The Safety and Efficacy of Using the O-Arm Intraoperative Imaging System for Deep Brain Stimulation Lead Implantation

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.

How I do it - asleep DBS placement for Parkinson's disease

BACKGROUND

Traditionally, functional neurosurgery relied in stereotactic atlases and intraoperative micro-registration in awake patients for electrode placement in Parkinson's disease. Cumulative experience on target description, refinement of MRI, and advances in intraoperative imaging has enabled accurate preoperative planning and its implementation with the patient under general anaesthesia.

METHODS

Stepwise description, emphasising preoperative planning, and intraoperative imaging verification, for transition to asleep-DBS surgery.

CONCLUSION

Direct targeting relies on MRI anatomic landmarks and accounts for interpersonal variability. Indeed, the asleep procedure precludes patient distress. A particular complication to avoid is pneumocephalus; it can lead to brain-shift and potential deviation of electrode trajectory.

Molecular Mechanisms and Therapeutic Strategies for Levodopa-Induced Dyskinesia in Parkinson’s Disease: A Perspective Through Preclinical and Clinical Evidence

Parkinson’s disease (PD) is the second leading neurodegenerative disease that is characterized by severe locomotor abnormalities. Levodopa (L-DOPA) treatment has been considered a mainstay for the management of PD; however, its prolonged treatment is often associated with abnormal involuntary movements and results in L-DOPA-induced dyskinesia (LID). Although LID is encountered after chronic administration of L-DOPA, the appearance of dyskinesia after weeks or months of the L-DOPA treatment has complicated our understanding of its pathogenesis. Pathophysiology of LID is mainly associated with alteration of direct and indirect pathways of the cortico-basal ganglia-thalamic loop, which regulates normal fine motor movements. Hypersensitivity of dopamine receptors has been involved in the development of LID; moreover, these symptoms are worsened by concurrent non-dopaminergic innervations including glutamatergic, serotonergic, and peptidergic neurotransmission. The present study is focused on discussing the recent updates in molecular mechanisms and therapeutic approaches for the effective management of LID in PD patients.

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.

Frameless x-ray-based lead re-implantation after partial hardware removal of deep brain stimulation system with preservation of intracerebral trajectories

Background

Deep brain stimulation (DBS) is an established treatment for patients with medical refractory movement disorders with continuously increasing use also in other neurological and psychiatric diseases. Early and late complications can lead to revision surgeries with partial or complete DBS-system removal. In this study, we aimed to report on our experience with a frameless x-ray-based lead re-implantation technique after partial hardware removal or dysfunction of DBS-system, allowing the preservation of intracerebral trajectories.

Methods

We describe a surgical procedure with complete implant removal due to infection except for the intracranial part of the electrode and with non-stereotactic electrode re-implantation. A retrospective analysis of a patient series treated using this technique was performed and the surgical outcome was evaluated including radiological and clinical parameters.

Results

A total of 8 DBS-patients with lead re-implantation using the frameless x-ray-based method were enrolled in the study. A revision of 14 leads was performed, whereof a successful lead re-implantation could be achieved without any problems in 10 leads (71%). In two patients (one patient with dystonia and one patient with tremor), the procedure was not successful, so we placed both leads frame-based stereotactically.

Conclusions

The described x-ray-based technique allows a reliable frameless electrode re-implantation after infection and electrode dysfunction and might represent an efficient alternative to frame-based procedures for lead revision making the preservation of intracerebral trajectories possible.

Intraoperative Computed Tomography for Registration of Stereotactic Frame in Frame-Based Deep Brain Stimulation

BACKGROUND

Deep brain stimulation (DBS) electrode placement utilizing a frame-based technique requires registration of the stereotactic frame with computed tomography (CT) or magnetic resonance (MR) imaging. This traditionally has been accomplished with a conventional CT scanner. In recent years, intraoperative CT has become more prevalent.

OBJECTIVE

To compare the coordinates obtained with intraoperative CT and conventional CT for registration of the stereotactic frame for DBS.

METHODS

Patients undergoing DBS electrode placement between 2015 and 2017, who underwent both conventional and intraoperative CT for registration of the stereotactic frame, were included for analysis. The coordinates for the stereotactic target, anterior commissure, and posterior commissure for each CT method were recorded. The mean, maximum, minimum, and standard deviation of the absolute difference for each of the paired coordinates was calculated. Paired t-tests were performed to test for statistical significance of the difference. The directional difference as well as the vector error between the paired coordinates was also calculated.

