Tag: Movement Disorders

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Brain Bleeding Associated With Cavitation During Focused Ultrasound Ablation

Neurosurgery 97:1215–1218, 2025

This report presents two cases of symptomatic intracranial hemorrhage occurring during MR-guided focused ultrasound (MRgFUS) ablation for movement disorders, associated with persistent cavitation activity despite power reductions. Both patients developed contralateral motor deficits after sonications; one recovered substantially, the other remained significantly disabled, and imaging confirmed hematomas at the targeted sites.

The authors review procedural variables, cavitation mechanisms, mitigation strategies, and institutional experience (~500 cases, 0.4% incidence), recommending a conservative approach—including treatment termination—when uncontrollable cavitation arises, and urging further study of patient- and system-related risk factors to minimize bleeding risk.

• MRgFUS Complication: Symptomatic brain bleeding can occur during magnetic resonance–guided focused ultrasound (MRgFUS) ablation for movement disorders, although it is a rare complication (approximately 0.4% incidence in a center with over 500 cases).

• Cavitation Risk: Persistent cavitation—microbubble formation and collapse during sonication—is strongly associated with the occurrence of brain hemorrhage in MRgFUS procedures, even when standard mitigation steps (such as lowering power) are taken.

• Case Outcomes: In two reported cases, both patients developed contralateral motor weakness and brain hematoma following persistent cavitation during MRgFUS; one patient recovered functional independence, while the other remained severely disabled.

• Technical Mitigation: When cavitation is detected, the recommended strategy is to reduce sonication power and, if needed, increase duration to maintain energy delivery; however, if uncontrollable cavitation persists, treatment termination should be considered.

• Patient Factors: Bleeding can occur even in patients without traditional vascular risk factors, suggesting procedural factors like cavitation may be more critical than patient comorbidities in these cases.

• Incidence and Reporting: Over 20,000 MRgFUS procedures have been performed globally with very few reports of symptomatic brain bleeding, highlighting the importance of continued reporting to refine safety practices.

• Clinical Implication: MRgFUS is an effective and generally safe treatment for movement disorders, but it is not without risk; both clinicians and patients should be aware that severe complications, though rare, are possible.

• Best Practice: A conservative approach is advised if cavitation cannot be controlled during MRgFUS, and further study into both technical and patient-related risk factors for hemorrhage is warranted.

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How Accurate Is Frameless Fiducial—Free Deep Brain Stimulation?

Operative Neurosurgery 27:431–439, 2024

Frameless deep brain stimulation (DBS) offers advantages in terms of patient comfort and reduced operative time. However, the need for bony fiducial markers for localization remains a drawback due to the time-consuming and uncomfortable procedure. An alternative localization method involves the direct tracking of an intraoperative 3-dimensional scanner. This study aims to assess the accuracy of the NexFrame frameless DBS system in conjunction with the O-Arm (Medtronic Inc.), both with and without fiducial markers.

METHODS: The locations of 100 DBS leads were determined, with 50 cases using fiducial-free localization and 50 involving fiducial markers. The coordinates were compared with the expected intraoperative targets. Absolute errors in the X, Y, and Z coordinates (ΔX, ΔY, and ΔZ) were calculated, along with the vector error (Euclidean) (vector error square root Δx 2 + Δy 2 + Δz 2 ).

RESULTS: The vector error averaged 1.61 ± 0.49 mm (right) and 1.52 ± 0.60 mm (left) for the group without fiducial bone markers and 1.66 ± 0.69 (right) and 1.44 ± 0.65 mm (left) for the other cohort (P = .76 right; P = .67 left). Absolute errors in the X, Y, and Z coordinates for the fiducial-free group were 0.88 ± 0.55, 0.79 ± 0.45, and 0.79 ± 0.57 mm (right) and 0.72 ± 0.37, 0.78 ± 0.56, and 0.77 ± 0.71 mm (left). For the group with fiducial markers, these errors were 0.87 ± 0.72, 0.92 ± 0.39, and 0.86 ± 0.50 mm (right) and 0.75 ± 0.33, 0.80 ± 0.51, and 0.73 ± 0.64 mm (left) with no statistically significant difference.

CONCLUSION: Our analysis of the accuracy of NexFrame DBS, both with and without fiducial markers, using an intraoperative navigable cone-beam computed tomography, demonstrates that both techniques provide sufficient and equivalent 3-dimensional accuracy.

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Direct targeting of the ventral intermediate nucleus of the thalamus in deep brain stimulation for essential tremor

J Neurosurg 136:662–671, 2022

The ventral intermediate nucleus of the thalamus (VIM) is an effective target for deep brain stimulation (DBS) to control symptoms related to essential tremor. The VIM is typically targeted using indirect methods, although studies have reported visualization of the VIM on proton density–weighted MRI. This study compares the outcomes between patients who underwent VIM DBS with direct and indirect targeting.

METHODS Between August 2013 and December 2019, 230 patients underwent VIM DBS at the senior author’s institution. Of these patients, 92 had direct targeting (direct visualization on proton density 3-T MRI). The remaining 138 patients had indirect targeting (relative to the third ventricle and anterior commissure–posterior commissure line).

RESULTS Coordinates of electrodes placed with direct targeting were significantly more lateral (p < 0.001) and anterior (p < 0.001) than those placed with indirect targeting. The optimal stimulation amplitude for devices measured in voltage was lower for those who underwent direct targeting than for those who underwent indirect targeting (p < 0.001). Patients undergoing direct targeting had a greater improvement only in their Quality of Life in Essential Tremor Questionnaire hobby score versus those undergoing indirect targeting (p = 0.04). The direct targeting group had substantially more symptomatic hemorrhages than the indirect targeting group (p = 0.04). All patients who experienced a postoperative hemorrhage after DBS recovered without intervention.

