Partial Gyrus Rectus Resection as a Technique to Improve the Exposure to the Anterior Communicating Artery Complex through the Junctional Triangle: A Quantitative Study.

Objective The junctional triangle, formed by the distal A1 anterior cerebral artery (ACA) segment, the proximal A2 ACA segment, and the medial surface of gyrus rectus (GR), is a corridor of access to superiorly and posteriorly projecting anterior communicating artery (AComA) aneurysms that is widened by GR retraction or resection. Exposure of the AComA complex through the junctional triangle after GR resection has not been previously quantitatively evaluated. Design GR resection extent and increase in artery exposure through the junctional triangle were assessed in this study. Setting This study was conducted in the laboratory with a pterional approach, exposing the AComA complex. Participants Ten sides of five cadaveric heads were considered. Main Outcome Measures Exposure extent of ipsilateral and contralateral A1, A2, and AComA and accessibility of branches coming off the AComA complex were measured before and after GR resection. The GR was resected until sufficient bilateral A2 and contralateral A1 exposures were achieved. GR resection span was measured. Results The mean (standard deviation) resected span of GR was 7 ± 3.9 mm. After GR resection, the exposed span of the ipsilateral A2 increased from 2 ± 0.7 mm to 4 ± 1.1 mm ( p = 0.001); contralateral A2 exposure increased from 3 ± 1.5 mm to 4 ± 1.1 mm ( p = 0.03). Contralateral recurrent artery of Heubner (RAH) and orbitofrontal artery were accessible in five and eight specimens, respectively, before GR resection and in all 10 after resection. Conclusion GR resection improves exposure of bilateral A2 segments through the junctional triangle. Exposure improvement is greater for the ipsilateral A2 than contralateral A2. The junctional triangle concept is enhanced by partial GR resection during surgery for superior and posterior AComA aneurysms.

Applications of Microscope-Integrated Indocyanine Green Videoangiography in Cerebral Revascularization Procedures.

Indocyanine green videoangiography (ICG-VA) is a near-infrared range fluorescent marker used for intraoperative real-time assessment of flow in cerebrovascular surgery. Given its high spatial and temporal resolution, ICG-VA has been widely established as a useful technique to perform a qualitative analysis of the graft patency during revascularization procedures. In addition, this fluorescent modality can also provide valuable qualitative and quantitative information regarding the cerebral blood flow within the bypass graft and in the territories supplied. Digital subtraction angiography (DSA) is considered to be the gold standard diagnostic modality for postoperative bypass graft patency assessment. However, this technique is time and labor intensive and an expensive interventional procedure. In contrast, ICG-VA can be performed intraoperatively with no significant addition to the total operative time and, when used correctly, can accurately show acute occlusion. Such time-sensitive ischemic injury detection is critical for flow reestablishment through direct surgical management. In addition, ICG has an excellent safety profile, with few adverse events reported in the literature. This review outlines the chemical behavior, technical aspects, and clinical implications of this tool as an intraoperative adjunct in revascularization procedures.

Application of Fluorescein Fluorescence in Vascular Neurosurgery.

Background: Fluorescein sodium (FNa) is a fluorescent drug with a long history of use for assessing retinal blood flow in ophthalmology; however, its application in vascular neurosurgery is only now gaining popularity. This review summarizes the current knowledge about using FNa videoangiography in vascular neurosurgery. Methods: We performed a literature review on the usage of FNa for fluorescent videoangiography procedures in neurosurgery. We analyzed methods of injection, dosages of FNa, visualizing platforms, and interpretation of FNa videoangiography. We also reviewed practical applications of FNa videoangiography during various vascular neurosurgeries. Results: FNa videoangiography can be performed with intraarterial (intracarotid) or intravenous dye injections. Both methods provide excellent resolution with enhanced fluorescence that shows intravascular blood flow on top of visible surrounding anatomy, and both allow simultaneous purposeful microsurgical manipulations. Although it is invasive, an intracarotid FNa injection results in faster contrast appearance and higher-intensity fluorescence and requires a lower dose per injection (reported range, 1-50 mg) compared with peripheral intravenous FNa injection (reported range, 75-2,000 mg or 1-1.5 mg/kg body weight). Four optical excitation/detection tools for FNa videoangiography have been successfully used: conventional xenon-light operating microscope with a special filter set, pencil-type light-emitting diode probe with a filter set, laser-illumination operating microscope, and an endoscope with a filter set. FNa videoangiography was reported to be feasible and useful in various clinical scenarios, such as examining the feeders and drainers in arteriovenous malformation surgery, checking the patency of a microvascular anastomosis, and assessing blood flow during aneurysm clipping. FNa videoangiography can be repeated during the same procedure and used along with indocyanine green (ICG) videoangiography. Conclusions: Compared with ICG videoangiography, FNa videoangiography has the advantages of enabling real-time inspection and better visualization at deep locations; however, thick vessel walls limit visualization of FNa in larger vessels. FNa videoangiography is a useful tool in multiple neurovascular scenarios and merits further studies to establish its clinical value.

