General Anesthesia versus Local Anesthesia in StereotaXY (GALAXY) for Parkinson's disease: study protocol for a randomized controlled trial

Validation of the hotspot for dorsolateral subthalamic nucleus targeting in deep brain stimulation surgery for Parkinson's disease: a post hoc analysis of a randomised controlled trial

BACKGROUND

Visualisation of the dorsolateral subthalamic nucleus (STN) remains challenging on 1.5 and 3Tesla T2-weighted MRI. Our previously defined hotspot, relative to the well-visualised medial STN border, serves as an MRI landmark for dorsolateral STN identification in deep brain stimulation (DBS). We aimed to validate this hotspot in a separate trial cohort of Parkinson's disease (PD) patients and refine its location.

METHODS

In this post hoc analysis of a randomised controlled trial, in which the hotspot was taken into account during target planning, responses to DBS were evaluated using hemibody improvement on the Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor examination and compared with our historical cohort, as well as dopaminergic medication reduction. Then, a refined hotspot was calculated and the Euclidean distance from individual active contacts to the refined hotspot was correlated with motor improvement.

RESULTS

The first quartile of the hemibodies (poor responders) showed an average improvement of 13%, which was higher than the -8% in the historical control group (p=0.044). Dopaminergic medication reduction was greater in the current cohort compared with the historical cohort (p=0.020). Overall variability of hemibody motor improvement was reduced in the current cohort compared with the historical control group (p=0.003). Motor improvement correlated to the Euclidean distance from active contact to the refined hotspot (2.8 mm lateral, 1.1 mm anterior and 2.2 mm superior to the medial STN border) (p=0.001).

CONCLUSION

We validated the hotspot for dorsolateral STN targeting in DBS for patients with PD and showed an improved motor response in poor responders, a reduced variability in motor improvement and a greater dopaminergic medication reduction. We then refined the hotspot at 2.8 mm lateral, 1.1 mm anterior and 2.2 mm superior relative to the medial STN border, which visualises a readily implementable target within the dorsolateral STN on lower field strength MRI.

Cognitive and psychiatric outcomes in the GALAXY trial: effect of anaesthesia in deep brain stimulation

BACKGROUND

This study aims: (1) To compare cognitive and psychiatric outcomes after bilateral awake versus asleep subthalamic nucleus (STN) deep brain stimulation (DBS) surgery for Parkinson's disease (PD). (2) To explore the occurrence of psychiatric diagnoses, cognitive impairment and quality of life after surgery in our whole sample. (3) To validate whether we can predict postoperative cognitive decline.

METHODS

110 patients with PD were randomised to receive awake (n=56) or asleep (n=54) STN DBS surgery. At baseline and 6-month follow-up, all patients underwent standardised assessments testing several cognitive domains, psychiatric symptoms and quality of life.

RESULTS

There were no differences on neuropsychological composite scores and psychiatric symptoms between the groups, but we found small differences on individual tests and cognitive domains. The asleep group performed better on the Rey Auditory Verbal Learning Test delayed memory test (f=4.2, p=0.04), while the awake group improved on the Rivermead Behavioural Memory Test delayed memory test. (f=4.4, p=0.04). The Stroop III score was worse for the awake group (f=5.5, p=0.02). Worse scores were present for Stroop I (Stroop word card) (f=6.3, p=0.01), Stroop II (Stroop color card) (f=46.4, p<0.001), Stroop III (Stroop color-word card) (f=10.8, p=0.001) and Trailmaking B/A (f=4.5, p=0.04). Improvements were seen on quality of life: Parkinson's Disease Questionnaire-39 (f=24.8, p<0.001), and psychiatric scales: Hamilton Depression Rating Scale (f=6.2, p=0.01), and Hamilton Anxiety Rating Scale (f=5.5, p=0.02).

CONCLUSIONS

This study suggests that the choice between awake and asleep STN DBS does not affect cognitive, mood and behavioural adverse effects, despite a minor difference in memory. STN DBS has a beneficial effect on quality of life, mood and anxiety symptoms.

