Posterior inferior cerebellar artery (PICA) is one of the three vessels that provide arterial supply to the cerebellum. It is the most variable and tortuous cerebellar. English Translation, Synonyms, Definitions and Usage Examples of Spanish Word ‘arteria cerebelosa posteroinferior’. Reporte de caso RESUMEN Los aneurismas que se forman de la ACPI (arteria cerebelosa posteroinferior) son poco comunes, la inci-dencia que se reporta es.

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Regression of syringomyelia and tonsillar herniation after posterior fossa arachnoid cyst excision. Case report and literature review. Ros de San Pedro; A. Hospital Universitario Virgen de la Arrixaca. Some reports have documented posterior fossa cysts resulting in syringomyelic obstruction of cerebrospinal fluid CSF flow caused by cyst displacement within the foramen magnum.

Posterior Inferior Cerebellar Artery CVA

Rarely the syringomyelia is caused by acquired Chiari malformation due to a retrocerebellar arachnoid cyst. To report the case of a year-old man with hydrocephalus and syringomyelia, who was found to have a Chiari malformation secondary to a posterior fossa arachnoid cyst.

After endoscopic third ventriculostomy, the patient was submitted to foramen magnum decompression and arachnoid cyst removal that were followed by resolution of both the Chiari malformation and the syringomyelia. In most published cases the syringomye lia has been attributed to obstruction of CSF flow at theforamen magnum by the arachnoid cyst itself. There is only one previous report of a posterior fossa arachnoid cyst producing tonsillar descent and syringomyelia.

Posterior fossa arachnoid cysts can result in acquired Chiari malformation and syringomyelia. In our view, the management of these patients should be directed at decompressing the foramen magnum and include the removal of the walls of the coexistent arachnoid cyst as it seems to be the crucial factor that accounts for the development of the syringomyelia that these patients present.

Descompresion del agujero magno. Arachnoid cysts are benign collections of cerebrospinal fluid CSF that develop as the result of an abnormal duplication of the arachnoid membranes during brain development.

Posterior fossa arachnoid cysts roughly represent one fourth of all these congenital pouches. There have been several reports of large arachnoid cysts associated with syringomyelia ,10, These patients have been managed with a variety of procedures including foramen magnum decompression, with or without cyst removal, cysto-peritoneal shunting or endoscopic cyst fenestration 28,10, In the majority of these cases, the development of syringomyelia has been related to the obstruction of CSF flow caused by the downward invagination of the cyst itself within the foramen magnum.

Adifferent mechanism has been put forward by Bauer et al. From current literature, it becomes obvious that patients with cerenelosa or Chiari malformation must be managed in an individualized manner taking into account the pathogenetic factors involved in their development 1, In the present work, the authors report what they believe represents the second case of a patient with syringomyelia and acquired Chiari malformation due to a retrocerebellar cyst, review the current literature, and propose to perform foramen magnum decompression together with cyst wall excision as the treatment of choice for these complex cases.

A year-old man psoteroinferior first seen because of headaches, right arm weakness and insensibility to pain and temperature on his arterka hand.

He also referred having had 3 episodes of drop attack. On physical examination the patient was fully conscious and had a bilateral 6 th cranial nerve paresis and loss of hearing on the left side. Motor power and ability were diminished on his upper extremity but there was no atrophy. Deep reflexes could not be elicited on the right arm.


There was also dissociated hypoesthesia on his right arm and shoulder. The rest of the examination was unremarkable. Magnetic resonance imaging MRI showed a retrocerebellar arachnoid cyst, descent of the cerebellar tonsils and a syringomyelic cavity extending from C2 to T6 Fig.

Computerized ceregelosa cerebral scan disclosed the presence of hydrocephalus. Preoperative MRI study of the patient showing: On 3 Augustan endoscopic third ventriculostomy was performed, after which the headaches markedly improved.

Neuroimaging studies showed no changes in his posterior fossa cyst, cerebellar tonsil’s location or syringomyelia. Clinically, the patient’s condition seemed to be deteriorating. On 4 April, the patient underwent suboccipital craniectomy and Cl laminectomy with ample removal of the arachnoid cyst’s walls.

The dura mater was closed with a dural graft. Histopathological study of the excised tissues showed flattened cells of meningothelial origin on a loose fibrous wall with normal vessels. The patient made an uneventful recovery, and at 10month follow-up visit he manifested to have gained some strength on his right hand, although the objective neurological examination remained unchanged. However, a MRI control showed normalization postrroinferior the cerebellar tonsils’ position and a significant shrinkage of the cervicothoracic syringomyelic cavity Fig.

MRI performed 10 months after posterior fossa decompression and cyst excision illustrating a reduction in the size of the arachnoid cyst and normal intracranial position of the cerebellar tonsils, and b marked shrinkage of the intramedullary cavity.

