Frameless Robot-Assisted Deep Brain Stimulation Surgery: An Initial Experience

Evolution of Deep Brain Stimulation Techniques for Complication Mitigation

Complication mitigation in deep brain stimulation has been a topic matter of much discussion in the literature. In this article, we examine how neurosurgeons as individuals and as a field generated and adapted techniques to prevent infection, lead fracture/lead migration, and suboptimal outcomes in both the acute period and longitudinally. The authors performed a MEDLINE search inclusive of articles from 1987 to June 2023 including human studies written in English. Using the Rayyan platform, two reviewers (J.P. and R.M.) performed a title screen. Of the 776 articles, 252 were selected by title screen and 172 from abstract review for full-text evaluation. Ultimately, 124 publications were evaluated. We describe the initial complications and inefficiencies at the advent of deep brain stimulation and detail changes instituted by surgeons that reduced them. Furthermore, we discuss the trend in both undesired short-term and long-term outcomes with emphasis on how surgeons recognized and modified their practice to provide safer and better procedures. This scoping review adds to the literature as a guide to both new neurosurgeons and seasoned neurosurgeons alike to understand better what innovations have been trialed over time as we embark on novel targets and neuromodulatory technologies.

Efficacy and safety of robot-assisted deep brain stimulation for Parkinson's disease: a meta-analysis

Objective

This meta-analysis aims to assess the effectiveness and safety of robot-assisted deep brain stimulation (DBS) surgery for Parkinson's disease(PD).

Methods

Four databases (Medline, Embase, Web of Science and CENTRAL) were searched from establishment of database to 23 March 2024, for articles studying robot-assisted DBS in patients diagnosed with PD. Meta-analyses of vector error, complication rate, levodopa-equivalent daily dose (LEDD), Unified Parkinson's Disease Rating Scale (UPDRS), UPDRS II, UPDRS III, and UPDRS IV were performed.

Results

A total of 15 studies were included in this meta-analysis, comprising 732 patients with PD who received robot-assisted DBS. The pooled results revealed that the vector error was measured at 1.09 mm (95% CI: 0.87 to 1.30) in patients with Parkinson's disease who received robot-assisted DBS. The complication rate was 0.12 (95% CI, 0.03 to 0.24). The reduction in LEDD was 422.31 mg (95% CI: 68.69 to 775.94). The improvement in UPDRS, UPDRS III, and UPDRS IV was 27.36 (95% CI: 8.57 to 46.15), 14.09 (95% CI: 4.67 to 23.52), and 3.54 (95% CI: -2.35 to 9.43), respectively.

Conclusion

Robot-assisted DBS is a reliable and safe approach for treating PD. Robot-assisted DBS provides enhanced accuracy in contrast to conventional frame-based stereotactic techniques. Nevertheless, further investigation is necessary to validate the advantages of robot-assisted DBS in terms of enhancing motor function and decreasing the need for antiparkinsonian medications, in comparison to traditional frame-based stereotactic techniques.Clinical trial registration: PROSPERO(CRD42024529976).

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.

Robot-assisted vs. manually guided stereoelectroencephalography for refractory epilepsy: a systematic review and meta-analysis

Robotic assistance has improved electrode implantation precision in stereoelectroencephalography (SEEG) for refractory epilepsy patients. We sought to assess the relative safety of the robotic-assisted (RA) procedure compared to the traditional hand-guided one. A systematic search on PubMed, Web of Science, Embase, and Cochrane was performed for studies directly comparing robot-assisted vs. manually guided SEEG to treat refractory epilepsy. The primary outcomes included target point error (TPE), entry point error (EPE), time of implantation of each electrode, operative time, postoperative intracranial hemorrhage, infection, and neurologic deficit. We included 427 patients from 11 studies, of whom 232 (54.3%) underwent robot-assisted surgery and 196 (45.7%) underwent manually guided surgery. The primary endpoint, TPE, was not statistically significant (MD 0.04 mm; 95% CI - 0.21, - 0.29; p = 0.76). Nonetheless, EPE was significantly lower in the intervention group (MD - 0.57 mm; 95% CI - 1.08; - 0.06; p = 0.03). Total operative time was significantly lower in the RA group (MD - 23.66 min; 95% CI - 32.01, - 15.31; p < 0.00001), as well as the individual time of implantation of each electrode (MD - 3.35 min; 95% CI - 3.68, - 3.03; p < 0.00001). Postoperative intracranial hemorrhage did not differ between groups: robotic (9/145; 6.2%) vs. manual (8/139; 5.7%) (RR 0.97; 95% CI 0.40-2.34; p = 0.94). There was no statistically relevant difference in infection (p = 0.4) and postoperative neurological deficit (p = 0.47) incidence between the two groups. In this analysis, there is a potential relevance in the RA procedure when comparing the traditional one, since operative time, time of implantation of each electrode, and EPE were significantly lower in the robotic group. More research is needed to corroborate the superiority of this novel technique.