Development of a Simulation Model for Fluorescence-Guided Brain Tumor Surgery.

Objective: Fluorescence dyes are increasingly used in brain tumor surgeries, and thus the development of simulation models is important for teaching neurosurgery trainees how to perform fluorescence-guided operations. We aimed to create a tumor model for fluorescence-guided surgery in high-grade glioma (HGG). Methods: The tumor model was generated by the following steps: creating a tumor gel with a similar consistency to HGG, selecting fluorophores at optimal concentrations with realistic color, mixing the fluorophores with tumor gel, injecting the gel into fresh pig/sheep brain, and testing resection of the tumor model under a fluorescence microscope. The optimal tumor gel was selected among different combinations of agar and gelatin. The fluorophores included fluorescein, indocyanine green (ICG), europium, chlorin e6 (Ce6), and protoporphyrin IX (PpIX). The tumor model was tested by neurosurgeons and neurosurgery trainees, and a survey was used to assess the validity of the model. In addition, the photobleaching phenomenon was studied to evaluate its influence on fluorescence detection. Results: The best tumor gel formula in terms of consistency and tactile response was created using 100 mL water at 100°C, 0.5 g of agar, and 3 g of gelatin mixed thoroughly for 3 min. An additional 1 g of agar was added when the tumor gel cooled to 50°C. The optimal fluorophore concentration ranges were fluorescein 1.9 × 10-4 to 3.8 × 10-4 mg/mL, ICG 4.9 × 10-3 to 9.8 × 10-3 mg/mL, europium 7.0 × 10-2 to 1.4 × 10-1 mg/mL, Ce6 2.2 × 10-3 to 4.4 × 10-3 mg/mL, and PpIX 1.8 × 10-2 to 3.5 × 10-2 mg/mL. No statistical differences among fluorophores were found for face validity, content validity, and fluorophore preference. Europium, ICG, and fluorescein were shown to be relatively stable during photobleaching experiments, while chlorin e6 and PpIX had lower stability. Conclusions: The model can efficiently highlight the "tumor" with 3 different colors-green, yellow, or infrared green with color overlay. These models showed high face and content validity, although there was no significant difference among the models regarding the degree of simulation and training effectiveness. They are useful educational tools for teaching the key concepts of intra-axial tumor resection techniques, such as subpial dissection and nuances of fluorescence-guided surgery.

Surgical treatment of falcotentorial meningiomas: a retrospective review of a single-institution experience.

OBJECTIVE: Meningiomas at the falcotentorial junction represent a rare subgroup of complex meningiomas. Debate remains regarding the appropriate treatment strategy for and optimal surgical approach to these tumors, and surgical outcomes have not been well described in the literature. The authors reviewed their single-institution experience in the management, approach selection, and outcomes for patients with falcotentorial meningiomas. METHODS: From the medical records, the authors identified all patients with falcotentorial meningiomas treated with resection at the Barrow Neurological Institute between January 2007 and October 2017. Perioperative clinical, surgical, and radiographic data were retrospectively collected. For patients who underwent the supracerebellar infratentorial approach, the tentorial angle was defined as the angle between the line joining the nasion with the tuberculum sellae and the tentorium in the midsagittal plane. RESULTS: Falcotentorial meningiomas occurred in 0.97% (14/1441) of the patients with meningiomas. Most of the patients (13/14) were female, and the mean patient age was 59.8 ± 11.3 years. Of 17 total surgeries (20 procedures), 11 were single-stage primary surgeries, 3 were two-stage primary surgeries (6 procedures), 2 were reoperations for recurrence, and 1 was a reoperation after surgery had been aborted because of brain edema. Hydrocephalus was present in 5 of 17 cases, 4 of which required additional treatment. Various approaches were used, including the supracerebellar infratentorial (4/17), occipital transtentorial/transfalcine (4/17), anterior interhemispheric transsplenial (3/17), parietal transventricular (1/17), torcular (2/17), and staged supracerebellar infratentorial and occipital transtentorial/transfalcine (3/17) approaches. Of the 17 surgeries, 9 resulted in Simpson grade IV resection, and 3, 1, and 4 surgeries resulted in Simpson grades III, II, and I resection, respectively. The tentorial angle in cases with Simpson grade I resection was significantly smaller than in those with an unfavorable resection grade (43.3° ± 4.67° vs 54.0° ± 3.67°, p = 0.04). Complications occurred in 10 of 22 approaches (17 surgeries) and included visual field defects (6 cases, 2 permanent and 4 transient), hemiparesis (2 cases), hemidysesthesia (1 case), and cerebellar hematoma (1 case). CONCLUSIONS: Falcotentorial meningiomas are challenging lesions. A steep tentorial angle is an unfavorable preoperative radiographic factor for achieving maximal resection with the supracerebellar infratentorial approach. Collectively, the study findings show that versatility is required to treat patients with falcotentorial meningiomas and that treatment goals and surgical approach must be individualized to obtain optimal surgical results.