TRIAL REGISTRATION NUMBER

NTR5809.

Utilizing 7-Tesla Subthalamic Nucleus Connectivity in Deep Brain Stimulation for Parkinson Disease

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective surgical treatment for patients with advanced Parkinson disease (PD). Combining 7.0-Tesla (7T) T2- and diffusion-weighted imaging (DWI) sequences allows for selective segmenting of the motor part of the STN and, thus, for possible optimization of DBS.

MATERIALS AND METHODS

7T T2 and DWI sequences were obtained, and probabilistic segmentation of motor, associative, and limbic STN segments was performed. Left- and right-sided motor outcome (Movement Disorders Society Unified Parkinson's Disease Rating Scale) scores were used for evaluating the correspondence between the active electrode contacts in selectively segmented STN and the clinical DBS effect. The Bejjani line was reviewed for crossing of segments.

RESULTS

A total of 50 STNs were segmented in 25 patients and proved highly feasible. Although the highest density of motor connections was situated in the dorsolateral STN for all patients, the exact partitioning of segments differed considerably. For all the active electrode contacts situated within the predominantly motor-connected segment of the STN, the average hemi-body Unified Parkinson's Disease Rating Scale motor improvement was 80%; outside this segment, it was 52% (p < 0.01). The Bejjani line was situated in the motor segment for 32 STNs.

CONCLUSION

The implementation of 7T T2 and DWI segmentation of the STN in DBS for PD is feasible and offers insight into the location of the motor segment. Segmentation-guided electrode placement is likely to further improve motor response in DBS for PD. However, commercially available DBS software for postprocessing imaging would greatly facilitate widespread implementation.

General Anesthesia vs Local Anesthesia in Microelectrode Recording-Guided Deep-Brain Stimulation for Parkinson Disease: The GALAXY Randomized Clinical Trial

Importance

It is unknown if there is a difference in outcome in asleep vs awake deep brain stimulation (DBS) of the subthalamic nucleus for advanced Parkinson disease.

Objective

To determine the difference in adverse effects concerning cognition, mood, and behavior between awake and asleep DBS favoring the asleep arm of the study.

Design, Setting, and Participants

This study was a single-center prospective randomized open-label blinded end point clinical trial. A total of 187 persons with Parkinson disease were referred for DBS between May 2015 to March 2019. Analysis took place from January 2016 to January 2020. The primary outcome follow-up visit was conducted 6 months after DBS.

Interventions

Bilateral subthalamic nucleus DBS was performed while the patient was asleep (under general anesthesia) in 1 study arm and awake in the other study arm. Both arms of the study used a frame-based intraoperative microelectrode recording technique to refine final target placement of the DBS lead.

Main Outcomes and Measures

The primary outcome variable was the between-group difference in cognitive, mood, and behavioral adverse effects as measured by a composite score. The secondary outcomes included the Movement Disorders Society Unified Parkinson's Disease Rating Scale, the patient assessment of surgical burden and operative time.

Results

A total of 110 patients were randomized to awake (local anesthesia; n = 56; mean [SD] age, 60.0 (7.4) years; 40 [71%] male) or to asleep (general anesthesia; n = 54; mean [SD] age, 61.3 [7.9] years; 38 [70%] male) DBS surgery. The 6-month follow-up visit was completed by 103 participants. The proportion of patients with adverse cognitive, mood, and behavioral effects on the composite score was 15 of 52 (29%) after awake and 11 of 51 (22%) after asleep DBS (odds ratio, 0.7 [95% CI, 0.3-1.7]). There was no difference in improvement in the off-medication Movement Disorders Society Unified Parkinson's Disease Rating Scale Motor Examination scores between groups (awake group: mean [SD], -27.3 [17.5] points; asleep group: mean [SD], -25.3 [14.3] points; mean difference, -2.0 [95% CI, -8.1 to 4.2]). Asleep surgery was experienced as less burdensome by patients and was 26 minutes shorter than awake surgery.