Application of the robot-assisted implantation in deep brain stimulation

INTRODUCTION

This work aims to assess the accuracy of robotic assistance guided by a videometric tracker in deep brain stimulation (DBS).

METHODS

We retrospectively reviewed a total of 30 DBS electrode implantations, assisted by the Remebot robotic system, with a novel frameless videometric registration workflow. Then we selected 30 PD patients who used stereotactic frame surgery to implant electrodes during the same period. For each electrode, accuracy was assessed using radial and axial error.

RESULTS

The average radial error of the robot-assisted electrode implantation was 1.28 ± 0.36 mm, and the average axial error was 1.20 ± 0.40 mm. No deaths or associated hemorrhages, infections or poor incision healing occurred.

CONCLUSION

Robot-assisted implantation guided by a videometric tracker is accurate and safe.

Robot-Assisted Deep Brain Stimulation: High Accuracy and Streamlined Workflow

BACKGROUND

A number of stereotactic platforms are available for performing deep brain stimulation (DBS) lead implantation. Robot-assisted stereotaxy has emerged more recently demonstrating comparable accuracy and shorter operating room times compared with conventional frame-based systems.

OBJECTIVE

To compare the accuracy of our streamlined robotic DBS workflow with data in the literature from frame-based and frameless systems.

METHODS

We retrospectively reviewed 126 consecutive DBS lead placement procedures using a robotic stereotactic platform. Indications included Parkinson disease (n = 94), essential tremor (n = 21), obsessive compulsive disorder (n = 7), and dystonia (n = 4). Procedures were performed using a stereotactic frame for fixation and the frame pins as skull fiducials for robot registration. We used intraoperative fluoroscopic computed tomography for registration and postplacement verification.

RESULTS

The mean radial error for the target point was 1.06 mm (SD: 0.55 mm, range 0.04-2.80 mm) on intraoperative fluoroscopic computed tomography. The mean operative time for an asleep, bilateral implant without implantable pulse generator placement was 238 minutes (SD: 52 minutes), and skin-to-skin procedure time was 116 minutes (SD: 42 minutes).

CONCLUSION

We describe a streamlined workflow for DBS lead placement using robot-assisted stereotaxy with a comparable accuracy profile. Obviating the need for checking and switching coordinates, as is standard for frame-based DBS, also reduces the chance for human error and facilitates training.

Awake Deep Brain Stimulation Surgery Without Intraoperative Imaging Is Accurate and Effective: A Case Series

BACKGROUND

The success of deep brain stimulation (DBS) surgery depends on the accuracy of electrode placement. Several factors can affect this such as brain shift, the quality of preoperative planning, and technical factors. It is crucial to determine whether techniques yield accurate lead placement and effective symptom relief. Many of the studies establishing the accuracy of frameless techniques used intraoperative imaging to further refine lead placement.

OBJECTIVE

To determine whether awake lead placement without intraoperative imaging can achieve similar minimal targeting error while preserving clinical results.

METHODS

Eighty-two trajectories in 47 patients who underwent awake, frameless DBS lead placement with the Fred Haer Corporation STarFix system for essential tremor or Parkinson's disease were analyzed. Neurological testing during lead placement was used to determine appropriate lead locations, and no intraoperative imaging was performed. Accuracy data were compared with previously performed studies.

RESULTS

The Euclidean error for the patient cohort was 1.79 ± 1.02 mm, and the Pythagorean error was 1.40 ± 0.95 mm. The percentage symptom improvement evaluated by the Unified Parkinson's Disease Rating Scale for Parkinson's disease or the Fahn-Tolosa-Marin scale for essential tremor was similar to reported values at 58% ± 17.2% and 67.4% ± 24.7%, respectively. The operative time was 95.0 ± 30.3 minutes for all study patients.

CONCLUSION

Awake, frameless DBS surgery with the Fred Haer Corporation STarFix system does not require intraoperative imaging for stereotactic accuracy or clinical effectiveness.

Review of the Standard and Advanced Screening, Staging Systems and Treatment Modalities for Cervical Cancer

Simple Summary

This review discusses the timeline and development of the recommended screening tests, diagnosis system, and therapeutics implemented in clinics for precancer and cancer of the uterine cervix. The incorporation of the latest automation, machine learning modules, and state-of-the-art technologies into these aspects are also discussed.