Quantitative analysis of ipsilateral and contralateral supracerebellar infratentorial and occipital transtentorial approaches to the cisternal pulvinar: laboratory anatomical investigation.

OBJECTIVE: The cisternal pulvinar is a challenging location for neurosurgery. Four approaches for reaching the pulvinar without cortical transgression are the ipsilateral supracerebellar infratentorial (iSCIT), contralateral supracerebellar infratentorial (cSCIT), ipsilateral occipital transtentorial (iOCTT), and contralateral occipital transtentorial/falcine (cOCTF) approaches. This study quantitatively compared these approaches in terms of surgical exposure and maneuverability. METHODS: Each of the 4 approaches was performed in 4 cadaveric heads (8 specimens in total). A 6-sided anatomical polygonal region was configured over the cisternal pulvinar, defined by 6 reachable anatomical points in different vectors. Multiple polygons were subsequently formed to calculate the areas of exposure. The surgical freedom of each approach was calculated as the maximum allowable working area at the proximal end of a probe, with the distal end fixed at the posterior pole of the pulvinar. Areas of exposure, surgical freedom, and the working distance (surgical depth) of all approaches were compared. RESULTS: No significant difference was found among the 4 different approaches with regard to the surgical depth, surgical freedom, or medial exposure area of the pulvinar. In the pairwise comparison, the cSCIT approach provided a significantly larger lateral exposure (39 ± 9.8 mm2) than iSCIT (19 ± 10.3 mm2, p < 0.01), iOCTT (19 ± 8.2 mm2, p < 0.01), and cOCTF (28 ± 7.3 mm2, p = 0.02) approaches. The total exposure area with a cSCIT approach (75 ± 23.1 mm2) was significantly larger than with iOCTT (43 ± 16.4 mm2, p < 0.01) and iSCIT (40 ± 20.2 mm2, p = 0.01) approaches (pairwise, p ≤ 0.01). CONCLUSIONS: The cSCIT approach is preferable among the 4 compared approaches, demonstrating better exposure to the cisternal pulvinar than ipsilateral approaches and a larger lateral exposure than the cOCTF approach. Both contralateral approaches described (cSCIT and cOCTF) provided enhanced lateral exposure to the pulvinar, while the cOCTF provided a larger exposure to the lateral portion of the pulvinar than the iOCTT. Medial exposure and maneuverability did not differ among the approaches. A short tentorium may negatively impact an ipsilateral approach because the cingulate isthmus and parahippocampal gyrus tend to protrude, in which case they can obstruct access to the cisternal pulvinar ipsilaterally.

