Publications by authors named "Nicollas Nunes Rabelo"

46 Publications

Letter: Neurosurgery and Manned Spaceflight.

Neurosurgery 2021 Apr 16. Epub 2021 Apr 16.

Family Medicine Department New York Medical College Valhalla, New York, USA.

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http://dx.doi.org/10.1093/neuros/nyab133DOI Listing
April 2021

Letter: Neurosurgery and Manned Spaceflight.

Neurosurgery 2021 Apr 16. Epub 2021 Apr 16.

Family Medicine Department New York Medical College Valhalla, New York, USA.

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http://dx.doi.org/10.1093/neuros/nyab133DOI Listing
April 2021

Case Report: Untreatable Headache in a Child With Ventriculoperitoneal Shunt Managed by Use of New Non-invasive Intracranial Pressure Waveform.

Front Neurosci 2021 10;15:601945. Epub 2021 Feb 10.

Brain4care, São Paulo, Brazil.

brain4care, a new Food and Drug Administration (FDA)-cleared non-invasive sensor that monitors intracranial pressure waveforms, was used in a 13-year-old girl who presented with untreatable headaches. The patient had a history of craniopharyngioma resection and a ventriculoperitoneal shunt placement 7 years prior to the use of the device. Secondary obstructive hydrocephalus was also a present factor in the case. The hypothesis was that due to the hydrocephalus, the child presented chronic headaches and needed constant readjustment into the ventriculoperitoneal shunt to regulate the cerebrospinal fluid inside her ventricles in order to control the patient's intracranial pressure (ICP). The device was chosen considering the risks to submit a patient into the regular invasive method to measure ICP. It was identified that the device could also indicate altered intracranial compliance due to the ratio between the P1 and P2 amplitudes (P2/P1 ratio > 1).
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http://dx.doi.org/10.3389/fnins.2021.601945DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7928322PMC
February 2021

Cortical spreading depolarization and ketamine: a short systematic review.

Neurophysiol Clin 2021 Mar 18;51(2):145-151. Epub 2021 Feb 18.

Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil. Electronic address:

Introduction: Cortical spreading depolarization (SD) describes pathological waves characterized by an almost complete sustained depolarization of neurons and astrocytes that spreads throughout the cortex. In this study, we carried out a qualitative review of all available evidence, clinical and preclinical, on the use of ketamine in SD.

Methods: We performed a systematic review of Medline, with no restrictions regarding publishing date or language, in search of articles reporting the use of ketamine in SD. The search string was composed of "ketamine," "spreading," "depolarization," and "depression" in both (AND) and (OR) combinations.

Results: Twenty studies were included in the final synthesis. Many studies showed that ketamine effectively blocks SD in rats, swine, and humans. The first prospective randomized trial was published in 2018. Ten patients with severe traumatic brain injury or subarachnoid hemorrhage were enrolled, and ketamine showed a significant, dose-dependent effect on the reduction of SD.

Conclusion: The available evidence from preclinical studies is helping to translate the role of ketamine in blocking spreading depolarizations to clinical practice, in the settings of migraine with aura, traumatic brain injury, subarachnoid hemorrhage, and hemorrhagic and ischemic stroke. More randomized controlled trials are needed to determine whether interrupting the ketamine-blockable SDs effectively leads to an improvement in outcome and to assess the real occurrence of adverse effects.
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http://dx.doi.org/10.1016/j.neucli.2021.01.004DOI Listing
March 2021

Management of Giant Thrombosed MCA Aneurysm: Double STA-MCA Revascularization.

World Neurosurg 2021 Feb 4;149. Epub 2021 Feb 4.

Department of Neurosurgery, Hospital Força Aérea do Galeão, Rio de Janeiro, Brazil. Electronic address:

Giant middle cerebral artery (MCA) aneurysms are rare complex cerebrovascular lesions to treat. The management of those aneurysms may be very challenging, despite the introduction of refined microsurgical techniques and the rapid progress in endovascular methods, which often require bypass surgery as part of the strategy. This approach is particularly relevant to giant, dolichoectatic, and thrombotic aneurysms. This video shows the surgical strategy and stepwise depiction of the surgical treatment of a complex giant thrombosed aneurysm using a double-barrel superficial temporal artery (STA) to MCA bypass (Video 1). Informed written consent was obtained from the patient and his family. The patient was a 50-year-old man, previously healthy, who presented with headache, memory difficulty, and left-sided involuntary movements for 2 months. Computed tomography scan showed a giant round calcified and heterogeneous lesion compatible with a thrombosed MCA aneurysm. Brain magnetic resonance imaging showed the same lesion with a flow void signal inside in a serpentine fashion and a complete hemosiderin halo. Conventional angiography showed the false lumen and the filling of the distal MCA branches with a certain degree of arterial delay. The lesion was located between M1 and M3 segments of MCA. Extracranial-intracranial STA-MCA bypass was performed. Then we opened the aneurysm sac for decompression and observed the lenticulostriate artery branches arising away from the aneurysm sac. The complete clipping and patency of the anastomosis was validated during surgery by indocyanine green angiography. Postoperative cerebral computed tomography angiography revealed good patency from the STA to the MCA. The patient was neurologically intact without complains.
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http://dx.doi.org/10.1016/j.wneu.2021.01.125DOI Listing
February 2021

Hippocampal vascularization: Proposal for a new classification.