The most frequent reported cause of cerebellar tonsil herniation is the Chiari type 1 congenital malformation. This anomaly is one of the four types of hindbrain malformations described by Hans Chiari in 1, Chiari Type I malformation is often described as the caudal displacement of the cerebellar tonsils below the level of the foramen magnum with or without syringomyelia 1, Several theories have been proposed to explain both the tonsillar descent and the frequently associated syringomyelia According to Gardner’s theory the primary event consists of an imperforation of the rhombic roof, the supratentorial raised intracranial pressure displaces the tentorium and a shallow posterior fossa develops Evidence supports the hypothesis that the main problem in the Chiari I malformation is a posterior cranial fossa of smaller than normal volume The posterior fossa originates by endochondral ossification of the cartilaginous scaffold that forms the cranial base as well as the first four somites that model the occipital bone 4,9.

Marin-Padilla and Marin Padilla attributed the development of the Chiari malformation to a primary defect in the development of the basicranium 9. The production of syringomyelia in the context of the Chiari type 1 malformation has been amply reviewed and is beyond the scope of our study 1, In a recent study, based on dynamic-MRI studies, Oldfield et al.

The so-called “acquired” Chiari malformation seems to be better characterized 1. In these cases there exists a pressure gradient across the cranial and spinal compartments, due either to increased intracranial pressure, as happens in supratentorial masses or hydrocephalus, or to CSF diversion into the spinal compartment.

Several publications have documented the denovo appearance of tonsillar herniation in a variety of conditions including supra e infratentorial brain tumors, pseudotumor cerebri, craniosynostosis, cranio-encephalic disproportion, or overdrainage of CSF 1.

In our literature review, we found 15 cases of syringomyelia accompanying diverse cystic processes of the posterior cranial fossa, such as congenital arachnoid cysts, Dandy-Walker malformation, Blake’s pouch cyst, and posttraumatic CSF pouches, which are summarized in the Table ,10, In 14 instances the obstruction to the normal flow of CSF through the foramen magnum was due to blockage by the walls of the cyst itself. In all these cases, there was a coexistent syringomyelia 2,3,10, Ten patients had hydrocephalus of diverse severity that would contribute to the formation of the hydromyelic cavity.


Posterior inferior cerebellar artery

Those cases were managed with a variety of artria aimed at addressing the underlying pathogenetic mechanism, and included ventriculo- and cysto-peritoneal shunting, endoscopic fenestration, or direct approach to the cyst by foramen magnum decompression and cyst opening or excision. The case reported by Bauer et al.

Although hydrocephalus was a contributing factor, the Chiari malformation and the syringomyelic cavity in our case must be the consequence of the pressure exerted by the retrocerebellar cyst, as demonstrated posteroinfeeior the resolution of the tonsillar descent and the syringomyelia following osseous decompression and surgical excision of the cyst walls.

As in other instances of hydrocephalus-associated syringomyelia, the initial treatment for hydrocephalus in our patient was aimed at alleviating the raised intracranial pressure to prevent the risk of acute cerebellar herniation that can occur during the posterior fossa procedure. The second operation comprised foramen magnum decompression and ample fenestration of the cyst walls that lead to the resolution of both the tonsillar descent and the syringomyelia.

We have reported the second case of the successful management of syringomyelia associated to acquired Chiari malformation secondary to a retrocerebellar arachnoid cyst. We have briefly reviewed cases of syringomyelia associated with posterior fossa cysts.

As in other instances of syringomyelia, we recommend to address the surgical management in accordance with the hypothetical underlying mechanism. Surgical treatment of Chiari I malformation: Neurosurg Focus ;11 1 article 2.

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Dynamic CSF flow study in the pathophysiology of syringomyelia associated with arachnoid cysts of the posterior fossa. Br J Neurosurg ; Syringomyelia in association with posterior fossa cysts. Arachnoid cyst resulting in tonsillar herniation and syringomyelia in a patient with achondroplasia. Neurosurg Focus ; 19 5 E Hydromyelia associated with posterior fossa cyst. Surg Neurol ; Syringomyelia associated with hydrocephalus and Blake’s pouch cyst. Retrocerebellar arachnoid cyst with syringomyelia: Neurol India ; Syringomyelia as a sequelae of the 4 th ventricular dilatation from traumatic hydrocephalus and cerebellar atrophy.

J Korean Neurosurg Soc ; Morphogenesis of experimentally induced Arnold-Chiari malformation. J Neurol Sci ; Endoscopic fenestration of posterior fossa arachnoid cyst for the treatment of presyrinx myelopathy. Neurol Med Chir Tokyo Pathophisiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils.

Posterior inferior cerebellar artery | Radiology Reference Article |

Implications for diagnosis and treatment. J Neurosurg ; Syringomyelia with Chiari malformation: Acta Neurochir Wien ; ; Syringomyelia associated with a posterior fossa cyst. Illustration of two cases. Acute presentation of syringomyelia.

Report of three cases.

Introduction Arachnoid cysts are benign collections of cerebrospinal fluid CSF that develop as the result of an abnormal duplication of the arachnoid membranes during brain development. Case report A year-old man was first seen because of headaches, right arm weakness and insensibility to pain and temperature on his right hand. Discussion The most frequent reported cause of cerebellar tonsil herniation is the Chiari type 1 congenital malformation. Conclusions We have reported the second case of the successful management of syringomyelia associated to acquired Chiari malformation secondary to a retrocerebellar arachnoid cyst.