Advances in Technical Aspects of Deep Brain Stimulation Surgery

Why are clinical trials of deep brain stimulation terminated? An analysis of clinicaltrials.gov

Background

Although deep brain stimulation (DBS) has established uses for patients with movement disorders and epilepsy, it is under consideration for a wide range of neurologic and neuropsychiatric conditions.

Objective

To review successful and unsuccessful DBS clinical trials and identify factors associated with early trial termination.

Methods

The ClinicalTrials.gov database was screened for all studies related to DBS. Information regarding condition of interest, study aim, trial design, trial success, and, if applicable, reason for failure was collected. Trials were compared and logistic regression was utilized to identify independent factors associated with trial termination.

Results

Of 325 identified trials, 79.7% were successful and 20.3% unsuccessful. Patient recruitment, sponsor decision, and device issues were the most cited reasons for termination. 242 trials (74.5%) were interventional with 78.1% successful. There was a statistically significant difference between successful and unsuccessful trials in number of funding sources (p = 0.0375). NIH funding was associated with successful trials while utilization of other funding sources (academic institutions and community organizations) was associated with unsuccessful trials. 83 trials (25.5%) were observational with 84.0% successful; there were no statistically significant differences between successful and unsuccessful observational trials.

Conclusion

One in five clinical trials for DBS were found to be unsuccessful, most commonly due to patient recruitment difficulties. The source of funding was the only factor associated with trial success. As DBS research continues to grow, understanding the current state of clinical trials will help design successful future studies, thereby minimizing futile expenditures of time, cost, and patient engagement.

A Novel Closed-Loop Electrical Brain Stimulation Device Featuring Wireless Low-Energy Ultrasound Power and Communication

OBJECTIVES

This study aimed to indicate the feasibility of a prototype electrical neuromodulation system using a closed-loop energy-efficient ultrasound-based mechanism for communication, data transmission, and recharging.

MATERIALS AND METHODS

Closed-loop deep brain stimulation (DBS) prototypes were designed and fabricated with ultrasonic wideband (UsWB) communication technology and miniaturized custom electronics. Two devices were implanted short term in anesthetized Göttingen minipigs (N = 2). Targeting was performed using preoperative magnetic resonance imaging, and locations were confirmed postoperatively by computerized tomography. DBS systems were tested over a wide range of stimulation settings to mimic minimal, typical, and/or aggressive clinical settings, and evaluated for their ability to transmit data through scalp tissue and to recharge the DBS system using UsWB.

RESULTS

Stimulation, communication, reprogramming, and recharging protocols were successfully achieved in both subjects for amplitude (1V-6V), frequency (50-250 Hz), and pulse width (60-200 μs) settings and maintained for ≥six hours. The precision of pulse settings was verified with <5% error. Communication rates of 64 kbit/s with an error rate of 0.05% were shown, with no meaningful throughput degradation observed. Time to recharge to 80% capacity was <9 minutes. Two DBS systems also were implanted in the second test animal, and independent bilateral stimulation was successfully shown.

CONCLUSIONS

The system performed at clinically relevant implant depths and settings. Independent bilateral stimulation for the duration of the study with a 4F energy storage and full rapid recharge were achieved. Continuous function extrapolates to six days of continuous stimulation in future design iterations implementing application specific integrated circuit level efficiency and 15F storage capacitance. UsWB increases energy efficiency, reducing storage requirements and thereby enabling device miniaturization. The device can enable intelligent closed-loop stimulation, remote system monitoring, and optimization and can serve as a power/data gateway to interconnect the intrabody network with the Internet of Medical Things.

High-Throughput Microelectrode Arrays for Precise Functional Localization of the Globus Pallidus Internus

The globus pallidus internus (GPi) was considered a common target for stimulation in Parkinson's disease (PD). Located deep in the brain and of small size, pinpointing it during surgery is challenging. Multi-channel microelectrode arrays (MEAs) can provide micrometer-level precision functional localization, which can maximize the surgical outcome. In this paper, a 64-channel MEA modified by platinum nanoparticles with a detection site impedance of 61.1 kΩ was designed and prepared, and multiple channels could be synchronized to cover the target brain region and its neighboring regions so that the GPi could be identified quickly and accurately. The results of the implant trajectory indicate that, compared to the control side, there is a reduction in local field potential (LFP) power in multiple subregions of the upper central thalamus on the PD-induced side, while the remaining brain regions exhibit an increasing trend. When the MEA tip was positioned at 8,700 μm deep in the brain, the various characterizations of the spike signals, combined with the electrophysiological characteristics of the β-segmental oscillations in PD, enabled MEAs to localize the GPi at the single-cell level. More precise localization could be achieved by utilizing the distinct characteristics of the internal capsule (ic), the thalamic reticular nucleus (Rt), and the peduncular part of the lateral hypothalamus (PLH) brain regions, as well as the relative positions of these brain structures. The MEAs designed in this study provide a new detection method and tool for functional localization of PD targets and PD pathogenesis at the cellular level.

