Tag: functional neurosurgery

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Fully Endoscopic Microvascular Decompression for Hemifacial Spasm Using 2-Dimensional/3-Dimensional Endoscopy

Operative Neurosurgery 30:870–879, 2026

This clinical case series reports outcomes of 204 patients who underwent fully endoscopic microvascular decompression (MVD) for hemifacial spasm (HFS), comparing 2D and preliminary 3D endoscopic techniques and analyzing learning-curve effects. Detailed methods, operative technique, intraoperative monitoring (LSR), and complication rates are presented alongside imaging and intraoperative findings.

Results show a 97.1% overall effectiveness with low long-term complication rates and improving outcomes over time; the 3D endoscope afforded improved stereoscopic perception though with higher cost and minor drawbacks, and the authors recommend further study of 3D endoscopy in MVD.

Study scope Retrospective analysis of 204 hemifacial spasm patients treated with fully endoscopic microvascular decompression using 2D (191) or 3D (13) endoscopy (July 2017–Oct 2024); mean follow-up 20.4 months.

Surgical approach Procedures used a retrosigmoid infrafloccular route with LSR monitoring; polytetrafluoroethylene (Teflon) pledgets placed between facial nerve REZ and offending vessels, with further exploration if LSR persisted.

Effectiveness At last follow-up, 198/204 (97.1%) had cessation or significant reduction of spasms (excellent 86.8%, good 10.3%).

Complications Immediate postoperative complications included facial weakness (7), hearing loss (11), tinnitus (1), infection (1), dysphagia (1), and CSF leak (1); 10 patients had persistent complications at last follow-up (6 hearing loss, 3 facial weakness, 1 tinnitus).

Learning curve Outcomes improved over time: effectiveness 95.6% → 97.1% → 98.5% (early/middle/late), while complication rates decreased 5.9% → 5.9% → 2.9%.

Offending vessels Most common offending vessel was AICA (43.1%), with multiple vessels in 33.3% of cases (including combinations with VA and PICA).

3D endoscopy pros/cons 3D endoscope provided subjectively better stereoscopic vision/depth perception aiding surgery, but had drawbacks including slight vertigo and high cost.

Overall conclusion Fully endoscopic MVD offers wide visualization of the neurovascular conflict region and helps minimize brain injury from retraction; favorable outcomes and low complications once technical proficiency is achieved, with more research needed on 3D’s role.

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Long-term outcomes of microvascular decompression for trigeminal neuralgia in multiple sclerosis

J Neurosurg 144:1122–1133, 2026

This systematic review and meta-analysis evaluates microvascular decompression (MVD) outcomes for trigeminal neuralgia in patients with multiple sclerosis (TN-MS). The authors pooled 30 studies (265 unique TN-MS patients), finding neurovascular compression in 96.6% and a pooled long-term pain-free (BNI I) success rate of about 30%, with low heterogeneity and primarily transient sensory complications.

The report discusses limited, mostly retrospective evidence, methodological limitations, and potential dual mechanisms of TN in MS. Authors conclude MVD yields lower success than in classic TN but remains a reasonable option for selected TN-MS patients with demonstrable neurovascular compression; they call for prospective studies and refined patient selection.

Objective Evaluate long-term pain relief and complications of microvascular decompression (MVD) for trigeminal neuralgia in patients with multiple sclerosis (TN-MS), a group traditionally considered poor candidates for MVD.

Methods Systematic review/meta-analysis (PRISMA) of PubMed, Embase, Scopus, and Web of Science (search June 2024); primary endpoint was long-term pain-free status BNI I at final follow-up using random-effects meta-analysis of proportions.

Evidence base 30 studies were included, covering 429 TN-MS patients treated with MVD, representing 265 unique patients.

Neurovascular compression Compression was identified in 96.6% of reported TN-MS cases (via MRI and/or intraoperative findings).

Long-term efficacy Pooled long-term pain-free outcome (BNI I) after MVD was 30.2% (95% CI 24.2%–36.9%), with low heterogeneity across analyses.

Complications The most commonly reported complication after MVD was transient facial numbness (with other complications variably reported).