Surg Neurol Int 2020 6;11:378. Epub 2020 Nov 6.

Department of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo, Brazil.

Background: Anatomy of the hippocampal arterial supply is key to successful surgeries in this area. The goal of the current study is to present the results we obtained from our microsurgical dissections of the temporal lobe and to propose a new classification for the hippocampal arteries (HAs).

Methods: Fifty-six brain hemispheres were analyzed. All dissections in this study were made using 3-40× at the surgical microscope.

Results: The hippocampal arterial vasculature can be divided into six groups, according to their frequencies: Group A: mixed arterial vasculature originating from the anterior choroidal artery anterior choroidal artery, posterior cerebral artery (PCA), anterior infratemporal artery (AIA), and splenic artery (SA). Group B: Main origin at the temporal branches - main inferotemporal trunk, middle inferotemporal artery, posterior inferotemporal artery, AIA, or main branch of PCA. Group C: AIA as the main branch of the hippocampus. Group D: HAs originating from the main branch of PCA. Group E: A single hippocampal artery with the origin at the main branch of PCA. This single artery covered all of the structure and is named Ushimura's artery. Group F: The hippocampal vessels arose exclusively from the parieto-occipital artery, calcarine artery (CA), and the SA.

Conclusion: This study proposes a new classification for the hippocampal vascularization, according to the origin of HAs. One of the groups has not yet been described in the literature - in which the HAs arise from the parieto-occipital artery, SA, and CA.
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http://dx.doi.org/10.25259/SNI_708_2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771501PMC
November 2020

C-Reactive Protein Levels Are Higher in Patients With Fusiform Intracranial Aneurysms: A Case-Control Study.

World Neurosurg 2021 Feb 3;146:e896-e901. Epub 2020 Dec 3.

Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. Electronic address:

Background: Comprehending the risk factors that contribute to the formation of fusiform aneurysms (FAs) might provide some insight into treatment and prevention strategies. This case-control study aimed to compare the levels of serum C-reactive protein (CRP), as a biomarker, between patients with fusiform and saccular intracranial aneurysms.

Methods: We retrospectively analyzed medical records from 2010 to 2019. Thirty-five patients were identified as having FAs: 13 (37.1%) were ruptured, and 22 were unruptured. An age-matched sample of 70 controls (2:1) with saccular aneurysms was obtained from the same records: 36 (51.4%) ruptured and 34 unruptured.

Results: Patients with FAs had median CRP values of 0.61 mg/dL (IQR: 1.5), compared with 0.29 mg/dL (IQR: 0.42) in controls (P < 0.01). Within both the ruptured and the unruptured group, median CRP was higher in patients with FAs compared with controls (P < 0.01). Diabetes, smoking status, hypertension, and sex did not significantly influence CRP levels. Age-adjusted analyses showed that fusiform morphology was independently associated with higher CRP levels for unruptured aneurysms (OR 1.2, 95% CI 1.05-1.43), but not for ruptured aneurysms (OR 1.02, 95%CI 0.99-1.05).

Conclusions: CRP was higher in patients with FAs than controls, and it constituted an independent predictor of fusiform morphology for patients with unruptured aneurysms. Inflammation might be an especially important factor in FA formation and growth, and further studies could use this finding to design new treatment strategies.
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http://dx.doi.org/10.1016/j.wneu.2020.11.042DOI Listing
February 2021

Comparison of surgical and endovascular treatments for fusiform intracranial aneurysms: systematic review and individual patient data meta-analysis.

Neurosurg Rev 2020 Nov 17. Epub 2020 Nov 17.

Department of Neurology, Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.

Fusiform intracranial aneurysms (FIA) are associated with significant morbidity and mortality. We carried out a systematic review and meta-analysis of individual participant data with propensity score adjustment to compare the functional and angiographic outcomes between surgical and endovascular approaches to FIA. We conducted a systematic review for articles on the treatment of FIA with individual patient-level detailing. Data from patients treated for FIA in our institution from 2010 to 2018 were also collected. The primary studied outcome was morbidity, and secondary outcomes were angiographic results and retreatment. Propensity score-adjusted mixed-effects logistic regression models evaluated treatment options, stratified by anatomical location. Compiling original and published data, there were 312 cases, of which 79 (25.3%) had open surgery, and 233 (74.5%) were treated with endovascular procedures. There were no differences between treatment groups, for neither cavernous ICA (OR 1.04, 95% CI 0.05-23.6) nor supraclinoid aneurysms (OR 7.82, 95% CI 0.65-94.4). Both size (OR 1.11, 95% CI 1.03-1.19) and initial mRS (OR 2.0, 95% CI 1.2-3.3) were risk factors for morbidity, independent of location. Neither age nor rupture status influenced the odds of posterior morbidity. Unfavorable angiographic outcomes were more common in the endovascular group for supraclinoid and vertebrobasilar aneurysms (χ, P < 0.01). There were no differences between morbidity of surgical and endovascular treatments for FIA, regardless of aneurysm location. Size and initial mRS were correlated with functional outcomes, whereas age and rupture status were not. Microsurgery seems to yield better long-term angiographic results compared to endovascular procedures.
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http://dx.doi.org/10.1007/s10143-020-01440-xDOI Listing
November 2020

Cavernous carotid aneurysms do not influence the occurrence of upstream ipsilateral aneurysm.

