Spinal vascular malformations are a group of blood vessel disorders that may cause acute or long-lasting spinal cord dysfunction. These are rare malformations but may cause severe complications if left untreated.
Some common spinal vascular malformations include arteriovenous malformations, capillary telangiectasis, arteriovenous fistula, and cavernous malformations.
Let’s understand more about them:
Arteriovenous malformation (AVM)
Before we move ahead, let’s quickly understand about AVM.
Arteriovenous malformation (AVM) is a tangle of abnormal blood vessels connecting veins and arteries.
Typically, blood flows from the heart to the arteries, which get smaller until they turn into capillaries. Nutrients and oxygen exchange takes place in the capillaries. The blood then passes from capillaries to your heart through veins.
But in AVM, arteries directly connect to veins, without capillaries in between, and form a knot of blood vessels. This creates an area of high pressure. The veins cannot take this pressure and enlarge and bulge to accept extra blood.
Spinal Dural Arteriovenous Fistulas
They are the most common of all spinal vascular malformations, contributing to about 70% of these cases. It is seen more in middle to old, aged men and is believed to be acquired condition.
This condition is characterized by an abnormal connection between arteries and veins in the dura, which is the outer covering of your spinal cord. This abnormal connection causes the high-pressure arterial blood to drain in the low-pressure veins. The veins are not able to drain the blood efficiently and pressure in them rises. This elevated pressure hampers the blood supply to the spinal cord and it progressively gets damaged.
These lesions usually do not rupture. Endovascular treatment and open surgery are both good treatment option for them, however these days endovascular treatment is being preferred because of relatively less morbidity.
Spinal Arteriovenous Malformations
Spinal arteriovenous malformation (AVM), or glomus AVM, is a condition characterized by an abnormal connection between arteries and veins in the substance of the spinal cord. These connections occur in a specific collection of abnormal blood vessels, known as the AVM nidus.
These malformations contribute to 20% of spinal vascular malformation cases. It is seen more commonly in children and young individuals. Spinal AVM can rupture and bleed into the spinal fluid, resulting in a sudden weakness in your extremities.
Juvenile Arteriovenous Malformations
These malformations usually occur in the spinal bone, spinal cord, or dural covering of the spine. Juvenile AVMs are seen to form in early development and are present at birth. These malformations have a high flow and are large, making it challenging to treat them.
Pial Spinal Arteriovenous Fistulas
These malformations occur between an artery and vein on the spinal cord surface. These are extremely rare lesions and usually diagnosed when a vein has enlarged due to high pressure and compresses the spinal cord. More often the veins become engorged with increased blood flow and the blood supply to the cord is impaired causing it to dysfunction.