Deep Brain Stimulation Offers Hope for Symptom Control

This article originally appeared in Pathways, a magazine published for physicians and the community by UMass Memorial Medical Center.

Neurosurgeon Julie Pilitsis, MD, PhD, a member of the UMass Memorial movement disorders team, performs both the framed and frameless deep brain stimulation procedure.

For appropriately selected patients with Parkinson's disease, essential tremor and dystonia, deep brain stimulation (DBS) offers considerable hope for symptom control and improved quality of life when medical therapy ceases to be effective. Julie Pilitsis, MD, PhD, director of functional neurosurgery and a member of the UMass Memorial movement disorders team, has performed this potentially life-changing surgery at the Medical Center for just over one year. UMass Memorial is, in fact, the only facility in Central Massachusetts with this capability.

"Most standard DBS practices will do a handful of cases to start," she said. "We've done 30 in less than a year, so we're ahead of the curve."

New frameless procedure enhances patient comfort

Dr. Pilitsis also is the first physician in New England to perform the frameless DBS procedure, which can significantly reduce patient discomfort.

"The traditional DBS procedure requires a box-like frame to be bolted to the skull, similar to a halo brace, then it's secured to the operating table," she explained. The frame has a scale to target coordinates off each axis, so the surgeon can determine precisely where to place the probe. "But there's no neck mobility, and it can be very claustrophobic for the patient," Dr. Pilitsis noted.

"With the frameless method, rather than putting a box on the patient's head, we put markers on his or her skull," she said. "There's minimal discomfort since we use a topical anesthetic. And rather than being in a rigid frame attached to the table, the patient is placed in a collar that opens in the front, so he or she can adjust positions and not feel claustrophobic."

Importantly, the accuracy of the frameless and framed techniques was found to be equal, according to a study published in the Journal of Neurosurgery.

When is DBS appropriate?

Dr. Pilitsis acknowledges that with Parkinson's disease, the optimal timing for DBS is still being refined. "It's generally thought that this type of surgical intervention is appropriate for patients who've lived with the disease for at least five years and have tried a number of medications, but they've either stopped getting enough benefit to have a good quality of life, or they're experiencing severe side effects," she said. In as many as 75 percent of Parkinson's patients, the medications used for symptom control lose effectiveness over time, resulting in either too little or too much movement.

"Anyone with dementia is not a good candidate," she added. "And while depression and anxiety can go hand-in-hand with Parkinson's, they're not necessarily a contraindication if the patient is receiving treatment. We have the patient undergo neuropsychiatric evaluation to make sure."

With essential tremor, surgery is appropriate for those whose quality of life has been compromised. Essential tremor affects 20 times more people than Parkinson's, Dr. Pilitsis pointed out, but not as many people realize that DBS is a treatment option for this condition.

"I had a patient who loved to cross-stitch but couldn't do it at all because of essential tremor," Dr. Pilitsis related. "DBS helped her resume her hobby."

Thorough evaluation 

Patient evaluation and selection is the principal role of neurologist Paula Ravin, MD, director of the UMass Memorial Movement Disorders Center, who follows more than 600 long-term Parkinson's patients and evaluates referrals for DBS. The screening team also includes neurologist Peter Novak, MD, PhD; neuropsychologist Joan Swearer, PhD; neuropsychologist Brian Dessureau, PhD;
Jill Damon, PhD; and Lindsey Jolley, PA.

Evaluation involves extensive testing that includes motor assessment both on and off medication, neuropsychiatric assessment for cognitive function, and counseling to ensure the patient fully understands the risks and potential benefits of surgery. Team meetings are held to review and select appropriate candidates and to schedule electrode and battery implantation and subsequent programming.

Implantation and programming

DBS implantation is a painstaking procedure in which tiny electrodes are threaded deep into the brain to provide an electrical impulse to either the subthalamic nucleus, the ventralis intermedius nucleus of the thalamus or the globus pallidus - areas that control movement. The electrodes are connected to wires that snake from the skull, behind the ear and down to a battery-powered impulse generator that is placed beneath the skin, under the collarbone.

The battery is implanted during a second procedure a week after electrode placement, and it is turned on about a week after that. Then Dr. Ravin begins programming the device, which can take from two to four visits.

"The entire process, from initial discussion through completed programming, can take four to six months and require as many as eight visits," Dr. Ravin noted. For patients in the region, having this capability at UMass Memorial is considerably more convenient than traveling into Boston for multiple visits. Further, every effort is made to cluster visits whenever possible.

Documented outcomes

DBS outcomes vary from disease to disease. "In Parkinson's patients, we see a 50 to 80 percent improvement in motor outcomes, rigidity, tremor and dyskinesias," said Dr. Pilitsis, referring to national outcomes data. "Results can be even more impressive with essential tremor, with 80 to 90 percent improvement. For dystonia, it depends on the type," she added, noting that a 50 to 70 percent improvement in generalized dystonia has been reported, but secondary dystonia (such as spasmodic torticollis) is a relatively new indication for which preliminary data suggests as high as a 50 percent improvement in well-selected patients.

Both Drs. Pilitsis and Ravin emphasize that DBS is not a cure for movement disorders. "But as far as significantly reducing patients' medication and restoring their quality of life, this procedure does that," Dr. Pilitsis said. "And it's relatively safe, with a less-than-one-percent stroke risk. Compared to many other things we do - and not just in the neurosurgery world - that's a relatively low risk."

Patient evaluation can be scheduled quickly

"We're available for consultation about whether DBS is worth considering for a patient," Dr. Ravin said. "Too often, patients don't get referred until they're very disabled or cognitively impaired. We'd rather see patients get referred when any question arises about the next step in treatment so we can provide feedback."

Initial evaluation can be scheduled within two weeks - something that can take months at other institutions. "Call us directly," Dr. Ravin noted, referring to herself or Dr. Pilitsis at the Movement Disorder Center, 508-334-0605.

"Also, because of all the things happening in Parkinson's research, referring a patient here for the next step in treatment could also mean participation in a clinical trial, new medications or surgery," she added. "There are a lot of options today, and most patients can live a full life span with appropriate therapy."