuroscience Institute in Sacramento, "we are having about a 70% [seizure-free] success rate" in the six children and two young adults who have undergone the procedure and been followed for up to a year," said neurologist Michael Chez, director of Sutter’s pediatric and adult epilepsy program. He and his team have treated lesions of the frontal, nonmesial temporal, occipital, and parietal lobes.

"We’ve had some very nice results with a very minimally invasive technique. The outcomes are very promising. We have another six surgeries planned," he said at the annual meeting of the American Epilepsy Society.

Meanwhile, Miami Children’s Hospital reported about a 50% seizure-free success rate following laser ablation in 10 pediatric patients followed for up to 18 months. "The outcomes look comparable" to those achieved with open surgery, and should improve with additional experience. "I think [the technique] has incredible promise," said Dr. Ian Miller, director of neuroinformatics at the hospital.

A handful of epilepsy centers in the United States are developing the technique following the Food and Drug Administration’s approval for soft tissue ablation several years ago.

Hospital stays are much shorter with laser ablation, about 24 hours instead of 3 or more days following open surgery. Laser ablation is also probably less damaging to nearby healthy brain tissue, better able to reach deep-seated foci, more acceptable to patients and parents weary of open techniques, and better tolerated by patients who could not tolerate open procedures and the work-up that precedes them, said Dr. Chez, who noted that developmental disabilities ruled out open procedures in six of his eight patients.

To date, laser ablation has been used in perhaps 85 adult and pediatric epilepsy patients across the United States. Investigators will need to pool their outcomes to compare them to open surgery, and determine the best-case scenario where laser ablation would be helpful, said Miami Children’s neurosurgeon Sanjiv Bhatia, who is also developing the technique there.

After the probe is placed in the operating room – which takes about 30 minutes – patients are rolled into the MRI suite for monitoring during ablation. EEGs with plastic electrodes are monitored, as well. "We can see exactly where the probe is and the spike activity going away during ablation," Dr. Chez said.

Instead of using direct electrophysiologic recording, the investigators are using advanced functional imaging techniques including magnetic EEGs, three-dimensional computer modeling, and stereotactic probe guidance. "The question is if that is ultimately going to be enough to replace direct recordings," Dr. Bhatia said.

For now, the greatest challenge is accurately defining the epileptogenic lesion through a closed skull, without the benefit of the multiple-depth electrodes and grid mapping used during open surgery. "The key to these procedures is having very solid localization," Dr. Miller noted.

The researchers said they had no relevant financial disclosures.

Craniotomies and open resections may soon no longer be necessary to remove focal, well-circumscribed refractory epileptogenic lesions from the brain, two small studies have shown.

Two research teams reported positive, early results for laser ablation, an alternative approach in which a narrow probe is inserted through a small hole in the skull to kill epileptogenic neurons with heat under real-time MRI and EEG guidance.

At the Sutter Neuroscience Institute in Sacramento, "we are having about a 70% [seizure-free] success rate" in the six children and two young adults who have undergone the procedure and been followed for up to a year," said neurologist Michael Chez, director of Sutter’s pediatric and adult epilepsy program. He and his team have treated lesions of the frontal, nonmesial temporal, occipital, and parietal lobes.

"We’ve had some very nice results with a very minimally invasive technique. The outcomes are very promising. We have another six surgeries planned," he said at the annual meeting of the American Epilepsy Society.

Meanwhile, Miami Children’s Hospital reported about a 50% seizure-free success rate following laser ablation in 10 pediatric patients followed for up to 18 months. "The outcomes look comparable" to those achieved with open surgery, and should improve with additional experience. "I think [the technique] has incredible promise," said Dr. Ian Miller, director of neuroinformatics at the hospital.

A handful of epilepsy centers in the United States are developing the technique following the Food and Drug Administration’s approval for soft tissue ablation several years ago.

Hospital stays are much shorter with laser ablation, about 24 hours instead of 3 or more days following open surgery. Laser ablation is also probably less damaging to nearby healthy brain tissue, better able to reach deep-seated foci, more acceptable to patients and parents weary of open techniques, and better tolerated by patients who could not tolerate open procedures and the work-up that precedes them, said Dr. Chez, who noted that developmental disabilities ruled out open procedures in six of his eight patients.

