3-D simulation of posterior fossa reduction in Chiari I / Simulação em 3D da redução da fossa posterior no Chiari do tipo I

ABSTRACT We proposed a 3D model to evaluate the role of platybasia and clivus length in the development of Chiari I (CI). Using a computer aided design software, two DICOM files of a normal CT scan and MR were used to simulate different clivus lengths (CL) and also different basal angles (BA). The final posterior fossa volume (PFV) was obtained for each variation and the percentage of the volumetric change was acquired with the same method. The initial normal values of CL and BA were 35.65 mm and 112.66º respectively, with a total PFV of 209 ml. Ranging the CL from 34.65 to 29.65 – 24.65 – 19.65, there was a PFV decrease of 0.47% – 1.12% – 1.69%, respectively. Ranging the BA from 122.66º to 127.66º – 142.66º, the PFV decreased 0.69% – 3.23%, respectively. Our model highlights the importance of the basal angle and clivus length to the development of CI.

RESUMO No presente estudo, propusemos a criação de um modelo computacional em 3D com elaboração de software onde dois arquivos em formato DICOM com uma TC e RNM de crânio foram usados para simular diferentes mensurações na extensão do clivus (EC) e no ângulo basal (AB). O volume final da fossa posterior (VFP) foi obtido em cada variação, bem como a percentagem de volume alterada. O tamanho inicial da EC era de 35,65 mm e o do AB era de 112.66º, com um VFP de 209 ml. Variando a EC de 34,65 para 29,65 – 24.65 e 19.65, houve uma diminuição do VFP de 0.47%, 1.12% e 1.69%, respectivamente. Variando o AB de 122,66º para 127,66º e 142,66º, o VFP diminui para 0.69% e 3.23%, respectivamente. Nosso modelo enfatiza a importância da patogênese do aumento do AB e do encurtamento do clivus no desenvolvimento do Chiari I.

Upper airway dimensions in patients with craniocervical junction malformations with and without sleep apnea. A pilot case-control study / Dimensões da via aérea superior em pacientes com malformações da transição craniocervical com e sem apnéia do sono. Um estudo piloto caso-controle

Objective Patients with craniocervical junction malformations (CCJM) tend to suffer more frequently from sleep respiratory disturbances, which are more frequent and severe in patients with basilar invagination. Here we evaluate if patients with CCJM and sleep respiratory disorders (SRD) present smaller airway dimensions than patients without SRD. Method Patients with CCCM with and without sleep respiratory disturbances were evaluated clinically by Bindal's score, modified Mallampati classification, full-night polysomnography and upper airway cone beam tomography. Results Eleven patients had sleep respiratory disorders (SRD), and nine patients performed control group without SRD. CCJM patients with SRD were predominantly female, older, had higher BMI, were more likely to have Mallampati grades 3 and 4 and had statistically significant smaller anteroposterior diameter of the upper airway than patients without SRD. Conclusion Patients with CCJM and sleep respiratory disturbances have higher BMI, higher Mallampati score and smaller anterior posterior diameter of the upper airway. .

Objetivo : Pacientes com malformação da transição craniocervical (MTCC) tendem a apresentar mais frequentemente distúrbios respiratórios do sono (DRS), os quais são mais intensos em pacientes com invaginação basilar. O objetivo desse estudo é avaliar se pacientes com MTCC e DRS apresentam dimensões das vias aéreas reduzidas em comparação a pacientes sem DRS. Método : Pacientes com MTCC com e sem apneia do sono foram avaliados com a escala de Bindal, classificação de Mallampati modificada, polissonografia de noite inteira e tomografia da via aérea superior. Resultados Onze pacientes tinham DRS e nove não apresentaram esses distúrbios (grupo controle). Pacientes com MTCC e DRS foram principalmente mulheres, mais velhos, apresentaram maior IMC e maior gradação na escala de Mallampati, além de menor diâmetro anteroposterior de via aérea superior do que pacientes sem DRS. Conclusão Pacientes com MTCC e DRS têm maior IMC, maior pontuação na escala de Mallampati e menor diâmtero anteroposterior da via aérea superior. .