Abstract

Cancer arising from the uterine cervix is the fourth most common cause of cancer death among women worldwide. Almost 90% of cervical cancer mortality has occurred in low- and middle-income countries. One of the major aetiologies contributing to cervical cancer is the persistent infection by the cancer-causing types of the human papillomavirus. The disease is preventable if the premalignant lesion is detected early and managed effectively. In this review, we outlined the standard guidelines that have been introduced and implemented worldwide for decades, including the cytology, the HPV detection and genotyping, and the immunostaining of surrogate markers. In addition, the staging system used to classify the premalignancy and malignancy of the uterine cervix, as well as the safety and efficacy of the various treatment modalities in clinical trials for cervical cancers, are also discussed. In this millennial world, the advancements in computer-aided technology, including robotic modules and artificial intelligence (AI), are also incorporated into the screening, diagnostic, and treatment platforms. These innovations reduce the dependence on specialists and technologists, as well as the work burden and time incurred for sample processing. However, concerns over the practicality of these advancements remain, due to the high cost, lack of flexibility, and the judgment of a trained professional that is currently not replaceable by a machine.

Frameless Robot-Assisted vs Frame-Based Awake Deep Brain Stimulation Surgery: An Evaluation of Technique and New Challenges

BACKGROUND

Methodological approaches to deep brain stimulation (DBS) continue to evolve from awake frame-based to asleep frameless procedures with robotic assistance, primarily directed to optimize operative efficiency, lead accuracy, and patient comfort. Comparison between the 2 is scarce.

OBJECTIVE

To analyze the impacts of methodological differences on operative efficiency and stereotactic accuracy using a frame compared with a frameless robotic platform while maintaining the awake state and use of multiple microelectrode recording (MER) trajectories.

METHODS

Thirty-four consecutive patients who underwent bilateral awake frameless robot-assisted DBS were compared with a previous cohort of 30 patients who underwent frame-based surgery. Patient demographics, operative times, and MER data were collected for both cohorts. Two-dimensional radial errors of lead placements were calculated.

RESULTS

Preoperative setup, surgical, and total operating room times were all significantly greater for the robot-assisted cohort (P < .001). The need for computed tomography imaging when referencing the robotic fiducials led to increased setup duration because of patient transport, unnecessary for the frame-based cohort. Multiple simultaneous MER trajectories increased surgical time (mean 26 min) for the robot-assisted cohort only. The mean radial errors in the robot-assisted and frame cohorts were 0.98 ± 0.66 and 0.74 ± 0.49 mm (P = .03), respectively.

CONCLUSION

The use of a truly frameless robotic platform such as the Mazor Renaissance (Mazor Robotics Ltd) presented challenges when implementing techniques used during awake frame-based surgery. Maintaining good accuracy, intraoperative reference imaging, and limited MER trajectories will help integrate frameless robot assistance into the awake DBS surgical workflow.

Estimating the Risk of Deep Brain Stimulation in the Modern Era: 2008 to 2020

BACKGROUND

Deep brain stimulation (DBS) was first approved by the United States Food and Drug Administration in 1997. Although the fundamentals of DBS remain the same, hardware, software, and imaging have evolved significantly.

OBJECTIVE

To test our hypothesis that the aggregate complication rate in the medical literature in the past 12 years would be lower than what is often cited based on early experience with DBS surgery.

METHODS

PubMed, PsycINFO, and EMBASE were queried for studies from 2008 to 2020 that included patients treated with DBS from 2007 to 2019. This yielded 34 articles that evaluated all complications of DBS surgery, totaling 2249 patients.

RESULTS

The overall complication rate in this study was 16.7% per patient. There was found to be a systemic complication rate of 0.89%, intracranial complication rate of 2.7%, neurological complication rate of 4.6%, hardware complication rate of 2.2%, and surgical site complication rate of 3.4%. The infection and erosion rate was 3.0%.

CONCLUSION

This review suggests that surgical complication rates have decreased since the first decade after DBS was first FDA approved. Understanding how to minimize complications from the inception of a technique should receive more attention.

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.