Br J Neurosurg 2020 Nov 10:1-3. Epub 2020 Nov 10.

Division of Neurological Surgery, Hospital das Clinicas, University of São Paulo Medical School, Sao Paulo, Brazil.

Objective: Cavernous carotid aneurysms (CCA) comprehend around 5% of all intracranial aneurysms. The main risk factors for an intracranial aneurysm seem not to influence the incidence of CCAs. The aim of this study was to investigate the association of CCAs and the presence of upstream aneurysms.

Methods: 1403 patients, admitted in Hospital das Clinicas de São Paulo, Brazil, from September 2009 to August 2018, enrolled this study. Diagnosis was performed with Digital Subtraction Angiography (DSA). Upstream aneurysm was defined as an intracranial aneurysm on anterior cerebral circulation, ipsilateral to the CCA (if present) or crossing the midline (e.g. anterior communicating artery).

Results: 177 individuals were diagnosed with CCA (12.6% of the population), totalizing 225 aneurysms (10% of the total number of aneurysms, 2253). No association was found between CCA and UA ( .090, OR: 1.323, 95% CI: 0.957-1.828). Studying only patients with CCA, multivariable analysis showed smoking as the only factor associated with UA ( .010, OR: 0.436, 95% CI: 0.232-0.821).

Conclusions: Cavernous carotid aneurysms were present in 12% of our population, mostly in female. They seem to be independent of the modifiable risk factors already associated with intracranial aneurysms. A higher frequency of mirror aneurysms was seen in this location. CCA did not influence the presence of ipsilateral and anterior circulation aneurysms.
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http://dx.doi.org/10.1080/02688697.2020.1820950DOI Listing
November 2020

Multiple and mirror intracranial aneurysms: study of prevalence and associated risk factors.

Br J Neurosurg 2020 Nov 9:1-5. Epub 2020 Nov 9.

Division of Neurological Surgery, Hospital das Clinicas, University of São Paulo Medical School, Sao Paulo, Brazil.

Objective: Multiple intracranial aneurysms (MIA) account for 30% of all intracranial aneurysms, while mirror aneurysms, a subgroup of MIA, are present in 5% of all patients with cerebral aneurysms. We investigated the risk factors associated with the presence of multiple and mirror intracranial aneurysms.

Methods: 1404 patients, 314 males (22.4%) and 1090 female (77.6%) were enrolled for this study. Diagnosis was performed with a digital subtraction angiography (DSA). Multiplicity was defined as the presence of two or more aneurysms and mirror aneurysms as one pair of aneurysms involving bilateral corresponding arteries. Patients were followed-up from September 2009 till August 2018. Individuals' characteristics such as sex, age, smoking, hypertension and use of contraceptives were evaluated.

Results: Five hundred and twelve patients (36.4%) were diagnosed with MIA, approximately 4%/year. We observed 203 pairs of mirror aneurysms, accounting for 406 aneurysms (13% of the population). There was an increased frequency of females with multiple () and mirror aneurysms (636). Smoking was associated with multiplicity (), as well as advanced age (), but there was no significant relation with presence of mirror aneurysms. We observed higher frequency of baby aneurysms (<3mm) in the group of patients with MIA, while giant aneurysms (>25 mm) were most found in patients with only one aneurysm (). No differences between patients who used contraceptives against patients who did not use were found ().

Conclusions: Gender and smoking, known risk factors to the development of a single intracranial aneurysm, are proportionally increased in patients with MIA. Hypertension and oral contraceptives were not associated with multiplicity.
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http://dx.doi.org/10.1080/02688697.2020.1817849DOI Listing
November 2020

Relationship of superior sagittal sinus with sagittal midline: A surgical application.

Surg Neurol Int 2020 25;11:309. Epub 2020 Sep 25.

Department of Neurosurgery, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

Background: Interhemispheric approach is widely used to surgical management of midline tumors and vascular lesion in and around the third ventricle. Complete exposure of the superior sagittal sinus to obtain adequate working space of midline lesion is difficult, because of the risk to inadvertent injury to the sinus and bridging veins, which may cause several neurological deficits. Understanding the SSS neuroanatomy and its relationships with external surgical landmarks avoid such complications. The objective of this study is to accurately describe the position of SSS and its displacement in relation with sagittal midline by magnetic resonance imaging.

Methods: A retrospective cross-sectional, observational study was performed. Magnetic resonance image of 76 adult patients with no pathological imaging was analyzed. The position of the halfway between nasion and bregma, bregma, halfway between bregma and lambda, and lambda was performed. The width and the displacement of the superior sagittal sinus accordingly to the sagittal midline were assessed in those landmarks.

Results: The mean width of superior sagittal sinus at halfway between nasion and bregma, bregma, halfway between bregma and lambda, and lambda was 5.62 ± 2.5, 6.5 ± 2.8, 7.4 ± 3.2, and 8.5 ± 2.1 mm, respectively, without gender discrepancy. The mean displacement according to the midline at those landmarks showed a statistically significant difference to the right side among sexes.

