Dural Sinus Malformations

What Are Dural Sinus Malformations?

Dural sinus malformations (DSMs), a type of AV shunt, are very rare congenital cerebrovascular malformation. 

There are two types of DSMs: 

• DSMs involving the confluence of major veins (sinuses) – These are the lesions that can cause heart and breathing problems and brain injury to patients.
• DSMs involving the jugular bulb – This type causes minimal symptoms.

What Causes Dural Sinus Malformations?

The true cause of DSMs is not fully understood at this time, but potential causes include clot formation in one of the major veins. The localized high pressure in the vein (due to the clot), can sometimes open abnormal connections between the arteries and the affected vein.

What Are the Signs & Symptoms of Dural Sinus Malformations?

Symptoms of DSMs are very similar to those of a vein of Galen malformation (VOGM). They typically begin shortly after birth or during early childhood with symptoms including:

• In newborns with congestive heart failure (sometimes the condition is noted in ultrasound before birth)
• Infants with abnormally enlarged head and developmental delay (the enlarged head occurs because the malformation blocks the normal flow or absorption of cerebrospinal fluid)
• Infants presenting with failure to thrive (difficulty feeding and gaining weight)
• Older children with a large head and possibly seizures and/or strokes; sometimes learning difficulties are noted

How Are Dural Sinus Malformations Diagnosed?

Early diagnosis and treatment of DSM is crucial in order to avoid irreversible brain injuries or heart and respiratory failure.

Dural sinus malformations are increasingly being diagnosed on pre-natal ultrasounds of the fetus. Fetal MRI can be done to get better information about the possible DSM noted on ultrasound. It allows better assessment of the brain, heart and other potentially affected organs.

How Are Dural Sinus Malformations Treated?

The treatment of DSM’s is mainly “endovascular” (through the blood vessels), using ultrasound and fluoroscopy guidance.

A pediatric neurointerventional radiologist advances a small plastic tube (catheter) either through the umbilical artery (available during the first week after birth) or the leg artery at the groin, or directly from the carotid artery in certain cases. Catheters can also be inserted from the leg vein (at the level of the groin). The catheters are navigated to the location of the abnormal connection between the arteries and veins, and these abnormal connections are closed using injection of liquid “glue” and sometimes “coils” (miniature “slinkies” made of platinum).

Depending on the size of the malformation, several treatments may be needed to resolve the strain on the heart and lungs and the brain.

Effective management/treatment of patients with DSM needs cooperation among a team of specialists from several disciplines including neurointerventional radiology, cardiology, critical care, neurology and neurosurgery.

What Are the Long-Term Effects of Dural Sinus Malformations?

Without treatment, the prognosis of dural sinus malformations involving the torcular and adjacent sinuses (major veins of the brain) is not favorable. With timely and successful endovascular treatment, the prognosis can be significantly improved.