For Parkinson’s patients and their doctors, some solid advice on surgery

Almost a decade has passed since the FDA approved an electronic “pacemaker” device to control the tremors, rigidity and abnormal gait that come with Parkinson’s disease, and some 70,000 patients have had surgery to implant it deep in their brains. With that, a clearer picture is emerging of who benefits most from the procedure, what its risks are, and how deep brain stimulation stacks up against an older surgical procedure in relieving Parkinson’s symptoms.

Parkinson’s patients most likely to improve with deep-brain stimulation are younger, initially responded well to the drug levodopa, have physical disability but few cognitive or psychiatric symptoms, and get their pacemakers programmed by a highly trained technician, according to an expert panel of Parkinson’s disease specialists. Patients who are still responding to the drug levodopa, whose effectiveness will decline over time, don’t seem better off getting deep-brain stimulation early: it’s best to wait at least five years after diagnosis before proceeding to the pacemaker, said the experts, whose “Consensus” document was published this week in the Archives of Neurology.

Roughly a million Americans suffer from Parkinson’s disease, a degenerative disease that causes tremors, balance problems and halting movement. This year, about 60,000 will get a diagnosis of Parkinson’s--and as the population ages, that number is expected to rise.

Patients who have the device implanted in a region of the brain called the subthalamic nuclei (or STN) get some benefits over those whose device is implanted in a region called the globus pallidus pars interna (GPi)--they need less medicine to control their symptoms. But new research suggests that those who get the pacemaker sunk into their brain’s STN are more likely to become depressed and impulsive, and to suffer declines in verbal fluency, visuomotor processing speed and executive function, than those who have the device implanted in the brain’s GPi.

For Parkinson’s patients whose tremors, rigidity and walking problems have become disabling, deep-brain stimulation can bring remarkable relief. But the authors of the new consensus document stressed that it does not appear to slow or halt the progression of the disease, which will, in time, overwhelm the effects of the pacemaker. They also underscored that the surgery is not without risks: as many as 10% of surgical patients suffer intracranial hemorrhage and as many as 15% suffer post-operative infection.

It’s not cheap, either: surgery for Parkinson’s can cost as much as $100,000.

The consensus document comes in a period of rapid expansion of surgeries to implant deep-brain-stimulation devices for Parkinson’s disease. The complex procedure of implanting and programming the device is spreading beyond specialty hospitals and academic medical centers--the result of aggressive marketing by Medtronic, the medical device giant that holds the patent. Against that backdrop, the consensus document underscored the importance of selecting patients for surgery who are likely to benefit most, and of expertise on the part of neurologist, surgeon and device programmer.

“It is a business,” said neurologist Jeff M. Bronstein, the consensus document’s lead author and director of UCLA’s movement disorder program. Patients who are “shopping” for treatments will find no shortage of hospitals and surgical centers eagerly offering the surgery, he said. But not all are well equipped and trained to implant and program the device, and not all have the integrity to steer patients toward another treatment or procedure if they are unlikely to have a good outcome, Bronstein added. And for some patients, he said, an older surgery, which selectively destroys part of the brain affected by Parkinson’s, should still be considered.

--Melissa Healy/Los Angeles Times