PORTLAND, OR—Performing deep brain stimulation (DBS) surgery for Parkinson’s disease using intraoperative CT imaging while the patient is under general anesthesia had clinical advantages and no disadvantages over surgery using microelectrode recording (MER) for lead placement with the patient awake, in a prospective, open-label study of 64 patients. The study was presented at the Fourth World Parkinson Congress.
The change in motor scores following surgery was the same for asleep and awake patients, said study coauthor Shannon Anderson, a physician assistant at Oregon Health & Science University in Portland. “What was surprising to us was that verbal fluency ... the ability to come up with the right word, actually improved in our asleep DBS group, which is a huge complication for patients [and] has a really negative impact on their life.”
Shannon Anderson
Awake surgery with MER for lead targeting has been the preferred method. Surgery under general anesthesia with intraoperative CT (ICT) has been known to have lower morbidity and be more cost effective, but comparative clinical outcomes were previously not known.
Patients with Parkinson’s disease and motor complications (n = 64) were enrolled prospectively at Oregon Health & Science University. Thirty received asleep procedures under general anesthesia with ICT guidance for lead targeting to the globus pallidus pars interna (GPi; n = 21) or to the subthalamic nucleus (STN; n = 9). Thirty-four patients received DBS devices with MER guidance (15 STN; 19 GPi). At baseline, the two groups were similar in age (mean age, 61.1 and 62.7) and off-medication motor subscale scores of the Unified Parkinson’s Disease Rating Scale (mUPDRS; mean, 43.0 and 43.5). The university investigators optimized the DBS parameters at one, two, three, and six months after implantation. The same surgeon performed all the procedures at the same medical center.
Motor improvements were similar between the asleep and awake cohorts. At six months, the ICT (asleep) group experienced a mean improvement in motor abilities of 14.3 on the mUPDRS off medication and on DBS, compared with an improvement of 17.6 for the MER (awake) group.
Greater Fluency With Asleep DBS
Asleep DBS with ICT resulted in improvements in aspects of language, whereas awake patients lost language abilities. The asleep group showed a 0.8-point increase in phonemic fluency and a 1.0-point increase in semantic fluency at six months versus a worsening on both language measures (–3.5 points and –4.7 points, respectively) if DBS was performed via MER on awake patients.
Both cohorts showed significant improvements on the 39-item Parkinson’s Disease Questionnaire at six months. The cohorts did not differ in their degrees of improvement. Similarly, both had improvements on scores of activities of daily living, and both cohorts had a 4 to 4.5 hours per day increase in on time without dyskinesia and a 2.6 to 3.5 hours per day decrease in on time with dyskinesia.
Patients tolerated asleep DBS well, and there were no serious complications.
Surgery while patients are asleep is much shorter. “It is about two hours long, as opposed to four, five, sometimes eight, 10 hours with the awake. There [are fewer] complications, so less risk of hemorrhage or seizures or things like that,” Ms. Anderson said. A separate study found that asleep surgery results in more accurate placement of the electrodes. “All of those things considered, we feel the asleep version is definitely the superior choice between the two,” she said.
Being asleep is much more comfortable for the patient, added study leader Matthew Brodsky, MD, Associate Professor of Neurology at Oregon Health & Science University. “But the biggest advantage is that it is a single pass into the brain as opposed to multiple passes.” The average number of passes using MER is two to three per side of the brain, and in some centers, four or more. “Problems such as speech prosody are related to pokes in the brain, if you will, rather than stimulation,” he said.
Ms. Anderson said MER “is a fantastic research tool, and it gives us a lot of information on the electrophysiology, but really, there is no need for it in the clinical application of DBS.”
Based on the asleep procedure’s accuracy, lower rate of complications, shorter operating room time, and noninferiority in terms of motor outcomes, she said, “Our recommendation is that in more centers, more neurosurgeons be trained in this technique .... We would like to see the clinical field move toward that area and really reserve MER for the research side of things.”
A Barrier for Patients
“If you talk to folks who are considering brain surgery for their Parkinson’s, for some of them, the idea of being awake in the operating room and undergoing this is a barrier that they cannot quite overcome,” Dr. Brodsky said. “So, having this as an option makes it easier for them to sign up for the process.”