Task synergies in neurovascular surgery: Image-guided navigation using a thermoplastic facial mask for the resection of a symptomatic occult to MRI brain microarteriovenous malformation.

Due to the size of microarteriovenous malformations (mAVM), its precise angioarchitecture description often requires a supraselective DSA and detecting the nidus during microsurgical resection is challenging. An accurate intraoperative navigation system is desirable but available softwares which can combine DSA and MRI are not always available. The authors present here a technical note describing the use of a stereotactic thermoplastic mask with a fiducial box to guide the resection of a mAVM.

Clinical improvement after cranioplasty and its relation to body position and cerebral hemodynamics.

Cranioplasty after decompressive craniectomy (DC) has been found to improve the neurological condition. The underlying mechanisms are still unknown. The aim of this study is to investigate the roles of the postural changes and atmospheric pressure (AP) in the brain hemodynamics and their relationship with clinical improvement. Seventy-eight patients were studied before and 72 h after cranioplasty with cervical and transcranial color Doppler ultrasound (TCCS) in the sitting and supine positions. Craniectomy size, shape, and force exerted by the AP (torque) were calculated. Neurological condition was assessed with the National Institutes of Health Stroke Scale (NIHSS) and the Barthel index. Twenty-eight patients improved after cranioplasty. Their time elapsed from the DC was shorter (214 vs 324 days), preoperative Barthel was worse (54 vs 77), internal carotid artery (ICA) mean velocity of the defect side was lower while sitting (14.4 vs 20.9 cm/s), and torque over the craniectomy was greater (2480.3 vs 1464.3 N*cm). Multivariate binary logistic regression showed the consistency of these changes. TCCS findings were no longer present postoperatively. Lower ICA (defect side) velocity in the sitting position correlates significantly with clinical improvement. Greater torque exerted by the AP might explain different susceptibilities to postural changes, corrected by cranioplasty.

Supervised Machine Learning Methods and Hyperspectral Imaging Techniques Jointly Applied for Brain Cancer Classification.

Hyperspectral imaging techniques (HSI) do not require contact with patients and are non-ionizing as well as non-invasive. As a consequence, they have been extensively applied in the medical field. HSI is being combined with machine learning (ML) processes to obtain models to assist in diagnosis. In particular, the combination of these techniques has proven to be a reliable aid in the differentiation of healthy and tumor tissue during brain tumor surgery. ML algorithms such as support vector machine (SVM), random forest (RF) and convolutional neural networks (CNN) are used to make predictions and provide in-vivo visualizations that may assist neurosurgeons in being more precise, hence reducing damages to healthy tissue. In this work, thirteen in-vivo hyperspectral images from twelve different patients with high-grade gliomas (grade III and IV) have been selected to train SVM, RF and CNN classifiers. Five different classes have been defined during the experiments: healthy tissue, tumor, venous blood vessel, arterial blood vessel and dura mater. Overall accuracy (OACC) results vary from 60% to 95% depending on the training conditions. Finally, as far as the contribution of each band to the OACC is concerned, the results obtained in this work are 3.81 times greater than those reported in the literature.

Reduction in the infection rate of cranioplasty with a tailored antibiotic prophylaxis: a nonrandomized study.

BACKGROUND: Cranioplasty carries a high risk of surgical site infections (SSIs) for a scheduled procedure, particularly with antibiotic-resistant bacteria. METHODS: The goal of this retrospective study was to measure the effect of tailored antibiotic prophylaxis on SSIs resulting from cranioplasties. The authors collected a prospective database of cranioplasties from 2009 to 2018. Risk factors for SSI were registered, as well as infection occurring during the first year postoperatively. A new protocol was initiated in 2016 consisting of antibiotic prophylaxis tailored to the colonizing flora of the skin of the scalp and decolonization of patients who were nasal carriers of methicillin-resistant S. aureus (MRSA); infection rates were compared. RESULTS: One hundred nine cranioplasties were identified, 64 in the old protocol and 45 in the new protocol. Of the 109 cranioplasties, 16 (14.7%) suffered an infection, 14 (21.9%) in the old protocol group and 2 (4.4%) in the new protocol group (OR for the new protocol 0.166, 95% CI 0.036-0.772). Multiple surgeries (OR 3.44), Barthel ≤ 70 (OR 3.53), and previous infection (OR 3.9) were risk factors for SSI. Of the bacteria identified in the skin of the scalp, 22.2% were resistant to routine prophylaxis (cefazoline). Only one patient was identified as a nasal carrier of MRSA and was decolonized. CONCLUSIONS: A high percentage of bacteria resistant to routine prophylaxis (cefazoline) was identified in the skin of these patients' scalps. The use of tailored antibiotic prophylaxis reduced significantly the infection rate in this particular set of patients.

