Stereotactic and Functional Neurosurgery最新文献

Background: Deep brain stimulation (DBS) is an established therapy for movement disorders. However, conventional DBS often involves complete scalp shaving and a visible subclavicular incision for implantable pulse generator (IPG) placement, which may cause cosmetic and psychological burden, particularly in younger or female patients. To address these issues, we developed a cosmetic-oriented DBS technique combining a no-shave cranial approach with trans-axillary fossa IPG implantation.

Methods: In this single-center retrospective series, we analyzed 60 consecutive patients who underwent DBS implantation using a no-shave cranial approach with trans-axillary fossa IPG placement. Procedural characteristics and postoperative complications were reviewed retrospectively.

Results: Sixty patients underwent DBS implantation with this cosmetic-oriented protocol. Mean age at surgery was 50.4 ± 14.7 years and mean follow-up was 31.6 ± 18.3 months. Mean operative time including IPG placement was 159.1 ± 64.4 min (range 70-353). Early postoperative infection occurred in 2 patients (3.3%), both confined to the axillary IPG pocket within 1 month; no cranial infections or hematomas were observed. Non-infectious complications occurred in 3 patients (5.0%) (one cervical extension foreign-body reaction, one cranial insertion-site reaction, and one lateral IPG displacement requiring revision). Mild transient axillary tightness was reported in 10 patients (16.7%) and resolved without intervention.

Conclusion: This cosmetic-oriented DBS method demonstrated a low infection rate and consistent concealment of cranial and axillary incisions, with no apparent signal of increased risk in this series. The approach appears technically feasible across different ages and in both sexes, although patient satisfaction was not formally evaluated.

Introduction: Deep brain stimulation (DBS) is an established therapy that can significantly improve patients' quality of life in several disorders. Besides its benefits, hardware-related problems including erosion and wound infections are well known problems. In the present series, we describe a novel phenomenon manifesting as denial for hardware-related skin erosion in patients with movement disorders benefiting from DBS in various targets.

Methods: Patients were collected from two large DBS cohorts over a period of 28 years. The skin erosion was identified upon the occasion of a routine follow-up with the patients apparently being unaware/not noticing its occurrence. Demographic, clinical and operative data were analyzed. Additionally, the hardware-related skin erosion and its time of diagnosis, as well as the consecutive treatment were registered.

Results: Overall, five patients were identified with denial for hardware-related skin erosion. Three were men, two were women. The mean age at surgery was 66 years (range, 54 to 78). Three patients had dystonia, two patients had Parkinson's disease. DBS targets were the globus pallidus internus, and various thalamic nuclei. All patients benefited markedly from chronic DBS (mean improvement of 76.7% according to the specific rating scales). The hardware-related skin erosion was diagnosed at a median follow-up of 18 months after DBS implantation (range, 5 to 264 months). Despite multiple surgical attempts at preservation, the neurostimulation system was ultimately explanted in three patients.

Conclusion: Denial towards hardware-related skin erosion in DBS, most probably denial, is a rare but potentially serious complication during chronic DBS.

Background Brain atrophy is common in Parkinson's disease (PD) and contributes to motor and cognitive decline. However, the predictive value of neuroimaging-based volumetric measures for motor outcomes following deep brain stimulation (DBS) remains unclear. This study examines whether preoperative volumetric assessment can predict motor outcomes after subthalamic nucleus (STN) DBS in PD. Methods Preoperative T1-weighted 3D MP-RAGE MRI scans were analyzed to measure subcortical, ventricular, and cortical volumes using Brainlab software. Motor outcomes were assessed by changes in the Movement Disorder Society - Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III) scores pre- and postoperatively in 39 participants. Stepwise logistic regression was performed to determine associations between brain volumes and DBS response. Results Smaller substantia nigra compacta volume (0.81 [IQR 0.74-0.85] vs 0.72 [IQR 0.69-0.73]), larger ventricular system (26.1 [IQR 21.4-30.05] vs 34.1 [IQR 28.6-40.87]), and lower atrophy ratio (41.76 [IQR 37.59-50.71] vs 29.63 [IQR 25.9-36.55]) were significantly associated with reduced motor improvement following STN-DBS. The predictive model based on these values demonstrated excellent performance (AUC 0.95, 95% CI: 0.87-1; p < 0.01) in forecasting poorer DBS treatment outcomes as measured by the MDS-UPDRS-III scale. Conclusions Our findings highlight the impact of enlargement of ventricular system and brain atrophy, particularly of the substantia nigra, on motor outcomes after STN-DBS. The association between atrophy measures and executive dysfunction suggests that subclinical dementia may underlie poor DBS response. Future studies should further explore the role of neurodegeneration in DBS response to optimize patient selection and electrode targeting.

