A Brief Insight on Magnetic Resonance Conditional Neurosurgery Robots.

The brain is a delicate organ in the human body that requires extreme care. Brain-related diseases are unavoidable. Perse, neurosurgery is a complicated procedure that demands high precision and accuracy. Developing a surgical robot is a complex task. To date, there are only a handful of neurosurgery robots in the market that distinctly undergo clinical procedures. These robots have exorbitant cost that hinders the utmost care progress in the area as they are unaffordable. This paper looked at the historical perspective and presented insight literature of the magnetic resonance conditional stereotactic neurosurgery robots that find their ways in clinics, abandoning research projects and promising research yet to undergo clinical use. In addition, the study also gives a thorough insight into the advantage of magnetic resonance imaging modalities and magnetic resonance conditional robots and the future challenges in automation use. Image compatibility test data and accuracy results are also examined because they guarantee that these systems work correctly in particular imaging settings. The primary differences between these systems include actuation and control technologies, construction materials, and the degree of freedom. Thus, one system has an advantage over the other.

Fusion of Preoperative and Postoperative Imaging May Predict the Diagnostic Yield of Stereotactic Needle Brain Biopsies.

BACKGROUND: Stereotactic needle brain biopsy is a commonly used neurosurgical procedure. However, up to 15% of biopsies result in undiagnostic pathology reports. Repeat biopsy or continued management without a diagnosis are often considered after undiagnostic biopsies. There have been no reports about the role of postoperative imaging in predicting the diagnostic yield of stereotactic biopsies. METHODS: We retrospectively assessed all stereotactic biopsies performed over an 11-year period. We performed fusion of immediate postoperative computed tomography (CT) with preoperative MRI, to document whether the air bubble in the postoperative CT was located within the targeted lesion. We then evaluated the association of this fusion-based accuracy assessment with the diagnostic yield of the biopsy. RESULTS: Fewer than 5% of biopsies did not have an air bubble on postoperative CT. A total of 226 biopsies were performed for 219 patients. In our sample, 213 of 226 biopsies were accurate (94.2% accuracy rate), and 203 of 226 biopsies gave a definitive diagnosis (89.8% diagnostic rate). In those cases where the fusion was accurate, the diagnostic rate was 93.9%. When the fusion was inaccurate, the diagnostic rate was only 23.1% (odds ratio 51.5, 95% confidence interval 12.6-210.44, P < 0.001). Of all patient, imaging, surgical, and admission parameters, the only parameter that correlated with diagnostic outcome of the biopsy was the fusion construct accuracy. CONCLUSIONS: Fusion of immediate postoperative CT with preoperative imaging is predictive of the diagnostic rate. In cases where the pathology report following a biopsy is not diagnostic, this fusion may be useful in making decisions regarding repeat biopsy or considering other diagnostic options.

Use of Stereoelectroencephalography Beyond Epilepsy: A Systematic Review.

BACKGROUND: Stereoelectroencephalography (sEEG) is an increasingly popular surgical technique used clinically to study neural circuits involved in medication-refractory epilepsy, and it is concomitantly used in the scientific investigation of neural circuitry underlying behavior. METHODS: Using PRISMA guidelines, the U.S. National Library of Medicine at the National Institutes of Health PubMed database was queried for investigational or therapeutic applications of sEEG in human subjects. Abstracts were analyzed independently by 2 authors for inclusion or exclusion. RESULTS: The study search identified 752 articles, and after exclusion criteria were applied, 8 studies were selected for in-depth review. Among those 8 studies, 122 patients were included, with indications ranging from schizophrenia to Parkinson disease. All the included studies were single-institution case series representing level IV scientific evidence. CONCLUSIONS: sEEG is an important method in epilepsy surgery that could be applied to other neurologic and psychiatric diseases. Information from these studies could provide additional pathophysiologic information and lead to further development and refinement of neuromodulation therapies for such conditions.

The intervention, the patient and the illness - Personalizing non-invasive brain stimulation in psychiatry.