Symptomatic ptosis cerebelli after suboccipital craniectomy in a patient with severe brain trauma.

PRIMARY OBJECTIVE: To report the first case of symptomatic cerebellar ptosis after a large suboccipital craniectomy in a patient with severe brain trauma and a review of the literature. PATIENT AND METHODS: A 36-year-old man suffered severe traumatic brain injury after a four-metre fall. He underwent a large suboccipital craniectomy because his computed tomography scan revealed a posterior fossa subdural haematoma and cerebellar swelling. Four weeks after admission, he developed communicating hydrocephalus, and a ventriculoperitoneal shunt was placed. Although he experienced good recovery, seven months after the trauma he complained of cephalea, dizziness, recurrent vomiting and diplopia. Magnetic resonance imaging (MRI) showed descent of the cerebellum through a wide bone defect. RESULTS: We performed a posterior fossa cranioplasty after other causes of delayed worsening were ruled out, such as shunt malfunction, overdrainage and ischaemic lesions. The patient improved, and a post-operative MRI confirmed the upward migration of the cerebellum. CONCLUSIONS: Cerebellar ptosis must be considered in cases of delayed symptoms after large suboccipital craniectomy regardless of pathology. Posterior fossa cranioplasty to provide structural support to slumped cerebellum can improve or resolve symptoms.

[Competency-based Neurosurgery Residency Programme]. / El nuevo programa de Residencia en Neurocirugía basado en competencias.

A programme proposal for competency-based Neurosurgery training adapted to the specialization project is presented. This proposal has been developed by a group of neurosurgeons commissioned by the SENEC (Spanish Society of Neurosurgery) and could be modified to generate a final version that could come into force coinciding with the implementation of the specialization programme. This document aims to facilitate the test of the new programme included in the online version of our journal. DURATION OF THE PROGRAMME: Total training period is 6 years; initial 2 years belong to the surgery specialization and remaining 4 years belong to core specialty period. STRUCTURE OF THE PROGRAMME: It is a competency-based programmed based on the map used by the US Accreditation Council for Graduate Medical Education (ACGME) including the following domains of clinical competency: Medical knowledge, patient care, communication skills, professionalism, practice-based learning and improvement, health systems, interprofessional collaboration and professional and personal development. Subcompetencies map in the domains of Knowledge and Patient care (including surgical competencies) was adapted to the one proposed by AANS and CNS (annex 1 of the programme). A subcompetency map was also used for the specialization rotations. INSTRUCTION METHODS: Resident's training is based on personal study (self-learning) supported by efficient use of information sources and supervised clinical practice, including bioethical instruction, clinical management, research and learning techniques. EVALUATION METHODS: Resident evaluation proposal includes, among other instruments, theoretical knowledge tests, objective and structured evaluation of the level of clinical competency with real or standardised patients, global competency scales, 360-degree evaluation, clinical record audits, milestones for residents progress and self-assessment (annex 2). Besides, residents periodically assess the teaching commitment of the department's neurosurgeons and other professors participating in rotations, and annually assess the overall operation of the programme. Results of evaluations are registered, together with other relevant data, in the Resident's Book. PROGRAMME'S NATIONAL COMMITTEE: The creation of a Programme Committee directly attached to the SENEC (National Commission) that, aside from generating a final version of the programme, monitors its implementation (level of adherence and operation in the different departments), assumes the creation of test banks and the centralized administration of knowledge tests (in the middle of the residency and/or at the end of it) and centralizes information collected by tutors that could be used for re-accreditation of the services, is proposed.

[The method of selection of the residents in Spain. Analysis of the examination MIR and offer of a new methodology]. / El método de selección de los residentes en España. Análisis del examen MIR y propuesta de una nueva metodología.

