Stereotactic and Functional Neurosurgery最新文献

Introduction: Postherpetic neuralgia (PHN) is a pain syndrome that develops within few months after the acute herpetic outbreak. The pain may be accompanied by specific cutaneous signs in the distribution of affected dermatomes and feel unbearable reaching up to 9-10/10 on visual analog scale (VAS). Despite the introduction of new medications, drug resistance develops in at least 50% of cases. Neuromodulation techniques such as spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) are considered as ones of the last resorts for PHN treatment, especially in pharmacoresistant patients. Recently, several studies with limited number of cases have shown high efficiency of neuromodulation (regression of pain syndrome in more than 82% of cases) after SCS in PHN patients, but these findings require further confirmation and have not been supported by large RCTs.

Methods: Initially, 32 patients diagnosed with chronic drug-resistant PHN underwent a trial of SCS. Based on the trial results, a decision was made whether to implant a permanent SCS system. The condition of all patients implanted with SCS system was assessed using the VAS, SF-36, Patient Global Impression of Change (PGIC), and Medicine Quantification Scale, version III (MQS) questionnaires before the surgery and in the long-term follow-up. We also conducted systematic follow-up of patients who did not pass the test stimulation stage, using them as a control group to track the levels of pain. The hypothesis of normal distribution for quantitative values was tested using Shapiro-Wilk tests.

Results: During the trial period, tonic spinal stimulation was effective in 16 out of 32 (50%) patients with drug-resistant PHN. Among 14 patients with implanted stimulators, a significant pain reduction (more than 50% from the baseline) was observed in 10 patients (71.4%). The pain level in patients with a tonic SCS was statistically lower than in patients receiving conservative therapy. For the entire group of patients with implanted SCS, a significant improvement was also observed in results of SF-36, PGIC, and MQS.

Conclusion: Our clinical series demonstrates that tonic SCS was effective in 50% of patients with refractory PHN undergoing SCS trial. Significant improvement in pain control obtained during the long-term follow-up in patients treated with tonic SCS improves the quality of life and reduces the need for analgesic medications.

Introduction: Freezing of gait (FOG) is a clinical phenomenon with major life impairments and significant reduction in quality of life for affected patients. FOG is a feature of Parkinson's Disease and a hallmark of primary progressive freezing of gait (PPGF), currently reclassified as Progressive Supranuclear Palsy-progressive gait freezing (PSP-PGF). The pathophysiology of FOG and particularly PGF, which is a rare degenerative disorder with a progressive natural history of gait decline, are poorly understood. Mechanistically, changes in oscillatory activity and synchronization in frontal cortical regions, the basal ganglia, and the midbrain locomotor region have been reported, indicating that dysrhythmic oscillations and coherence could play a causal role in the pathophysiology of FOG. DBS and SCS have been tested as therapeutic neuromodulation avenues for FOG with mixed outcomes.

Methods: We analyzed gait and balance in three patients with PSP-PGF who received percutaneous thoracic spinal cord stimulation (SCS) and utilized magnetoencephalography (MEG), electroencephalography (EEG), and electromyography (EMG) to evaluate functional connectivity between the brain and spine.

Results: Gait and balance did not worsen over a 13-month period. This observation was accompanied by decreased beta-band spectral power in the whole brain and particularly in the basal ganglia. This was accompanied by increased functional connectivity in and between the sensorimotor cortices, basal ganglia, temporal cortex, and cerebellum, and a surge in corticomuscular coherence when SCS was paired with visual cues Conclusion: Our results suggest synergistic activity between brain and spinal circuits upon SCS for FOG in PGF, which may have implications for future brain-spine interfaces and closed-loop neuromodulation for patients with FOG.

Introduction: Deep Brain Stimulation (DBS) of the superolateral branch of the medial forebrain bundle (slMFB) is currently being researched in clinical trials and open case series as a therapeutic option for treatment resistant major depressive disorder (TR-MDD) and treatment resistant obsessive-compulsive disorder (TR-OCD). There are numerous publications describing stimulation in such proximity to the ventral tegmental area (VTA) and open questions remain concerning the stimulation target and its functional environment. As of right now, we are not aware of any publications that compare the typical electrode placements with the histologically supported tractographic depiction of the target structure.

Methods: We used three cadaver midbrain samples with presumed unaltered anatomy. After fixation, staining and slicing, the histological samples were warped to the MNI (Montreal Neurological Institute) big brain environment. Utilizing a tractographic atlas, a qualitative analysis of the typical slMFB stimulation site in the lateral VTA utilizing a subset of clinically implanted DBS electrodes in n=12 patients, successfully implanted for TR-OCD was performed.

