Foix-Alajouanine syndrome (Spinal dural arteriovenous fistula and related changes in spinal cord).
The present case shows very characteristic features of 'spinal dural arteriovenous fistula' (Spetzler (4) classification: arteriovenous fistula, intradural, dorsal type A [single arterial feeder]) and related changes in the spinal cord, historically classified as Foix-Alajouanine syndrome (1).
At the dura the arteriovenous shunt (Figure 1, yellow arrow) between a radiculomeningeal artery and radicular vein is partially obscured by a nerve root. The arterialized vein courses rostrally before turning (Figure 1, red arrow) caudally along the posterior surface of the spinal cord and shows evidence of remote thrombosis (Figure 2, inset).
Spinal dural arteriovenous fistula is a rare acquired condition, typically affecting middle-aged men (M:F ~ 5:1). The arteriovenous shunt causes chronic venous congestion and hypertension (reflected in the abnormal network of microvessels) and resulting progressive ischemic myelopathy. The initial symptoms are often non-specific and the clinical evolution variable (2). In the pre-MRI era (present case), the diagnosis was often delayed or missed. MR-imaging typically shows longitudinal T2-signal abnormality in the central cord and perimedullary flow voids. Catheter angiography identifies the exact level of the fistula and influences selection of its therapeutic neurosurgical disconnection or endovascular occlusion (3). In the present case, remote Wallerian degeneration of the gracile fasciculi (Figures 4, 5) correlated with the clinical finding of complete loss of position and vibration sensation below a mid lumbar level.
Contributed by John P. Rossiter MB, BCh, PhD, Donald G. Brunet MD