PORTLAND, ORE. – Performing deep brain stimulation 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 for lead placement with the patient awake, in a prospective, open-label study of 64 patients.

Regarding motor outcomes after asleep surgery, “We found that it was noninferior, so in other words, the change in scores following surgery were the same for asleep and awake patients,” physician assistant and study coauthor Shannon Anderson said during a poster session at the World Parkinson Congress. “What was surprising to us was that verbal fluency ... the ability to come up with the right word, actually improved in our asleep DBS [deep brain stimulation] group, which is a huge complication for patients [and] has a really negative impact on their life.”

Awake surgery with microelectrode recording (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 better cost effectiveness, but comparative clinical outcomes were previously not known.

Patients with Parkinson’s disease and motor complications (n = 64) were enrolled prospectively at the Oregon Health & Science University in Portland. 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 61.1-62.7 years) and off-medication motor subscale scores of the Unified Parkinson’s Disease Rating Scale (mUPDRS; mean 43.0-43.5). The university investigators optimized the DBS parameters at 1, 2, 3, and 6 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 6 months, the ICT (asleep) group experienced a mean improvement in motor abilities of 14.3 (plus or minus 10.88) on the mUPDRS off-medication and on DBS, compared with an improvement of 17.6 (plus or minus 12.26) for the MER (awake) group (P = .25).

Better language measures 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 6 months versus a worsening on both language measures (–3.5 points and –4.7 points, respectively; both P less than .001) if DBS was performed via MER on awake patients.

Although both cohorts showed significant improvements on the 39-item Parkinson’s Disease Questionnaire at 6 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 4-4.5 hours/day increase in “on” time without dyskinesia and a 2.6-3.5 hours/day decrease in “on” time with dyskinesia.

Patients tolerated asleep DBS well, and there were no serious complications.

The sleep surgery is much shorter, “so it’s about 2 hours long as opposed to 4, 5, sometimes 8, 10 hours with the awake. There [are fewer] complications, so less risk of hemorrhage or seizures or things like that,” Ms. Anderson said. “In a separate study, we found that it’s a much more accurate placement of the electrodes so the target is much more accurate. So, all of those things considered, we feel the asleep version is definitely the superior choice between the two.”

Being asleep is much more comfortable for the patient, added study leader Matthew Brodsky, MD. “But the biggest advantage is that it’s 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’s 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 more centers, more neurosurgeons be trained in this technique ... We’d like to see the clinical field move toward that area and really reserve microelectrode recording for the research side of things.”

“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 can’t quite overcome,” Dr. Brodsky said. “So, having this as an option makes it easier for them to sign up for the process.”

Richard Smeyne, PhD, director of the Jefferson Comprehensive Parkinson’s Center at Thomas Jefferson University in Philadelphia, said that the asleep procedure is the newer one and can target either the GPi or the STN. “The asleep DBS seems to have a little bit better improvement on speech afterwards than the awake DBS, and there could be several causes of this,” he said. “Some might be operative in that you can make smaller holes, you can get really nice guidance, you don’t have to sort of move around as in the awake DBS.”

In addition, CT scanning with the patients asleep in the operating room allows more time in the scanner and greater precision in anatomical placement of the DBS leads.

“If I had to choose, looking at this particular study, it would suggest that the asleep DBS is actually a better overall way to go,” Dr. Smeyne said. However, he had no objection to awake procedures “if the neurosurgeon has a record of good results with it ... But if you have the option ... that becomes an individual choice that you should discuss with the neurosurgeon.”

Some of the work presented in the study was supported by a research grant from Medtronic. Ms. Anderson and Dr. Brodsky reported having no other financial disclosures. Dr. Smeyne reported having no financial disclosures.

imnews@frontlinemedcom.com

Asleep deep brain stimulation placement offers advantages in Parkinson’s