Nongalenic Arteriovenous Fistulas: History of Treatment and Technology

Kristen Upchurch, MD; Lei Feng, MD, PhD; Gary R. Duckwiler, MD; John G. Frazee, MD; Neil A. Martin, MD; Fernando Viñuela, MD


Neurosurg Focus. 2006;20(6) 

In This Article

Clinical Aspects

Clinical Presentation

The size, angioarchitecture, and high-flow state of nongalenic AVFs, as well as the age of the patient, dictate their clinical presentation, which takes different forms depending on the presence of mass effect, arterial steal, or venous hypertension.[36,38] Although commonly congenital, nongalenic AVFs typically present after the neonatal period.[21] Those that are diagnosed in the neonatal period are usually found secondary to congestive heart failure, similar to vein of Galen malformations. After the neonatal period, infants with nongalenic AVFs present with increasing head circumference or focal neurological deficit. Adolescents and adults who have nongalenic AVFs present with headache, seizures, and focal neurological deficit.[21,35,36,38] Acute presentation due to subarachnoid or intracerebral hemorrhage is much less common but does occur.[21,36,38]

Asymptomatic adults with nongalenic AVFs have rarely been described. In a 1987 case series at the UWO, all of the adults with high-flow nongalenic AVFs associated with giant intracranial varices were symptomatic due to neurological and/or cardiac disease.[38] All patients in a 1989 series at the University of California San Francisco and all adults with these cerebral lesions in a 1993 Mayo Clinic series were symptomatic.[15,36] Described in a case report published in 2004, an adult patient with Rendu-Osler-Weber syndrome came to medical attention as a result of neurological symptoms due to a spinal AVF, underwent an examination that revealed a field cut, and was found also to have a cerebral AVF.[27] One adult with nongalenic AVFs described in a UWO-UCLA 1992 series as both asymptomatic and without neurological deficits came to medical attention because of a vascular abnormality: this 25-year-old woman presented with a massive cirsoid aneurysm (AVF) of the scalp and was found to have two ipsilateral nongalenic cerebral AVFs.[21] A truly asymptomatic patient who recently underwent successful endovascular treatment at UCLA was found to harbor two large, discrete nongalenic cerebral AVFs, one right temporal and the other right me dial parietal (Figs. 2-6). These lesions were incidentally discovered when the patient underwent cerebral imaging for staging after melanoma diagnosis.

Figure 2.

Pretreatment T2-weighted MR images, axial views, obtained in a patient recently treated with endovascular embolization at UCLA, showing large flow voids, consistent with the diagnosis of right temporal nongalenic AVF (A) and right medial parietal nongalenic AVF (B).

Figure 3.

Magnetic resonance angiography image obtained in the same patient as in Fig. 2, demonstrating dilated feeding arteries without a nidus, consistent with the diagnosis of two discrete nongalenic AVFs, each associated with a giant varix. TOF = time of flight.

Figure 4.

Diagnostic pretreatment angiograms from the same patient as in Fig. 2. The anterior oblique view of the right ICA injection (A) demonstrates the right temporal AVF's feeding arteries off the right MCA. The lateral view of the right ICA injection (B) shows the venous drainage of the right temporal AVF into the right superficial middle cerebral vein, vein of Labbé, and transverse sinus.

Figure 5.

Midtreatment angiograms of the same patient as in Fig. 2. In the anteroposterior view of the right ICA injection after embolization of the right temporal AVF, the right medial parietal AVF is now visualized (A). The lateral view of the left ICA injection demonstrates the venous drainage of the right medial parietal AVF (B).

Figure 6.

Posttreatment angiogram of the same patient as in Fig. 2, demonstrating a lateral view of the left ICA injection after embolization of the right medial parietal AVF.

Diagnosis of Nongalenic AVFs

In Dandy's era, the diagnosis of a nongalenic cerebral AVF was based on clinical symptoms and signs (for example, auscultation of bruits), substantiated by pneumoencephalography, and then confirmed by direct visualization at craniotomy.[8] Currently, initial computerized tomography and MR imaging studies are routinely obtained, followed by digital subtraction angiography, the diagnostic gold standard.[38] In a 1993 Mayo Clinic series, the following three angiographic criteria were suggested for the diagnosis of cerebral AVFs: 1) rapid circulation time due to high-velocity flow; 2) enlarged feeding arteries; and 3) direct filling of a large varix (described as "jet phenomenon" on MR an giography).[36] Currently, precise delineation of lesion angioarchitecture using biplanar and three-dimensional rotational selective and superselective angiography permits accurate diagnosis of nongalenic AVFs and also serves as a guide for planning treatment.[16,38,39] Overlapping arterial and venous collateral vessels may make visualization of an AVF difficult during routine angiographic injections. It is crucial to use superselective angiography to distinguish nongalenic cerebral AVFs from AVMs, given that the treatment strategies for these lesions differ.[36,38]


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