INTRODUCTION: The method for selecting medical graduates for residency positions has a strong influence on teaching and learning strategies in medical schools. The methodology currently used in Spain does not seem appropriate for ranking the candidates or improving curriculum development. Thus, and taking into account the most consistent methodologies used in the United Kingdom and USA, we have designed a new method to be used in our country. OBJECTIVES: To analyze the limitations of the methodology used in Spain, and propose a new one aimed to improve the accuracy of selection itself and avoiding the negative influence of the current method on curricular development. In addition, we emphasize the necessity of improving teaching and learning in the clinical context to assure that graduating students reach an adequate level of clinical competence. CONCLUSIONS: The method for selecting candidates to residency post currently used in Spain, which relies mainly on testing theoretical knowledge, should be changed for an alternative methodology taking into account student,s performance through the course and assessing his/her ability for clínical contextualization of knowledge and level of clinical competence.

[Selection of medical graduates for residency posts. A comparative study of the methodologies used in different countries]. / La selección de los graduados en Medicina para los puestos de residencia. Estudio comparativo de los métodos usados en diferentes países.

INTRODUCTION: The design of an appropriate method for the selection of medical graduates for residency posts is extremely important, not only for the efficiency of the method itself (accurate identification of most competent candidates), but also for its influence on the study and teaching methodologies operating in medical schools. Currently, there is a great variation in the criteria used in different countries and there is no definitively appropriate method. The use of isolated or combined criteria, such as the marks obtained by students in medical schools, their performance in tests of theoretical knowledge and evaluations of clinical competence, or personal interviews, have a limited value for identifying those candidates who will perform better during the residency and later on during independent practice. OBJECTIVES: To analyse the variability in the methodologies used for the selection of residents employed in different countries, in particular those used in the United Kingdom and USA, where external agencies and medical schools make systematic analyses of curriculum development. The advantages and disadvantages of national or transnational licensing examinations on the process of convergence and harmonization of medical degrees and residency programmes through Europe are discussed. The present analysis is used to design a new and more efficient multi-criteria methodology for resident selection in Spain, which will be published in the next issue of this journal. CONCLUSIONS: Since the multi-criteria methods used in UK and USA appear to be most consistent, these have been employed for designing the new methodology that could be applied in Spain. Although many experts in medical education reject national examinations for awarding medical degrees or ranking candidates for residency posts, it seems that, when appropriately designed, they can be used to verify the level of competence of graduating students without necessarily distorting curriculum implementation or improvement.

Impact of a Hospitalist Co-Management Program on Medical Complications and Length of Stay in Neurosurgical Patients.

BACKGROUND: The impact of co-management on clinical outcomes in neurosurgical patients is uncertain. This study aims to describe the implementation of a hospitalist co-management program in a neurosurgery department and its impact on the incidence of complications, mortality, and length of stay. METHODS: The authors used a quasi-experimental study design that compared a historical control period (July-December 2017) to a prospective intervention arm. During the intervention period, patients admitted to a neurosurgery inpatient unit who were older than 65 years, suffered certain conditions, or were admitted from ICUs were included in the co-management program. Two hospitalists joined the surgical staff and intervened in the diagnostic and therapeutical plan of patients, participating in clinical decisions and coordinating patient navigation with neurosurgeons. The incidence of moderate or severe complications measured by the Accordion Severity Grading System, in-hospital mortality, and length of stay of the two cohorts were compared. Multivariate regression was used to adjust for confounders, and the average treatment effect was estimated using inverse probability of treatment weighting. RESULTS: The adjusted incidence of moderate or severe complications was lower among co-managed patients (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.39-0.91). Mortality was unchanged (OR 0.83, 95% CI 0.15-4.17). Length of stay was lower in co-managed patients, with a 1.3-day reduction observed after inverse probability of treatment weighting analysis. CONCLUSION: Hospitalist co-management was associated with a reduced incidence of complications and length of stay in neurosurgical patients, but there was no difference in in-hospital mortality.

Predicting Regions of Local Recurrence in Glioblastomas Using Voxel-Based Radiomic Features of Multiparametric Postoperative MRI.

