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Objective: To evaluate acute and chronic changes seen on angiographic and histopathological studies of porcine rete mirabile, comparing those treated with the Menox liquid embolic system (LES) and those treated with the Onyx LES. Materials and Methods: Five pigs, each weighing approximately 35 kg, were submitted to rete mirabile embolization under general anesthesia and fluoroscopic guidance, with the Menox LES or Onyx LES. Four animals were treated with the Menox LES and underwent cerebral angiography, followed by euthanasia, at 1, 30, 60, and 90 days after embolization. One animal was treated with the Onyx LES underwent the same procedures at 30 days after embolization. In a subsequent histopathological analysis, we compared the Menox LES and Onyx LES in terms of the acute and chronic changes observed. Results: We observed no significant changes in blood pressure, heart rate, or electrocardiographic parameters that could be attributed to the super-selective infusion of dimethyl sulfoxide or the Menox embolic agent. Fluoroscopy showed adequate material opacity, appropriate progression to the center of the rete mirabile and complete unilateral embolization. Microcatheters were uneventfully detached from the embolized nidus. We observed mild to moderate intravascular and extravascular inflammatory responses, without histological evidence of necrotizing arteritis. There were no adverse neurovascular events. Conclusion: The Menox LES appears to be safe and effective, as well as being apparently equivalent to the Onyx LES in terms of the postprocedure angiographic and histopathological findings.

Purpose: To determine the normal optical nerve sheath (ONS) diameter ultrasonography (ONSUS) and evaluate the possible effects of drugs on ONS diameter during anesthetic induction in healthy pigs. Methods: Healthy piglets were divided into three groups: a control group, that received xylazine and ketamine (X/K); other that received xylazine, ketamine and propofol (X/K/P); and a third group that received xylazine, ketamine, and thiopental (X/K/T). The sheath diameter was assessed by ultrasonography calculating the average of three measurements of each eye from the left and right sides. Results: 118 animals were anesthetized (49 X/K 33 X/K/P and 39 X/K/T). Mean ONS sizes on both sides in each group were 0.394 ± 0.048 (X/K), 0.407 ± 0.029 (X/K/P) and 0.378 ± 0.042 cm (X/K/T) (medians of 0.400, 0.405 and 0.389, respectively). The ONS diameter varied from 0.287–0.512 cm (mean of 0.302 ± 0.039 cm). For group X/K, the mean diameter was 0.394 ± 0.048 cm. Significant differences in ONS sizes between the groups P and T (X/K/P > X/K/T, p = 0.003) were found. No statistically significant differences were detected when other groups were compared (X/K = X/K/P, p = 0.302; X/K = X/K/T, p = 0.294). Conclusions: Sedation with thiopental lead to significative ONS diameter reduction in comparison with propofol. ONSUS may be useful to evaluate responses to thiopental administration.

Introdução: A hipertensão intracraniana é uma condição frequente na prática neurocirúrgica, sendo o diagnóstico precoce importante para definição de tratamento. Modelos experimentais de hipertensão intracraniana podem ser utilizados para conhecer os aspectos das condições hemodinâmicas encefálicas e estudar o efeito de novas medicações ou intervenções. Soluções osmoticamente ativas têm sido utilizadas para tratamento de hipertensão intracraniana com resultados conflitantes. Analisamos os efeitos da solução salina hipertônica a 20% e manitol a 20% sobre a pressão intracraniana aferida por cateter intraparenquimatoso e medidas ultrassonográficas da bainha do nervo óptico em modelo experimental suíno de hematoma intracerebral na fase aguda. Métodos: Foi realizado um estudo experimental em modelo animal de hipertensão intracraniana com 20 suínos de ambos os sexos com peso aproximado de 40kg. Nos grupos A (5 suínos) e B (5 suínos), foram simulados um hematoma intracraniano por meio da insuflação de uma sonda de Foley com volume final de 4ml. Nos grupos C (5 suínos) e D (5 suínos), atingimos um volume final de 7ml. Os valores de 4ml e 7ml são equivalentes a uma coleção de, aproximadamente, 80ml e 140ml em um humano adulto levando-se em consideração a proporção entre o peso do cérebro do animal (média de 75g) e o peso do cérebro de um adulto normal (1500g). Após a insuflação do balão, utilizamos manitol a 20% (grupos A e C) e solução salina hipertônica a 20% (grupos B e D). Resultados: O modelo experimental utilizado foi eficaz no aumento da pressão intracraniana. Manitol a 20% e solução salina a 20% não foram eficazes na diminuição da pressão intracraniana aferida por cateter intraparenquimatoso, mas foram eficazes na diminuição dos valores de ultrassom da bainha do nervo óptico nos grupos de 7ml sem diferença entre as soluções. Conclusões: O modelo experimental suíno de hipertensão intracraniana apresenta boa reprodutibilidade. Solução salina hipertônica a 20% diminuiu os valores de bainha do nervo óptico em modelo experimental suíno de hipertensão intracraniana sem inferioridade em relação ao manitol a 20%. Ultrassom da bainha nervo óptico é método não invasivo, de baixo custo, com facilidade de repetição e pode auxiliar na prestação de cuidados em pacientes com hipertensão intracraniana Introduction: Intracranial hypertension, a frequent neurosurgical occurrence, is a severe condition in which early diagnosis is essential to provide prompt treatment. Experimental models employing invasive and noninvasive techniques for the assessment of intracranial hypertension can be used to elucidate the hemodynamic aspects of the condition as well as the effect of new medications/interventions for its management. Osmotically active solutions have been used to treat intracranial hypertension, but with conflicting results. We analyzed the effects of 20% hypertonic saline solution and 20% mannitol on intracranial pressure, measured via an intraparenchymal catheter and ultrasound measurements of the optic nerve sheath, in an experimental porcine model of acute-phase intracerebral hematoma. Methods: This experimental study was conducted on 20 pigs of both sexes, weighing approximately 40 kg, divided into four groups. In groups A and B (five pigs each), an intracranial hematoma was simulated by insufflation through a Foley tube, to a final volume of 4 mL. In Groups C and D (five pigs each), we attained a final volume of 7 mL. The values of 4 and 7 mL correspond to a collection of approximately 80 and 140 mL in an adult human, considering the ratio between the weight of the animal\'s brain (average 75 g) and that of a standard adult brain (1,500 g). After balloon inflation, 20% Mannitol was used in groups A and C, whereas 20% hypertonic saline solution was used in groups B and D. Results: The experimental model was effective in increasing the intracranial pressure. Measured using an intraparenchymal catheter, 20% mannitol and 20% saline solution were ineffective in reducing intracranial pressure. However, they effectively reduced the optic nerve sheath ultrasound values in the 7-mL groups, with no difference between the solutions. Conclusion: The experimental porcine model of intracranial hypertension exhibited good reproducibility, wherein 20% hypertonic saline decreased the optic nerve sheath values, without a significant difference from 20% mannitol. Optic nerve sheath ultrasound is a non-invasive, low-cost, easy-to-repeat method that can help determine appropriate care for intracranial hypertension patients