RESULTS

The mean absolute difference between conventional and intraoperative CT for the coordinate pairs was less than 0.279 mm or 0.211 degrees for all coordinate pairs analyzed. This was not statistically significant for any of the coordinate pairs. Moreover, the maximum absolute difference between all coordinate pairs was 1.04 mm.

CONCLUSION

Intraoperative CT imaging provides stereotactic frame registration coordinates that are similar to those obtained by a standard CT scanner. This may save time and hospital resources by obviating the need for the patient to go to the radiology department for a CT scan.

Validation of 3D fluoroscopy for image-guidance registration in depth electrode implantation for medically refractory epilepsy

BACKGROUND

Frame registration is a critical step to ensure accurate electrode placement in stereotactic procedures such as stereoelectroencephalography (SEEG) and is routinely done by merging a computed tomography (CT) scan with the preoperative magnetic resonance (MR) examination. Three-dimensional fluoroscopy (XT) has emerged as a method for intraoperative electrode verification following electrode implantation and more recently has been proposed as a registration method with several advantages.

METHODS

We compared the accuracy of SEEG electrode placement by frame registration with CT and XT imaging by analyzing the Euclidean distance between planned and post-implantation trajectories of the SEEG electrodes to calculate the error in both the entry (EP) and target (TP) points. Other variables included radiation dose, efficiency, and complications.

RESULTS

Twenty-seven patients (13 CT and 14 XT) underwent placement of SEEG electrodes (319 in total). The mean EP and TP errors for the CT group were 2.3 mm and 3.3 mm, respectively, and 1.9 mm and 2.9 mm for the XT group, with no statistical difference (p = 0.75 and p = 0.246). The time to first electrode placement was similar (XT, 82 ± 10 min; CT, 84 ± 22 min; p = 0.858) and the average radiation exposure with XT (234 ± 55 mGy*cm) was significantly lower than CT (1245 ± 123 mGy*cm) (p < 0.0001). Four complications were documented with equal incidence in both groups.

CONCLUSIONS

The use of XT as a method for registration resulted in similar implantation accuracy compared with CT. Advantages of XT are the substantial reduction in radiation dose and the elimination of the need to transfer the patient out of the room which may have an impact on patient safety and OR efficiency.

Fusing of Preoperative Magnetic Resonance and Intraoperative O-arm Images in Deep Brain Stimulation Enhance Intuitive Surgical Planning and Increase Accuracy of Lead Placement

Intraoperative fluoroscopy and microelectrode recording (MER) are useful techniques for guiding lead placement in deep brain stimulation (DBS). Recent advances in magnetic resonance imaging (MRI) have enabled information on the location of the basal ganglia, as the target of DBS, to be obtained preoperatively. However, intraoperative images with few artifacts are required to enable accurate fusion of preoperative imaging data with intraoperative lead position data. With our method, we first fuse preoperative MRI and pre-frame fixed computed tomography (CT) images, then fuse the CT images exactly after mounting the frame, using this fusion image as a platform image. Compared with before and after frame fixation, the pre-frame fixed CT has less artifacts, facilitating the identification of soft tissues such as the ventricles and cortical surface on pre-frame fixed CT images. By fusing the structural information for these soft tissues between pre-frame fixed CT and MR images, this fusion process can provide improved accuracy that is intuitively understood by the surgeon. Using platform images, surgical planning and intraoperative lead positioning can then be evaluated on the same coordinate axis. Positional data on the lead acquired as three-dimensional (3D) data are then added to the platform image. The proposed surgical steps permit the acquisition of accurate lead position data.

The Accuracy of Direct Targeting Using Fusion of MR and CT Imaging for Deep Brain Stimulation of the Subthalamic Nucleus in Patients with Parkinson's Disease

INTRODUCTION

 In 33 consecutive patients with Parkinson's disease (PD) undergoing awake deep brain stimulation (DBS) without microelectrode recording (MER), we assessed and validated the precision and accuracy of direct targeting of the subthalamic nucleus (STN) using preoperative magnetic resonance imaging (MRI) and stereotactic computed tomography (CT) image fusion combined with immediate postoperative stereotactic CT and postoperative MRI, and we report on the side effects and clinical results up to 6 months' follow-up.