The globally accepted surgical strategy in glioblastomas is removing the enhancing tumor. However, the peritumoral region harbors infiltration areas responsible for future tumor recurrence. This study aimed to evaluate a predictive model that identifies areas of future recurrence using a voxel-based radiomics analysis of magnetic resonance imaging (MRI) data. This multi-institutional study included a retrospective analysis of patients diagnosed with glioblastoma who underwent surgery with complete resection of the enhancing tumor. Fifty-five patients met the selection criteria. The study sample was split into training (N = 40) and testing (N = 15) datasets. Follow-up MRI was used for ground truth definition, and postoperative structural multiparametric MRI was used to extract voxel-based radiomic features. Deformable coregistration was used to register the MRI sequences for each patient, followed by segmentation of the peritumoral region in the postoperative scan and the enhancing tumor in the follow-up scan. Peritumoral voxels overlapping with enhancing tumor voxels were labeled as recurrence, while non-overlapping voxels were labeled as nonrecurrence. Voxel-based radiomic features were extracted from the peritumoral region. Four machine learning-based classifiers were trained for recurrence prediction. A region-based evaluation approach was used for model evaluation. The Categorical Boosting (CatBoost) classifier obtained the best performance on the testing dataset with an average area under the curve (AUC) of 0.81 ± 0.09 and an accuracy of 0.84 ± 0.06, using region-based evaluation. There was a clear visual correspondence between predicted and actual recurrence regions. We have developed a method that accurately predicts the region of future tumor recurrence in MRI scans of glioblastoma patients. This could enable the adaptation of surgical and radiotherapy treatment to these areas to potentially prolong the survival of these patients.

Acute perfusion changes after spontaneous SAH: a perfusion CT study.

BACKGROUND: Perfusion computed tomography (CT) is a rapid technique that allows the measurement of acute disturbances in local and global cerebral blood flow in patients suffering stroke and spontaneous subarachnoid haemorrhage (SAH). The purpose of this study was to establish the relationship between different measures of brain perfusion made on dynamic-contrast CT reconstructions performed as soon as SAH has been diagnosed and the severity of the bleeding determined by the clinical grade, the extent of the bleeding and the outcome of the patients. METHODS: After the diagnosis of SAH by conventional CT, a perfusion CT was performed before CT angiography. All imaging studies were performed on a six-slice spiral CT scanner. All images were analysed using perfusion software developed by Philips, which produces perfusion CT quantitative data based on temporal changes in signal intensity during the first pass of a bolus of an iodinated contrast agent. Measurements of mean transient time (MTT), time to peak (TTP), cerebral blood volume (CBV) and cerebral blood flow (CBF) in volumes of interest corresponding to territories perfused by the major cerebral arteries were performed. Different data regarding severity of the bleeding-such as level of consciousness, amount of bleeding in conventional CT-were collected. All poor-grade patients received a ventriculostomy catheter so that ICP recordings were obtained. Also, the occurrence of delayed cerebral ischaemia (DCI) was recorded. Outcome was assessed by the Glasgow Outcome Scale 6 months after the bleeding. For statistical analysis, non-parametric correlations between variables were performed. FINDINGS: Thirty-nine patients have been included in the study since January 2007. In SAH patients there are increasing perfusion abnormalities as the severity of the bleeding increases. The most affected perfusion parameters are TTP and MTT, as they significantly increase with the clinical severity of the bleeding and the total volume of bleeding (P < 0.01, Spearman's Rho). When average MTT time is increased over 5.9 s there is a 20-fold (95% CI = 2.1-182) risk of poor outcome. All patients presenting this MTT time suffered from DCI. This value has a positive predictive value of 100% for DCI and 90% for a poor outcome. CONCLUSIONS: SAH causes cerebral blood flow abnormalities even in the acute phase of the illness, consisting mainly of an increase in circulation times (TTP and MTT), which are correlated with the severity of the bleeding.

Racemose Fourth Ventricle Neurocysticercosis Excision Through Telovelar Approach and Hydrodissection.

Intraventricular neurocysticercosis is associated with more severe complications and a worse overall outcome.1,2 Fourth ventricle neurocysticercosis (FVNCC) often presents with cerebrospinal fluid obstruction and hydrocephalus by means of direct mechanical occlusion of ventricular outlets by the cysts or due to an ependymal inflammatory response. Unfortunately, there is little consensus on the optimal management for FVNCC. If possible, surgical removal of cysticerci rather than medical therapy and/or shunt surgery is recommended.3 Endoscopic removal of cysts is described to be an effective treatment modality.4 However, endoscopic removal of inflamed or adherent ventricular cysticerci is associated with increased risk of complications.5 Although microdissection through a posterior fossa telovelar approach is a valid method for FVNCC,6,7 scarce reports describe the therapeutic decision making and provide a surgical video of adherent FVNCC cyst resection. Video 1 shows a 40-year-old female born in Honduras who presented with progressive headache. Computed tomography revealed ventriculomegaly and transependymal flow. Magnetic resonance imaging demonstrated obstructive hydrocephalus secondary to a multiloculated cystic mass within the fourth ventricle. According to the diagnostic criteria, probable racemose FVNCC was suspected.8 Magnetic resonance imaging raised suspicion that the cysts could be densely adherent to surrounding structures,9 precluding endoscopic removal. We performed a combined microscopic and endoscopic approach, which permitted removal of the cysts through a telovelar approach and hydrodissection technique without damaging nearby structures and treatment of the associated hydrocephalus through an endoscopic third ventriculostomy, allowing complete resolution of symptoms and avoidance of cerebrospinal fluid shunting.