Current hypotheses on the therapeutic action of non-invasive brain stimulation (NIBS) in psychiatric disorders build on the abundant data from neuroimaging studies. This makes NIBS a very promising tool for developing personalized interventions within a precision medicine framework. NIBS methods fundamentally vary in their neurophysiological properties. They comprise repetitive transcranial magnetic stimulation (rTMS) and its variants (e.g. theta burst stimulation - TBS) as well as different types of transcranial electrical stimulation (tES), with the largest body of evidence for transcranial direct current stimulation (tDCS). In the last two decades, significant conceptual progress has been made in terms of NIBS targets, i.e. from single brain regions to neural circuits and to functional connectivity as well as their states, recently leading to brain state modulating closed-loop approaches. Regarding structural and functional brain anatomy, NIBS meets an individually unique constellation, which varies across normal and pathophysiological states. Thus, individual constitutions and signatures of disorders may be indistinguishable at a given time point, but can theoretically be parsed along course- and treatment-related trajectories. We address precision interventions on three levels: 1) the NIBS intervention, 2) the constitutional factors of a single patient, and 3) the phenotypes and pathophysiology of illness. With examples from research on depressive disorders, we propose solutions and discuss future perspectives, e.g. individual MRI-based electrical field strength as a proxy for NIBS dosage, and also symptoms, their clusters, or biotypes instead of disorder focused NIBS. In conclusion, we propose interleaved research on these three levels along a general track of reverse and forward translation including both clinically directed research in preclinical model systems, and biomarker guided controlled clinical trials. Besides driving the development of safe and efficacious interventions, this framework could also deepen our understanding of psychiatric disorders at their neurophysiological underpinnings.

Automated neurosurgical stereotactic planning for intraoperative use: a comprehensive review of the literature and perspectives.

The creation of intracranial stereotactic trajectories, from entry point to target point, is still mostly done manually by the neurosurgeon. The development of automated stereotactic planning tools has been described in the literature. This systematic review aims to assess the effectiveness of stereotactic planning procedure automation and develop tools for patients undergoing neurosurgical stereotactic procedures. PubMed/MEDLINE, EMBASE, Google Scholar, CINAHL, PsycINFO, and Cochrane Register of Controlled Trials databases were searched from inception to September 1, 2019, at the exception of Google Scholar (from 1 January 2010 to September 1, 2019) in French and English. Eligible studies included all studies proposing automated stereotactic planning. A total of 1543 studies were screened. Forty-two studies were included in the systematic review, including 18 (42.9%) conference papers. The surgical procedures planned automatically were mainly deep brain stimulation (n = 14, 33.3%), stereoelectroencephalography (n = 12, 28.6%), and not specified (n = 10, 23.8%). The most frequently used surgical constraints to plan the trajectory were blood vessels (n = 32, 76.2%), cerebral sulci (n = 27, 64.3%), and cerebral ventricles (n = 23, 54.8%). The distance from blood vessels ranged from 1.96 to 4.78 mm for manual trajectories and from 2.47 to 7.0 mm for automated trajectories. At least one neurosurgeon was involved in 36 studies (85.7%). The automated stereotactic trajectory was preferred in 75.4% of the studied cases (range 30-92.9). Only 3 (7.1%) studies were multicentric. No study reported prospective use of the planning software. Stereotactic planning automation is a promising tool to provide valuable stereotactic trajectories for clinical applications.

A novel surgical technique for spontaneous intracerebral hematoma evacuation.

