Suboccipital craniectomy with opening of the fourth ventricle and duraplasty: study of 192 cases of craniovertebral malformations.

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM), and/or syringomyelia (SM) is based on restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction and creation of a large artificial cisterna magna, avoiding the caudal migration of the hindbrain. It is observed that a large craniectomy might facilitate an upward migration of the posterior fossa structures. There are many surgical techniques to decompress the posterior fossa; however, a gold standard approach remains unclear. The authors present the results of 192 cases of BI, CM, and SM treated between 1975 and 2008 and whose surgical treatment was characterized by a large craniectomy without tonsillectomy with the patient in the sitting position, large opening of the fourth ventricle, and duraplasty.

Suboccipital craniectomy with opening of the fourth ventricle and duraplasty: study of 192 cases of craniovertebral malformations / Descompressao da fossa posterior sem tonsilectomia em 192 casos de impressao basilar, malformacao de Chiari e/ou siringomielia

The prime objective in the surgical treatment of basilar impression (BI), Chiari malformation (CM), and/or syringomyelia (SM) is based on restoration of the normal cerebrospinal fluid (CSF) dynamics at the craniovertebral junction and creation of a large artificial cisterna magna, avoiding the caudal migration of the hindbrain. It is observed that a large craniectomy might facilitate an upward migration of the posterior fossa structures. There are many surgical techniques to decompress the posterior fossa; however, a gold standard approach remains unclear. The authors present the results of 192 cases of BI, CM, and SM treated between 1975 and 2008 and whose surgical treatment was characterized by a large craniectomy without tonsillectomy with the patient in the sitting position, large opening of the fourth ventricle, and duraplasty.

O principal objetivo no tratamento cirúrgico da impressão basilar, malformação de Chiari e/ou siringomielia fundamenta-se na restauração da dinâmica do líquido cefalorraqueano ao nível da transição craniovertebral e criação de cisterna magna ampla. Isto é fator importante para evitar a migração caudal das estruturas da fossa posterior. A craniectomia ampla facilita a migração cranial dessas estruturas. Existem várias técnicas cirúrgicas para descomprimir a fossa posterior, mas não há evidência sobre qual a melhor.. Os autores apresentam os resultados de 192 casos de impressão basilar, malformação de Chiari e siringomielia, operados entre 1975 e 2008, nos quais o tratamento cirúrgico se baseou em ampla craniectomia com o paciente em posição sentada, sem tonsilectomia, abertura ampla do quarto ventrículo e enxerto dural.

Impacted cisterna magna without syringomyelia associated with lancinating headache, throbbed nuchal pain and paraparesis treated byposterior fossa decompression

A 29-year-old woman with acute lancinating headache, throbbed nuchal pain and subacute paraparesis underwent brain MRI in supine position that depicted: the absence of the cisterna magna, filled by non herniated cerebellar tonsils and compression of the brain stem and cisternae of the posterior fossa, which are aspects of the impacted cisterna magna without syringomyelia and without hydrocephalus. During eight days, pain was constant and resistant to drug treatment. Osteodural-neural decompression of the posterior fossa, performed with the patient in sitting position, revealed: compression of the brainstem, fourth ventricle and foramen of Magendie by herniated cerebellar tonsils, which were aspirated. Immediately after surgery, the headache and nuchal pain remmited. MRI depicted the large created cisterna magna and also that the cerebellar tonsils did not compress the fourth ventricle, the foramen of Magendie and the brainstem, besides the enlargement of posterior fossa cisternae. Four months after surgery, headache, nuchal pain and paraparesis had disappeared but hyperactive patellar and Achilles reflexes remained.

Uma paciente de 29 anos de idade com quadro agudo de cefaléia lancinante, dor terebrante na nuca e paraparesia subaguda foi submetida a RM do encéfalo, em posição supina, que revelou: ausência da cisterna magna, preenchida por tonsilas cerebelares não herniadas e compressão do tronco encefálico e das cisternas da fossa posterior, compatíveis com o diagnóstico de cisterna magna impactada sem siringomielia e sem hidrocefalia. Por oito dias a dor foi constante e resistente aos analgésicos. Com a paciente em posição sentada, foi realizada descompressão osteodural-neural da fossa posterior associada a aspiração das tonsilas cerebelares. Os achados perioperatórios foram caracterizados por herniação das tonsilas cerebelares que comprimiam o tronco cerebral, o quarto ventrículo e o forame de Magendie. No pós-operatório imediato houve remissão da cefaléia e da dor na nuca. A RM evidenciou a cisterna magna recém-criada, alargamento do quarto ventrículo e das cisternas do tronco encefálico. Quatro meses depois, a paciente continuava sem cefaléia, sem dor na nuca e sem paraparesia. Entretanto, permaneceu a hiperatividade dos reflexos patelares e aquileus.

Impacted cisterna magna without syringomyelia associated with lancinating headache, throbbed nuchal pain and paraparesis treated byposterior fossa decompression.

A 29-year-old woman with acute lancinating headache, throbbed nuchal pain and subacute paraparesis underwent brain MRI in supine position that depicted: the absence of the cisterna magna, filled by non herniated cerebellar tonsils and compression of the brain stem and cisternae of the posterior fossa, which are aspects of the impacted cisterna magna without syringomyelia and without hydrocephalus. During eight days, pain was constant and resistant to drug treatment. Osteodural-neural decompression of the posterior fossa, performed with the patient in sitting position, revealed: compression of the brainstem, fourth ventricle and foramen of Magendie by herniated cerebellar tonsils, which were aspirated. Immediately after surgery, the headache and nuchal pain remmited. MRI depicted the large created cisterna magna and also that the cerebellar tonsils did not compress the fourth ventricle, the foramen of Magendie and the brainstem, besides the enlargement of posterior fossa cisternae. Four months after surgery, headache, nuchal pain and paraparesis had disappeared but hyperactive patellar and Achilles reflexes remained.

Basilar impression associated with impacted cisterna magna, spastic paraparesis and distress of balance: case report / Impressão basilar associada com cisterna magna impactada, paraparesia espástica e distúrbios do equilíbrio: relato de caso

We report on a 48 years-old man with basilar impression without syringohydromyelia, in which the cisterna magna was impacted by the cerebellar tonsils. Six months after posterior fossa decompression there was the disappearance of nuchal rigidity, vertigo, spastic paraparesis and improvement of balance. Nevertheless hyperreflexia and diminished pallesthesia of the lower limbs persisted.

O presente relato descreve um homem de 48 anos com impressão basilar, sem siringo-hidromielia, no qual a cisterna magna se achava impactada pelas tonsilas cerebelares. O quadro clínico era caracterizado, especialmente, por paraparesia espástica. Seis meses após a descompressão da fossa posterior houve regressão da rigidez de nuca, vertigem, paraparesia espástica inicialmente observadas e melhora do equilíbrio. A hiperreflexia e a hipopalestesia persistiram nos membros inferiores.