MATERIALS AND METHODS

 Preoperative nonstereotactic MRI and stereotactic CT images were merged and used for planning the trajectory and final lead position. Immediate postoperative stereotactic CT and postoperative nonstereotactic MRI provided the validation of the final electrode position. Changes in the Unified Parkinson's Disease Rating Scale III (UPDRS III) scores and the levodopa equivalent daily doses (LEDD) and appearance of adverse side effects were assessed.

RESULTS

 The mean Euclidian distance (ED) error between the planned position and the final position of the lead in the left STN was 1.69 ± 0.82 mm and that in the right STN was 2.12 ± 1.00. The individual differences between planned and final position in each of the three coordinates were less than 2 mm. The UPDRS III scores improved by 75% and LEDD decreased by 45%. Few patients experienced complications, such as postoperative infection (n = 1), or unwanted side effects, such as emotional instability (n = 1).

CONCLUSION

 Our results confirm that direct targeting of an STN on stereotactic CT merged with MRI could be a valid method for placement the DBS electrode. The magnitude of our targeting error is comparable with the reported errors when using MER and other direct targeting approaches.

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.

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.

Intraoperative Stereotactic Frame Registration Using a Three-Dimensional Imaging System with and without Preoperative Computed Tomography for Image Fusion

BACKGROUND

The O-arm O2 imaging system (OAO2) is an intraoperative cone beam 3D tomogram imaging tool with a wide enough field of view to perform intraoperative fiducial registration with standard stereotactic frames. However, the OAO2 3D images (cone beam CT) provide limited tissue contrast, which may reduce the accuracy of fusion to a preoperative targeting MRI for planning awake deep brain stimulation (DBS) surgeries. Therefore, most users obtain a preoperative CT scan to use as the reference exam for computational fusion with the preoperative targeting MRI and the intraoperative OAO2 cone beam CT.

OBJECTIVE

In this study, we retrospectively analyzed the discrepancy between stereotactic coordinates of deep brain targets on MRI derived from intraoperative OAO2 fiducial registration with and without the use of preoperative CT as the reference for image fusion.

METHODS

Preoperative stereotactic CT/MRI and intraoperative OAO2 cone beam CT were retrospectively evaluated for 27 consecutive DBS patients, using two commercial surgical planning software packages (BrainLab Elements and Medtronic Stealth 8). The anterior commissure, posterior commissure, and left subthalamic nucleus were identified on preoperative MRI. Each patient had intraoperative fiducial registration using the OAO2 with a Leksell headframe. For each subject, the reference scan for image fusion was set as either the preoperative CT or the preoperative MRI (volumetric T1 with contrast). Computed stereotactic coordinates for each target were then compared.

RESULTS

For 8 of 27 subjects, a discrepancy greater than 1.0 mm for at least one designated target was observed utilizing the Medtronic Stealth S8 planning station when a preoperative CT scan was not used. An additional 5 (5/27) had a discrepancy greater than 2 mm. The most common discrepancy was in the z axis. No coordinate discrepancies greater than 1 mm were observed utilizing BrainLab Elements.

CONCLUSIONS

Caution is advised in fusing intraoperative OAO2 images directly to preoperative MRI without a preoperative CT as the reference exam for image fusion, as the specific fusion algorithm employed may unpredictably affect targeting accuracy.

Clinical use of computer-assisted orthopedic surgery in horses

OBJECTIVE

To describe clinical applications of computer-assisted orthopedic surgery (CAOS) in horses with a navigation system coupled with a cone beam computed tomography unit.

STUDY DESIGN

Retrospective clinical case series.

ANIMALS

Thirteen adult horses surgically treated with CAOS.

METHODS

Medical records were searched for horses that underwent CAOS between 2016 and 2019. Data retrieved included signalment, diagnosis, lameness grade prior to surgery, surgical technique and complications, anesthesia and surgery time, and information pertaining to the perioperative case management and outcome.

