Simplifying Surgery for Movement Disorders

Deep Brain Stimulation (DBS) is an effective treatment of movement disorders when standard drug therapies don't work or have lost their effectiveness. DBS involves surgery that implants electrodes deep into the brain. The length, difficulty and expense of the surgical procedure has limited its availability for those suffering from tremors, rigidity, stiffness and slower movement as a result of neurological disorders including dystonia, multiple sclerosis, Parkinson's disease and even obsessive compulsive disease.

A team of electrical engineers and neuroscientists at Vanderbilt University had developed a pilot guidance system that automates the most difficult part of the operation - identifying the proper location in which to insert the electrodes.

The largest task facing surgeons in DBS procedures is determining exact electrode placement since they cannot see the structure they are seeking. The target is identified by its electrical characteristics. Surgeons must first insert a recording electrode and monitor the electrical activity of the neurons it touches. This can be hit or miss and may have to be repeated several times.

The computer aided guidance system eases the task and shortens it by compensating for variations in the three-dimensional brain structure of each patient. Using a brain atlas that was created by combining brain scans of 21 post-operative DBS patients into one another by using sophisticated computer-mapping allows surgeons to better predict the location of the target area in a new patient.

Using the guidance system has meant that surgeons have hit the target area on the first insertion two-thirds of the time compared to the 20% success rate experience when not working with it.

The developers, Benoit Dawant, professor of electrical engineering, computer engineering and radiological sciences and Peter Konrad, associate professor of neurological surgery and biomedical engineering, are working on a number of improvements to the guidance system. Konrad notes that the guidance system saves patients from risks of a prolonged procedure or having to undergo two procedures. "We have reduced a two-day procedure down to five hours," he says.