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Swiss team uses non-invasive
deep brain ablation in study
By AMANDA PEDERSEN
Medical Device Daily Staff Writer
InSightec (Tirat Carmel, Israel) reported that a team at
the University Children’s Hospital (Zurich) has completed a
10-patient feasibility study testing the use of noninvasive
transcranial MR-guided focused ultrasound surgery
(MRgFUS) for the treatment of neuropathic pain.
According to the company, 10 adult patients diagnosed
with chronic neuropathic pain underwent non-invasive
deep brain ablation surgery (central lateral thalamotomy)
with transcranial MRgFUS and showed improvement in
pain scores and reduction of pain medication with no
adverse effects at three months follow-up. This is the first
study in the world to test non-invasive transcranial focused
ultrasound as a treatment modality for functional brain disorders,
InSightec noted.
“This study showed that we can perform successful
operations in the depth of the brain without opening the
cranium or physically penetrating the brain with medical
tools, something that appeared to be unimaginable only a
few years ago,” said Daniel Jeanmonod, MD, a neurosurgeon
at the University of Zurich. “By eliminating any physical
penetration into the brain, we hope to duplicate the
therapeutic effects of invasive deep brain ablation without
the side effects for a wider group of patients.”
Neurosurgeons currently treat patients with functional
neurological disorders such as neuropathic pain or
Parkinson’s disease by inserting a tiny probe through the
cranium and brain to reach and ablate damaged tissue. For
the patient, the procedure really is as simple as it sounds.
Eyal Zadicario, director of Neuro Programs at Insightec,
told Medical Device Daily that for the patient, instead of
going in for surgery, they are basically going in for an MRI.
The patient is sent through an MRI scanner similar to a regular
diagnostic MRI scanner, he said, only this scanner has
a special ultrasound system integrated into it which can
non-invasively ablate tissue inside the brain. Zadicario said
it is an outpatient procedure and no anesthesia is used at
all. In the study, he said, the 10 patients were kept under
watch in a hospital for 24 hours, but nothing was done to
them during that post-procedure monitoring time.
InSightec says that the more traditional invasive treatment
works to alleviate pain and other symptoms, however
it exposes the patient to complications, including infections,
bleeding and damage to surrounding brain tissue,
Jeanmonod explained. Also, only patients whose target tissue
lies in the clear path of the probe are eligible for the
invasive procedure, he said.
“We now have early clinical evidence suggesting that
transcranial MRgFUS provides a safe and effective way to
non-invasively ablate tissue deep within the brain,” said
MEDICAL DEVICE INNOVATION 2010
Ernst Martin, MD, director of the Magnetic Resonance
Center at the University Children’s Hospital. “While we need
to monitor these patients further, we are very encouraged
by the results to date and look forward to continuing our
research. A non-invasive treatment that reduces the risk of
infection and bleeding will fill an unmet need for many
patients who currently have run out of treatment options
or are unwilling to undergo invasive brain surgery because
of the risks associated with it.”
According to InSightec, the Swiss research team is planning
a larger study for functional brain disorders and
expands its clinical research to movement disorders, such
as Parkinson’s disease and tremor, and to other functional
neurological disorders later this year. Additional sites in
North America are also expected to initiate clinical research
programs in functional brain disorders with transcranial
MRgFUS later this year.
Zadicario said there are basically three main advantages
to being able to do this procedure noninvasively:
Being able to treat tissue in the brain, especially tissue that
is deep in the brain, without having to cut through normal
healthy tissue to get there; not being concerned with
restrictions of getting to the deep brain target as is sometimes
the case during the minimally invasive method of
doing this procedure; and of course the patient is not at risk
of developing the complications associated with surgical
intervention such as bleeding or infection.
“When we do it noninvasively under MR guidance . . . we
basically see the tissue that we treat and treat it,” he said. It
is a much more accurate method than the surgical method,
he noted. One patient in the study suffered nerve damage
from a spinal tumor that led to severe pain and cramps in
his right arm. The pain persisted for years and the patient
ultimately reported depression and suicidal thoughts
because of his condition. Immediately after receiving transcranial
MRgFUS treatment on his brain, he reported that
the pain had disappeared. A short time later he was able to
resume normal activities that his neuropathic pain had prevented
him from doing, such as gardening and outings in
the country with his family.
According to the company, the ExAblate 400 is the first
system to use MR guided focused ultrasound technology
that combines MRI – to visualize the body anatomy, plan
the treatment and monitor treatment outcome in real time
– and high intensity focused ultrasound to target brain tissue
non-invasively. MR thermometry allows the physician
to control and adjust the treatment in real time to ensure
that the targeted area is fully treated and surrounding tissue
is spared, InSightec said. The ExAblate 400 is a platform
for a variety of transcranial indications, such as brain
tumors, functional neurosurgery, stroke and targeted drug
delivery, the company noted. The ExAblate 2000, based on
the same technology, was approved by the FDA in 2004 as
a treatment for symptomatic uterine fibroids. That system
received a CE mark for pain palliation of bone metastases in
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