CONCLUSIONS Patients who underwent direct VIM targeting for DBS treatment of essential tremor had similar clinical outcomes to those who underwent indirect targeting. Direct VIM targeting is safe and effective.

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Electrocorticography During Deep Brain Stimulation Surgery

Neurosurgery 88:E420–E426, 2021

Intraoperative research during deep brain stimulation (DBS) surgery has enabled major advances in understanding movement disorders pathophysiology and potential mechanisms for therapeutic benefit. In particular, over the last decade, recording electrocorticography (ECoG) from the cortical surface, simultaneously with subcortical recordings, has become an important research tool for assessing basal gangliathalamocortical circuit physiology.

OBJECTIVE: To provide confirmation of the safety of performing ECoG duringDBS surgery, using data fromcenters involved in 2 BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative-funded basic human neuroscience projects. METHODS: Datawere collected separately at 4 centers. The primary endpoint was complication rate, defined as any intraoperative event, infection, or postoperative magnetic resonance imaging abnormality requiring clinical follow-up. Complication rates for explanatory variables were compared using point biserial correlations and Fisher exact tests.

RESULTS: A total of 367 DBS surgeries involving ECoG were reviewed. No cortical hemorrhages were observed. Seven complications occurred: 4 intraparenchymal hemorrhages and 3 infections (complication rate of 1.91%; CI=0.77%-3.89%). The placement of 2 separate ECoG research electrodes through a single burr hole (84 cases) did not result in a significantly different rate of complications, compared to placement of a single electrode (3.6% vs 1.5%; P = .4). Research data were obtained successfully in 350 surgeries (95.4%).

CONCLUSION: Combined with the single report previously available, which described no ECoG-related complications in a single-center cohort of 200 cases, these findings suggest that research ECOG during DBS surgery did not significantly alter complication rates.

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Simultaneous bilateral stereotactic procedure for deep brain stimulation implants

Simultaneous bilateral stereotactic procedure for deep brain stimulation implants

J Neurosurg 125:85–89, 2016

Currently, bilateral procedures involve 2 sequential implants in each of the hemispheres. The present report demonstrates the feasibility of simultaneous bilateral procedures during the implantation of deep brain stimulation (DBS) leads.

Methods Fifty-seven patients with movement disorders underwent bilateral DBS implantation in the same study period. The authors compared the time required for the surgical implantation of deep brain electrodes in 2 randomly assigned groups. One group of 28 patients underwent traditional sequential electrode implantation, and the other 29 patients underwent simultaneous bilateral implantation. Clinical outcomes of the patients with Parkinson’s disease (PD) who had undergone DBS implantation of the subthalamic nucleus using either of the 2 techniques were compared.

Results Overall, a reduction of 38.51% in total operating time for the simultaneous bilateral group (136.4 ± 20.93 minutes) as compared with that for the traditional consecutive approach (220.3 ± 27.58 minutes) was observed. Regarding clinical outcomes in the PD patients who underwent subthalamic nucleus DBS implantation, comparing the preoperative off-medication condition with the off-medication/on-stimulation condition 1 year after the surgery in both procedure groups, there was a mean 47.8% ± 9.5% improvement in the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-III) score in the simultaneous group, while the sequential group experienced 47.5% ± 15.8% improvement (p = 0.96). Moreover, a marked reduction in the levodopa-equivalent dose from preoperatively to postoperatively was similar in these 2 groups. The simultaneous bilateral procedure presented major advantages over the traditional sequential approach, with a shorter total operating time.

Conclusions A simultaneous stereotactic approach significantly reduces the operation time in bilateral DBS procedures, resulting in decreased microrecording time, contributing to the optimization of functional stereotactic procedures.

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Limbic and Motor Function Comparison of Deep Brain Stimulation of the Zona Incerta and Subthalamic Nucleus

Neurosurgery 70[ONS Suppl 1]:ons125–ons131, 2012 DOI: 10.1227/NEU.0b013e318232fdac

Psychiatric and neuropsychological side effects of subthalamic nucleus (STN) stimulation have been increasingly recognized. Most programming regimens focus on contacts 0 and 1, whereas contact 3, which often is located near or in the zona incerta (ZI), is usually not used. The question of whether ZI stimulation may limit limbic effects has not been answered.

OBJECTIVE: To examine the effects of short-term stimulation near or in the ZI (contact 3) compared with stimulation of the STN using standard trajectories and targeting as measured by limbic and motor functions.

METHODS: Motor and limbic functions of 11 patients with STN DBS were assessed with the Unified Parkinson Disease Rating Scale-3, structured gait video analysis, Visual Analog Scale mood scales, task testing of impulsivity, and facial recognition under routine STN programming and under stimulation in or near the ZI. Postoperative magnetic resonance imaging confirmed the location of contact 3 near or in the ZI.

RESULTS: Data analysis with repeated-measures analysis of variance revealed that motor scores remained stable with both stimulation settings, with specific improvements in finger taps (P = .02) and rapid alternating movements (P = .03) in ZI stimulation. Stimulation near or in the ZI led to a decrease in self- reported anxiety and depression (P = .03 for both) and an improvement in fear recognition (P = .02).

CONCLUSION: We provide preliminary evidence that stimulation in or near the ZI results in maintained motor function while improving self-reported depression and anxiety in patients with bilateral STN DBS. Stimulation in or near the ZI may provide a useful programming setting for patients prone to psychiatric side effects.

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