Embolization of Arteriovenous Malformations of the Spinal Cord

Abstract

Arteriovenous malformations of the spinal cord (SCAVMs) are rare lesions of congenital origin (Hurth et al. 1978) that represent only about one-tenth of cerebral AVMs (Cogen and Stein 1983). Their natural history (Aminoff and Logue 1974a,b; Bailey and Sperl 1969; Hurth et al. 1978; Tobin 1976) and their physiopathology (Aminoff et al. 1974; Arseni and Samitca 1959; Gross and Ralston 1959; Hurth et al. 1978; Spetzler et al. 1989; Wyburn Mason 1943) are still poorly understood, and the treatment required is often difficult, controversial, and challenging (Ausman et al. 1977; Cogen and Stein 1983; Djindjian 1975, 1976; Djindjian and Merland 1978; Doppman et al. 1971; Horton et al. 1986; Houdart et al. 1974;Kito et al. 1983;Krayenbuhl et al. 1969; Latchaw and Gold 1979; Malis 1979; Margolis and Birchfield 1974; Margolis et al. 1979; Morgan et al. 1986; Newton and Adams 1968; Ommaya et al. 1969; Patterson and Voorhies 1978; Riche et al. 1983; Stein 1979; Theron et al. 1986; Yasargil et al. 1975). This lack of knowledge stems from the small size of the published series and the different classifications used by different authors, based on surgical (Rosenblum et al. 1987; Spetzler et al. 1989) or angiographic (Riche et al. 1983a,b, 1985) considerations. We believe that the distinction between intra- and extramedullary location, widely used in the literature and regarded as a determinant of further treatment, is anatomically inappropriate since all the lesions are subpial, as is also the case with their cerebral homologues (Hassler et al. 1989; Maillot 1991; Nicholas and Weller 1988). This distinction is relevant in respect of surgical data and concerns, but it cannot be applied to endovascular approaches. For example, SCAVMs fed by the anterior spinal axis and previously described as intramedullary may in fact be purely extramedullary, embedded in the anterior spinal sulcus without involvement of the spinal cord itself, like sulcal AVMs of the brain. We shall therefore concentrate our analysis primarily on the anatomic (Garcia-Monaco and Lasjaunias 1990; Lasjaunias and Berenstein 1990) and angioarchitectural aspects of SCAVMs (Berenstein and Lasjaunias 1992; Lasjaunias and Berenstein 1990; Rodesch et al. 1991). Spinal cord angiography at present remains the gold standard for evaluation of these lesions; MRI, although providing diagnostic indications in respect of SCAVMs and excellent information on the spinal cord itself, is unable to reveal the exact location and type of AV shunt involved (Di Chiro et al. 1985; Doppman et al. 1987; Masaryk et al. 1987; Modik et al. 1989; Rodesch et al. 1991). Currently MRI and MR angiographic study are unable to provide any of the answers required in order to reach decisions on therapy and technique.