Background: Local field potentials (LFPs) represent the summed electrical activity of neuronal populations and provide a critical window into synaptic and oscillatory dynamics across brain networks. In recent decades, advances in deep brain stimulation (DBS) and chronic sensing technology have established LFPs as essential biomarkers for understanding movement disorders and optimizing neuromodulation therapies.

Summary: This review synthesizes evidence on LFPs in movement disorders, focusing on methodological aspects, functional characterization, disease-specific findings, and clinical applications. In Parkinson's disease (PD), exaggerated beta-band activity in the subthalamic nucleus and globus pallidus internus (GPi) correlates with bradykinesia and rigidity, while dyskinesias are linked to broadband gamma activity and disrupted cross-frequency coupling. Essential tremor (ET) shows tremor-frequency synchronization in the thalamus and related networks. In dystonia, theta and alpha oscillations in the GPi correlate with symptom severity and guide DBS targeting. Tics in Tourette syndrome involve thalamic low-frequency oscillations, while chorea in Huntington's disease is associated with elevated beta-gamma power. Clinically, LFPs are increasingly used for intraoperative targeting, postoperative programming, outpatient monitoring, and as biomarkers for adaptive DBS (aDBS).

Key messages: LFPs provide fundamental insights into disease-specific neural oscillations across PD, ET, dystonia, tics, and chorea. Pathological patterns serve as reliable biomarkers of symptom states. By leveraging these signals, DBS can be more accurately targeted, programming can be streamlined, and long-term outpatient monitoring can be enhanced. aDBS based on LFP biomarkers is already in clinical use for PD, offering superior motor control and fewer side effects than conventional stimulation.

Introduction: Subthalamic nucleus deep brain stimulation (STN-DBS) effectively improves motor symptoms in Parkinson's disease (PD), but long-term survival outcomes and mortality predictors remain unclear. This study aimed to evaluate survival and 10-year clinical outcomes after STN-DBS.

Methods: We retrospectively analyzed 608 patients with PD who underwent bilateral STN-DBS between 2006 and 2023. Kaplan-Meier and Cox regression analyses assessed survival and preoperative predictors. Motor (Movement Disorder Society Unified Parkinson's Disease Rating Scale [MDS-UPDRS Part III]), cognitive (Montreal Cognitive Assessment [MoCA], Mini-Mental State Examination), and medication (levodopa equivalent daily dose [LEDD]) data were compared between baseline and 10 years postoperatively.

Results: During a mean follow-up of 4.8 ± 3.5 years, 42 deaths (6.9%) occurred, yielding an age-adjusted mortality rate of 3.3 per 100,000 person-years. The estimated 5- and 10-year survival rates were 95% and 77%, respectively. The most frequent cause of death was aspiration pneumonia (11.9%). In multivariate Cox analysis, lower preoperative MoCA scores (hazard ratio [HR] = 0.83, 95% CI 0.73-0.95, p < 0.01) and higher OFF state MDS-UPDRS Part III scores (HR = 1.03, 95% CI 1.00-1.07, p < 0.05) independently predicted mortality, whereas age at surgery was not significantly associated with survival. Among 118 patients with 10-year follow-up, OFF state motor and cognitive scores worsened significantly (p < 0.01), while ON state motor scores (p = 0.21) and total LEDD (p = 0.06) remained stable, suggesting sustained motor control and medication-sparing effects.