Interpretation MVD is less effective in TN-MS than in classic TN, but can still provide meaningful benefit, particularly when neurovascular compression is present.

Conclusion/implication MVD should not be categorically excluded for TN-MS; further prospective studies are needed to improve selection and outcomes.

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Historical evolution of microvascular decompression after Jannetta’s establishment: Anatomical maps and physiological compasses—a narrative review

Acta Neurochirurgica (2026) 168:74

This narrative review chronicles five decades of refinement in microvascular decompression (MVD) for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia, tracing developments from Jannetta’s microsurgical breakthrough to contemporary practice. It emphasizes evolving microsurgical anatomy, tailored craniotomies, endoscopic/exoscopic visualization, and nuanced decompression techniques such as noncompressive transposition versus prosthetic interposition.

The article also highlights operative support advances—high-resolution MRI/MRA, virtual simulation, and intraoperative neuromonitoring (BAEP, LSR)—as physiological “compasses” that improve safety and outcome durability. Together, anatomical “maps” and physiological feedback frame current standards and ongoing challenges in achieving long-term, biologically harmonious decompression.

Microvascular Decompression (MVD) Evolution: MVD has developed from Jannetta’s original microsurgical demonstration of vascular compression into a safe, durable, and standardized surgical treatment for neurovascular compression syndromes, especially trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN).

Anatomical Foundations: Detailed microsurgical anatomy, including the “Rule of Three” for the cerebellopontine angle (CPA), enables tailored, minimally invasive approaches and underpins the understanding of neurovascular conflicts and surgical route selection.

Tailored Surgical Approaches: Three individualized approaches—lateral supracerebellar-infratentorial for TN, infrafloccular for HFS, and transcondylar fossa for GPN—minimize cerebellar retraction and optimize decompression, improving safety and efficacy.

Decompression Strategies: Techniques have shifted from prosthetic interposition (placing a material between vessel and nerve) to noncompressive transposition (mobilizing and securing the vessel away from the nerve), with evidence supporting better long-term outcomes for transposition.

Visualization and Simulation Advances: The integration of endoscopic/exoscopic systems, neuronavigation, and virtual simulation has enhanced visualization, surgical precision, and education, extending the original ethos of microscopic surgery.

Intraoperative Monitoring: Real-time monitoring using brainstem auditory evoked potentials (BAEPs) and lateral spread response (LSR) on facial EMG helps avoid complications and assess decompression adequacy, significantly reducing postoperative morbidity.

Role of Imaging: High-resolution MRI and MRA now routinely identify neurovascular compression preoperatively, though imaging findings are considered supportive rather than diagnostic due to limited specificity in low-grade conflicts.

Sustained First-Line Role: Despite advances in radiosurgery and pharmacotherapy, MVD remains the first-line surgical option for appropriately selected patients, due to its proven long-term efficacy and safety.

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Shifts in epilepsy treatment: a 12-year review of surgical approaches and outcomes in lesional and nonlesional epilepsy

J Neurosurg 144:259–272, 2026

This study analyzes national inpatient trends from 2009–2020 comparing lesional and nonlesional epilepsy patients who underwent surgical or neuromodulation treatments. Using NIS data with propensity score matching, it reports demographic differences, socioeconomic disparities, and shifting utilization patterns across VNS, RNS, DBS, resection, radiosurgery, and LITT.

The findings reveal increasing adoption of RNS and LITT, declining VNS and radiosurgery, higher costs for most interventions, and shorter length of stay with LITT. Persistent racial and income-based inequities in access and differing outcomes by lesion status prompt calls for tailored care and further cost-effectiveness and long-term outcome studies.

Distinct Patient Profiles: Lesional epilepsy patients are older, more likely male, have higher comorbidity burdens, and higher income/Medicare coverage compared to nonlesional epilepsy patients, who are more prevalent in lower income quartiles and rely more on Medicaid or private insurance.

Surgical Treatment Trends: Use of responsive neurostimulation (RNS) and laser interstitial thermal therapy (LITT) increased significantly for both lesional and nonlesional epilepsy from 2009–2020, while vagus nerve stimulation (VNS) declined for nonlesional epilepsy; deep brain stimulation (DBS) and radiosurgery declined for both groups.

