Pial arteriovenous fistula in the posterior fossa

Fistula arteriovenosa pial na fossa posterior

LETTERS

Pial arteriovenous fistula in the posterior fossa

Fistula arteriovenosa pial na fossa posterior

Luciana Rossi Guerra^I; Leandro de Assis Barbosa^II; Livia Guidoni de Assis Barbosa^III; Derval de Paula Pimentel^IV; Fabrízio Isaac Schawb Leite^V

^IMD, Residente de Radiologia pelo Centro Diagnóstico por Imagem de Vitória (CDI), Vitória ES, Brazil

^IIMD, PhD Neurocirurgião e Neurorradiologista Intervencionista - Hospital Metropolitano e Vitória Apart Hospital, Serra ES, Brazil. Hospital Central de Vitória e Centro Integrado de Atenção a Saúde, Vitória ES, Brazil

^IIIMD, Residente de Radiologia, CDI

^IVMD, Neurocirurgião e Neurorradiologista Intervencionista, Hospital Metropolitano e Vitória Apart Hospital, Serra ES, Brazil. Hospital Central de Vitória e Centro Integrado de Atenção a Saúde, Vitória ES, Brazil

^VMD, Neurocirurgião, Hospital Metropolitano e Vitoria Apart Hospital, Serra ES, Brazil. Hospital Central de Vitória e Centro Integrado de Atenção a Saúde, Vitória ES, Brazil

^{Correspondence}

Intracranial pial arteriovenous fistulas (AVFs) are rare congenital abnormality that can cause severe morbidity and mortality, particularly in neonates¹. AVFs are rare cerebrovascular lesions of the brain that were considered to be distinct from other arteriovenous malformations (AVMs) by Lasjaunias, in 1986². Intracranial pial AVFs have a single or multiple arterial connections to a single venous channel. They differ from brain AVMs in that they lack a true nidus. They differ from dural AVFs in that they derive their arterial supply from pial or cortical arteries and are not located within the dura mater³. They may be localized anywhere in the brain but display a preference for the supratentorial regions³.

Pial AVFs can be acquired traumatically or iatrogenically or may be congenital. Their natural evolution is unfavorable, conservative management of pial AVFs has been associated with mortality in 63% of patients⁴.

CASE

A 6-month old boy present macrocephaly, asymptomatic, without apparent motor injury, did not show any skin lesion and no signs of heart failure. A transfontanele ultrasound Doppler showed evidence of large arteriovenous shunt (AVS) at posterior fossa with patent flow (Fig 1A and 1B). Additional investigation with computed tomography (Fig 1C) and magnetic resonance showed extensive vascular mass partially occupying posterior fossa, leading to displacement and compression of the brainstem and no signs of hydrocephalus. The magnetic resonance (Fig 1D) and digital subtraction arteriography (Fig 2A and 2B) confirmed AVF with single feeder originated from the vertebrobasilar junction and single draining in cerebellar vein toward torcule.

The AVF was treated via an endovascular route with detachable coils. Elective embolizations of the AVFs were done with coils at 6 months of age, resulting in complete exclusion of the lesions, as shown on the postembolization internal carotid angiogram on anterior posterior and lateral views (Fig 2C and 2D).

DISCUSSION

Intracranial pial AVFs are rare cerebrovascular lesions. They are a direct communication between a pial artery and cerebellar vein, without an intervening nidus and located in the subpial meningeal space. This newly distinguished subtype of intradural AVS is necessary because it corresponds to an architecture that engenders specific symptoms, occurs in a special age group, constitutes the phenotype of a well-defined disease, and requires a specific therapeutic technical approach⁵.

This pathology has different clinical presentations. Neonates can present with intractable cardiac failure and intracranial bruit. In infancy, it can present with hydrocephalus and seizures. Older children or young adults can present with intracranial hemorrhage¹.

Owing to the absence of a nidus, closure of the shunt by either endovascular or surgical technique represents a satisfactory therapeutic procedure². But the indications, the time, and the method of treatment chosen for management of AVFs depend on a variety of factors such as the age at presentation, presenting symptoms, the status of the brain, and the status of the other organs⁵.

In conclusion, emergent diagnosis and treatment of this pathology is crucial due to its associated with high morbidity and mortality. Endovascular techniques can provide safe and successful treatment for these infants.

Received 1 March 2011

Received in final form 7 April 2011

Accepted 14 April 2011

• 1. Meyers PM, Halbach VV, Barkovich AJ. Anomalies of cerebral vasculature: diagnostic and endovascular considerations. In: Barkovich AJ (Ed). Pediatric neuroimaging. 3^rd ed. Philadelphia: Lippincott Williams & Wilkins, 2000;777-796.
• 2. Lasjaunias P, Manelfe C, Chiu M. Angiographic architectures of intracranial vascular malformations and fistulas: pretherapeutic aspects. Neurosurg Rev 1986;9:253-263.
• 3. Hoh BL, Putman CM, Budzik RF, et al. Surgical and endovascular flow disconnection of intracranial pial single-channel arteriovenous fistulae. Neurosurgery 2001;49:1351-1363.
• 4. Nelson K, Nimi Y, Lasjaunias P, et al. Endovascular embolization of congenital intracranial pial arteriovenous fistulas. Neuroimaging Clin N Am 1992;2:309-317.
• 5. Lasjaunias P, Ter Brugge KG, Berenstein A. Cerebral arteriovenous fistulas. In: Heilmann U (Ed). Surgical Neuroangiography 3. 2^rd ed. New York: Springer Verlag, 2006:227-270.

Publication Dates

• Publication in this collection
  01 Sept 2011
• Date of issue
  Aug 2011