Conclusion: Long-term survival after STN-DBS in PD was favorable. Preoperative cognitive and motor status, rather than age, determined long-term prognosis, emphasizing the enduring therapeutic value of STN-DBS.

Introduction: Freezing of gait (FOG) in advanced Parkinson's disease (PD) remains a therapeutic challenge, with conventional subthalamic nucleus deep brain stimulation (STN-DBS) demonstrating limited efficacy.

Methods: This multicenter, prospective, single-blind study investigated the effects of combined high-frequency STN stimulation and ultra-low-frequency substantia nigra pars reticulata (SNr) stimulation in six PD patients with refractory FOG. Assessments included Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, New Freezing of Gait Questionnaire (NFOGQ), Gait and Falls Questionnaire (GFQ), and Schwab and England Activities of Daily Living (ADL) scale.

Results: Dual-target stimulation significantly outperformed STN-only stimulation in improving appendicular motor symptoms (MDS-UPDRS Part III: p = 0.04 medication-ON, p = 0.009 medication-OFF) and reducing FOG severity (NFOGQ: p = 0.02, GFQ: p = 0.01 vs. STN-DBS). Postural stability remained unchanged, while ADL scores improved clinically (p = 0.04). Volume of tissue activated (VTA) analysis revealed more STN VTA connectivity in cerebrum, in contrast with more SNr VTA connectivity in cerebellum.

Conclusion: These findings highlight the potential of dual-target free-frequency DBS for multimodal symptom control in PD and hopefully bring new sights in understanding mechanisms of DBS treatments in FOG.

Introduction: Stereo-electroencephalography (SEEG) is a safe and effective procedure for the identification of the epileptogenic zone to guide epilepsy surgery. Electrode tract oedema in SEEG is poorly understood. This study reports on its incidence and its clinical and biochemical correlations.

Methods: The presence of oedema along the electrode tract on patients after removal of SEEG electrodes was recorded and described. The number of electrodes, duration of implantation, and trend of serum inflammatory markers of patients with and without oedema, and with different extents of oedema were compared.

Results: A total of 79.2% of patients and 34.3% of electrodes were associated with oedema. Two radiographic distributions of oedema are described. No differences were found between the number of electrodes, duration of implantation, and the trends of serum inflammatory markers of patients with and without oedema. The trend of the WCC differed between patients who had diffuse compared to localised oedema, but this difference is unlikely to be clinically significant.

Conclusions: Radiographic electrode tract oedema is common in SEEG and runs a benign clinical course in our series.

Introduction: This study evaluates hippocampal dosimetry and neurocognitive outcomes in patients undergoing Gamma Knife radiosurgery (GKRS) for benign sellar, parasellar, and suprasellar lesions. While hippocampal protection has been well studied in whole-brain radiotherapy, its relevance in stereotactic radiosurgery (SRS) remains underexplored. This study systematically investigates hippocampal radiation dose thresholds and associated neurocognitive outcomes in patients undergoing single-fraction GKRS specifically for benign sellar and parasellar lesions. Although cognitive outcomes after SRS have been previously studied in various contexts, specific hippocampal radiation thresholds and their cognitive impacts in this particular patient population have not been clearly defined.

Methods: A prospective analysis was conducted on 41 patients who underwent GKRS, with hippocampal dosimetry assessed using dose-volume parameters (D_min, D_max, D_mean, D40, and D100) following RTOG 0933 contouring protocols. Neurocognitive function was evaluated at baseline and 6 months post-treatment using standardized neuropsychological tests, including assessments of memory, executive function, and emotional well-being. The relationships between hippocampal radiation exposure and cognitive changes were analyzed through correlation and regression models.

