Complication Rate No Higher With DBS in Older PD Patients

Pauline Anderson

August 28, 2014

Older patients with Parkinson's disease undergoing deep brain stimulation (DBS) have about the same rate of surgical complications as younger patients, new research shows.

The risks for postoperative hemorrhage, pneumonia, pulmonary embolism, and infection were about the same for patients older than age 75 years as for those 75 years and younger, the study found.

The results suggest that older patients shouldn't be refused this treatment option on the basis of age alone, according to study author Shivanand P. Lad, MD, PhD, assistant professor, neurosurgery, Duke University Medical Center, Durham, North Carolina.

"Patients in their 70s or older can now be somewhat reassured, at least from a surgical perspective, that their complication rates are similar to younger patients."

DBS, which has been around for some 20 years, is a "fairly safe and routine operation" for people with PD, said Dr. Lad. "It works well for patients who are medically refractory or have side effects from some of the medications in terms of dyskinesia, and whose symptoms, especially tremor and rigidity, can be helped with DBS."

The study, funded by the National Institutes of Health, is published online August 25 in JAMA Neurology.

Dr. Shivanand P. Lad

For this report, the researchers used data from the large and comprehensive Thomson Reuters MarketScan national database, which contains information from Medicare, Medicaid, and commercial insurance claims. The study included 1757 patients who had undergone DBS for PD between 2000 and 2009.

The mean age of the patients was 61.2 years. About a third (33.1%) were 65 years or older and 7.0% were 75 years or older.

Researchers divided the patients into 5-year age groups ranging from under 50 to 90 years.

The study showed that 7.5% of the patients experienced at least 1 surgical complication. Wound infection was the most common (3.6%), followed by pneumonia (2.3%).

After adjustment for sex, Charlson Comorbidity Index, and insurance type, overall complications within 30 days of surgery were not significantly associated with patient age (per 5-year increment, odds ratio [OR], 1.00; 95% confidence interval [CI], 0.83 - 1.19; P = .96).

There was no significant association between age and the 30-day incidence of hemorrhagic complications (OR, 0.82; 95% CI, 0.60 - 1.11; P = .19), infection (OR, 0.95; 95% CI, 0.71 - 1.27; P = .72) or pneumonia (OR, 1.19; 95% CI, 0.87 - 1.63; P = .28).

The authors did note that for every 5-year increase in age, the risk for pneumonia within 30 days bordered on significant (OR, 1.28; 95% CI, 1.00 - 1.64; P = .06).

While pneumonia might be an issue with procedures that involve placing a breathing tube into the trachea, most aspects of DBS surgeries are done while patients are awake, with no need for general anesthesia or intubation, commented Dr. Lad. In those cases, he said, the risks are reduced.

Of the 123 patients older than 75 years in the study, 7.3% had a complication within 90 days compared with 7.5% of the younger cohort (P = .93)

Therapeutic Window

As it stands, neurosurgeons may be avoiding DBS operations on elderly patients with PD because of concerns about serious surgical complications. They aren't actively expanding the "therapeutic window" for DBS, said the authors.

"Many neurologists who might have been out in practice for a significant period of time are still somewhat reticent to offer DBS," said Dr. Lad.

And if they do recommend DBS, it's typically not very early in the disease process. Research shows that the peak for the incidence of PD is around age 75 years, but the peak for DBS is around 60 years, said Dr. Lad.

"People are referred to surgery as a late and last resort, and it shouldn't necessarily be that way," he said. "Overall, we'd like to see DBS be considered earlier in the care continuum for management of PD."

Many patients who have the surgery later in life wished they had had it earlier, said Dr. Lad. A "young" 80-year-old patient may want to be able to enjoy his or her remaining years with as good a quality of life as possible, he said.

Some people believe that DBS should be offered even before medication becomes refractory. This approach will be tested in an upcoming trial funded by the National Institutes of Health, said Dr. Lad, whose own center will be a pilot site.

In the meantime, DBS should be considered on the basis of a patient's physiologic age and not necessarily on chronologic age, said Dr. Lad.

"For patients who are otherwise healthy in terms of their cardiac and pulmonary status and are medically refractory and have symptoms we feel will respond well, for example tremor and rigidity, then certainly surgery can move up on the potential list of therapeutic options rather than continued medical management."

While some of these older patients may have a higher rate of deterioration in axial symptoms, such as freezing of gait and postural instability after surgery, careful preoperative evaluation focusing on axial scores off medication particularly for gait may predict better outcomes, said the authors.

Safer Surgery

Dr. Lad stressed that DBS is becoming increasingly safe. "As the technology has improved, as programming has improved, as well as the understanding of the networks for modulating, the ability to see our targets as well as steer the current and modulate the circuit that is responsible for the tremor, I think surgery itself is becoming even more effective and as safe as it's ever been."

Because the analysis was retrospective and nonrandomized, the findings are susceptible to procedure bias, with healthier older persons being preferentially selected for surgical intervention. Another possible study limitation was miscoding of procedures leading to possible inaccuracies.

Asked to comment on these findings, Michael S. Okun, MD, professor, University of Florida Center for Movement Disorders and Neuro-restoration, Gainesville, and national medical director, National Parkinson Foundation, said that high-risk elderly patients who have a lot of comorbidities should and do get screened out at experienced DBS centers.

"This article should definitely not be translated to mean that in practice we should be operating on all older patients who need DBS," said Dr. Okun. "A better message is that older patients who pass a careful multidisciplinary DBS screening may possibly have similar outcomes to younger patients."

The study was funded by the National Institutes of Health. Dr. Lad has consulted for and received grant support from Medtronic and St. Jude Medical. He serves as Director of the Duke Neuro-Outcomes Center, which has received research funding from the National Institutes of Health, Medtronic, and St. Jude.

JAMA Neurol. Published online August 25, 2014. Abstract


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