Resective Surgery Patterns: Resective surgery utilization increased significantly for nonlesional epilepsy, but not for lesional epilepsy, indicating a growing acceptance of surgery in nonlesional cases despite the absence of overt lesions.

Healthcare Disparities: White patients, and those in higher income quartiles, have higher probabilities of receiving advanced treatments (VNS, RNS, DBS, resective surgery, radiosurgery); Black patients have persistently lower access regardless of income, and Hispanic patients show variable, income-dependent access.

Outcomes by Modality: RNS and LITT are associated with shorter or unchanged length of stay (LOS) and higher likelihood of routine discharge, while DBS and resective surgery increase LOS and costs; all surgical interventions increase hospital charges.

LITT Advantages: LITT is linked to decreased LOS and improved routine discharge rates, especially for lesional epilepsy, but incurs higher total charges compared to other modalities.

Mortality Impact: None of the interventions (VNS, RNS, DBS, resective surgery, radiosurgery, LITT) significantly affected mortality in either lesional or nonlesional epilepsy groups.

Need for Tailored Approaches: Persistent demographic, socioeconomic, and clinical differences between lesional and nonlesional epilepsy patients highlight the importance of individualized treatment strategies and further research on long-term and cost-effectiveness outcomes.

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Deep brain stimulation for obsessive-compulsive disorder: evolution of tractography-based targeting

J Neurosurg 144:293–304, 2026

This clinical study describes the development and prospective application of patient-specific tractography to refine anterior limb of the internal capsule (ALIC) deep brain stimulation (DBS) targeting for treatment-refractory obsessive-compulsive disorder (OCD). The authors generated a common responder connectivity map highlighting ALIC pathways to vmPFC/OFC, vlPFC, thalamus, STN, and midbrain, then used that map to guide implantation in a new cohort, achieving consistent and rapid Y-BOCS improvements.

The team also built a tractography-based stimulation model linking activation of specific unilateral ALIC pathways to symptom reduction, demonstrating selective prediction of obsessive–compulsive symptom improvement (but not mood or anxiety). Results suggest that tractography-guided “sweet spot” targeting at the ventral ALIC near the GPe can reduce trial-and-error programming and support precision ALIC DBS implementation.

Patient-specific tractography targeting: Using individualized diffusion MRI tractography to guide deep brain stimulation (DBS) lead placement in the anterior limb of the internal capsule (ALIC) for obsessive-compulsive disorder (OCD) enables more precise and consistent targeting of therapeutic white matter pathways.

Common responder map: A map of white matter connections shared by DBS responders was generated, highlighting key pathways to the ventromedial/orbitofrontal cortex (vmPFC/OFC), ventrolateral prefrontal cortex (vlPFC), and midbrain; targeting this “sweet spot” led to improved and predictable clinical outcomes.

Improved clinical efficacy: Tractography-based ALIC DBS resulted in an 80% response rate (≥35% Y-BOCS reduction) among prospective patients, with faster and more consistent OCD symptom improvement compared to prior methods.

Reduced trial-and-error programming: Targeting based on the common responder map minimized the need for multiple adjustments in stimulation parameters, streamlining clinical implementation.

Symptom specificity: Stimulation of the tractography-defined target selectively improved OCD symptoms (obsessions and compulsions) with less impact on mood or anxiety and minimal side effects such as hypomania.

Tractography-based predictive model: A quantitative model using patient-specific pathway activation predicted OCD symptom improvement (Y-BOCS reduction), with strongest predictive value for connections to vlPFC, vmPFC/OFC, thalamus, and midbrain, but not for depression or anxiety scores.

Updated common responder map validation: High-resolution 7T MRI data from additional responders confirmed the importance of connections to vlPFC, vmPFC/OFC, thalamus, and midbrain in therapeutic response.

Potential for clinical scalability: This precision targeting approach, if validated in larger cohorts, could enhance the predictability, effectiveness, and broader adoption of DBS for treatment-resistant OCD.