Stereotactic removal of intracerebral hematoma is a routine procedure for treating hypertensive intracerebral hemorrhage, but the complex sequence of operations limits its adoption. We explored the application of a novel surgical technique for the removal of spontaneous intracerebral hematomas. The surgical technique based on computed tomography (CT) images was used in hematoma projection and surgical planning. Markers placed on the scalp based on an Android smartphone app allowed the installation of a stereotactic head frame to facilitate the selection of the best trajectory to the hematoma center for removing the hematoma. Forty-two patients with spontaneous intracerebral hemorrhage were included in the study, including 33 cases of supratentorial hemorrhage, 5 cases of cerebellum hemorrhage, and 4 cases of brain stem hemorrhage. The surgical technique combined with the stereotactic head frame helped the tip of the drainage tube achieve the desired position. The median surgical time was 45 (range 25-75) min. The actual head frame operating time was 10 (range 5-15) min. Target alignment performed by the surgical technique was accurate to ≤ 10.0 mm in all 42 cases. No patient experienced postoperative rebleeding. In 33 cases of supratentorial intracerebral hemorrhage, an average evacuation rate of 77.5% was achieved at postoperative 3.1 ± 1.4 days, and 29 (87.9%) cases had a residual hematoma of < 15 ml. The novel surgical technique helped to quickly and effortlessly localize hematomas and achieve satisfactory hematoma removal. Clinical application of the stereotactic head frame was feasible for intracerebral hemorrhage in various locations.

Outcomes of stereoelectroencephalography exploration at an epilepsy surgery center.

OBJECTIVES: Epilepsy surgery is offered in resistant focal epilepsy. Non-invasive investigations like scalp video EEG monitoring (SVEM) help delineate epileptogenic zone. Complex cases may require intracranial video EEG monitoring (IVEM). Stereoelectroencephalography (SEEG)-based intracerebral electrode implantation has better spatial resolution, lower morbidity, better tolerance, and superiority in sampling deep structures. Our objectives were to assess IVEM using SEEG with regard to reasoning behind implantation, course, surgical interventions, and outcomes. MATERIALS AND METHODS: Seventy-two admissions for SEEG from January 2014 to December 2018 were included in the study. Demographic and clinical data were retrospectively collected. RESULTS: The cohort comprised of 69 adults of which 34 (47%) had lesional MRI. Reasons for SEEG considering all cases included non-localizing ictal onset (76%), ictal-interictal discordance (21%), discordant semiology (17%), proximity to eloquent cortex (33%), nuclear imaging discordance (34%), and discordance with neuropsychology (19%). Among lesional cases, additional reasons included SVEM discordance (68%) and dual or multiple pathology (47%). Forty-eight patients (67%) were offered resective surgery, and 41 underwent it. Twenty-three (56%) had at least one year post-surgical follow-up of which 14 (61%) had Engels class I outcome. Of the remaining 23 who were continued on medical management, 4 (17%) became seizure-free and 12 (51%) had reduction in seizure frequency. CONCLUSION: SEEG monitoring is an important and safe tool for presurgical evaluation with good surgical and non-surgical outcomes. Whether seizure freedom following non-surgical management could be related to SEEG implantation, medication change, or natural course needs to be determined.

Postoperative outcomes following pediatric intracranial electrode monitoring: A case for stereoelectroencephalography (SEEG).

BACKGROUND: For patients with medically refractory epilepsy, intracranial electrode monitoring can help identify epileptogenic foci. Despite the increasing utilization of stereoelectroencephalography (SEEG), the relative risks or benefits associated with the technique when compared with the traditional subdural electrode monitoring (SDE) remain unclear, especially in the pediatric population. Our aim was to compare the outcomes of pediatric patients who received intracranial monitoring with SEEG or SDE (grids and strips). METHODS: We retrospectively studied 38 consecutive pediatric intracranial electrode monitoring cases performed at our institution from 2014 to 2017. Medical/surgical history and operative/postoperative records were reviewed. We also compared direct inpatient hospital costs associated with the two procedures. RESULTS: Stereoelectroencephalography and SDE cohorts both showed high likelihood of identifying epileptogenic zones (SEEG: 90.9%, SDE: 87.5%). Compared with SDE, SEEG patients had a significantly shorter operative time (118.7 versus 233.4 min, P < .001) and length of stay (6.2 versus 12.3 days, P < .001), including days spent in the intensive care unit (ICU; 1.4 versus 5.4 days, P < .001). Stereoelectroencephalography patients tended to report lower pain scores and used significantly less narcotic pain medications (54.2 versus 197.3 mg morphine equivalents, P = .005). No complications were observed. Stereoelectroencephalography and SDE cohorts had comparable inpatient hospital costs (P = .47). CONCLUSION: In comparison with subdural electrode placement, SEEG results in a similarly favorable clinical outcome, but with reduced operative time, decreased narcotic usage, and superior pain control without requiring significantly higher costs. The potential for an improved postoperative intracranial electrode monitoring experience makes SEEG especially suitable for pediatric patients.