Hemodynamic alterations following a cerebellar arteriovenous malformation resection: Case report and densitometric quantitative analysis from CT imaging.

BACKGROUND: Cerebellar arteriovenous malformations (cAVMs) are rare and challenging lesions with an aggressive natural history. The mechanisms whereby a patient can worsen clinically after a supratentorial AVM resection include an acute alteration in cerebral hemodynamics, which is a known cause of postoperative hyperemia, edema and/or hemorrhage. These phenomena has not been described for cAVMS. Moreover, the underlying pathophysiology of edema and hemorrhage after AVM resection still remains controversial. METHODS: We report a patient that presented an abrupt neurological deterioration after cAVM surgical resection. Emergent external ventricular drainage to treat incipient hydrocephalus only partially reverted the patient's deterioration. Consecutive post-surgery CT images revealed fourth ventricle compression secondary to cerebellar swelling that concurred with a new neurological deterioration. Densitometric analysis was performed in these CT images to reveal the nature of these changes as well as their evolution over time. RESULTS: Importantly, we demonstrated a dynamic increase in the cerebellum mean density at the interval of Hounsfield values which correspond to hyperemia values. These changes were dynamic, and when hyperemia resolved and cerebellar density returned to basal levels, the fourth ventricle re-expanded and the patient neurologically recovered. CONCLUSIONS: This study demonstrated the utility of quantitative CT image analysis in the context of hemodynamic alterations following cAVM resection. Densitometric CT analysis demonstrated that hyperemic changes, but not ischemic ones, were time-dependent and were responsible for swelling and hemorrhage that conditioned neurological status and patient's evolution.

Intracranial Pressure Monitoring in Patients With Severe Traumatic Brain Injury: Extension of the Recommendations and the Effect on Outcome by Propensity Score Matching.

BACKGROUND: Intracranial pressure (ICP) monitoring is recommended for patients with traumatic brain injury (TBI) with a Glasgow Coma Scale (GCS) <9 on admission and revealing space-occupying lesions or swelling on computed tomography. However, previous studies that have evaluated its effect on outcome have shown conflicting results. OBJECTIVE: To study the effect of ICP monitoring on outcome after adjustment of patient's characteristics imbalance and determine the potential benefit on patients with higher GCS that deteriorates early or in the absence of computed tomography results suggesting high ICP. METHODS: We searched for adult patients with TBI admitted between 1996 and 2020 with a GCS <9 on admission or deterioration from higher scores within 24 hours after TBI. Patients were divided into groups if they fulfilled strict (Brain Trauma Foundation guidelines) or extended criteria (patients who worsened after admission or without space-occupying lesions) for ICP monitoring. Propensity score analyses based on nearest neighbor matching was performed. RESULTS: After matching, we analyzed data from 454 patients and 184 patients who fulfilled strict criteria or extended criteria for ICP monitoring, respectively. A decreased on in-hospital mortality was detected in monitored patients following strict and extended criteria . Those patients with a higher baseline risk of poor outcome showed higher odds of favorable outcome if they were monitored. CONCLUSION: ICP monitoring in patients with severe TBI within 24 hours after injury following strict and extended criteria was associated with a decreased in-hospital mortality. The identification of patients with a higher risk of an unfavorable outcome might be useful to better select cases that would benefit more from ICP monitoring.

The influence of aneurysm morphology on the volume of hemorrhage after rupture.