Robotic Applications in Cranial Neurosurgery: Current and Future

Robotics applied to cranial surgery is a fast-moving and fascinating field, which is transforming the practice of neurosurgery. With exponential increases in computing power, improvements in connectivity, artificial intelligence, and enhanced precision of accessing target structures, robots are likely to be incorporated into more areas of neurosurgery in the future-making procedures safer and more efficient. Overall, improved efficiency can offset upfront costs and potentially prove cost-effective. In this narrative review, we aim to translate a broad clinical experience into practical information for the incorporation of robotics into neurosurgical practice. We begin with procedures where robotics take the role of a stereotactic frame and guide instruments along a linear trajectory. Next, we discuss robotics in endoscopic surgery, where the robot functions similar to a surgical assistant by holding the endoscope and providing retraction, supplemental lighting, and correlation of the surgical field with navigation. Then, we look at early experience with endovascular robots, where robots carry out tasks of the primary surgeon while the surgeon directs these movements remotely. We briefly discuss a novel microsurgical robot that can perform many of the critical operative steps (with potential for fine motor augmentation) remotely. Finally, we highlight 2 innovative technologies that allow instruments to take nonlinear, predetermined paths to an intracranial destination and allow magnetic control of instruments for real-time adjustment of trajectories. We believe that robots will play an increasingly important role in the future of neurosurgery and aim to cover some of the aspects that this field holds for neurosurgical innovation.

Robotic-Assisted Stereotaxy for Deep Brain Stimulation Lead Implantation in Awake Patients

BACKGROUND

Robotic-assisted stereotaxy has been increasingly adopted for lead implantation in stereoelectroencephalography based on its efficiency, accuracy, and precision. Despite initially being developed for use in deep brain stimulation (DBS) surgery, adoption for this indication has not been widespread.

OBJECTIVE

To describe a recent robotic-assisted stereotaxy experience and workflow for DBS lead implantation in awake patients with and without microelectrode recording (MER), including considerations for intraoperative research using electrocorticography (ECoG).

METHODS

A retrospective review of 20 consecutive patients who underwent simultaneous bilateral DBS lead implantation using robotic-assisted stereotaxy was performed. Radial error was determined by comparing the preoperative target with the DBS lead position in the targeting plane on postoperative computed tomography. Information regarding any postoperative complications was obtained by chart review.

RESULTS

A novel method for robot coregistration was developed. We describe a standard workflow that allows for MER and/or ECoG research, and a streamlined workflow for cases in which MER is not required. The overall radial error for lead placement across all 20 patients was 1.14 ± 0.11 mm. A significant difference (P = .006) existed between the radial error of the first 10 patients (1.46 ± 0.19 mm) as compared with the second 10 patients (0.86 ± 0.09 mm). No complications were encountered.

CONCLUSION

Robotic-assisted stereotaxy has the potential to increase precision and reduce human error, compared to traditional frame-based DBS surgery, without negatively impacting patient safety or the ability to perform awake neurophysiology research.

Targeting accuracy of robot-assisted deep brain stimulation surgery in childhood-onset dystonia: a single-center prospective cohort analysis of 45 consecutive cases

OBJECTIVE

Deep brain stimulation (DBS) is an established treatment for pediatric dystonia. The accuracy of electrode implantation is multifactorial and remains a challenge in this age group, mainly due to smaller anatomical targets in very young patients compared to adults, and also due to anatomical abnormalities frequently associated with some etiologies of dystonia. Data on the accuracy of robot-assisted DBS surgery in children are limited. The aim of the current paper was to assess the accuracy of robot-assisted implantation of DBS leads in a series of patients with childhood-onset dystonia.

METHODS

Forty-five children with dystonia undergoing implantation of DBS leads under general anesthesia between 2017 and 2019 were included. Robot-assisted stereotactic implantation of the DBS leads was performed. The final position of the electrodes was verified with an intraoperative 3D scanner (O-arm). Coordinates of the planned electrode target and actual electrode position were obtained and compared, looking at the radial error, depth error, absolute error, and directional error, as well as the euclidean distance. Functional assessment data prospectively collected by a multidisciplinary pediatric complex motor disorders team were analyzed with regard to motor skills, individualized goal achievement, and patients' and caregivers' expectations.

RESULTS

A total of 90 DBS electrodes were implanted and 48.5% of the patients were female. The mean age was 11.0 ± 0.6 years (range 3-18 years). All patients received bilateral DBS electrodes into the globus pallidus internus. The median absolute errors in x-, y-, and z-axes were 0.85 mm (range 0.00-3.25 mm), 0.75 mm (range 0.05-2.45 mm), and 0.75 mm (range 0.00-3.50 mm), respectively. The median euclidean distance from the target to the actual electrode position was 1.69 ± 0.92 mm, and the median radial error was 1.21 ± 0.79. The robot-assisted technique was easily integrated into the authors' surgical practice, improving accuracy and efficiency, and reducing surgical time significantly along the learning curve. No major perioperative complications occurred.

