American/ English/French connection classification

Three major centers — including the National Institutes of Health in Bethesda (Di Chiro and Wener, 1973; Oldfield et al., 1983), the National Hospital for Neurology and Neurosurgery in London (Aminoff et al., 1974; Kendall and Logue, 1977), and Hospital Lariboisiere in Paris (Djindjian, 1975) — generated a combined effort of independent yet collaborative intellectual investigations that yielded what is referred to as the American/ English/French connection classification system.

This system separates spinal vascular malformations (SVMs) into three types, with a fourth subtype.

Type I: spinal dural AVM AKA AV-fistula (AVF). The most common type (80%) of SVM in the adult ¹⁾. Fed by the radicular artery, which forms an AV shunt (fistula) at the dural root sleeve (located in the intervertebral foramen) ²⁾ and drains into an engorged spinal vein on the posterior cord. Usually in lumbar or lower thoracic spine. Slow flow. High pressure in the draining vein may cause venous congestion of the cord. Cord involvement may be distant to the fistula. Symptoms: LBP and progressive myeloradiculopathy or cauda equina syndrome (due to venous congestion) with urinary retention usually in middle-aged patients, 90% males. Up to 35% have pain. 15–20% are associated with other AVMs (cutaneous or other). Rarely bleed

a) Type I A: single arterial feeder

b) Type I B: two or more arterial feeders

Kendall and Logue first published a description of this type of lesion in 1977 with the novel recognition that these were actually not intradural sAVMs, but rather dural-based lesions with drainage into the previously not yet described coronal plexus of veins.

In total, this type comprises 80% of sVMs.

intradural AVMs (high flow): 75% present with acute onset of symptoms, usually from hemorrhage (SAH or intramedullary)

Type II True Spinal intramedullary arteriovenous malformation.

Type II: AKA spinal glomus AVM.Intramedullary.True AVM of the spinal cord.15–20% of all SVMs. Compact nidus fed by medullary arteries with the AV shunt contained at least partially within the spinal cord or pia. May be associated with feeding artery aneurysms. Worse prognosis than dural AVM ³⁾. Fed by 1, or at most 2–3 feeders 80% of the time.

Type III AKA juvenile spinal arteriovenous malformation.

These malformations are arteriovenous abnormalities of the spinal cord parenchyma fed by multiple vessels. These juvenile malformations are extensive lesions with abnormal vessels that can be both intramedullary and extramedullary in location. These lesions are typically found in young adults and children.

Type IV: see Perimedullary arteriovenous fistula.

sub type I: single arterial supply (ASA), single small fistula, slow ascending perimedullary venous drainage

sub type II: multiple arterial supply (ASA and PSA), multiple medium fistulae, slow ascending perimedullary venous drainage

sub type III: multiple arterial supply (ASA and PSA), single giant fistula, large ectatic venous drainage.

Miscelaneous spinal vascular lesions:

Spinal cord cavernoma.

Spinal cord venous angioma

Vertebral hemangioma.