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Central thalamic deep brain stimulation for disorders of consciousness: an individual participant data meta-analysis

J Neurosurg 143:1217–1226, 2025

This individual participant data meta-analysis evaluates central thalamic deep brain stimulation (DBS) for chronic disorders of consciousness, pooling 49 patients from seven centers to assess neurological outcomes via the JFK Coma Recovery Scale–Revised. Results show modest mean CRS-R improvement, with age and shorter delay to implantation predicting better gains, but insufficient evidence that DBS alters the natural recovery trajectory.

The report details heterogeneity in targets, stimulation schedules, and methodological limitations—no randomized controls, selection bias, and variable reporting—highlighting the need for matched comparative studies, standardized outcome metrics, and refined targeting (CL vs CM-Pf/DTTm) to determine DBS efficacy and optimize patient selection.

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Multi-institutional recommendations on the use of 7T MRI in deep brain stimulation

J Neurosurg 143:1165–1175, 2025

This multi-institutional review presents consensus recommendations for integrating 7T ultrahigh-field MRI into deep brain stimulation (DBS) workflows, drawing on experience from over 1,000 procedures. It summarizes technical challenges—B1+ heterogeneity, susceptibility and gradient nonlinear distortions—and practical solutions for acquisition, distortion correction, and coregistration to ensure stereotactic accuracy.

The document details optimized sequences and target-specific imaging strategies (STN, GPi, thalamic nuclei, ANT, CM), advanced modalities (DTI/DiMANI, QSM, tractography), and multidisciplinary workflow considerations to improve patient-specific anatomical and connectivity-based DBS targeting and programming.

• 7T MRI Advantages: Ultrahigh-field 7T MRI provides superior spatial resolution, signal-to-noise ratio, and tissue contrast, enabling clearer visualization of deep brain structures critical for deep brain stimulation (DBS) targeting compared to 1.5T and 3T MRI.

• Improved DBS Targeting: 7T MRI enhances direct anatomical and connectivity-based targeting for DBS, supporting more precise, patient-specific electrode placement for Parkinson’s disease, essential tremor, and epilepsy.

• Key Technical Challenges: 7T MRI introduces unique challenges including B1+ transmit field inhomogeneity, increased image distortions (gradient nonlinearity and susceptibility), and chemical shift artifacts, all of which require specialized correction and protocol optimization.

• Distortion Correction and Coregistration: Accurate DBS planning with 7T MRI demands robust correction for gradient and susceptibility distortions, careful coregistration with stereotactic CT, and often manual or nonlinear registration adjustments for optimal anatomical alignment.

• Recommended Imaging Sequences: Specific 7T MRI sequences, such as T2-weighted, FGATIR, MP2RAGE, SWI, QSM, and advanced diffusion imaging (DTI/DiMANI), are recommended for visualizing common DBS targets (STN, GPi, thalamic nuclei), each offering distinct advantages for different structures.

• Connectivity and Tractography: Advanced diffusion MRI at 7T allows submillimetric tractography, enabling functional parcellation of DBS targets (e.g., STN, GPi, DRTT), which can improve patient outcomes by supporting symptom- and network-specific targeting.

• Clinical Impact: Implementation of 7T MRI in over 1000 DBS procedures across multiple centers has demonstrated that, with appropriate workflow and expertise, technical challenges can be managed and targeting accuracy and patient outcomes can be improved.

• Multidisciplinary Collaboration: Effective use of 7T MRI for DBS requires close collaboration between neurosurgeons, MR technicians, physicists, and neuroradiologists to optimize protocols and address the complexity of ultrahigh-field imaging

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Afferent and efferent fiber systems of the human amygdala: anatomical, pathophysiological, and clinical significance

J Neurosurg 143:1202–1216, 2025

This paper presents a comprehensive neuroanatomical and radiological analysis of the human amygdala, detailing its nuclei, major afferent and efferent fiber systems, and spatial relationships using white matter fiber dissection and diffusion tensor tractography. The authors synthesize structural descriptions with functional roles in emotion, memory, olfaction, and seizure propagation, emphasizing clinical relevance for neuroclinicians.