Robot-Assisted Minimally Invasive Asleep Single-Stage Deep Brain Stimulation Surgery: Operative Technique and Systematic Review

BACKGROUND AND OBJECTIVES

Robotic assistance has garnered increased use in neurosurgery. Recently, this has expanded to include deep brain stimulation (DBS). Several studies have reported increased accuracy and improved efficiency with robotic assistance, but these are limited to individual robotic platforms with smaller sample sizes or are broader studies on robotics not specific to DBS. Our objectives are to report our technique for robot-assisted, minimally invasive, asleep, single-stage DBS surgery and to perform a meta-analysis comparing techniques from previous studies.

METHODS

We performed a single-center retrospective review of DBS procedures using a floor-mounted robot with a frameless transient fiducial array registration. We compiled accuracy data (radial entry error, radial target error, and 3-dimensional target error) and efficiency data (operative time, setup time, and total procedure time). We then performed a meta-analysis of previous studies and compared these metrics.

RESULTS

We analyzed 315 electrodes implanted in 160 patients. The mean radial target error was 0.9 ± 0.5 mm, mean target 3-dimensional error was 1.3 ± 0.7 mm, and mean radial entry error was 1.1 ± 0.8 mm. The mean procedure time (including pulse generator placement) was 182.4 ± 47.8 minutes, and the mean setup time was 132.9 ± 32.0 minutes. The overall complication rate was 8.8% (2.5% hemorrhagic/ischemic, 2.5% infectious, and 0.6% revision). Our meta-analysis showed increased accuracy with floor-mounted over skull-mounted robotic platforms and with fiducial-based registrations over optical registrations.

CONCLUSION

Our technique for robot-assisted, minimally invasive, asleep, single-stage DBS surgery is safe, accurate, and efficient. Our data, combined with a meta-analysis of previous studies, demonstrate that robotic assistance can provide similar or increased accuracy and improved efficiency compared with traditional frame-based techniques. Our analysis also suggests that floor-mounted robots and fiducial-based registration methods may be more accurate.

The history of deep brain stimulation

Deep brain stimulation (DBS) surgery is an established and effective treatment for several movement disorders (tremor, Parkinson's disease, and dystonia), and is under investigation in numerous other neurological and psychiatric disorders. However, the origins and development of this neurofunctional technique are not always well understood and recognized. In this mini-review, we review the history of DBS, highlighting important milestones and the most remarkable protagonists (neurosurgeons, neurologists, and neurophysiologists) who pioneered and fostered this therapy throughout the 20th and early 21st century. Alongside DBS historical markers, we also briefly discuss newer developments in the field, and the future challenges which accompany such progress.

Effectiveness and reliability of hypnosis in stereotaxy: a randomized study

BACKGROUND

Patients suffering from Parkinson's disease (PD) may experience pain during stereotactic frame (SF) fixation in deep brain stimulation (DBS). We assessed the role of hypnosis during the SF fixation in PD patients undergoing awake bilateral subthalamic nucleus (STN) DBS.

METHODS

N = 19 patients were included (N = 13 males, mean age 63 years; N = 10 allocated to the hypnosis and N = 9 allocated to the control groups). Patients were randomly assigned to the interventional (hypnosis and local anesthesia) or non-interventional (local anesthesia only) groups. The primary outcome was the pain perceived (the visual analogue scale (VAS)). Secondary outcomes were stress, anxiety, and depression, as measured by the perceived stress scale (PSS) and hospital anxiety and depression scale (HADS). Procedural distress was measured using the peritraumatic distress inventory (PDI-13).