Results: A joint qualitative overlay analysis of predominantly tyrosine-hydroxylase stained histology at different resolutions in an anatomical common space was achieved. Localization of the DBS-lead bodies was found in the typical positions in front of the red nuclei in the lateral VTA. DBS lead tip region positions explained the oculomotor side effects of stimulation related to para-nigral or parabrachial pigmented sub-nuclei of the VTA, respectively. The location of active electrode contacts suggest downstream and antidromic effects on the greater VTA related medial forebrain bundle system.

Conclusion: This is the first dedicated joint histopathological overlay analysis of DBS electrodes targeting the slMFB and lateral VTA in a common anatomical space. This analysis might serve to better understand the DBS target region for this procedure.

Introduction: One of the challenges in directional deep brain stimulation (DBS) is to determine the orientation of implanted electrodes relative to targeted regions. Post-operative images must be aligned with a model of the implanted lead, usually a computer-based model provided by the manufacturer. This paper shows that models can alternatively be obtained by capturing images of individual leads using micro-CT, a high-resolution CT technique. Contrary to computer-aided design models, lead models generated this way provide realistic X-ray contrast and finer details.

Methods: We scanned DBS leads from various vendors using a Bruker SkyScan 1276 micro-CT system. To reduce beam-hardening artefacts, samples were scanned at maximum X-ray tube voltage (100 kV) and with copper filtering. Images were made publicly available for download and 3D visualisation.

Conclusion: Detailed images of single DBS leads can be generated using standard micro-CT systems. Their use as reference models could improve lead orientation algorithms, in particular those dedicated to X-ray modalities. Furthermore, the possibility to share models online could broaden access for clinical research.

Introduction: Spinal cord stimulation (SCS) is an effective treatment for patients with refractory chronic pain. Despite its efficacy, rates of reoperation after initial implantation of SCS remain high. While revision rates after index SCS surgeries are well reported, less is known about rates and risk factors associated with repeat reoperations. We sought to evaluate patient, clinical, and surgical characteristics associated with repeat reoperation among patients who underwent an initial SCS revision procedure.

Methods: We performed a retrospective review of patients who underwent SCS revision surgery performed at a single institution between 2008 and 2022. Patients were stratified by whether they underwent a single revision (SR) or multiple revision (MR) surgeries. Multivariate logistic regression was performed to determine risk factors associated with repeat SCS revision. Kaplan-Meier survival analysis was used to compare rates of devices requiring revision across groups.

Results: A total of 54 patients underwent an initial SCS revision. Of these, 15 (28%) underwent a second revision. The most common indication for revision surgery was lead migration (65%). No significant differences were observed in age, body mass index, comorbidities, lead type, and revision indication among the SR and MR groups. On multivariate adjusted analysis, only cervical lead position was significantly associated with repeat reoperation (OR 7.10, 95% CI [1.14, 44.3], p = 0.036). Time to reoperation after a single and MR SCS surgeries did not differ.

Conclusions: Among patients who undergo SCS reoperation, a substantial portion requires additional revisions. Cervical lead placement may be associated with a higher risk of repeat revision surgery compared to thoracic lead positioning. Consideration of lead positioning in the decision to perform and undergo reoperation may therefore result in lower revision rates and improved clinical outcomes among SCS patients with MRs.

Introduction: Complex epilepsy networks with multifocal onset zones that overlap with eloquent cortex may benefit from combined surgical approaches. However, limited data exist on outcomes associated with performing these therapies in tandem. In this case series, we report on 6 patients who underwent combination surgery with either resection or laser interstitial thermal therapy (LITT) and neuromodulation with responsive neurostimulation (RNS) or deep brain stimulation (DBS).

Methods: We performed a retrospective review of adult patients with medically refractory epilepsy who underwent staged combination epilepsy surgeries during the same admission at our institution. Six cases treated between 2019 and 2023 were identified. All patients underwent a presurgical work-up including invasive intracranial monitoring and underwent a combined approach with either surgical resection, LITT, RNS, or DBS. We extracted data on demographic, clinical, and surgical characteristics. The primary outcome was change in seizure frequency from baseline.

Results: The mean age was 42.7 years old (4 female). All patients had at least one epileptogenic zone in the temporal lobe, two in extratemporal neocortex, two in periventricular nodular heterotopia. For the staged combination approach, 3 patients underwent LITT followed by RNS, two underwent resection and RNS, and one received LITT and DBS. The mean reduction in seizure frequency per month at last follow-up was 90%. Postoperatively, 1 patient experienced superior visual field deficits related to LITT, and another had postoperative deep vein thrombosis.

Conclusion: All patients experienced at least an 83% reduction in seizures. This case series demonstrates the potential benefits of a combined surgical approach in patients with multifocal seizures and at least one lesion that can be safely resected or ablated. Future prospective studies are warranted.

Introduction: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy effectively treats medication-resistant essential tremor (ET). Usually, intracranial calcifications are excluded as no-pass zones because of their low penetrability which may limit the effectiveness of treatment and lead to unintended side effects. This case report illustrates the efficacy of unilateral MRgFUS for tremor control in a patient with extensive basal ganglia calcifications due to Fahr's disease.