The study maps key pathways—the ansa peduncularis, ventral and dorsal amygdalofugal routes, stria terminalis, medial forebrain bundle, olfactory striae, and stria medullaris thalami—correlating anatomy with neurosurgical applications such as deep brain stimulation and lesion resection. Anatomical findings are supported by illustrative dissections, tractography, and a clinical cavernoma case demonstrating surgical implications.

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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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Long-term outcomes of peripheral nerve field stimulation in patients with refractory trigeminal neuralgia: a cohort study

J Neurosurg 143:982–986, 2025

Peripheral nerve field stimulation (PNFS) for refractory trigeminal neuralgia showed high long-term treatment failure, especially in females, with frequent complications and revisions. Only half of male patients reported lasting benefit. PNFS should be considered cautiously for this condition.

Peripheral nerve field stimulation (PNFS) was studied for refractory trigeminal neuralgia with a long-term follow-up.

Fifteen patients (6 male, 9 female; median age 70) were included, with a median follow-up of 93 months.

PNFS had a high rate of long-term treatment failure, especially in females.

The median time to treatment failure was 2 years (5.1 years in males, 1.5 years in females; p = 0.003).

Only 3 patients (all male) reported ongoing benefit.

Complications and revision surgeries were common (4 patients, 7 revisions).

No significant differences in outcomes were found between classic and secondary trigeminal neuralgia or by patient age.

PNFS should be considered cautiously due to limited long-term efficacy and frequent complications.

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Outcome comparison between interposition and “contactless” transposition microvascular decompression approaches for trigeminal neuralgia

J Neurosurg 143:970–981, 2025

This study compared interposition and “contactless” transposition (Teflon and pericranial sling) microvascular decompression techniques for trigeminal neuralgia. Both were effective, but sling transposition showed improved midterm pain control and fewer complications. The only significant predictor of pain freedom was MRI evidence of clear nerve compression.

• Microvascular decompression (MVD) is a main surgical treatment for trigeminal neuralgia (TN), traditionally using Teflon interposition between nerve and artery.

• Recurrence of TN pain after MVD is often due to Teflon complications, prompting the development of “contactless” transposition techniques such as Teflon and pericranial sling transpositions.

• This retrospective study compared outcomes of interposition, Teflon transposition, and pericranial sling transposition in 305 TN patients.

• Sling transposition was mainly used for severe compression by the superior cerebellar artery and involved securing the artery to the tentorium with a pericranial graft.

• All techniques had similar short-term pain relief and complication rates, but sling transposition showed significantly higher pain-free rates at 2 years compared to other methods.

• Clear vascular compression on MRI was the only significant predictor of pain freedom in multivariate analysis.

• Sling transposition uses autologous tissue, avoids foreign body reactions, and may provide more durable pain control, but is technically more complex.

• Further long-term studies are needed to confirm the durability of sling transposition for TN pain control.

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Measurement of CSF flow and brain motion in Chiari malformation type I subjects undergoing posterior fossa decompression surgery

J Neurosurg 143:13–23, 2025

Advanced MRI techniques show that in Chiari malformation type I, presurgical CSF flow and brain motion measurements better predict improvements after posterior fossa decompression surgery than traditional tonsillar descent metrics, potentially enabling more accurate identification of patients likely to benefit from surgery.

• Chiari malformation type I (CM-I) is defined by ≥5 mm cerebellar tonsil herniation through the foramen magnum, but tonsillar descent does not correlate well with symptom severity or surgical outcome.

• Posterior fossa decompression (PFD) surgery improves symptoms in ~75% of symptomatic CM-I patients, but carries risks, making optimal patient selection important.

• This study used advanced MRI (phase-contrast for CSF flow and DENSE for brain motion) to evaluate 108 CM-I patients, 61 of whom had PFD surgery.

• After PFD, CSF stroke volume increased by 28.9%, brainstem motion decreased by 17.3%, and cerebellar motion decreased by 45.2%.

• Improvements in CSF flow and brain motion after surgery were better predicted by presurgical CSF flow and brain motion, not by the amount of tonsillar descent.

• Presurgical dynamic measures (CSF flow, brain motion) are more informative for predicting surgical benefit than conventional anatomical metrics.