Publication Patterns of Presentations at the 16th Quadrennial Meeting of the World Society for Stereotactic and Functional Neurosurgery.

BACKGROUND: The quality of a scientific meeting can be quantified by the rate of full publications arising from the presented abstracts and the impact factor of the journals in which the studies were published. OBJECTIVES: The aim of this study was to investigate the publication rates of presentations from the 2013 World Society for Stereotactic and Functional Neurosurgery (WSSFN) quadrennial meeting. METHODS: Scopus and PubMed databases were searched for the authors of the presentations to identify full publications arising from the relevant abstracts. Author and content matching were used to match an abstract with a full publication. Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis. RESULTS: In total, 77% (57/74), 56% (44/79), and 50% (79/157) of the paper, flash, and poster presentations, respectively, have been published, with an overall publication rate of 58% (180/310). Articles received a total of 5,227 citations, with an average of 29 ± 64.1 citations per article. The first authors who published their studies had a significantly higher h-index than those who did not publish (p = 0.003). The most preferred journals for publication were Journal of Neurosurgery, Acta Neurochirurgica, and Stereotactic and Functional Neurosurgery. The majority of the articles (117/180 [65%]) were published in a quartile 1 or 2 journal. The average journal impact factor (JIF) was 4.5 for all presentations, and 7.8 for paper session presentations. Studies presented in paper sessions were published in significantly higher-impact factor journals than those presented in poster sessions (p < 0.001). CONCLUSIONS: The WSSFN Congress had a relatively high overall publication rate (58%) compared to both other neurosurgical congresses and congresses in other scientific fields. The average JIF of 7.8 is a reflection of the high quality and high impact of the paper session presentations.

How technical progress reshaped behavioral neuroendocrinology during the last 50 years and some methodological remarks.

The first issue of Hormones and Behavior was published 50 years ago in 1969, a time when most of the techniques we currently use in Behavioral Endocrinology were not available. Researchers have during the last 5 decades developed techniques that allow measuring hormones in small volumes of biological samples, identify the sites where steroids act in the brain to activate sexual behavior, characterize and quantify gene expression correlated with behavior expression, modify this expression in a specific manner, and manipulate the activity of selected neuronal populations by chemogenetic and optogenetic techniques. This technical progress has considerably transformed the field and has been very beneficial for our understanding of the endocrine controls of behavior in general, but it did also come with some caveats. The facilitation of scientific investigations came with some relaxation of methodological exigency. Some critical controls are no longer performed on a regular basis and complex techniques supplied as ready to use kits are implemented without precise knowledge of their limitations. We present here a selective review of the most important of these new techniques, their potential problems and how they changed our view of the hormonal control of behavior. Fortunately, the scientific endeavor is a self-correcting process. The problems have been identified and corrections have been proposed. The next decades will obviously be filled with exciting discoveries in behavioral neuroendocrinology.

Patient phenotypes and clinical outcomes in invasive monitoring for epilepsy: An individual patient data meta-analysis.