Conclusions and Relevance

There was no difference in the primary outcome of asleep vs awake DBS. Future large randomized clinical trials should examine some of the newer asleep based DBS technologies because this study was limited to frame-based microelectrode-guided procedures.

Trial Registration

trialregister.nl Identifier: NTR5809.

New Frontiers for Deep Brain Stimulation: Directionality, Sensing Technologies, Remote Programming, Robotic Stereotactic Assistance, Asleep Procedures, and Connectomics

Over the last few years, while expanding its clinical indications from movement disorders to epilepsy and psychiatry, the field of deep brain stimulation (DBS) has seen significant innovations. Hardware developments have introduced directional leads to stimulate specific brain targets and sensing electrodes to determine optimal settings via feedback from local field potentials. In addition, variable-frequency stimulation and asynchronous high-frequency pulse trains have introduced new programming paradigms to efficiently desynchronize pathological neural circuitry and regulate dysfunctional brain networks not responsive to conventional settings. Overall, these innovations have provided clinicians with more anatomically accurate programming and closed-looped feedback to identify optimal strategies for neuromodulation. Simultaneously, software developments have simplified programming algorithms, introduced platforms for DBS remote management via telemedicine, and tools for estimating the volume of tissue activated within and outside the DBS targets. Finally, the surgical accuracy has improved thanks to intraoperative magnetic resonance or computerized tomography guidance, network-based imaging for DBS planning and targeting, and robotic-assisted surgery for ultra-accurate, millimetric lead placement. These technological and imaging advances have collectively optimized DBS outcomes and allowed “asleep” DBS procedures. Still, the short- and long-term outcomes of different implantable devices, surgical techniques, and asleep vs. awake procedures remain to be clarified. This expert review summarizes and critically discusses these recent innovations and their potential impact on the DBS field.

Targeting of the Subthalamic Nucleus in Patients with Parkinson's Disease Undergoing Deep Brain Stimulation Surgery

Precise stereotactic targeting of the dorsolateral motor part of the subthalamic nucleus (STN) is paramount for maximizing clinical effectiveness and preventing side effects of deep brain stimulation (DBS) in patients with advanced Parkinson's disease. With recent developments in magnetic resonance imaging (MRI) techniques, direct targeting of the dorsolateral part of the STN is now feasible, together with visualization of the motor fibers in the nearby internal capsule. However, clinically relevant discrepancies were reported when comparing STN borders on MRI to electrophysiological STN borders during microelectrode recordings (MER). Also, one should take into account the possibility of a 3D inaccuracy of up to 2 mm of the applied stereotactic technique. Pneumocephalus and image fusion errors may further increase implantation inaccuracy. Even when implantation has been successful, suboptimal lead anchoring on the skull may cause lead migration during follow-up. Meticulous pre- and intraoperative imaging is therefore indispensable, and so is postoperative imaging when the effects of DBS deteriorate during follow-up. Thus far, most DBS centers employ MRI targeting, multichannel MER, and awake test stimulation in STN surgery, but randomized trials comparing surgery under local versus general anesthesia and additional studies comparing MER-STN borders to high-field MRI-STN may change this clinical practice. Further developments in imaging protocols and improvements in image fusion processes are needed to optimize placement of DBS leads in the dorsolateral motor part of the STN in Parkinson's disease.

Bilateral Subthalamic Nucleus Deep Brain Stimulation under General Anesthesia: Literature Review and Single Center Experience

Bilateral subthalamic nucleus (STN) Deep brain stimulation (DBS) is a well-established treatment in patients with Parkinson's disease (PD). Traditionally, STN DBS for PD is performed by using microelectrode recording (MER) and/or intraoperative macrostimulation under local anesthesia (LA). However, many patients cannot tolerate the long operation time under LA without medication. In addition, it cannot be even be performed on PD patients with poor physical and neurological condition. Recently, it has been reported that STN DBS under general anesthesia (GA) can be successfully performed due to the feasible MER under GA, as well as the technical advancement in direct targeting and intraoperative imaging. The authors reviewed the previously published literature on STN DBS under GA using intraoperative imaging and MER, focused on discussing the technique, clinical outcome, and the complication, as well as introducing our single-center experience. Based on the reports of previously published studies and ours, GA did not interfere with the MER signal from STN. STN DBS under GA without intraoperative stimulation shows similar or better clinical outcome without any additional complication compared to STN DBS under LA. Long-term follow-up with a large number of the patients would be necessary to validate the safety and efficacy of STN DBS under GA.