Case presentation: A 69-year-old right-handed male with debilitating Fahn-Tolosa-Marin grade 3-4 bilateral hand tremor underwent unilateral left MRgFUS thalamotomy. The treatment involved careful preoperative planning to accommodate his extensive basal ganglia calcifications, element path consideration, and skull density ratio to ensure accurate and effective lesioning. Posttreatment, the patient exhibited complete abolition of tremor on the treated side with minor transient dysarthria and imbalance. Follow-up at 12 weeks posttreatment showed sustained tremor relief and an absence of any adverse effects, validating the procedural adjustments made to accommodate the unique challenges posed by his intracranial calcifications.

Conclusion: MRgFUS can be safely and effectively applied in certain patients with extensive basal ganglia calcifications - in this case, due to Fahr's disease. This case report suggests expanding the application of MRgFUS to patients with extensive intracranial calcifications who previously might not have been considered suitable candidates for MRgFUS.

Introduction: The number of intracranial depth electrodes implanted in stereoelectroencephalography (SEEG) investigations is primarily driven by the preimplantation hypothesis about SOZ location. Targeting is not standardized and highly variable between centers. Whether some of these electrodes may prove redundant, or target low-yield areas too frequently, is uncertain.

Methods: We identified a retrospective multi-institutional cohort implanted with depth electrodes for iEEG monitoring between 2003 and 2022. We collected preoperative clinical features and iEEG investigation parameters, including the number of depth electrodes and contacts implanted. We built a propensity-matched cohort with respect to these covariates and evaluated outcomes, which included (1) the likelihood of SOZ localization, (2) complications, and (3) seizure-free outcomes as a function of electrode contact coverage. In addition, we aimed to identify brain regions commonly explored in conjunction with each other and identify the likelihood of a region being implicated in initial electroclinical seizure onset.

Results: One hundred and sixty-seven patients were followed for a median of 3.8 (range 2, 18) years after SEEG. Propensity-matched cohorts demonstrated that a higher number of implanted contacts were associated with a greater likelihood of proceeding to treatment, but were not associated with SOZ localization, seizure freedom (Engel I), favorable seizure outcomes (Engel I/II), or complications, per Bayes factor analysis. Lateral orbitofrontal, supramarginal, posterior cingulate, inferior parietal, and inferior temporal areas were least likely to be implicated in initial electrographic onset, whereas hippocampus, caudal middle frontal, pericalcarine, and parahippocampal areas were most likely when controlling for electrode coverage.

Conclusions: SEEG effectively localizes the SOZ in both lesional and non-lesional etiologies, and clinicians are generally optimizing the electrode coverage for hypothetical SOZ localization, leading to further therapeutic surgeries that may confer seizure freedom. Nevertheless, several areas are possibly being explored despite low likelihood (<2.5%) of participation within the SOZ.

Introduction: Hemispheric surgery is a multistep, highly effective, and radical surgical procedure in the treatment of drug-resistant epilepsy due to extensive unilateral hemispheric disease. The procedure ranges from a resective procedure (hemispherectomy) to disconnection (hemispherotomy) and has developed substantially over the last century from morbid to elegant, minimally invasive, and routinely practiced procedures. Bearing in mind the numerous articles that have been published on hemispherectomy and hemispherotomy, we aimed to highlight the top 100 cited and impactful articles to create familiarity with the topic. We anticipate that this will be a helpful guide for clinicians and academics navigating the literature on this subject.

Methods: A Scopus title-based search on the top 100 most-cited articles on "hemispherectomy" and "hemispherotomy" was performed in September 2023 with no restrictions. The top 100 most-cited articles were then retrieved. The article title, first author, first author's specialty, country of origin, first author's institution at the time of publication, journal of publication, year of publication, citation count, and citations per year were collected. The Google Scholar database citation count for each paper was added for correlation and comprehensive coverage.

Results: The top 100 most-cited articles were cited 92 times per paper on average. The publication dates ranged from 1949 to 2016. The most frequently cited article "Clinical outcomes of hemispherectomy for epilepsy in childhood and adolescence" with 307 citations was published by A.M. Devlin et al. (2003) in the journal Brain. The USA was the highest publishing country (41 articles). The highest-publishing journal was Neurology. The most prolific first authors were A. Smith, J. Schramm, and J. Villemure, each with four publications. The institution with the most contributions was McGill University and its affiliated Health Centers, with nine publications in total. Neurosurgery was the most common specialty among the first authors. Most of the included studies were cohort studies or case series.

Conclusion: We identified the top 100 cited articles on hemispherectomy and hemispherotomy using the Scopus database and supplemented our results with Google Scholar. We highlighted the most prominent authors, institutions, countries, journals, and study designs and illuminated the historical development of hemispherectomy and hemispherotomy procedures, in addition to landmark and currently trending papers.