CONCLUSIONS

Robot-assisted stereotactic implantation of DBS electrodes in the pediatric age group is a safe and accurate surgical method. Greater accuracy was present in this cohort in comparison to previous studies in which conventional stereotactic frame-based techniques were used. Robotic DBS surgery and neuroradiological advances may result in further improvement in surgical targeting and, consequently, in better clinical outcome in the pediatric population.

Comparison of clinical outcomes and accuracy of electrode placement between robot-assisted and conventional deep brain stimulation of the subthalamic nucleus: a single-center study

BACKGROUND

Several surgical methods are used for deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). This study aimed to compare clinical outcomes and electrode placement accuracy after robot-assisted (RAS) versus frame-based stereotactic (FSS) STN DBS in Parkinson's disease.

METHODS

In this single-center open-label study, we prospectively collected data from 48 consecutive PD patients who underwent RAS (Neuromate®; n = 20) or FSS (n = 28) STN DBS with the same MRI-based STN targeting between October 2016 and December 2018 in the university neurological hospital of Lyon, France. Clinical variables were assessed before and 1 year after surgery. The number of electrode contacts within the STN was determined by merging post-operative CT and pre-operative MRI using Brainlab® GUIDE™XT software.

RESULTS

One year after surgery, the improvement of motor manifestations (p = 0.18), motor complications (p = 0.80), and quality of life (p= 0.30) and the reduction of dopaminergic treatment (p = 0.94) and the rate of complications (p = 0.99) were similar in the two groups. Surgery duration was longer in the RAS group (p = 0.0001). There was no difference in the number of electrode contacts within the STN.

CONCLUSION

This study demonstrates that RAS and FSS STN DBS for PD provide similar clinical outcomes and accuracy of electrode placement.

O-Arm Stereotactic Imaging in Deep Brain Stimulation Surgery Workflow: A Utility and Cost-Effectiveness Analysis

INTRODUCTION

Deep brain stimulation (DBS) surgery is an established treatment for movement disorders. Advances in neuroimaging techniques have resulted in improved targeting accuracy that may improve clinical outcomes. This study aimed to evaluate the safety and feasibility of using the Medtronic O-arm device for the acquisition of intraoperative stereotactic imaging, targeting, and localization of DBS electrodes compared with standard stereotactic MRI or computed tomography (CT).

METHODS

Patients were recruited prospectively into the study. Routine frame-based stereotactic DBS surgery was performed. Intraoperative imaging was used to facilitate and verify the accurate placement of the intracranial electrodes. The acquisition of coordinates and verification of the position of the electrodes using the O-arm were evaluated and compared with conventional stereotactic MRI or CT. Additionally, a systematic review of the literature on the use of intraoperative imaging in DBS surgery was performed.

RESULTS

Eighty patients were included. The indications for DBS surgery were dystonia, Parkinson's disease, essential tremor, and epilepsy. The globus pallidus internus was the most commonly targeted region (43.7%), followed by the subthalamic nucleus (35%). Stereotactic O-arm imaging reduced the overall surgical time by 68 min, reduced the length of time of acquisition of stereotactic images by 77%, reduced patient exposure to ionizing radiation by 24.2%, significantly reduced operating room (OR) costs per procedure by 31%, and increased the OR and neuroradiology suite availability.

CONCLUSIONS

The use of the O-arm in DBS surgery workflow significantly reduced the duration of image acquisition, the exposure to ionizing radiation, and costs when compared with standard stereotactic MRI or CT, without reducing accuracy.

Brain-Responsive Neurostimulation for Loss of Control Eating: Early Feasibility Study

BACKGROUND

Loss of control (LOC) is a pervasive feature of binge eating, which contributes significantly to the growing epidemic of obesity; approximately 80 million US adults are obese. Brain-responsive neurostimulation guided by the delta band was previously found to block binge-eating behavior in mice. Following novel preclinical work and a human case study demonstrating an association between the delta band and reward anticipation, the US Food and Drug Administration approved an Investigational Device Exemption for a first-in-human study.

OBJECTIVE

To assess feasibility, safety, and nonfutility of brain-responsive neurostimulation for LOC eating in treatment-refractory obesity.

METHODS

This is a single-site, early feasibility study with a randomized, single-blinded, staggered-onset design. Six subjects will undergo bilateral brain-responsive neurostimulation of the nucleus accumbens for LOC eating using the RNS® System (NeuroPace Inc). Eligible participants must have treatment-refractory obesity with body mass index ≥ 45 kg/m2. Electrophysiological signals of LOC will be characterized using real-time recording capabilities coupled with synchronized video monitoring. Effects on other eating disorder pathology, mood, neuropsychological profile, metabolic syndrome, and nutrition will also be assessed.