Conclusion: In this study, we demonstrate that sagittal midline may approximate external location of the superior sagittal sinus. Our data showed that in the majority of the cases, the superior sagittal sinus is displaced to the right side of sagittal midline as far as 16.3 mm. The data we obtained provide useful information that suggest that neurosurgeons should use safety margin to perform burr holes and drillings at the sagittal midline.
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http://dx.doi.org/10.25259/SNI_509_2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568091PMC
September 2020

Biomarkers for traumatic brain injury: a short review.

Neurosurg Rev 2020 Oct 19. Epub 2020 Oct 19.

Division of Neurosurgery, University of São Paulo, São Paulo, Brazil.

Cellular response to TBI is a mixture of excitotoxicity, neuroinflammation, and cell death. Biomarkers that can track these lesions and inflammatory processes are being explored for their potential to provide objective measures in the evaluation of TBI, from prehospital care to rehabilitation. By understanding the pathways involved, we could be able to improve diagnostic accuracy, guide management, and prevent long-term disability. We listed some of the recent advances in this translational, intriguing, fast-growing field. Although the knowledge gaps are still significant, some markers are showing promising results and could be helping patients in the near future.
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http://dx.doi.org/10.1007/s10143-020-01421-0DOI Listing
October 2020

Options to manage postcraniotomy acute pain in neurosurgery: no protocol available.

Br J Neurosurg 2021 Feb 23;35(1):84-91. Epub 2020 Sep 23.

Department of Neurosurgery, UniAtenas Center University, Paracatu, MG, Brazil.

The physical processes of incision, traction and hemostasis used for craniotomy, stimulate nerve fibers and specific nociceptors, resulting in postoperative pain. During the first 24 h after craniotomy, 87% of patients have postoperatory pain. The rate of suffering pain after craniotomy falls 3% for every year of life. The objective of this study is to review the available therapeutic options to help physicians treating this pain, and discuss pain mechanisms, pathophysiology, plasticity, risk factors and psychological factors. This is a narrative review of the literature from 1970 to June 2019. Data were collected by doing a search in PubMed, EMBASE, Cochrane Reviews and a manual search of all relevant literature references. The literature includes some drugs treatment: Opioids, codeine, morphine, and tramadol, anti-inflammatory non-steroids such as cyclooxygenase-2 inhibitors, gabapentin. It discusses: side effects, pharmacodynamics and indications of each drug, anatomy and Inervation of Skull and its Linigs, pathogenesis of pain Post-craniotomy, scalp nerve block, surgical nerve injury, neuronal plasticity, surgical factors and chronic post-surgical pain.
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http://dx.doi.org/10.1080/02688697.2020.1817852DOI Listing
February 2021

Giant cavernous haemangioma in cavernous sinus.

Br J Neurosurg 2020 Sep 22:1-2. Epub 2020 Sep 22.

Pathology Department, Santa Casa of Passos, Passos, Brazil.

The aim of this article is show the neuroimaging, the pathological analysis and makes a brief review regarding to a giant cavernous haemangioma located in cavernous sinus in a 72 years old patient. A brief review was made in the literature searching for the key words "hemangioma" and "cavernous sinus" in the databases PubMed and Scielo for the last ten years. The images addressed were obtained by magnetic resonance imaging (MRI) in FLAIR, T1 and T1-weighted contrast-enhanced. The intracranial cavernous haemangiomas are rare conditions that comprise from 0,1 to 4% of intracranial vascular malformations. Diagnosis is made by MRI, when available SPECT (99mTc) is used to confirm and the treatment is done surgically with complement of radiotherapy and radiosurgery. The reported neuroimaging and pathological analysis show a giant cavernous hemangioma in cavernous sinus, a benign neoplasm involving the left internal carotid artery and maintaining contact with the contralateral internal carotid artery formed by abundant vascular structures, but without the presence of a muscular tunic.
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http://dx.doi.org/10.1080/02688697.2020.1821868DOI Listing
September 2020

Microsurgical anatomy of language.

Clin Anat 2021 Jan 23;34(1):154-168. Epub 2020 Sep 23.

Division of Neurosurgery, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.

The localizationist model, which focused on classical cortical areas such as Broca's and Wernicke's, can no longer explain how language processing works. Over recent years, several studies have revealed new language-related cortical and subcortical areas, resulting in a transition from localizationist concepts to a hodotopical model. These studies have described language processing as an extensive and complex network of multiple interconnected cortical areas and subcortical pathways, differing from the classical circuit described by the localizationist perspective. The hodotopical model was made possible by a paradigm shift in the treatment of cerebral tumors, especially low-grade gliomas: total or subtotal tumor resections with cortical and subcortical mapping on awake patients have become the gold standard treatment for lesions located in the dominant hemisphere. In this article, we review current understating of the microsurgical anatomy of language.
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http://dx.doi.org/10.1002/ca.23681DOI Listing
January 2021

Association between intracranial aneurysm and meningiomas: An integrative survival Analysis with identification of prognostic factors.

Clin Neurol Neurosurg 2020 Nov 8;198:106128. Epub 2020 Aug 8.

Department of Neurosurgery, Clinical Hospital, São Paulo University, USP, São Paulo, Brazil. Electronic address:

Objective: To analyze prognostic factors in clinical association between intracranial aneurysm (IA) and meningioma. Prognostic factors on overall survival (OS) were evaluated.