Implementation of Intraoperative Cone-Beam Computed Tomography (O-arm) for Stereotactic Imaging During Deep Brain Stimulation Procedures

BACKGROUND

Intraoperative cone-beam computed tomography (iCBCT) allows for rapid 3-dimensional imaging. However, it is currently unknown whether this imaging technique offers sufficient accuracy for stereotactic registration during deep brain stimulation (DBS) procedures.

OBJECTIVE

To determine the accuracy of iCBCT, with the O-arm O2 (Medtronic), for stereotactic registration by comparing this modality to stereotactic magnetic resonance imaging (MRI).

METHODS

All DBS patients underwent a preoperative non-stereotactic 3 Tesla MRI, stereotactic 1.5 Tesla MRI, stereotactic O-arm iCBCT, postimplantation O-arm iCBCT, and postoperative conventional multidetector computed tomography (CT) scan. We compared stereotactic (X, Y, and Z) coordinates of the anterior commissure (AC), the posterior commissure (PC), and midline reference (MR) between stereotactic MRI and iCBCT. For localisation comparison of electrode contacts, stereotactic coordinates of electrode tips were compared between the postoperative multidetector CT and iCBCT.

RESULTS

A total of 20 patients were evaluated. The average absolute difference in stereotactic coordinates of AC, PC, and MR was 0.4 ± 0.4 mm for X, 0.4 ± 0.4 mm for Y, and 0.7 ± 0.5 mm for Z. The average absolute difference in X-, Y-, and Z-coordinates for electrode localisation (N = 34) was 0.3 ± 0.3 mm, 0.6 ± 0.3 mm, and 0.6 ± 0.6 mm. These differences were small enough not to be considered clinically relevant.

CONCLUSION

Stereotactic MRI and O-arm iCBCT yield comparable coordinates in pre- and postoperative imaging. Differences found are below the threshold of clinical relevance. Intraoperative O-arm CBCT offers rapid stereotactic registration and evaluation of electrode placement. This increases patient comfort and neurosurgical workflow efficiency.

Asleep Surgery May Improve the Therapeutic Window for Deep Brain Stimulation of the Subthalamic Nucleus

OBJECTIVE

The effect of anesthesia type in terms of asleep vs. awake deep brain stimulation (DBS) surgery on therapeutic window (TW) has not been investigated so far. The objective of the study was to investigate whether asleep DBS surgery of the subthalamic nucleus (STN) improves TW for both directional (dDBS) and omnidirectional (oDBS) stimulation in a large single-center population.

MATERIALS AND METHODS

A total of 104 consecutive patients with Parkinson's disease (PD) undergoing STN-DBS surgery (80 asleep and 24 awake) were compared regarding TW, therapeutic threshold, side effect threshold, improvement of Unified PD Rating Scale motor score (UPDRS-III) and degree of levodopa equivalent daily dose (LEDD) reduction.

RESULTS

Asleep DBS surgery led to significantly wider TW compared to awake surgery for both dDBS and oDBS. However, dDBS further increased TW compared to oDBS in the asleep group only and not in the awake group. Clinical efficacy in terms of UPDRS-III improvement and LEDD reduction did not differ between groups.

CONCLUSIONS

Our study provides first evidence for improvement of therapeutic window by asleep surgery compared to awake surgery, which can be strengthened further by dDBS. These results support the notion of preferring asleep over awake surgery but needs to be confirmed by prospective trials.