• These quantitative imaging assessments may help identify which patients will benefit most from surgery, improving patient care.

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Stratifying trigeminal neuralgia and characterizing an abnormal property of brain functional organization: a resting-state fMRI and machine learning study

J Neurosurg 143:74–82, 2025

Resting-state fMRI and machine learning revealed distinct brain connectivity and activity differences between classical and idiopathic trigeminal neuralgia (TN) and controls. These findings identify potential neuroimaging biomarkers for TN subtypes, aiding diagnosis and understanding of TN pathophysiology.

Primary trigeminal neuralgia (TN) includes classical (CTN) and idiopathic (ITN) types, sharing clinical features but differing in neurovascular compression (NVC) presence.

• Resting-state fMRI and machine learning were used to analyze brain functional connectivity and spontaneous activity in 50 TN patients (28 CTN, 22 ITN) and 43 controls.

• TN patients showed increased connectivity between the medial prefrontal cortex (mPFC) and left planum temporale, and decreased connectivity between mPFC and left superior frontal gyrus.

• CTN patients had further reduced connectivity between the left insula and left occipital pole, and decreased activity in the right temporal pole compared to ITN.

• TN patients exhibited heightened neural activity in frontal regions compared to controls.

• Machine learning (support vector machine) distinguished TN patients from controls with moderate accuracy (AUC 0.80).

• Findings suggest potential fMRI biomarkers for TN subtypes, aiding understanding of pathophysiology and improving diagnosis.

• Study limitations include small sample size and exclusion of bilateral/secondary TN, warranting further research.

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Deep learning–based segmentation of the trigeminal nerve and surrounding vasculature in trigeminal neuralgia

J Neurosurg 143:83–91, 2025

This study developed and validated deep learning U-Net models for automated 3D segmentation of the trigeminal nerve and surrounding vasculature in MRI of trigeminal neuralgia patients, enabling objective quantification of neurovascular conflict features and potentially improving preoperative evaluation and treatment planning.

• Deep learning (U-Net) models were used to segment the trigeminal nerve and surrounding vasculature in patients with trigeminal neuralgia using high-resolution CISS MRI.

• Six U-Net variants with different encoder backbones were tested; SE-ResNet50 performed best overall (Dice score = 0.775, IoU = 0.681).

• The models quantified anatomical features such as the surface area of neurovascular contact and distance to the contact point, showing no significant difference from manual segmentations.

• The best model achieved 100% sensitivity and specificity in detecting neurovascular conflict in the testing set.

• Automated 3D segmentation allows for objective, quantitative evaluation, improving on subjective and time-intensive manual methods.

• Limitations include inability to distinguish vessel type (artery vs. vein) and data from a single institution; future work should address these.

• The method may help standardize neurovascular conflict assessment and improve treatment selection for trigeminal neuralgia.

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Designing and clinical application of a 3D-printed personalized model of a radiofrequency needle guide with a maxillary fixator for puncture of the gasserian ganglion for trigeminal neuralgia treatment

J Neurosurg 142:1256–1262, 2025

The study presents a 3D-printed personalized model (3D PPM) for radiofrequency needle guidance in trigeminal neuralgia treatment, reducing radiation exposure and pain during procedures. It showed effectiveness in controlled needle insertion and minimized postoperative complications compared to traditional methods.

• A 3D-printed personalized model (3D PPM) of a radiofrequency needle guide with a maxillary fixator was designed for gasserian ganglion puncture in trigeminal neuralgia treatment.

• 3D PPM reduces radiation exposure and pain during needle insertion, and minimizes postoperative complications.

• The study found that the use of 3D PPM significantly decreased radiation time and dose area product compared to traditional methods.

• Pain severity during the procedure was less in patients using 3D PPM, with more reporting mild pain compared to those not using it.

• Cheek swelling was less frequent in the group using 3D PPM, though not statistically significant due to small sample size.

• The 3D PPM enhances the accuracy of needle insertion and reduces radiation exposure, making it beneficial for less experienced neurosurgeons.

• Limitations include the unsuitability for patients with metal dental implants or missing teeth due to fixation issues.