OBJECTIVE: Invasive monitoring provides valuable clinical information in patients with drug-resistant epilepsy (DRE). However, there is no clear evidence indicating either stereoelectroencephalography (SEEG) or subdural electrodes (SDE) as the optimal method. Our goal was to examine differences in postresection seizure freedom rates between SEEG- and SDE-informed resective epilepsy surgeries. Additionally, we aimed to determine potential clinical indicators for SEEG or SDE monitoring in patients with drug-resistant epilepsy. METHODS: A systematic literature review was performed in which we searched for primary articles using keywords such as "electroencephalography", "intracranial grid", and "epilepsy." Only studies containing individual patient data (IPD) were included for analysis. A one-stage IPD meta-analysis was performed to determine differences in rates of seizure freedom (International League Against Epilepsy (ILAE) guidelines and Engel classification) and resection status between SEEG and SDE patients. A Cox proportional-hazards regression was performed to determine the effect of time on seizure freedom status. Additionally, a principal component analysis was performed to investigate primary drivers of variance between these two groups. RESULTS: This IPD meta-analysis compared differences between SEEG and SDE invasive monitoring techniques in 595 patients from 33 studies. Our results demonstrate that while there was no difference in seizure freedom rates regardless of resection (p = 0.0565), SEEG was associated with a lower rate of resection compared with SDE (82.00% SEEG, 92.74% SDE, p = 0.0002). Additionally, while SDE was associated with a higher rate of postresection seizure freedom (54.04% SEEG, 64.32% SDE, p = 0.0247), the difference between seizure freedom rates following SEEG- or SDE-informed resection decreased with long-term follow-up. A principal component analysis showed that cases resulting in SEEG were associated with lower risk of morbidity than SDE cases, which were strongly collinear with multiple subpial transections, anterior temporal lobectomy, amygdalectomy, and hippocampectomy. SIGNIFICANCE: In this IPD meta-analysis of SEEG and SDE invasive monitoring techniques, SEEG and SDE were associated with similar rates of seizure freedom at latest follow-up. The former was associated with lower rates of resection. Furthermore, the clinical phenotypes of patients undergoing SEEG monitoring was associated with lower rates of complications. Future long-term prospective registries of IPD are promising options for clarifying the differences in these intracranial monitoring techniques as well as the unique patient phenotypes that may be associated with their indication.

Mechanisms and Risk Factors Contributing to Visual Field Deficits following Stereotactic Laser Amygdalohippocampotomy.

Selective laser amygdalohippocampotomy (SLAH) is a minimally invasive surgical treatment for medial temporal lobe epilepsy. Visual field deficits (VFDs) are a significant potential complication. The objective of this study was to determine the relationship between VFDs and potential mechanisms of injury to the optic radiations and lateral geniculate nucleus. We performed a retrospective cross-sectional analysis of 3 patients (5.2%) who developed persistent VFDs after SLAH within our larger series (n = 58), 15 healthy individuals and 10 SLAH patients without visual complications. Diffusion tractography was used to evaluate laser catheter penetration of the optic radiations. Using a complementary approach, we evaluated evidence for focal microstructural tissue damage within the optic radiations and lateral geniculate nucleus. Overablation and potential heat radiation were assessed by quantifying ablation and choroidal fissure CSF volumes as well as energy deposited during SLAH.SLAH treatment parameters did not distinguish VFD patients. Atypically high overlap between the laser catheter and optic radiations was found in 1/3 VFD patients and was accompanied by focal reductions in fractional anisotropy where the catheter entered the lateral occipital white matter. Surprisingly, lateral geniculate tissue diffusivity was abnormal following, but also preceding, SLAH in patients who subsequently developed a VFD (all p = 0.005).In our series, vision-related complications following SLAH, which appear to occur less frequently than following open temporal lobe -surgery, were not directly explained by SLAH treatment parameters. Instead, our data suggest that variations in lateral geniculate structure may influence susceptibility to indirect heat injury from transoccipital SLAH.

Stereotactic Lesion in the Forel's Field H: A 2-Years Prospective Open-Label Study on Motor and Nonmotor Symptoms, Neuropsychological Functions, and Quality of Life in Parkinson Disease.