EXPECTED OUTCOMES

Safety/feasibility of brain-responsive neurostimulation of the nucleus accumbens will be examined. The primary success criterion is a decrease of ≥1 LOC eating episode/week based on a 28-d average in ≥50% of subjects after 6 mo of responsive neurostimulation.

DISCUSSION

This study is the first to use brain-responsive neurostimulation for obesity; this approach represents a paradigm shift for intractable mental health disorders.

Accuracy study of a binocular-stereo-vision-based navigation robot for minimally invasive interventional procedures

BACKGROUND

Medical robot is a promising surgical tool, but no specific one has been designed for interventional treatment of chronic pain. We developed a computed tomography-image based navigation robot using a new registration method with binocular vision. This kind of robot is appropriate for minimal invasive interventional procedures and easy to operate. The feasibility, accuracy and stability of this new robot need to be tested.

AIM

To assess quantitatively the feasibility, accuracy and stability of the binocular-stereo-vision-based navigation robot for minimally invasive interventional procedures.

METHODS

A box model was designed for assessing the accuracy for targets at different distances. Nine (three sets) lead spheres were embedded in the model as puncture goals. The entry-to-target distances were set 50 mm (short-distance), 100 mm (medium-distance) and 150 mm (long-distance). Puncture procedure was repeated three times for each goal. The Euclidian error of each puncture was calculated and statistically analyzed. Three head phantoms were used to explore the clinical feasibility and stability. Three independent operators conducted foramen ovale placement on head phantoms (both sides) by freehand or under the guidance of robot (18 punctures with each method). The operation time, adjustment time and one-time success rate were recorded, and the two guidance methods were compared.

RESULTS

On the box model, the mean puncture errors of navigation robot were 1.7 ± 0.9 mm for the short-distance target, 2.4 ± 1.0 mm for the moderate target and 4.4 ± 1.4 mm for the long-distance target. On the head phantom, no obvious differences in operation time and adjustment time were found among the three performers (P > 0.05). The median adjustment time was significantly less under the guidance of the robot than under free hand. The one-time success rate was significantly higher with the robot (P < 0.05). There was no obvious difference in operation time between the two methods (P > 0.05).

CONCLUSION

In the laboratory environment, accuracy of binocular-stereo-vision-based navigation robot is acceptable for target at 100 mm depth or less. Compared with freehand, foramen ovale placement accuracy can be improved with robot guidance.

Case Report on Deep Brain Stimulation Rescue After Suboptimal MR-Guided Focused Ultrasound Thalamotomy for Essential Tremor: A Tractography-Based Investigation

Essential tremor (ET) is the most prevalent movement disorder in adults, and can often be medically refractory, requiring surgical intervention. MRI-guided focused ultrasound (MRgFUS) is a less invasive procedure that uses ultrasonic waves to induce lesions in the ventralis intermedius nucleus (VIM) to treat refractory ET. As with all procedures for treating ET, optimal targeting during MRgFUS is essential for efficacy and durability. Various studies have reported cases of tremor recurrence following MRgFUS and long-term outcome data is limited to 3–4 years. We present a tractography-based investigation on a case of DBS rescue for medically refractory ET that was treated with MRgFUS that was interrupted due to the development of dysarthria during the procedure. After initial improvement, her hand tremor started to recur within 6 months after treatment, and bilateral DBS was performed targeting the VIM 24 months after MRgFUS. DBS induced long-term tremor control with monopolar stimulation. Diffusion MRI tractography was used to reconstruct the dentatorubrothalamic (DRTT) and corticothalmic (CTT) tracts being modulated by the procedures to understand the variability in efficacy between MRgFUS and DBS in treating ET in our patient. By comparing the MRgFUS lesion and DBS volume of activated tissue (VAT), we found that the MRgFUS lesion was located ventromedially to the VAT, and was less than 10% of the size of the VAT. While the lesion encompassed the same proportion of DRTT streamlines, it encompassed fewer CTT streamlines than the VAT. Our findings indicate the need for further investigation of targeting the CTT when using neuromodulatory procedures to treat refractory ET for more permanent tremor relief.