RESULTS

In the hypnosis group, VASmean was 5.6 ± 2.1, versus 6.4 ± 1.2 in the control group (p = 0.31). Intervention and control groups reported similar VASmax scores (7.6 ± 2.1 versus 8.6 ± 1.6 (p = 0.28), respectively). Both groups had similar HADS scores (6.2 ± 4.3 versus 6.7 ± 1.92, p = 0.72 (HADSa) and 6.7 ± 4.2 versus 7.7 ± 3, p = 0.58 (HADSd)), so were the PSS scores (26.1 ± 6.3 versus 25.1 ± 7, p = 0.75). Evolutions of VASmean (R2 = 0.93, 95% CI [0.2245, 1.825], p = 0.03) and PDI-13 scores (R2 = 0.94, 95% CI [1.006, 6.279], p = 0.02) significantly differ over follow-up with patients in the hypnosis groups showing lower scores.

CONCLUSION

In this unblinded, randomized study, hypnosis does not influence pain, anxiety, and distress during awake SF fixation but modulates pain memory over time and may prevent the integration of awake painful procedures as a bad experience into the autobiographical memory of patients suffering from PD. A randomized controlled study with more data is necessary to confirm our findings.

Thirty Years of Global Deep Brain Stimulation: "Plus ça change, plus c'est la même chose"?

BACKGROUND

The advent of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease 30 years ago has ushered a global breakthrough of DBS as a universal method for therapy and research in wide areas of neurology and psychiatry. The literature of the last three decades has described numerous concepts and practices of DBS, often branded as novelties or discoveries. However, reading the contemporary publications often elicits a sense of déjà vu in relation to several methods, attributes, and practices of DBS. Here, we review various applications and techniques of the modern-era DBS and compare them with practices of the past.

SUMMARY

Compared with modern literature, publications of the old-era functional stereotactic neurosurgery, including old-era DBS, show that from the very beginning multidisciplinarity and teamwork were often prevalent and insisted upon, ethical concerns were recognized, brain circuitries and rational for brain targets were discussed, surgical indications were similar, closed-loop stimulation was attempted, evaluations of surgical results were debated, and controversies were common. Thus, it appears that virtually everything done today in the field of DBS bears resemblance to old-time practices, or has been done before, albeit with partly other tools and techniques. Movement disorders remain the main indications for modern DBS as was the case for lesional surgery and old-era DBS. The novelties today consist of the STN as the dominant target for DBS, the tremendous advances in computerized brain imaging, the sophistication and versatility of implantable DBS hardware, and the large potential for research.

KEY MESSAGES

Many aspects of contemporary DBS bear strong resemblance to practices of the past. The dominant clinical indications remain movement disorders with virtually the same brain targets as in the past, with one exception: the STN. Other novel brain targets - that are so far subject to DBS trials - are the pedunculopontine nucleus for gait freezing, the anteromedial internal pallidum for Gilles de la Tourette and the fornix for Alzheimer's disease. The major innovations and novelties compared to the past concern mainly the unmatched level of research activity, its high degree of sponsorship, and the outstanding advances in technology that have enabled multimodal brain imaging and the miniaturization, versatility, and sophistication of implantable hardware. The greatest benefit for patients today, compared to the past, is the higher level of precision and safety of DBS, and of all functional stereotactic neurosurgery.

Anthropology of Deep Brain Stimulation; the 30th Anniversary of STN DBS in 2023

Background

The year 2023 marks the 30th anniversary of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease (PD). This procedure prompted a universal interest in DBS for various brain disorders and resulted in a unique expansion of clinical and scientific collaboration between many disciplines, with impact on many aspects of society.

Objective

To study the anthropology of DBS, that is, its ethno-geographic origins, its evolution, its impact on clinicians and scientists, and its influence on society at large.

Material and Methods

The authors scrutinized the geo-ethnic origins of the pioneers of modern DBS, and they evaluated, based on the literature and on a long-term praxis, the development of DBS and its impact on clinicians, on healthcare, and on society.

Results

Scientists and clinicians from various geo-ethnic origins pioneered modern DBS, leading to worldwide spread of this procedure and to the establishment of large multidisciplinary teams in many centers. Neurologists became actively involved in surgery and took on new laborious tasks of programming ever more complicated DBS systems. Publications sky-rocketed and the global spread of DBS impacted positively on several aspects of society, including healthcare, awareness of neurological diseases, interdisciplinary relations, conferences, patient organizations, unemployment, industry, etc.

Conclusions

STN DBS has boosted the field of deep brain electrotherapy for many neurological and psychiatric illnesses, and DBS has generated a global benefit on many aspects of society, well beyond its clinical benefits on symptoms of diseases. With the ever-increasing indications for DBS, more positive global impact is expected.