Methods: We selected articles, published from January 1944 to December 2018 on the Medical databases (Web of Sciences, Medline and EMBASE) and included case series and reports. Clinical information was obtained and variables associated with the primary outcome of 27-mo survival were identified through Cox regression models.

Results: The study evaluated 77 patients. Female represented 76.6 % (n = 59), a ratio of 3.27 female: 1 male. The age range was 7-84 years old, with an average of 54.74 (SD: 14.30). Age and sex were not significant statistically different between the two groups for overall survival (OS) (log-rank P = 0.806), (log-rank P = 0.983) respectively. 77.9 % (n = 60) were ipsilateral, the same side was 4 times more common in univariate analysis (P = 0.052; 95 % CI, 0.924-17.319). Most aneurysms were detected in the internal carotid artery, 29.87 %. In Clinical data, 62.33 % (n = 48) had exclusive tumor symptoms, while 25.97 % (n = 20) presented exclusively subarachnoid hemorrhage (SAH). In multivariate analysis, although there is an independent protective factor for those who did not have SAH (HR; 0.099; CI; 0.010-0.986; P = 0.049) and the treatment is an independent predictor for OS (HR, 42.096; CI, 4.270-415.056; P = 0.01).

Conclusion: This is the first study to approach this association. This is not just an occasional finding, but it seems to have a shared pathophysiology. Unruptured aneurysms and treatment modality were protective independent factors for OS. Prospective studies are warranted to provide definitive answers.
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http://dx.doi.org/10.1016/j.clineuro.2020.106128DOI Listing
November 2020

In Reply to the Letter to the Editor Regarding "Development and Evaluation of a Pediatric Mixed Reality Model for Neuroendoscopic Surgical Training".

World Neurosurg 2020 08;140:446-447

Pediatric Neurosurgery-Center/CENEPE, São Paulo, Brazil; Fetal and Perinatal Medicine Group-Samaritano Hospital, São Paulo, Brazil.

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http://dx.doi.org/10.1016/j.wneu.2020.06.116DOI Listing
August 2020

A hybrid simulation model for pre-operative planning of transsphenoidal encephalocele.

Neurosurg Rev 2020 Aug 8. Epub 2020 Aug 8.

University of São Paulo (USP), São Paulo, Brazil.

Congenital transsphenoidal encephalocele (CTE) surgical correction is a challenging procedure. Although rare, this anomaly, characterized with neural herniation elements, including the pituitary gland or optic pathway through the sphenoid bone with anatomical alteration, can be presented in many different ways and should be individually analyzed. Significant advances in medical technology and the 3D models may simulate the complex anatomical relations of the human body. Nowadays, medical education relies on the availability of standardized materials that can reliably emulate human anatomy. Therefore, realistic anatomical models have become an alternative for cadavers or animal specimens. In this technical note, the authors present a new technique to create personalized models that combine 3D printing, molding, and casting to create an anatomically and tactilely realistic model based on magnetic resonance and computerized tomography images. Produced from different silicon types, the model recreated the anatomic alterations precisely, allowing a multidisciplinary team to determine the adequate surgical approach for this patient. We describe a case of congenital transsphenoidal encephalocele of a 3-year-old boy, whose surgical correction was planned using a hybrid model. The technical description of the model is given in detail. This new hybrid model allowed a detailed discussion of the surgical approach aspects by having tissues of different consistencies and resistances and a very high prediction rate. This approach may allow a reduction in surgery time and possible complications after operative procedures.
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http://dx.doi.org/10.1007/s10143-020-01361-9DOI Listing
August 2020

Letter to the Editor. The minipterional craniotomy: beyond the keyhole concept.

J Neurosurg 2020 Jul 24:1-2. Epub 2020 Jul 24.

1Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Brazil; and.

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http://dx.doi.org/10.3171/2020.4.JNS201241DOI Listing
July 2020

Tranexamic acid in Neurosurgery: a controversy indication-review.

Neurosurg Rev 2020 Jun 17. Epub 2020 Jun 17.

Department of Neurosurgery, University Center UNiAtenas, Paracatu, Minas Gerais, Brazil.

Tranexamic acid (TXA) is one of the measures indicated to reduce bleeding and the need for volume replacement. However, data on risks and benefits are controversial. This study analyzes the effectivity and risks of using tranexamic acid in neurosurgery. We selected articles, published from 1976 to 2019, on the PubMed, EMBASE, Science Direct, and The Cochrane Database using the descriptors: "tranexamic acid," "neurosurgery," "traumatic brain injury," "subdural hemorrhage," "brain aneurysm," and "subarachnoid hemorrhage." TXA can reduce blood loss and the need for blood transfusion in trauma and spinal surgery. Despite the benefits of TXA, moderate-to-high doses are potentially associated with neurological complications (seizures, transient ischemic attack, delirium) in adults and children. In a ruptured intracranial aneurysm, the use of TXA can considerably reduce the risk of rebleeding, but there is weak evidence regarding its influence on mortality reduction. The TXA use in brain surgery does not present benefit. However, this conclusion is limited because there are few studies. TXA in neurosurgeries is a promising method for the maintenance of hemostasis in affected patients, mainly in traumatic brain injury and spinal surgery; nevertheless, there is lack of evidence in brain and vascular surgeries. Many questions remain unanswered, such as how to determine the dosage that triggers the onset of associated complications, or how to adjust the dose for chronic kidney disease patients.
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http://dx.doi.org/10.1007/s10143-020-01324-0DOI Listing
June 2020

Extradural minipterional approach: Evolving indications of the minipterional craniotomy.