Electrophysiology and Structural Connectivity of the Posterior Hypothalamic Region: Much to Learn From a Rare Indication of Deep Brain Stimulation

Cluster headache (CH) is among the most common and debilitating autonomic cephalalgias. We characterize clinical outcomes of deep brain stimulation (DBS) to the posterior hypothalamic region through a novel analysis of the electrophysiological topography and tractography-based structural connectivity. The left posterior hypothalamus was targeted ipsilateral to the refractory CH symptoms. Intraoperatively, field potentials were captured in 1 mm depth increments. Whole-brain probabilistic tractography was conducted to assess the structural connectivity of the estimated volume of activated tissue (VAT) associated with therapeutic response. Stimulation of the posterior hypothalamic region led to the resolution of CH symptoms, and this benefit has persisted for 1.5-years post-surgically. Active contacts were within the posterior hypothalamus and dorsoposterior border of the ventral anterior thalamus (VAp). Delta- (3 Hz) and alpha-band (8 Hz) powers increased and peaked with proximity to the posterior hypothalamus. In the posterior hypothalamus, the delta-band phase was coupled to beta-band amplitude, the latter of which has been shown to increase during CH attacks. Finally, we identified that the VAT encompassing these regions had a high proportion of streamlines of pain processing regions, including the insula, anterior cingulate gyrus, inferior parietal lobe, precentral gyrus, and the brainstem. Our unique case study of posterior hypothalamic region DBS supports durable efficacy and provides a platform using electrophysiological topography and structural connectivity, to improve mechanistic understanding of CH and this promising therapy.

Robot-assisted versus manual navigated stereoelectroencephalography in adult medically-refractory epilepsy patients

OBJECTIVE

Stereoelectroencephalography (SEEG) has experienced a recent growth in adoption for epileptogenic zone (EZ) localization. Advances in robotics have the potential to improve the efficiency and safety of this intracranial seizure monitoring method. We present our institutional experience employing robot-assisted SEEG and compare its operative efficiency, seizure reduction outcomes, and direct hospital costs with SEEG performed without robotic assistance using navigated stereotaxy.

METHODS

We retrospectively identified 50 consecutive adult SEEG cases at our institution in this IRB-approved study, of which 25 were navigated with image guidance (hereafter referred to as "navigated") (02/2014-10/2016) and 25 were robot-assisted (09/2016-12/2017). A thorough review of medical/surgical history and operative records with imaging and trajectory plans was done for each patient. Direct inpatient costs related to each technique were compared.

RESULTS

Most common seizure etiologies for patients undergoing navigated and robot-assisted SEEG included non-lesional and benign temporal lesions. Despite having a higher mean number of leads-per-patient (10.2 ± 3.5 versus 7.2 ± 2.6, P = 0.002), robot-assisted cases had a significantly shorter mean operative time than navigated cases (125.5±48.5 versus 173.4±84.3 min, P = 0.02). Comparison of robot-assisted cases over the study interval revealed no significant difference in mean operative time (136.4±51.4 min for the first ten cases versus 109.9±75.8 min for the last ten cases, P = 0.25) and estimated operative time-per-lead (13.4±6.0 min for the first ten cases versus 12.9±7.7 min for the last ten cases, P = 0.86). The mean depth, radial, target, and entry point errors for robot-assisted cases were 2.12±1.89, 1.66±1.58, 3.05±2.02 mm, and 1.39 ± 0.75 mm, respectively. The two techniques resulted in equivalent EZ localization rate (navigated 88 %, robot-assisted 96 %, P = 0.30). Common types of epilepsy surgery performed consisted of implantation of responsive neurostimulation (RNS) device (56 %), resection (19.1 %), and laser ablation (23.8 %) for navigated SEEG. For robot-assisted SEEG, either RNS implantation (68.2 %) or laser ablation (22.7 %) were performed or offered. A majority of navigated and robot-assisted patients who underwent epilepsy surgery achieved either Engel Class I (navigated 36.8 %, robot-assisted 31.6 %) or II (navigated 36.8 %, robot-assisted 15.8 %) outcome with no significant difference between the groups (P = 0.14). Direct hospital cost for robot-assisted SEEG was 10 % higher than non-robotic cases.

CONCLUSION

This single-institutional study suggests that robotic assistance can enhance efficiency of SEEG without compromising safety or precision when compared to image guidance only. Adoption of this technique with uniform safety and efficacy over a short period of time is feasible with favorable epilepsy outcomes.

Assessment of Deep Brain Stimulation Implantation Surgery: A Practical Scale

BACKGROUND

Patients requiring deep brain stimulation (DBS) will undergo extensive preoperative and postoperative evaluations. However, the field lacks a robust scoring system for quantifying the outcomes of DBS surgery. We sought to determine whether a practical scale could assess the outcomes of DBS surgery and the clinical significance.

