Greitz / intramedullary pulse pressure theory

What it is

The Greitz theory (intramedullary pulse pressure theory) is a more recent explanation for syrinx formation. It proposes that pressure effects within and around the spinal cord — related to fast CSF flow at the obstruction creating low-pressure (Venturi-like) effects and increased pulse pressure within the cord — drive fluid accumulation that forms a syrinx.

Understanding Greitz / intramedullary pulse pressure theory

This theory shifts emphasis from fluid being pushed directly into a central canal toward the idea that the obstruction at the craniocervical junction creates abnormal pressure dynamics: fast CSF flow through the narrowed space produces a suction-like (Venturi) effect, and increased pulse pressure within the cord draws fluid from the surrounding tissue and small blood vessels into the cord, accumulating as a syrinx. It attempts to address observations that earlier theories did not fully explain (such as syrinxes not always connecting to the central canal). The Greitz theory is part of the evolving understanding of syrinx formation. Understanding it shows how thinking has continued to develop beyond the earlier piston and pressure-dissociation models.

Why it matters

Understanding the Greitz theory helps families see how the understanding of syrinx formation continues to evolve, with newer models emphasizing pressure effects within the cord itself — reflecting ongoing research.