Syringomyelia in three small breed dogs secondary to Chiari-like malformation: clinical and diagnostic findings

Three small breed dogs were referred for the evaluation of neurologic deficits. Upon physical and neurologic examination, all dogs displayed hyperesthesia, pain, and neck stiffness. Magnetic resonance imaging was performed on the brain and spinal cord, and all three dogs presented Chiari-like malformations and syringomyelia. These dogs were treated with prednisolone and furosemide, and showed rapid improvement of clinical signs. Chiari malformations and syringomyelia were not improved because of congenital disorders. This case report demonstrates the clinical and diagnostic features of Chiari-like malformations and syringomyelia in three small breed dogs.

Amigdalopexia cerebelosa en el manejo de la malformación de chiari de tipo I / Cerebellar amygdalopexy in the management of Chiari I malformation

Antecedentes. El tratamiento de la malformación de Chiari de tipo I asociada a siringomielia es controvertido. En este trabajo se presenta un análisis clínico, quirúrgico y radiológico de los pacientes con esta afección que fueron manejados durante un periodo de doce años. Material y métodos. Se incluyeron 48 pacientes, donde se encontró un discreto predominio en el sexo femenino. El cuadro clínico estuvo dominado por cefalea, dolor cervical, signos y síntomas cerebelosos, afección de nervios craneales bajos y lesión de la vía piramidal. Resultados. Tanto el grado de descenso amigdalino como el tamaño de la siringomielia fueron muy variables, sin encontrar correlación entre ambos. La cirugía consistió en una craniectomía occipital, laminectomía de C1, ascenso de amígdalas cerebelosas mediante coagulación bipolar y plastía de duramadre. Los mejores resultados clínicos se obtuvieron en el dolor y los síntomas cerebelosos, mientras que los peores fueron en la afección de los nervios craneales bajos y de la vía piramidal, sin embargo, en la gran mayoría de los pacientes se logró detener la progresión de los síntomas. No se presentaron complicaciones serias en el presente estudio. Conclusión. El procedimiento propuesto ofrece una alternativa segura, efectiva y comparable con otros métodos más riesgosos para el manejo de esta malformación.

BACKGROUND: The treatment of Chiari I malformation associated with syringomyelia is controversial. OBJECTIVE: We describe a series of patients with this disease treated during a twelve-year period. We also present clinical, surgical and radiological findings. MATERIAL AND METHODS: Forty eight patients were included; a non significant female predominance was found. Clinical course was characterized by headache, cerebellar signs and symptoms, neck pain and involvement of lower cranial nerves and pyramidal tract. The degree of tonsillar descent and syringomyelia size varied and a correlation between them was not found. Surgery consisted in an occipital craniectomy, C1 laminectomy and tonsillar elevation through bipolar coagulation and duraplasty. RESULTS: The best results were observed in pain and cerebellar symptoms, while a deficit of lower cranial nerves and pyramidal tract were observed. However, in most patients we were able to slow symptom progression. No adverse effects were documented. CONCLUSIONS: The surgicalprocedureproposed herein is an effective and safe treatment alternative for this malformation, and its results are comparable to other riskier procedures.

Malformación de Chiari: actualización bibliográfica y presentación de un caso resuelto con Remodelación de Fosa Posterior / Chiari malformation. Bibliography updating and submission of a caso solved whith Posterior Fossa Reconstruction

Desde que fue descripta en 1891 por Hanz Chiari, el conocimiento sobre esta patología presenta mas incertidumbres que conceptos claros. Esto se ve reflejado desde el momento en que muchas veces nos referimos erróneamente al conjunto de esta patología "malformacion de Harnold-Chiari", siendo el nombre correcto el de "Malformación de Chiari" puesto que fueron las investigaciones de este autor las que contribuyeron realmente al conocimiento y estudio de esta patología. La etiología y fisiopatología tambien fueron y son motivo de discusión. Numerosas teorias se han propuesto para explicar el origen y el desarrollo de esta patología, sin embargo todavia aún hoy, con la disposición de distintos métodos de estudio como la cine-resonancia magnetica que nos permiten analizar como suceden estos fenómenos, no hay unificación de criterios. Su tratamiento también es un punto de conflicto puesto que la variedad de propuestas terapéuticas de la bibliografía es amplia, tales como remodelación de fosa posterior, descompresión de la fosa posterior...