Surg Neurol Int 2020 16;11:109. Epub 2020 May 16.

Department of Neurosurgery, Hospital das Clinicas da Faculdade de Medicina, University of Sao Paulo, Brazil.

Background: In this paper, we report a clinical series of skull base lesions operated on trough the MiniPT, extending its application to skull base lesions, either using the classical minipterional or a variant, we call extradural minipterional approach (MiniPTEx).

Methods: We describe our surgical technique of operating on complex skull base lesions using a minipterional extradural approach. Anterior clinoidectomy, middle fossa peeling, transcavernous, and Kawase approaches were performed as needed. In total, we carried out 24 surgeries: three skull base tumors, 1 Moyamoya case, and 20 giant/complex intracranial aneurysms. All the patients present good neurological result (mRs < 3). Only two patients had paralysis of any cranial nerve and only one patient had a mild hemiparesis.

Results: This surgery series there are 24 cases, 10 patients were treated with exclusive MiniPT. MiniPT extradural approach was made in 14 patients. Twelve were treated using pure MiniPTEx approach, 1 patient using transcavernous approach, and in 1 patient, the anterior clinoid was resected with the combination of a MiniPT, a medium fossa peeling, and the Kawase anterior petrosectomy for skull base surgery.

Conclusion: We further advance the indications of the MiniPT by extending it to operate on the cranial base tumors or complex vascular lesions without additional morbidity. MiniPT approach may be safely associated with skull base techniques, including anterior and posterior clinoidectomies, peeling of the middle fossa, transcavernous approach, and anterior petrosectomy. The versatility of the MiniPT craniotomy and the feasibility of performing skull base surgery through the MiniPT technique have been demonstrated in this paper.
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http://dx.doi.org/10.25259/SNI_169_2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265366PMC
May 2020

Long term phonatory function following acoustic neuroma surgery: a cohort study.

Acta Otolaryngol 2020 Aug 29;140(8):646-650. Epub 2020 Apr 29.

Department of Neurosurgery, Universidade de Sao Paulo, São Paulo, Brazil.

Acoustic neuroma (AN) is a well-recognized cause of neurological morbidity, peripheral facial paralysis being one of the most prevalent. Phonatory dysfunction in the late post-operative term has not been properly addressed so far. The objective of this study is to describe the outcomes of phonatory function on the long-term follow-up of AN surgery and identify its prognostic factors. This cohort study included patients submitted to AN surgery from 1999 to 2014, with a mean follow up of 6.4 ± 4.5 years. To evaluate the phonatory function, we performed a combination of noninvasive acoustic and aerodynamic measurements including vocal intensity and stability, maximum declination rate of the glottal airflow (MDR) and transglottal pressure scale (TP). 101 patients were studied. 25 (24.7%) presented a deficit in phonatory function. Women comprised 56% and the mean age was 42.4 ± 13.8 years (range19-80). 100% presented reduced expiratory airflow capacity with excessive manifestation of the laryngeal musculature (TP > 1,23s ;MDR/z/
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http://dx.doi.org/10.1080/00016489.2020.1755054DOI Listing
August 2020

Development and Evaluation of Pediatric Mixed-Reality Model for Neuroendoscopic Surgical Training.

World Neurosurg 2020 07 6;139:e189-e202. Epub 2020 Apr 6.

Pediatric Neurosurgery, Center/CENEPE-Beneficência Portuguesa Hospital, São Paulo, Brazil; Fetal and Perinatal Medicine Group, Samaritano Hospital, São Paulo, Brazil.

Objective: Neurosurgical training requires several years of supervised procedures and represents a long and challenging process. The development of surgical simulation platforms is essential to reducing the risk of potentially intraoperative severe errors arising from inexperience. To present and perform a phase I validation process of a mixed reality simulation (realistic and virtual simulators combined) for neuroendoscopic surgical training.

Methods: Tridimensional videos were developed by the 3DS Max program. Physical simulators were made with a synthetic thermoretractile and thermosensible rubber, which, when combined with different polymers, produces >30 different textures that simulate consistencies and mechanical resistance of human tissues. Questionnaires regarding the role of virtual and realistic simulators were applied to experienced neurosurgeons to assess the applicability of the mixed-reality simulation for neuroendoscopic surgical training.

Results: The model was considered as a potential tool for training new residents in neuroendoscopic surgery. It was also adequate for practical application with inexperienced surgeons. According to the overall score, 83% of the surgeons believed that the realistic physical simulator presents distortions when compared with the real anatomic structure, afterwards the model improved 66% tridimensional reconstruction and 66% reported that the virtual simulator allowed a multiangular perspective ability.

Conclusions: This model provides a highly effective way of working with 3-dimensional data and significantly enhances the learning of surgical anatomy and operative strategies. The combination of virtual and realistic tools may safely improve and abbreviate the surgical learning curve.
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http://dx.doi.org/10.1016/j.wneu.2020.03.170DOI Listing
July 2020

Anterior communicating artery duplication associated with a triplication of anterior cerebral artery - A rare anatomical variation.