Results: The mean prescription dose was 12 Gy (range: 10-16 Gy), with a steep dose gradient facilitating hippocampal sparing. Receiver operating characteristic curve analysis identified hippocampal D40 ≥2.5 Gy and D100 ≥2.4 Gy as critical thresholds for neurocognitive decline, and these cutoff values were used in multivariable logistic regression analysis. Significant associations were found between higher hippocampal dose exposure and cognitive decline, particularly in verbal and memory retention domains. A 20% decline in verbal learning (Oktem Verbal Learning Test) was significantly associated with D40 ≥2.5 Gy (OR = 3.04, p = 0.006) and D100 ≥2.4 Gy (OR = 4.3, p = 0.031). Similarly, a 20% decline in memory retention (WMS Immediate Recall) was significantly linked to D40 ≥2.5 Gy (OR = 3.10, p = 0.041) and D100 ≥2.4 Gy (OR = 5.3, p = 0.045). Other factors, including age, gender, education level, and hippocampal volume, were not significantly associated with cognitive decline.

Conclusion: This preliminary study suggests that even relatively low-dose hippocampal radiation exposure in GKRS may potentially contribute to memory impairment. These initial findings provide insights into possible hippocampal dose thresholds specifically for single-fraction GKRS in benign lesions. However, larger prospective studies with longer follow-up periods are essential to validate these observations before recommending routine incorporation of hippocampal-sparing strategies into GKRS planning.

Introduction: Historically, stereotactic mesencephalotomy was developed as a "supraspinal" cordotomy for cancer and neuropathic pain. Early experiences relieved pain, but the procedure was never widely adopted because of the associated morbidity with midbrain lesioning. Contemporary image-guided lesioning could make this a feasible procedure for cancer patients suffering with pain.

Methods: A single-center, nonrandomized, early phase trial was designed to treat patients with severe, refractory pain from head and neck cancer with unilateral MRI-guided focused ultrasound mesencephalotomy. Safety was the primary outcome, but measures of efficacy were assessed with pain intensity and more functional components of pain.

Results: A discrete midbrain lesion was created for the 5 patients. All patients with advanced cancer had limited survival of less than 3 months, but they tolerated the procedure and experienced pain relief to different degrees. Two had profound pain relief, one was partial, and two others were very brief. One patient was transiently obtunded and other procedural morbidities were mild: numbness (3), oculomotor disturbance (1), and agitation (1). Electroencephalography, somatosensory evoked potentials, and quantitative sensory testing were obtained when possible.

Conclusion: Stereotactic focused ultrasound mesencephalotomy is a modern, image-guided, lesioning technique that may be effective for cancer pain.

Introduction: Deep brain stimulation (DBS) of the centromedian (CM) thalamic nucleus is a potential therapy for Lennox-Gastaut syndrome (LGS), a severe and drug-resistant epileptic encephalopathy. While long-term seizure outcomes with CM-DBS have been described, its acute electrophysiological effects and predictive value remain uncertain. We examined whether short-term changes in interictal epileptiform discharges (IEDs) following CM-DBS relate to seizure outcomes at 1 year.

Methods: Ten patients with LGS underwent CM-DBS implantation. About 1 month post-surgery, each patient had a 1-h scalp EEG. After a 10-min baseline, stimulation began at 1 V for 5 min, increasing in 1 V increments to 5 V or until paresthesias occurred. IEDs were detected automatically (Persyst v14c) and verified by an expert reviewer. Patients were followed for 1 year, with clinical response defined as ≥50% seizure reduction, i.e., responder. Correlations between acute IED change and seizure outcomes were assessed using Spearman's rank correlation.

Results: Nine of 10 patients showed reduced IED burden during acute stimulation (31%-100%). At 1 year, 8 were responders and 2 nonresponders. Overall, acute IED reduction did not correlate with seizure outcome (Spearman's ρ = 0.3, p = 0.35). A ≥50% reduction in IED burden was seen in 7 of 7 responders versus 1 of 3 nonresponders, suggesting a nonsignificant trend toward predictive value (p = 0.06).

Conclusion: Acute CM-DBS reduced IED burden in most patients with LGS but did not significantly predict long-term seizure outcomes. A trend toward greater IED reduction in responders suggests possible biomarker potential, though findings are preliminary and hypothesis-generating. Limitations include small sample size, high responder rate, and short EEG duration. Larger studies with extended monitoring are needed to clarify the clinical utility of acute EEG changes as predictors of CM-DBS efficacy.