RESULTS

In 10 cases, surgical implants were placed in the proximal phalanx, third metatarsal bone, ulna, or medial femoral condyle. In one case, navigated transarticular drilling was performed to promote ankylosis of the distal tarsal joints. In another case, an articular fragment of the middle phalanx was removed with the help of CAOS guidance. In the final case, a focal osteolytic lesion of the calcaneal tuber was curetted with the aid of CAOS. In seven cases, a purpose-built frame was used for the surgical procedure. All surgeries were performed successfully and according to the preoperative plan.

CONCLUSION

Computer-assisted orthopedic surgery can be an integral part of the clinical case management in equine surgery. To optimize workflow and time-efficiency, the authors recommend designating one team for operative planning and another for the execution of the surgical plan. Specialized equipment, such as the purpose-built frame, will further improve CAOS applications in equine surgery.

CLINICAL SIGNIFICANCE

After they have become familiar with the operational principles, equine surgeons can readily apply CAOS for a broad spectrum of indications.

Comparison of Intraoperative 3-Dimensional Fluoroscopy With Standard Computed Tomography for Stereotactic Frame Registration

BACKGROUND

Three-dimensional fluoroscopy via the O-arm (Medtronic, Dublin, Ireland) has been validated for intraoperative confirmation of successful lead placement in stereotactic electrode implantation. However, its role in registration and targeting has not yet been studied. After frame placement, many stereotactic neurosurgeons obtain a computed tomography (CT) scan and merge it with a preoperative magnetic resonance imaging (MRI) scan to generate planning coordinates; potential disadvantages of this practice include increased procedure time and limited scanner availability.

OBJECTIVE

To evaluate whether the second-generation O-arm (O2) can be used in lieu of a traditional CT scan to obtain accurate frame-registration scans.

METHODS

In 7 patients, a postframe placement CT scan was merged with preoperative MRI and used to generate lead implantation coordinates. After implantation, the fiducial box was again placed on the patient to obtain an O2 confirmation scan. Vector, scalar, and Euclidean differences between analogous X, Y, and Z coordinates from fused O2/MRI and CT/MRI scans were calculated for 33 electrode target coordinates across 7 patients.

RESULTS

Marginal means of difference for vector (X = -0.079 ± 0.099 mm; Y = -0.076 ± 0.134 mm; Z = -0.267 ± 0.318 mm), scalar (X = -0.146 ± 0.160 mm; Y = -0.306 ± 0.106 mm; Z = 0.339 ± 0.407 mm), and Euclidean differences (0.886 ± 0.190 mm) remained within the predefined equivalence margin differences of -2 mm and 2 mm.

CONCLUSION

This study demonstrates that O2 may emerge as a viable alternative to the traditional CT scanner for generating planning coordinates. Adopting the O2 as a perioperative tool may offer reduced transport risks, decreased anesthesia time, and greater surgical efficiency.

Feasibility and performance of a frameless stereotactic system for targeting subcortical nuclei in nonhuman primates

OBJECTIVE

Deep brain stimulation (DBS) is an effective therapy for different neurological diseases, despite the lack of comprehension of its mechanism of action. The use of nonhuman primates (NHPs) has been historically important in advancing this field and presents a unique opportunity to uncover the therapeutic mechanisms of DBS, opening the way for optimization of current applications and the development of new ones. To be informative, research using NHPs should make use of appropriate electrode implantation tools. In the present work, the authors report on the feasibility and accuracy of targeting different deep brain regions in NHPs using a commercially available frameless stereotactic system (microTargeting platform).

METHODS

Seven NHPs were implanted with DBS electrodes, either in the subthalamic nucleus or in the cerebellar dentate nucleus. A microTargeting platform was designed for each animal and used to guide implantation of the electrode. Imaging studies were acquired preoperatively for each animal, and were subsequently analyzed by two independent evaluators to estimate the electrode placement error (EPE). The interobserver variability was assessed as well.

RESULTS

The radial and vector components of the EPE were estimated separately. The magnitude of the vector of EPE was 1.29 ± 0.41 mm and the mean radial EPE was 0.96 ± 0.63 mm. The interobserver variability was considered negligible.

CONCLUSIONS

These results reveal the suitability of this commercial system to enhance the surgical insertion of DBS leads in the primate brain, in comparison to rigid traditional frames. Furthermore, our results open up the possibility of performing frameless stereotaxy in primates without the necessity of relying on expensive methods based on intraoperative imaging.