To date, laser ablation has been used in perhaps 85 adult and pediatric epilepsy patients across the United States. Investigators will need to pool their outcomes to compare them to open surgery, and determine the best-case scenario where laser ablation would be helpful, said Miami Children’s neurosurgeon Sanjiv Bhatia, who is also developing the technique there.

After the probe is placed in the operating room – which takes about 30 minutes – patients are rolled into the MRI suite for monitoring during ablation. EEGs with plastic electrodes are monitored, as well. "We can see exactly where the probe is and the spike activity going away during ablation," Dr. Chez said.

Instead of using direct electrophysiologic recording, the investigators are using advanced functional imaging techniques including magnetic EEGs, three-dimensional computer modeling, and stereotactic probe guidance. "The question is if that is ultimately going to be enough to replace direct recordings," Dr. Bhatia said.

For now, the greatest challenge is accurately defining the epileptogenic lesion through a closed skull, without the benefit of the multiple-depth electrodes and grid mapping used during open surgery. "The key to these procedures is having very solid localization," Dr. Miller noted.

The researchers said they had no relevant financial disclosures.

Craniotomies and open resections may soon no longer be necessary to remove focal, well-circumscribed refractory epileptogenic lesions from the brain, two small studies have shown.

Two research teams reported positive, early results for laser ablation, an alternative approach in which a narrow probe is inserted through a small hole in the skull to kill epileptogenic neurons with heat under real-time MRI and EEG guidance.

At the Sutter Neuroscience Institute in Sacramento, "we are having about a 70% [seizure-free] success rate" in the six children and two young adults who have undergone the procedure and been followed for up to a year," said neurologist Michael Chez, director of Sutter’s pediatric and adult epilepsy program. He and his team have treated lesions of the frontal, nonmesial temporal, occipital, and parietal lobes.

"We’ve had some very nice results with a very minimally invasive technique. The outcomes are very promising. We have another six surgeries planned," he said at the annual meeting of the American Epilepsy Society.

Meanwhile, Miami Children’s Hospital reported about a 50% seizure-free success rate following laser ablation in 10 pediatric patients followed for up to 18 months. "The outcomes look comparable" to those achieved with open surgery, and should improve with additional experience. "I think [the technique] has incredible promise," said Dr. Ian Miller, director of neuroinformatics at the hospital.

A handful of epilepsy centers in the United States are developing the technique following the Food and Drug Administration’s approval for soft tissue ablation several years ago.

Hospital stays are much shorter with laser ablation, about 24 hours instead of 3 or more days following open surgery. Laser ablation is also probably less damaging to nearby healthy brain tissue, better able to reach deep-seated foci, more acceptable to patients and parents weary of open techniques, and better tolerated by patients who could not tolerate open procedures and the work-up that precedes them, said Dr. Chez, who noted that developmental disabilities ruled out open procedures in six of his eight patients.

To date, laser ablation has been used in perhaps 85 adult and pediatric epilepsy patients across the United States. Investigators will need to pool their outcomes to compare them to open surgery, and determine the best-case scenario where laser ablation would be helpful, said Miami Children’s neurosurgeon Sanjiv Bhatia, who is also developing the technique there.

After the probe is placed in the operating room – which takes about 30 minutes – patients are rolled into the MRI suite for monitoring during ablation. EEGs with plastic electrodes are monitored, as well. "We can see exactly where the probe is and the spike activity going away during ablation," Dr. Chez said.

Instead of using direct electrophysiologic recording, the investigators are using advanced functional imaging techniques including magnetic EEGs, three-dimensional computer modeling, and stereotactic probe guidance. "The question is if that is ultimately going to be enough to replace direct recordings," Dr. Bhatia said.

For now, the greatest challenge is accurately defining the epileptogenic lesion through a closed skull, without the benefit of the multiple-depth electrodes and grid mapping used during open surgery. "The key to these procedures is having very solid localization," Dr. Miller noted.

The researchers said they had no relevant financial disclosures.