• Despite limitations, the study shows promising results for 3D PPM in radiofrequency therapy of the gasserian ganglion, suggesting further research is needed.

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A novel robot-assisted method for implanting intracortical sensorimotor devices for brain-computer interface studies

J Neurosurg 142:1280–1288, 2025

A novel robot-assisted method for implanting intracortical microelectrode arrays in brain-computer interface studies was successfully demonstrated in a tetraplegic participant. The technique ensured precise placement, facilitating high-quality signal communication for motor control and sensory feedback, with promising implications for restoring upper-limb function.

• A novel robot-assisted method for implanting intracortical microelectrode arrays in brain-computer interface (BCI) studies is presented, focusing on surgical techniques and challenges.

• The technique was applied in a 31-year-old male with tetraplegia, enabling 2D control of a virtual arm with high success rates and maintaining recording quality over time.

• The robotic neurosurgery technique provides high accuracy and time efficiency, reducing human error and surgeon burden in repetitive procedures.

• Preoperative imaging and robotic systems were used for precise planning and execution of array implantations, ensuring minimal cortical damage and high signal quality.

• The study demonstrated that robotic neurosurgery could be successfully translated into BCI device implantation, aiming to restore upper-limb function.

• Future challenges include refining insertion methods, increasing automation, and addressing intraoperative adjustments for microvessels.

• The study was conducted under an investigational device exemption from the US Food and Drug Administration and received institutional review board approval.

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Gamma Knife radiosurgery for relapsing trigeminal neuralgia following microvascular decompression

J Neurosurg 142:1247–1255, 2025

Salvage Gamma Knife radiosurgery (GKRS) offers effective, noninvasive treatment for relapsing trigeminal neuralgia after microvascular decompression, with a favorable complications profile. Patients with facial numbness and better initial pain responses may experience more durable pain relief following salvage GKRS.

• Gamma Knife radiosurgery (GKRS) is explored as a treatment for relapsing trigeminal neuralgia (TN) following microvascular decompression (MVD).

• The study aimed to assess the response rate, complications, and predictors of pain relapse for salvage GKRS after MVD.

• 83.1% of patients experienced initial pain relief after salvage GKRS, with a median time to relapse of 1.75 years.

• Facial numbness post-GKRS decreased pain relapse risk, while a worse initial pain response increased it.

• Radiofrequency ablation (RFA) prior to MVD reduced the likelihood of an initial response to GKRS.

• Salvage GKRS is presented as an effective, noninvasive option for recurring TN after MVD, with a favorable complications profile compared to salvage MVD.

• The study acknowledges limitations, including potential selection bias and small sample size, and suggests further research with larger cohorts

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The Rate and Risk Factors of Deep Brain Stimulation–Associated Complications

Operative Neurosurgery 28:519–527, 2025

The study investigates complications associated with deep brain stimulation (DBS) surgery, analyzing patient demographics, surgical techniques, and outcomes. It identifies factors influencing complications such as pneumocephalus, infection, and hemorrhage, aiming to improve patient selection and surgical strategies for better outcomes.

• Deep Brain Stimulation (DBS) is a recognized neurosurgical procedure for various neurological disorders, considered safe but not without complications. The study investigates these complications and their association with patient characteristics and surgical techniques.

• The study analyzed 481 patients who underwent DBS lead implantation between January 2012 and January 2020, with a total of 859 leads implanted.

• Common complications included pneumocephalus, edema, altered mental state, and infection. General anesthesia, hypertension, heart disease, and depression were linked to longer postoperative stays.

• High BMI was associated with increased rates of surgery-related infections and lead revision/explantation.

• Intraoperative mean arterial pressure and anesthesia type were significant predictors of postoperative pneumocephalus.

• The study found that certain comorbidities, such as hypertension, heart disease, and depression, were associated with longer hospital stays.

• Older patients were less likely to require lead revision/explantation, while those with high BMI were at higher risk.

• Infection prevention techniques, like vancomycin powder, were effective, with infection rates at the lower end of the reported range.

