What the Heck is Functional Neurosurgery? Restoring our Patients’ Quality of Life

Guest post written by Joshua M. Rosenow, MD, FAANS, FACS, from the Department of Neurological Surgery at Northwestern.

For most neurosurgical subspecialties, the name is
sufficient for an average to understand what we do. Spinal neurosurgery, neurosurgical oncology
and cerebrovascular neurosurgery are all reasonably self-explanatory. However, the
term “functional neurosurgery” fails to explain the breadth and depth of this
most interesting of neurosurgical fields. Functional neurosurgery is in the
midst of an explosion of innovation and progress, with new devices and expanding
indications that allow neurosurgeons to help more people than ever before.

Functional neurosurgery broadly deals with procedures that modify the functioning of the nervous system, from the brain itself down to peripheral nerves in the arm or leg. This can be done through a variety of techniques, such as removing an area of the brain causing seizures, infusing medication directly into the spinal fluid, or using an electrical stimulator on the brain or spinal cord to improve the symptoms of Parkinson’s disease or chronic pain. On any given day, functional neurosurgeons work with people experiencing such neurological disorders as complex regional pain syndrome, epilepsy, essential tremor, dystonia, Parkinson’s disease, nerve injuries, spinal cord injury, multiple sclerosis, trigeminal neuralgia, Tourette syndrome, failed back surgery syndrome, and brain trauma. At the Department of Neurosurgery at Northwestern, we continue to expand the boundaries of this field and improve the quality of life of patients.

For one-third of patients with epilepsy, they continue to
have seizures despite taking multiple medications. In the past, the only
surgical options available to these patients were either removal of the area of
the brain causing seizures or implantation of an electrical stimulator on the
vagus nerve in the neck (the VNS device) to send impulses to the brain. Now, we
can place a small laser fiber directly into the seizure zone through a tiny
opening in the skull and destroy it under real-time MRI guidance. Patients
typically only stay in the hospital one night and are back to full activity
very quickly. For some patients, the
area of the brain causing seizures can be identified but not removed without
causing disability. We now can implant electrodes directly in the affected region.
These electrodes are connected to a device mounted in the skull that
continually reads the electrical signals (EEG) from that area. We can then
teach the device to recognize the seizure patterns on the EEG, and the device
can deliver stimulation in response to these patterns like a “brain
defibrillator.” Not only can this responsive neurostimulation therapy
significantly reduce seizures, but we gain valuable information from many hours
of EEG recordings which gives us unprecedented insight into a person’s
epilepsy. Even the VNS device has significantly improved and can now sense a
person’s heart rate and deliver extra stimulation if the heart rate increases
at the start of a seizure.

For the last 30 years, neurosurgeons have used electrical
stimulation of deep brain structures to improve the slowness, stiffness, and
tremor of advanced Parkinson’s disease. Most recently, we have seen the
introduction of more sophisticated devices that improve therapy by allowing the
electricity to be directed preferentially in specific directions within the
brain to reduce unwanted spread of current and improve outcomes. We have also
seen the advancement of gene therapy trials that have the promise of reversing
the degeneration in the brain that leads to the disease. Many of these are
being done using MRI guidance to monitor the infusion of therapies into the
brain in real-time.

While we have been using electrical stimulation of the
spinal cord for more than 40 years to treat certain types of chronic pain, we
now have advanced methods of stimulation that bring more relief to patients
suffering from debilitating pain. In the past, the stimulation effect relied on
causing paresthesias — a dull buzzing or tingling feeling — in the affected
body region to block the pain signals. However, many patients complained about
this sensation, and the intensity of the sensation could vary significantly
with the person’s position. We now have multiple methods of stimulation, using
higher frequencies or short bursts of pulses, that produce very little of these
sensations and are not altered by positional changes. The result is tremendous
reductions in pain, allowing patients to wean off some or all of their pain
medication.

We are also working to bring hope to those with brain and
spinal cord injury through innovative research programs. Functional
neurosurgeons are heavily involved with brain-computer interface devices that
allow a person to execute commands on a computer screen or with a robot arm
using just their thoughts that are detected up by a small microchip implanted
in the brain. This can allow someone who is paralyzed or has a degenerative
disease like ALS (Lou Gehrig’s disease) to communicate and be more independent.
Advances in this technology are exploring the restoration of sensory functions and
enhancing memory function as well.

To those of us in the field of functional neurosurgery, we see this as the most exciting time for our specialty and look forward to continuing to help people with chronic neurologic conditions live better lives.