METHODS

A retrospective study was performed of the data from 150 patients who had undergone DBS from February 2017 to February 2019. An independence analysis and multivariate testing were used to identify significant independent predictors. The scale scores were computed by summing across the weighted predictors. The correlation between the scale scores and the intraoperative electrophysiological signal length (IESL), DBS power-on voltage, improvement rate in the unified Parkinson disease rating scale (UPDRS) and UPDRS part III (UPDRS III) scores was analyzed. Receiver operating characteristics curve analysis was used to quantify the discriminative capacity of the scale for predicting the prognosis.

RESULTS

Listwise exclusion of patients with incomplete data sets yielded a final sample of 130 patients with Parkinson disease who had undergone bilateral DBS. Multivariate testing identified 3 independent predictors of the prognosis, including electrode implantation duration, postoperative pneumocephalus volume, and electrode fusion error. The scale scores correlated significantly with the subthalamic nucleus DBS power-on voltage (r = -0.4063; P < 0.0001), globus pallidus internus DBS power-on voltage (r = -0.4723; P = 0.0014), and improvement rate of the UPDRS (r = 0.3490; P < 0.0001) and UPDRS III (r = 0.6623; P < 0.0001) scores. However, the scale scores did not significantly correlate with the subthalamic nucleus IESL and globus pallidus internus IESL. Receiver operating characteristics curve analysis revealed impressive outcome discrimination for the UPDRS and UPDRS III scores (UPDRS: area under the curve, 0.62, P = 0.0219; UPDRS III: area under the curve, 0.85, P < 0.0001).

CONCLUSIONS

We have introduced a novel practical scale capable of assessing the outcomes of DBS surgery and predicting the prognosis of patients after DBS surgery.

Neuroimaging of Deep Brain Stimulation

Deep brain stimulation is the most advanced and effective neuromodulation therapy for Parkinson disease, essential tremor, and generalized dystonia. This article discusses how imaging improves surgical techniques and outcomes and widens possibilities in translational neuroscience in Parkinson disease, essential tremor, generalized dystonia, and epilepsy. In movement disorders diffusion tensor imaging allows anatomic segment of cortical areas and different functional subregions within deep-seated targets to understand the side effects of stimulation and gain more data to describe the therapeutic mechanism of action. The introduction of visualization of white matter tracks increases the safety of neurosurgical techniques in functional neurosurgery and neuro-oncology.

Risk assessment methodology for trajectory planning in keyhole neurosurgery using genetic algorithms

BACKGROUND

Preoperative assessment to find the safest trajectory in keyhole neurosurgery can reduce post operative complications.

METHODS

We introduced a novel preoperative risk assessment semiautomated methodology based on the sum of N maximum risk values using a generic genetic algorithm for the safest trajectory search.

RESULTS

A set of candidates trajectories were found for two surgical procedures. The trajectories search is done using a risk map considering the proximity of voxels within risk structures in multiple points and a genetic algorithm to avoid an exhaustive search. The trajectories were validated by a group of neurosurgeons.

CONCLUSIONS

The trajectories obtained with the proposal method were shorter in 5% and have greater distance from the voxels within the blood vessels in 4.7%. The use of genetic algorithm (GA) speeds up the search for the safest trajectory, decreasing in 99.9% the time required for an exhaustive search.

Electrode Placement Accuracy in Robot-Assisted Asleep Deep Brain Stimulation

Deep brain stimulation (DBS) involves the implantation of electrodes into specific central brain structures for the treatment of Parkinson's disease. Image guidance and robot-assisted techniques have been developed to assist in the accuracy of electrode placement. Traditional DBS is performed with the patient awake and utilizes microelectrode recording for feedback, which yields lengthy operating room times. Asleep DBS procedures use imaging techniques to verify electrode placement. The objective of this study is to demonstrate the validity of an asleep robot-assisted DBS procedure that utilizes intraoperative imaging techniques for precise electrode placement in a large, inclusive cohort. Preoperative magnetic resonance imaging (MRI) was used to plan the surgical procedure for the 128 patients that underwent asleep DBS. During the surgery, robot assistance was used during the implantation of the electrodes. To verify electrode placement, intraoperative CT scans were fused with the preoperative MRIs. The mean radial error of all final electrode placements is 0.85 ± 0.38 mm. MRI-CT fusion error is 0.64 ± 0.40 mm. The average operating room time for bilateral and unilateral implantations are 139.3 ± 34.7 and 115.4 ± 42.1 min, respectively. This study shows the validity of the presented asleep DBS procedure using robot assistance and intraoperative CT verification for accurate electrode placement with shorter operating room times.