Surg Neurol Int 2020 6;11:36. Epub 2020 Mar 6.

Department of Neurosurgery, University of Sao Paulo, São Paulo.

Background: The anterior communicating artery complex may presente several anatomical variations, and many abnormalities have been reported in radiologiacal and cadaveric studies.

Case Description: The authors present a case of a 44-year-old Caucasian female, with a prior history of smoking and arterial systemic hypertension, admitted in the emergency department complaining of a sudden headache, nausea, and vomiting followed by tonic-clonic seizures. Computerized tomography (CT) and angiography (angio- CT) were carried out and showed Fisher Grade IV subarachnoid hemorrhage. Angio-CT revealed an anterior communicating artery (AComA) aneurysm. Minimally invasive craniotomy and microsurgical clipping were performed uneventfully. An unusual anatomical variation of the AComA complex characterized by duplication of the AComA associated with a triplication of anterior cerebral artery (ACA) was observed. The patient was discharged with no neurological deficits.

Concluision: This unique anatomical variation of the AComA-ACA complex constitute risck factors for development and rupture of aneurysms.
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http://dx.doi.org/10.25259/SNI_515_2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7110404PMC
March 2020

Augmented reality and physical hybrid model simulation for preoperative planning of metopic craniosynostosis surgery.

Neurosurg Focus 2020 03;48(3):E19

3University of São Paulo, USP; and.

Objective: The main objective of neurosurgery is to establish safe and reliable surgical techniques. Medical technology has advanced during the 21st century, enabling the development of increasingly sophisticated tools for preoperative study that can be used by surgeons before performing surgery on an actual patient. Laser-printed models are a robust tool for improving surgical performance, planning an operative approach, and developing the skills and strategy to deal with uncommon and high-risk intraoperative difficulties. Practice with these models enhances the surgeon's understanding of 3D anatomy but has some limitations with regard to tactile perception. In this study, the authors aimed to develop a preoperative planning method that combines a hybrid model with augmented reality (AR) to enhance preparation for and planning of a specific surgical procedure, correction of metopic craniosynostosis, also known as trigonocephaly.

Methods: With the use of imaging data of an actual case patient who underwent surgical correction of metopic craniosynostosis, a physical hybrid model (for hands-on applications) and an AR app for a mobile device were created. The hybrid customized model was developed by using analysis of diagnostic CT imaging of a case patient with metopic craniosynostosis. Created from many different types of silicone, the physical model simulates anatomical conditions, allowing a multidisciplinary team to deal with different situations and to precisely determine the appropriate surgical approach. A real-time AR interface with the physical model was developed by using an AR app that enhances the anatomic aspects of the patient's skull. This method was used by 38 experienced surgeons (craniofacial plastic surgeons and neurosurgeons), who then responded to a questionnaire that evaluated the realism and utility of the hybrid AR simulation used in this method as a beneficial educational tool for teaching and preoperative planning in performing surgical metopic craniosynostosis correction.

Results: The authors developed a practice model for planning the surgical cranial remodeling used in the correction of metopic craniosynostosis. In the hybrid AR model, all aspects of the surgical procedure previously performed on the case patient were simulated: subcutaneous and subperiosteal dissection, skin incision, and skull remodeling with absorbable miniplates. The pre- and postoperative procedures were also carried out, which emphasizes the role of the AR app in the hybrid model. On the basis of the questionnaire, the hybrid AR tool was approved by the senior surgery team and considered adequate for educational purposes. Statistical analysis of the questionnaire responses also highlighted the potential for the use of the hybrid model in future applications.

Conclusions: This new preoperative platform that combines physical and virtual models may represent an important method to improve multidisciplinary discussion in addition to being a powerful teaching tool. The hybrid model associated with the AR app provided an effective training environment, and it enhanced the teaching of surgical anatomy and operative strategies in a challenging neurosurgical procedure.
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http://dx.doi.org/10.3171/2019.12.FOCUS19854DOI Listing
March 2020

The Craniosynostosis Puzzle: New Simulation Model for Neurosurgical Training.

World Neurosurg 2020 06 25;138:e299-e304. Epub 2020 Feb 25.

Neurosurgery Department, São Paulo University, USP, São Paulo, Brazil. Electronic address:

Background: Neurosurgical training usually requires long hours for hands-on procedures, making it difficult for inexperienced surgeons to quickly learn in an error-proof environment. The objective of this study was to propose a puzzle-like new model for neurosurgical education that simulates craniosynostosis correction (scaphocephaly type) using Renier's H technique. A model of a 3-dimensional (3D) anatomic simulator for craniosynostosis training is presented and evaluated.

Methods: The cranial model was created using 1-mm computed tomography scan images from patients with scaphocephaly in the Digital Imaging and Communications in Medicine format. This information was processed using an algorithm to generate a 3D biomodel in resin. The puzzle model and its variable training models were assessed qualitatively by a team of expert neurosurgeons. Next, the model was applied in trainees and was evaluated using specific questionnaires.