Association between Wegener´s granulomatosis and severe lumbar pain

Introducción: La granulomatosis de Wegener (GW) es una enfermedad autoinmune sistémica caracterizada por vasculitis granulomatosa necrotizante que afecta principalmente a las vías respiratorias superiores, pulmones y riñones. Sin embargo, con menos frecuencia puede afectar a los músculos, las articulaciones, la piel, los ojos, el sistema cardiovascular y el sistema nervioso. La presencia de dolor lumbar consiste en una manifestación clínica inusual debido a la afectación del sistema nervioso. Objetivo: El objetivo de este estudio es alertar a los profesionales de la salud acerca de la posibilidad de cortar el dolor lumbar estar relacionado con la granulomatosis de Wegener, su impacto en la vida diaria del paciente, así como los signos clínicos y las formas de diagnóstico. Materiales y Métodos: Revisión de la literatura utilizando PubMed, MEDLINE, Google Scholar, SciELO, EBSCO. Los trabajos seleccionados entre 1995 y 2013 por un total de 48 obras de las cuales se seleccionaron 21 de acuerdo con sus informes de afectación neurológica, diagnóstico y tratamiento. Discusión: Los síntomas neurológicos pueden ocurrir en 22-50 por ciento de los pacientes durante el curso de la GW. sistema nervioso (SNC) central es poco frecuente (sólo 2-8 por ciento de los pacientes) dolor lumbar .Severe es una manifestación clínica poco frecuente y puede estar asociada con la participación de sistema nervioso central y periférico. CNS debido a la compresión de la médula espinal a nivel lumbar. sistema nervioso periférico debido a la compresión de las raíces nerviosas. Conclusión: La granulomatosis de Wegener es ser una enfermedad sistémica puede presentar diferentes manifestaciones clínicas De acuerdo con el sitio involucrado. Es asociaciones con el dolor lumbar es rara y la refleja la afectación neurológica. Por lo tanto, en pacientes con dolor lumbar grave sin diagnóstico confirmado, granulomatosis de Wegener no debería ser considerado.

Introduction: Wegener’s granulomatosis (WG) is a systemic autoimmune disease characterized by necrotizing granulomatousvasculitis which primarily affects upper respiratory tract, lungs and kidneys. However, less frequently can affect muscles,joints, skin, eyes, cardiovascular system and nervous system. The presence of lumbar pain consists in an unusual clinicalmanifestation due to the involvement of the nervous system. Objective: The objective of this study is to alert health professionalsabout the possibility that severe lumbar pain be related to Wegener’s granulomatosis, it’s impact on the patient’s dailylife as well as clinical signs and diagnosis forms. Materials and Methods: Literature review using PubMed, MEDLINE, GoogleScholar, SciELO, EBSCO. Selected works from 1995 to 2013 totaling 48 works of which 21 were selected according to theirreports of neurological involvement, diagnosis and treatment. Discussion: Neurological symptoms may occur in 22-50 percent of patients during the course of WG. Central nervous system (CNS) involvement is uncommon (only 2-8 percent of patients).Severelumbar pain is a rare clinic manifestation and it can be associated with the involvement of central and peripheral nervous system.CNS due to compression of the spinal cord at the lumbar level. Peripheral nervous system due to compression of nerveroots. Conclusion: Wegener’s granulomatosis for being a systemic disease can present different clinical manifestations accordingto the involved site. It’s associations with lumbar pain is rare and reflects it’s neurological involvement. Therefore, inpatients with severe lumbar pain without confirmed diagnosis, Wegener’s granulomatosis should be considered.

Semi-sitting Position in Neurosurgery: A Review / Posição semissentada em neurocirurgia: uma revisão

Specialists rarely perform neurosurgical procedures on patients in the semi-sitting position. This is due to several factors, most importantly, the perception of risks associated with this position and lack of practice in some services. Nevertheless, the benefit of this position is still the subject of controversy both in eurosurgery and neuroanesthesia. Our objective is to report on the benefits associated to its use for posterior fossa diseases and dorsal cervical spine procedures, through cases in the literature. We survey and analyze state-of -the art works that mention the semi-sitting position, based on searches in Pubmed, Scielo, Science Direct, and Lilacs.We found 46 original articles on the subject that we included in the review. This review emonstrates that the advantages for access in this position include gravitational drainage of venous blood and cerebrospinal fluid, easier surgical access to midline structures, as well as reduced cerebellar edema, surgery time and blood loss. This technique also allows ventilation with low pressure, less impairment of diaphragmatic motion, and better access to the tracheal tube. There are, however, some disadvantages, among which the most serious is paradoxical arterial embolism. We describe early detection methods of complications and discuss situations that can factor in to the choice of position. In summary, a semi-sitting position is safe and effective in neurosurgical posterior fossa and the upper cervical spine, provided there is a joint effort between neurosurgeons and anesthesiologists in selecting patients and complying with the technical standards favorable to this technique.