OBJECTIVE: Factors determining the risk of rupture of intracranial aneurysms have been extensively studied; however, little attention is paid to variables influencing the volume of bleeding after rupture. In this study the authors aimed to evaluate the impact of aneurysm morphological variables on the amount of hemorrhage. METHODS: This was a retrospective cohort analysis of a prospectively collected data set of 116 patients presenting at a single center with subarachnoid hemorrhage due to aneurysmal rupture. A volumetric assessment of the total hemorrhage volume was performed from the initial noncontrast CT. Aneurysms were segmented and reproduced from the initial CT angiography study, and morphology indexes were calculated with a computer-assisted approach. Clinical and demographic characteristics of the patients were included in the study. Factors influencing the volume of hemorrhage were explored with univariate correlations, multiple linear regression analysis, and graphical probabilistic modeling. RESULTS: The univariate analysis demonstrated that several of the morphological variables but only the patient's age from the clinical-demographic variables correlated (p < 0.05) with the volume of bleeding. Nine morphological variables correlated positively (absolute height, perpendicular height, maximum width, sac surface area, sac volume, size ratio, bottleneck factor, neck-to-vessel ratio, and width-to-vessel ratio) and two correlated negatively (parent vessel average diameter and the aneurysm angle). After multivariate analysis, only the aneurysm size ratio (p < 0.001) and the patient's age (p = 0.023) remained statistically significant. The graphical probabilistic model confirmed the size ratio and the patient's age as the variables most related to the total hemorrhage volume. CONCLUSIONS: A greater aneurysm size ratio and an older patient age are likely to entail a greater volume of bleeding after subarachnoid hemorrhage.

A clinically compatible drug-screening platform based on organotypic cultures identifies vulnerabilities to prevent and treat brain metastasis.

We report a medium-throughput drug-screening platform (METPlatform) based on organotypic cultures that allows to evaluate inhibitors against metastases growing in situ. By applying this approach to the unmet clinical need of brain metastasis, we identified several vulnerabilities. Among them, a blood-brain barrier permeable HSP90 inhibitor showed high potency against mouse and human brain metastases at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis applied to metastases treated with the chaperone inhibitor uncovered a novel molecular program in brain metastasis, which includes biomarkers of poor prognosis and actionable mechanisms of resistance. Our work validates METPlatform as a potent resource for metastasis research integrating drug-screening and unbiased omic approaches that is compatible with human samples. Thus, this clinically relevant strategy is aimed to personalize the management of metastatic disease in the brain and elsewhere.

Stratification of radiosensitive brain metastases based on an actionable S100A9/RAGE resistance mechanism.

Whole-brain radiotherapy (WBRT) is the treatment backbone for many patients with brain metastasis; however, its efficacy in preventing disease progression and the associated toxicity have questioned the clinical impact of this approach and emphasized the need for alternative treatments. Given the limited therapeutic options available for these patients and the poor understanding of the molecular mechanisms underlying the resistance of metastatic lesions to WBRT, we sought to uncover actionable targets and biomarkers that could help to refine patient selection. Through an unbiased analysis of experimental in vivo models of brain metastasis resistant to WBRT, we identified activation of the S100A9-RAGE-NF-κB-JunB pathway in brain metastases as a potential mediator of resistance in this organ. Targeting this pathway genetically or pharmacologically was sufficient to revert the WBRT resistance and increase therapeutic benefits in vivo at lower doses of radiation. In patients with primary melanoma, lung or breast adenocarcinoma developing brain metastasis, endogenous S100A9 levels in brain lesions correlated with clinical response to WBRT and underscored the potential of S100A9 levels in the blood as a noninvasive biomarker. Collectively, we provide a molecular framework to personalize WBRT and improve its efficacy through combination with a radiosensitizer that balances therapeutic benefit and toxicity.

Patients awaiting surgery for neurosurgical diseases during the first wave of the COVID-19 pandemic in Spain: a multicentre cohort study.

