Chiari Online Support Group

Tonsil descent

Nine years ago I had mri and it showed 1.1 cm decent not significant at all. Well I took a bad fall and wondered if the cm had any affect on my recovery so went for another mri. That showed 3.7 cm decent. The neurologist said that is significant change and sent me to neurosurgeon. He said the first mri must have been wrong as the tonsils don’t further descend, that doesn’t sound right to be. What do you all think

What an interesting situation. Are you having an increase in symptoms as well?

Sharon from ModSupport

Yes and I feel like since I hurt my leg I don’t sleep well which also increases symptoms. I guess it was the first neurologist that diagnosed me saying it’s only gone 1 cm in 48 years so you should have a while before symptoms get worse that made me think the decent would be progressive

Sorry to hear of the issues.

Let me suggest you get a copy of the reading of your images.

You are saying cm but 3.7cm is significant(as is 1.1cm). To meet the most common definition of a Chiari I Malformation, you need 0.5cm(5mm) of cerebellar tonsillar descent. I suspect you mean mm, not cm. The accuracy of an MRI is only about 1mm, so going from 1mm to 3mm may just be the accuracy of the MRI. However, going from 11 to 37mm is dramatic!

Whomever you see for this, make sure they have both sets of images for direct comparison. If the images were done in the same hospital system, the radiologist would typically directly compare images and state whether they felt there was a change or not.

That decimal point is a big deal!

While it is atypical for Chiaris to have further cerebellar tonsillar herniation(particularly in adults), it can happen. In the setting of worsening images and symptoms, many surgeons will consider decompression.

Hope these thoughts help.

Thank you I checked and it is cm on both. I’ll perhaps get another opinion with both images.

Wow, that is a big difference! I always request to chat with the radiologist when they go over the images the first time. I find this is really useful (I also find the human body fascinating, so that may contribute!).