Poly(vinyl alcohol) (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula [CH2CH(OH)]n. It is used in papermaking, textiles, and a variety of coatings. It is white (colourless) and odorless. It is sometimes supplied as beads or as solutions in water.

Microspheres or microbeads are tiny polyvinyl alcohol spheres or particles suspended in a sterile solution that are pushed through a catheter flowing forward from the catheter tip into vessels just short of the tumor itself. As they flow forward the vessel narrows and the particles lodge within the vessel forming a dam. As more particles lodge again a dense plug forms and blood flow stops.

A general supposition among neurointerventionalists is that embolization of cerebral AVM with silk sutures and PVA particles does not yield a durable occlusion.

Particle embolization (SPE) can safely provide durable AVM devascularization, therefore, appropriately selected nidi can be effectively treated with combined SPE and SRS ¹⁾.