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Benefits of stereotactic radiosurgical anterior capsulotomy for obsessive-compulsive disorder: a meta-analysis

J Neurosurg 141:394–405, 2024

Anterior capsulotomy (AC) is a therapeutic option for patients with severe, treatment-resistant obsessive-compulsive disorder (OCD). The procedure can be performed via multiple techniques, with stereotactic radiosurgery (SRS) gaining popularity because of its minimally invasive nature. The risk-benefit profile of AC performed specifically with SRS has not been well characterized. Therefore, the primary objective of this study was to characterize outcomes following stereotactic radiosurgical AC in OCD patients.

METHODS Studies assessing mean Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores before and after stereotactic radiosurgical AC for OCD were included in this analysis. Inverse-variance fixed-effect modeling was used for pooling, and random-effects estimate of the ratio of means and standard mean differences were calculated at 6 months, 12 months, and the last follow-up for Y-BOCS scores, as well as the last follow-up for the Beck Depression Inventory (BDI)/BDI-II scores. A generalized linear mixed model was used to generate fixed- and random-effects models for categorical outcomes. Univariate random-effects meta-regression was used to evaluate associations between postoperative Y-BOCS scores and study covariates. Adverse events were summed across studies. Publication bias was assessed with Begg’s test.

RESULTS Eleven studies with 180 patients were eligible for inclusion. The mean Y-BOCS score decreased from 33.28 to 17.45 at the last-follow up (p < 0.001). Sixty percent of patients were classified as responders and 10% as partial responders, 18% experienced remission, and 4% had worsened Y-BOCS scores. The degree of improvement in the Y-BOCS score correlated with time since surgery (p = 0.046). In the random-effects model, the mean BDI at the last follow-up was not significantly different from that preoperatively. However, in an analysis performed with available paired pre- and postoperative BDI/BDI-II scores, there was significant improvement in the BDI/BDI-II scores postoperatively. Adverse events numbered 235, with headaches, weight change, mood changes, worsened depression/anxiety, and apathy occurring most commonly.

CONCLUSIONS Stereotactic radiosurgical AC is an effective technique for treating OCD. Its efficacy is similar to that of AC performed via other lesioning techniques.

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Topographical anatomy of the subthalamic region with special interest in the human medial forebrain bundle

J Neurosurg 141:570–580, 2024

The medial forebrain bundle (MFB) is a novel promising deep brain stimulation (DBS) target in severe affective disorders that courses through the subthalamic region according to tractography studies. Its potential therapeutic role arose in connection with the development of hypomania during stimulation of the subthalamic nucleus (STN) in Parkinson’s disease, offering an alternative explanation for the occurrence of this side effect. However, until now its course exclusively described by tractography had not yet been confirmed by any anatomical method. The aim of this study was to fill this gap as well as to provide a detailed description of the fiber tracts surrounding the STN to facilitate a better understanding of the background of side effects occurring during STN DBS.

METHODS Ten human cadaveric brains (20 hemispheres) and 100 healthy subjects (200 hemispheres) from the S500 Release of the Human Connectome Project were involved in this study. Nineteen hemispheres were dissected according to Klingler’s method. One additional hemisphere was prepared for histological examinations to validate the macroscopical results and stained with neurofibril silver impregnation according to Krutsay. The authors also aimed to reconstruct the MFB using tractography and correlated the results with their dissections and histological findings.

RESULTS The white matter connections coursing through the subthalamic region were successfully dissected. The ansa lenticularis, lenticular fasciculus, thalamic fasciculus, ipsi- and contralateral cerebellar fibers, and medial lemniscus were revealed as closely related fiber tracts to the STN. However, the existence of a distinct fiber bundle corresponding to the MFB described by tractography could not be identified. Using tractography, the authors showed that the depiction of the streamlines representing the MFB was also strongly dependent on the threshold parameters.

CONCLUSIONS According to this study’s findings, the streamlines of the MFB described by tractography arise from the limitations of the diffusion-weighted MRI fiber tracking method and actually correspond to subthalamic fiber bundles, especially the ansa lenticularis and lenticular fasciculus, which erroneously continue in the anterior limb of the internal capsule, toward the prefrontal cortex.

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