BACKGROUND: Stereotactic lesion in the Forel's field H (campotomy) was proposed in 1963 to treat Parkinson disease (PD) symptoms. Despite its rationale, very few data on this approach have emerged. Additionally, no study has assessed its effects on nonmotor symptoms, neuropsychological functions and quality of life. OBJECTIVE: To provide a prospective 2-yr assessment of motor, nonmotor, neuropsychological and quality of life variables after unilateral campotomy. METHODS: Twelve PD patients were prospectively evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS), the Dyskinesia Rating Scale and the Parkinson's disease quality of life questionnaire (PDQ39) before campotomy, and after 6 and 24 mo. Nonmotor, neuropsychiatric, neuropsychological and quality of life variables were assessed. The impact of PD on global health was also rated. RESULTS: A significant reduction in contralateral rest tremor (65.7%, P < .001), rigidity (87.8%, P < .001), bradykinesia (68%, P < .001) and axial symptoms (24.2%, P < .05) in offmedication condition led to a 43.9% reduction in UPSDRS III scores 2 yr after campotomy (P < .001). Gait improved by 31.9% (P < .05) and walking time to cover 7 m was reduced by 43.2% (P < .05). Pain decreased by 33.4% (P < .01), while neuropsychiatric and neuropsychological functions did not change. Quality of life improved by 37.8% (P < .05), in line with a 46.7% reduction of disease impact on global health (P < .001). CONCLUSION: A significant 2-yr improvement of motor symptoms, gait performance and pain was obtained after unilateral campotomy without significant changes to cognition. Quality of life markedly improved in parallel with a significant reduction of PD burden on global health.

Biological Cardiac Tissue Effects of High-Energy Heavy Ions - Investigation for Myocardial Ablation.

Noninvasive X-ray stereotactic treatment is considered a promising alternative to catheter ablation in patients affected by severe heart arrhythmia. High-energy heavy ions can deliver high radiation doses in small targets with reduced damage to the normal tissue compared to conventional X-rays. For this reason, charged particle therapy, widely used in oncology, can be a powerful tool for radiosurgery in cardiac diseases. We have recently performed a feasibility study in a swine model using high doses of high-energy C-ions to target specific cardiac structures. Interruption of cardiac conduction was observed in some animals. Here we report the biological effects measured in the pig heart tissue of the same animals six months after the treatment. Immunohistological analysis of the target tissue showed (1.) long-lasting vascular damage, i.e. persistent hemorrhage, loss of microvessels, and occurrence of siderophages, (2.) fibrosis and (3.) loss of polarity of targeted cardiomyocytes and wavy fibers with vacuolization. We conclude that the observed physiological changes in heart function are produced by radiation-induced fibrosis and cardiomyocyte functional inactivation. No effects were observed in the normal tissue traversed by the particle beam, suggesting that charged particles have the potential to produce ablation of specific heart targets with minimal side effects.

Consistent linear and non-linear responses to invasive electrical brain stimulation across individuals and primate species with implanted electrodes.

BACKGROUND: Electrical neuromodulation via implanted electrodes is used in treating numerous neurological disorders, yet our knowledge of how different brain regions respond to varying stimulation parameters is sparse. OBJECTIVE/HYPOTHESIS: We hypothesized that the neural response to electrical stimulation is both region-specific and non-linearly related to amplitude and frequency. METHODS: We examined evoked neural responses following 400 ms trains of 10-400 Hz electrical stimulation ranging from 0.1 to 10 mA. We stimulated electrodes implanted in cingulate cortex (dorsal anterior cingulate and rostral anterior cingulate) and subcortical regions (nucleus accumbens, amygdala) of non-human primates (NHP, N = 4) and patients with intractable epilepsy (N = 15) being monitored via intracranial electrodes. Recordings were performed in prefrontal, subcortical, and temporal lobe locations. RESULTS: In subcortical regions as well as dorsal and rostral anterior cingulate cortex, response waveforms depended non-linearly on frequency (Pearson's linear correlation r < 0.39), but linearly on current (r > 0.58). These relationships between location, and input-output characteristics were similar in homologous brain regions with average Pearson's linear correlation values r > 0.75 between species and linear correlation values between participants r > 0.75 across frequency and current values per brain region. Evoked waveforms could be described by three main principal components (PCs) which allowed us to successfully predict response waveforms across individuals and across frequencies using PC strengths as functions of current and frequency using brain region specific regression models. CONCLUSIONS: These results provide a framework for creation of an atlas of input-output relationships which could be used in the principled selection of stimulation parameters per brain region.

The Origins of Human Functional Stereotaxis: A Reappraisal.