Results: Experts and trainees evaluated the model. The mean number of attempts without errors was 2.3 ± 0.675, for 1 error was 2.2 ± 0.918, and for 2 errors was 1.3 ± 0.707. The mean score of the simulator was 9.2 ± 0.421. Twelve residents (second evaluation) answered the questionnaire with a positive assessment of diagnosis capabilities, appropriateness of the model, time commitment, adequate environment, reliable 3D reconstruction, and teaching method. Three participants had used a 3D simulator previously, and the simulator was evaluated obtaining a 9.9 final average (range, 0-10).

Conclusions: The puzzle may be a complementary tool for surgical training. It allows several degrees of immersion and realism, offering symbolic, geometric, and dynamic information with 3D visualization. It provides additional data to support the practice of complex surgical procedures without exposing real patients to undue risk.
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http://dx.doi.org/10.1016/j.wneu.2020.02.098DOI Listing
June 2020

Vestibular schwannoma: predictive factors of long-term postoperative neurological outcome.

Acta Otolaryngol 2020 Mar 12;140(3):242-245. Epub 2020 Feb 12.

Neurosurgery Department, University of São Paulo, São Paulo, Brazil.

Vestibular schwannoma (VS) is a slow-growing, benign tumor that is usually diagnosed when symptoms develop. Surgical management aims to reduce long-term sequelae (LTS) associated with late diagnosis. Identify predictive factors of LTS after VS surgery and clinical outcome measured by modified Rankin scale (mRS). This cohort study included patients submitted to VS surgery from 1999 to 2014, with a mean follow-up of 6.4 ± 4.5 years. Disability was assessed across the mRS the primary outcome was defined by scores 3 to 6, which implied poor outcome in neurological recovery. Predictive factors were identified through multivariate logistic regression. A total of 101 patients were included in this study. Fifty-one (50.49%) presented mRS ≥ 3 on the late postoperative period. Men comprise 22.8%, and the mean age was 47.1 ± 16.0 years (range19-80). Patients with mRS ≥ 3 presented larger tumors (3.7 ± 1.1 cm vs. 3.2 ± 1.0 cm,  < .001), less total resection (50% vs. 76.7%,  < .010) and more neurofibromatosis II(NFII) (84.9% vs. 64.3%,  = .023). On multivariate analysis NFII, tumor size and type resection were predictive of degree of autonomy (mRS ≥3: NF II (OR 3.5, 95% CI 1.08-11.36,  = .036) and tumor size (each 1 cm, OR1.51, 95% CI 0.96-2.38,  = .050). Tumor size, presence of NFT II, type of surgical approach and number of surgeries were identified as predictive factors of functional sequelae in long-term follow-up after VS surgery.HighlightsOne-third of our patients presented some degree of disability that impact in autonomy (mRS ≥ 3) in the late postoperative period.Tumor size, NFII, surgical approach were predictive to comprise independency.Considering the cranial nerve monitoring and late diagnosis, our results can give some contribution to understanding the Brazilian profile of VS surgery.Our findings suggests the need to look over what it is well recognized and identify aspects that affect the prognosis such as functional disabilities in VS surgery.
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http://dx.doi.org/10.1080/00016489.2020.1722321DOI Listing
March 2020

Minimally Invasive Technique (Nummular Craniotomy) for Mesial Temporal Lobe Epilepsy: A Comparison of 2 Approaches.

World Neurosurg 2020 Feb 2;134:e636-e641. Epub 2019 Nov 2.

Department of Neurosurgery, University of São Paulo, São Paulo, Brazil. Electronic address:

Objective: To describe our series of a minimally invasive technique using a small scalp incision and keyhole craniotomy for the removal of mesial temporal lobe structures through a transcortical approach in patients with medically intractable mesial temporal lobe epilepsy (MTLE). Studies that directly compare the clinical outcomes between minimally invasive and conventional techniques are scarce, and this information is lacking in the literature.

Methods: The study enrolled 73 consecutive patients with refractory MTLE and unilateral hippocampal sclerosis; 30 patients were operated on with standard frontotemporal craniotomy between 2010 and 2013 and 43 patients were operated with a minimally invasive craniotomy (nummular craniotomy) between 2014 and 2016. The preoperative evaluation included clinical history, physical examination, video-electroencephalography, neuropsychologic assessment, and magnetic resonance imaging including thin-section coronal sequences.

Results: There were no deaths in either group. Postoperative complications in the standard frontotemporal craniotomy group included temporal muscle atrophy (n = 4; 13.3%), cerebrospinal fluid leakage (n = 1; 3.3%), and wound infection (n = 1; 3.3%). No complications were observed in the keyhole craniotomy group. There was no between-group difference in postoperative seizure control. The mean Engel class I seizure-free outcome was 90.4% in the standard frontotemporal craniotomy group and 90.7% in the nummular craniotomy group (P > 0.05). Lengths of hospitalization (2.81 vs. 4.37 days, P < 0.001) and operative time (85.79 vs. 142.73 minutes, P < 0.001) were lower in the keyhole than in the standard frontotemporal craniotomy group, respectively.

Conclusions: The nummular technique was associated with faster recovery, early hospital discharge, and fewer complications than the standard technique. No differences were observed in postoperative seizure control. Keyhole craniotomy is a safe, easy, and effective treatment option for medically intractable MTLE.
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http://dx.doi.org/10.1016/j.wneu.2019.10.160DOI Listing
February 2020