OBJECTIVES: The large number of infected patients requiring mechanical ventilation has led to the postponement of scheduled neurosurgical procedures during the first wave of the COVID-19 pandemic. The aims of this study were to investigate the factors that influence the decision to postpone scheduled neurosurgical procedures and to evaluate the effect of the restriction in scheduled surgery adopted to deal with the first outbreak of the COVID-19 pandemic in Spain on the outcome of patients awaiting surgery. DESIGN: This was an observational retrospective study. SETTINGS: A tertiary-level multicentre study of neurosurgery activity between 1 March and 30 June 2020. PARTICIPANTS: A total of 680 patients awaiting any scheduled neurosurgical procedure were enrolled. 470 patients (69.1%) were awaiting surgery because of spine degenerative disease, 86 patients (12.6%) due to functional disorders, 58 patients (8.5%) due to brain or spine tumours, 25 patients (3.7%) due to cerebrospinal fluid (CSF) disorders and 17 patients (2.5%) due to cerebrovascular disease. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was mortality due to any reason and any deterioration of the specific neurosurgical condition. Second, we analysed the rate of confirmed SARS-CoV-2 infection. RESULTS: More than one-quarter of patients experienced clinical or radiological deterioration. The rate of worsening was higher among patients with functional (39.5%) or CSF disorders (40%). Two patients died (0.4%) during the waiting period, both because of a concurrent disease. We performed a multivariate logistic regression analysis to determine independent covariates associated with maintaining the surgical indication. We found that community SARS-CoV-2 incidence (OR=1.011, p<0.001), degenerative spine (OR=0.296, p=0.027) and expedited indications (OR=6.095, p<0.001) were independent factors for being operated on during the pandemic. CONCLUSIONS: Patients awaiting neurosurgery experienced significant collateral damage even when they were considered for scheduled procedures.

Accuracy of percutaneous pedicle screws for thoracic and lumbar spine fractures compared with open technique.

BACKGROUND: This study aimed to compare the accuracy of screw placement between open pedicle screw fixation and percutaneous pedicle screw fixation (MIS) for the treatment of thoracolumbar spine fractures (TSF). METHODS: forty-nine patients with acute TSF who were treated with transpedicular screw fixation from January 2013 to December 2016 were retrospectively reviewed. The patients were divided into Open and MIS groups. Laminectomy was performed in either group if needed. The accuracy of the screw placement, the evolution of the Cobb sagittal angle postoperatively and at 12-month follow-up and the neurological status were recorded. AO type of fracture and TLICS score were also recorded. RESULTS: Mean age was 42 years old. Mean TLICS score was 6.29 and 5.96 for open and MIS groups respectively. Twenty-five MIS and 24 open surgeries were performed, and 350 (175 in each group) screws were inserted (7.14 per patient). Twenty-four and 13 screws were considered "out" in the open and MIS groups respectively (Odds ratio 1.98. 0.97-4,03 P=0.056). The Cobb sagittal angle went from 13.3º to 4.5º and from 14.9º to 8.2º in the Open and MIS groups respectively (both P<0.0001). Loss of correction at 12-month follow-up was 3.2º and 4.2º for the open and MIS groups, respectively. No neurological worsening was observed. CONCLUSIONS: For the treatment of acute thoracolumbar fractures, the MIS technique seems to achieve similar results to the open technique in relation to neurological improvement and deformity correction, while placing the screws more accurately.

Hemodynamic alterations following a cerebellar arteriovenous malformation resection: Case report and densitometric quantitative analysis from CT imaging.

BACKGROUND: Cerebellar arteriovenous malformations (cAVMs) are rare and challenging lesions with an aggressive natural history. The mechanisms whereby a patient can worsen clinically after a supratentorial AVM resection include an acute alteration in cerebral hemodynamics, which is a known cause of postoperative hyperemia, edema and/or hemorrhage. These phenomena has not been described for cAVMS. Moreover, the underlying pathophysiology of edema and hemorrhage after AVM resection still remains controversial. METHODS: We report a patient that presented an abrupt neurological deterioration after cAVM surgical resection. Emergent external ventricular drainage to treat incipient hydrocephalus only partially reverted the patient's deterioration. Consecutive post-surgery CT images revealed fourth ventricle compression secondary to cerebellar swelling that concurred with a new neurological deterioration. Densitometric analysis was performed in these CT images to reveal the nature of these changes as well as their evolution over time. RESULTS: Importantly, we demonstrated a dynamic increase in the cerebellum mean density at the interval of Hounsfield values which correspond to hyperemia values. These changes were dynamic, and when hyperemia resolved and cerebellar density returned to basal levels, the fourth ventricle re-expanded and the patient neurologically recovered. CONCLUSIONS: This study demonstrated the utility of quantitative CT image analysis in the context of hemodynamic alterations following cAVM resection. Densitometric CT analysis demonstrated that hyperemic changes, but not ischemic ones, were time-dependent and were responsible for swelling and hemorrhage that conditioned neurological status and patient's evolution.