In order to shed light on the first application of human functional stereotactic neurosurgery, whether it was in the realm of movement disorders, as has been claimed repeatedly, or in the realm of psychiatry, a review of the original scholarly literature was conducted. Tracking and scrutinising original publications by Spiegel and Wycis, the pioneers of human stereotactic neurosurgery, it was found that its origin and the very incentive for its development and first clinical use were to avoid the side effects of frontal leucotomy. The first applications of functional stereotactic neurosurgery were in performing dorsomedial thalamotomies in psychiatric patients; it was only later that the stereotactic technique was applied in patients with chronic pain, movement disorders and epilepsy. Spiegel and Wycis' first functional stereotactic operations were for obsessive-compulsive disorder, schizophrenia, and other psychiatric conditions.

Stereotaxy in rat models: Current state of the art, proposals to improve targeting accuracy and reporting guideline.

BACKGROUND: Stereotaxy is frequently employed in rodent models for precise brain injections or implantations. We intended to map the current practice in rat stereotaxy and list proposals to improve targeting accuracy. METHODS: We selected 235 publications on rat stereotaxy from the last 5 years. We collected data on the subjects, targets, coordinate system used, postoperative implant verification and analysis of subjects with off-target implants. RESULTS: Approximately 10,000 rats, mostly Sprague-Dawley and Wistar, were subjected to stereotaxy. Although referenced in 57% of the studies, only 10% of the subjects resembled those used in the Paxinos atlas. Popular procedures were injections (62%) and implantation of cannulas (20%) and electrodes (8%). Right-sided and bilateral targets were more often used than left-sided targets. Bregma served as a stereotaxic origin in 96% of the publications, although for 27% of the targets, the entry was closer to lambda. The Euclidian distance from the target to the interaural line midpoint and to lambda was shorter than to bregma in 38% and 5% of the cases, respectively. Bregma and the dura/brain surface were the most popular dorsoventral References Implantation accuracy was assessed almost exclusively histologically. 39% of the studies did not perform any accuracy check. The number of on-target implants was reported in only 8% of the studies. Only 15% of the publications reported that they excluded subjects with off-target implants. CONCLUSIONS: Although well-established, rat stereotaxy could be improved, mainly in acquiring target coordinates, selecting a stereotaxic origin and verifying and reporting accuracy.

Impact of Powdered Vancomycin on Preventing Surgical Site Infections in Neurosurgery: A Systematic Review and Meta-analysis.

BACKGROUND: Surgical site infections (SSIs) after spine and brain surgery present a major burden to patients and hospitals by increasing morbidity, mortality, and healthcare costs. OBJECTIVE: To review available literature investigating the role of intrawound powdered vancomycin against SSIs after neurosurgical operations. METHODS: All randomized and observational English language studies of intrawound powdered vancomycin use in spinal and cranial surgery were included and analyzed using random-effects modeling. RESULTS: In spine surgery (25 studies with 16 369 patients), patients in the vancomycin group had a significantly lower risk for any SSI (odds ratio [OR]: 0.41; 95% confidence interval [CI]: 0.30-0.57; P < .001; I2 = 47%). However, when separate analyses were conducted for superficial and deep SSIs, a significant difference was found only for deep (OR: 0.31; 95% CI: 0.22-0.45; P < .001; I2 = 29%). Subgroup analyses for different vancomycin powder dosages (1 g vs 2 g vs composite dose) did not point to any dose-related effect of vancomycin. In cranial surgery (6 studies with 1777 patients), use of vancomycin was associated with a significantly lower risk for SSIs (OR: 0.33; 95% CI: 0.18-0.60; P = .0003; I2 = 45%). In meta-regression analysis, trial-level variability of diabetes had no influence on the association of vancomycin powder use with SSIs. CONCLUSION: Use of vancomycin powder in spinal and cranial surgery might be protective against SSIs, especially against deep SSIs. No dose-related effect of vancomycin powder was identified. However, caution is needed in the clinical interpretation of these results, owing to the observational design of the included studies in this meta-analysis.