Especialistas raramente realizam procedimentos neurocirúrgicos em pacientes em posição semi-sentada. Vários são os fatores, o mais importante, a percepção dos riscos associados a esta posição e falta de prática emalguns serviços. No entanto, o benefício desta posição ainda é objeto de controvérsia tanto emneurocirurgia e Neuroanestesia. Nosso objetivo é relatar os benefícios associados ao seu uso para doenças da fossa posterior e procedimentos da coluna cervical dorsal. Realizado um levantamento e analise do estado-da-arte dos documentos que mencionam a posição semi-sentada, com base em pesquisas em Pubmed, Scielo, Science Direct e Lilacs. Encontraram-se 46 artigos originais sobre o assunto que foram incluídos na revisão. Esta avaliação demonstra que as vantagens do acesso nesta posição incluem a drenagem gravitacional de sangue venoso e no líquido cefalorraquidiano, o acesso cirúrgico mais fácil para estruturas da linha média, bem como diminuição do edema cerebelar, tempo de cirurgia e perda de sangue. Esta técnica também permite a ventilação com pressão baixa, menor comprometimento da mobilidade diafragmática, e um melhor acesso ao tubo traqueal. Há, algumas desvantagens, entre as quais a mais grave é a embolia arterial paradoxal. Descreve-se métodos de detecção precoce de complicações e discutir situações que pode fator para a escolha de posição. Em resumo, esta posição é segura e eficaz em fossa posterior e da coluna cervical superior, desde que haja um esforço conjunto entre neurocirurgiões e anestesistas na seleção de pacientes e em conformidade com as normas técnicas favoráveis a esta técnica.

Differential Diagnosis between Neoplastic and Non-Neoplastic Brain Lesions in Radiology / Diagnóstico diferencial entre lesões cerebrais neoplásicas e não neoplásicas em radiologia

Introduction The observation of multiple lesions in a skull computed tomography (CT) scan is always cause for concern because of the frequent possibility of neoplastic etiology, although granulomatous, infectious, vascular, iatrogenic, demielinating, trauma, parasitic diseases, and strokes can produce a similar aspect on radiology. A wide range of non-neoplastic conditions can mimic a brain tumor, both clinically and radiologically, representing a potential pitfall for physicians involved in patient care. The study's goal is to alert specialists to the possibility of other neoplastic and nonneoplastic etiologies in the differential diagnosis of hypodense lesions in non-contrast. Methods We performed a literature review using PubMed, Medline, Science Direct, Embase, Clinical Trials, Ebsco, and Scielo. Articles were selected in the period of 1986 to 2015. Discussion Knowledge of various etiologies when with multiple lesions appear on computed tomography allows specialists to guide the diagnosis to appropriate treatment, avoiding the irradiation of non-neoplastic lesions and unnecessary surgeries. The most common lesions were the neoplasm (74% to 86%), especially gliomas, followed by infections (8% to 15%), and infarcts (0.6% to 6%), which represent nonneoplastic lesions. Conclusion Given the relatively high percentage of wrong neuroradiology diagnoses, most cases may require histological diagnosis, because even magnetic resonance imaging (MRI) renders difculties in distinguishing such lesions.

Introdução Observação de múltiplas lesões na tomograa computadorizada de crânio (TC) é sempre motivo de preocupação por causa da possibilidade frequente de etiologia neoplásica, embora as doenças granulomatosas, infecciosas, vascular, iatrogênica, desmielinizante, trauma, e parasitárias podem produzir aspecto semelhante na radiologia. Uma ampla gama de condições não neoplásicas pode mimetizar um tumor cerebral, tanto clínica, quanto radiologicamente, representando uma armadilha potencial para os médicos envolvidos no cuidado ao paciente. O objetivo do estudo é alertar a possibilidade de outras etiologias neoplásicas e não neoplásicas no diagnóstico diferencial de lesões hipodensas em TC sem contraste. Métodos Revisão da literatura utilizando PubMed, MEDLINE, Google Scholar, Ensaios Clínicos, EBSCO, Scielo, Tópicos em radiologia. Foram selecionados por período 1986- 2015. Discussão O conhecimento de várias etiologias, quando confrontado com múltiplas lesões na tomograa computadorizada permite o direcionamento do diagnóstico para o tratamento adequado, evitando a irradiação de lesões não neoplásicas e cirurgias desnecessárias. As lesões mais frequentes são neoplasias (74% a 86%), especialmente gliomas, seguido de infecções (8% a 15%) e infartos (0,6% a 6%), que representam lesões não neoplásicas. Conclusão Como um possível resultado da percentagem relativamente elevada de diagnósticos errados neurorradiológicos, o diagnóstico histológico faz necessário, porque mesmo Ressonância pode ser difícil na diferenciação de tais lesões.