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

Abstract

-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.KEY WORDS: headache, nuchal pain, craniovertebral malformation, tight cisterna magna, impacted cisterna magna, Chiari malformation, posterior fossa decompression, paraparesis, herniated tonsils.Cisterna magna impactada sem siringomielia associada a cefaléia lancinante, dor na nuca terebrante e paraparesia tratadas com descompressão da fossa posterior RESUMO -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: ausên-cia da cisterna magna, preenchida por tonsilas cerebelares não herniadas e compressão do tronco encefá-lico 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.

Posterior fossa decompression with tonsillectomy in 104 cases of basilar impression, Chiari malformation and/or syringomyelia

“…The au-thors named the full cisterna magna as "tight cisterna magna" and designated Iskandar's description as "Chiari 0 malformation". Gonçalves da Silva et al 29 named this type of cisterna magna as "impacted cisterna magna".…”

A new entity: chiari zero malformation, and its surgical method

“…Recently, Iskandar and Tubbs et al used "Chiari zero malformation" to characterize this kind of syringomyelia disorder and advised craniovertebral decompression (CVD) as the surgical modality (8, 9,16,17). There is a very limited number of papers on the "Chiari zero malformation", and there is a query about the truth of this pathology (8, 9,10,14,16,17,18).…”

Impacted cisterna magna without syringomyelia associated or not with basilar impression and/or Chiari malformation

“…This kind of "up and down CM" was observed also in cases without SM. 19,21 Iskandar et al 7 reported on five cases of SM, in which the cisterna magna was filled with the cerebellar tonsils. In all five cases there was clinical improvement after posterior fossa decompression and a marked reduction in the size of the syrinx.…”

“…Spastic tetraparesis and paraparesis are frequently described in patients with BI and/or CM and SM. [9][10][11][12][13][14][15][16][17][18][19] In our five cases SM was absent, despite an evident obstruction of the CSF flow in the posterior fossa caused by the blockage of the foramen of Magendie by a membrane in four cases and the cerebellar tonsils in one case. This finding lead us to hypothesize about whether SM would not develop in the presence of foraminal obstruction, even knowing that the obstruction of the CSF flow in the posterior fossa is considered to be the prime condition for its development.…”

“…In the Northeast of Brazil there is a high prevalence of BI associated with CM reported by many authors [11][12][13][14][15][16][17][18][19][20] , although there is no suitable known reason for this fact.…”