Relative Contribution of Magnetic Resonance Imaging, Microelectrode Recordings, and Awake Test Stimulation in Final Lead Placement during Deep Brain Stimulation Surgery of the Subthalamic Nucleus in Parkinson's Disease

INTRODUCTION

For deep brain stimulation (DBS) surgery of the subthalamic nucleus (STN) in Parkinson's disease (PD), many centers employ visualization of the nucleus on magnetic resonance imaging (MRI), intraoperative microelectrode recordings (MER), and test stimulation in awake patients. The value of these steps is a subject for ongoing debate. In the current study, we determined the relative contribution of MRI targeting, multitrack MER, and awake test stimulation in final lead placement during STN DBS surgery for PD.

METHODS

Data on PD patients undergoing MRI-targeted STN DBS surgery with three-channel MER and awake test stimulation between February 2010 and January 2014 were analyzed to determine in which MER trajectory final leads were implanted and why this tract was chosen.

RESULTS

Seventy-six patients underwent implantation of 146 DBS leads. In 92% of the STN, the final leads were implanted in one of the three planned channels. In 6%, additional channels were needed. In 2%, surgery was aborted before final lead implantation due to anxiety or fatigue. The final leads were implanted in the channels with the longest STN MER signal trajectory in 60% of the STN (38% of the bilaterally implanted patients). This was the central channel containing the MRI target in 39% of the STN (18% bilaterally). The most frequently noted reasons why another channel than the central channel was chosen for final lead placement were (1) a lower threshold for side effects (54%) and (2) no or a too short trajectory of the STN MER signal (40%) in the central channel. The latter reason correlated with larger 2D (x and y) errors in our stereotactic method.

CONCLUSIONS

STN DBS leads were often not implanted in the MRI-planned trajectory or in the trajectory with the longest STN MER signal. Thresholds for side effects during awake test stimulation were decisive for final target selection in the majority of patients.

Verification of the Deep Brain Stimulation Electrode Position Using Intraoperative Electromagnetic Localization

BACKGROUND

Electromagnetic (EM) localization has typically been used to direct shunt catheters into the ventricle. The objective of this study was to determine if this method of EM tracking could be used in a deep brain stimulation (DBS) electrode cannula to accurately predict the eventual location of the electrode contacts.

METHODS

The Medtronic AxiEMTM system was used to generate the cannula tip location directed to the planned target site. Prior to clinical testing, a series of phantom modelling observations were made.

RESULTS

Phantom trials (n = 23) demonstrated that the cannula tip could be accurately located at the target site with an error of between 0.331 ± 0.144 and 0.6 ± 0.245 mm, depending on the orientation of the delivery system to the axis of the phantom head. Intraoperative EM localization of the DBS cannula was performed in 84 trajectories in 48 patients. The average difference between the planned target and the EM stylet location at the cannula tip was 1.036 ± 0.543 mm. The average error between the planned target coordinates and the actual target electrode location (by CT) was 1.431 ± 0.607 and 1.145 ± 0.636 mm for the EM stylet location in the cannula (p = 0.00312), indicating that EM localization reflected the position of the target electrode more accurately than the planned target.

CONCLUSIONS

EM localization can be used to verify the position of DBS electrodes intraoperatively with a high accuracy.

Comparison of Awake and Asleep Deep Brain Stimulation for Parkinson's Disease: A Detailed Analysis Through Literature Review

OBJECTIVES

Deep brain stimulation (DBS) for Parkinson's disease (PD) has been applied to clinic for approximately 30 years. The goal of this review is to explore the similarities and differences between "awake" and "asleep" DBS techniques.

METHODS

A comprehensive literature review was carried out to identify relevant studies and review articles describing applications of "awake" or "asleep" DBS for Parkinson's disease. The surgical procedures, clinical outcomes, costs and complications of each technique were compared in detail through literature review.

RESULTS

The surgical procedures of awake and asleep DBS surgeries rely upon different methods for verification of intended target acquisition. The existing research results demonstrated that the stereotactic targeting accuracy of lead placement obtained by either method is reliable. There were no significant differences in clinical outcomes, costs, or complications between the two techniques.

CONCLUSION

The surgical and clinical outcomes of asleep DBS for PD are comparable to those of awake DBS.