Chiari Patients: Pathological Findings

The chart below shows some of the findings we've seen in Chiari patients that we have recently operated on. Chiari patients fall into two categories: those without syringomyelia (14 patients) and those with syringomyelia (51 patients). 

Pathological Findings observed Intraoperatively

Pathological Finding	Chiari I and no Syrinx (14 patients)	Chiari I with Syrinx (51 patients)
extradural compression *	14 (100)	51 (100)
tonsillar impaction	14 (100)	51 (100)
arachnoid scar, dense +	6 (43)	19 (37)
gliosis #	1 (7)	5 (10)
vascular distortions ^	2 (14)	4 (6)

* MR imaging reveals distortion of cerebellum and presence of extradural bands at foramen magnum and/or C-1.
+ arachnoid scar adherent to impacted tonsills requiring microsurgical technique to remove.
# Gliotic tonsil tips; longstanding changes noted.
^ Tonsils displaced inferiorily with loop(s) of PICA(s) embedded in arachnoid membrane or aberrant position from longstanding compression.

From the chart, you can see that the first two, "extradural compression" and "tonsillar impaction" go along with the malformation itself. However, note that approximately 37% of the patients with a syrinx also have scar tissue built up.

This is why the surgeon must take his time and figure out what is causing the blockage of spinal fluid, and take appropriate actions in order to fix the blockage.