Does the amount it’s protruding have anything to do with the severity or need to get surgery

I was just recently told I have Chiari type 1 after getting an MRI in January. I have a lot of questions but my main one is that I’ve seen people talk about the amount of mm there’s is. I’m hoping to not have surgery as I am in college and that would take a toll on my current semester. So my question is does the mm have anything to do with the need for surgery? They told me mine was 7mm but honestly I have no clue what that really means. Additionally, I’m still waiting on a second MRI and was wondering how others dealt with the waiting of the situation?

Hey Kreyn,
There’s no nice way to put this, but the wait can be awful. Often they tend to give us partial information, then make statements like “…ohh, but don’t worry… …just wait until we get the follow scan…” . If you are anything like me, that line “…ohh, but don’t worry…” TOO LATE!!! I was a ball of stress before the appointment, that statement just adds to it.

Initially, I was given the “wait’n’watch” recommendation. I’d been symptomatic for many years and been given all sorts of pseudo-diagnosis ie It could be ‘x’ or it could be ‘y’, but nothing definitive. So the whole idea of waiting did not sit well with me and I sort out a 2nd opinion.

Some medicos are of the opinion that if the tonsil is less than a certain length, your symptoms will be minimal, but this is NOT always the case. Some people can have a rather large tonsil yet have minimal symptoms and yet for others their symptoms can be extreme but their herniation minimal. So although some medicos do like to draw a direct line between the size and symptoms, you only have to read through other member’s stories to find a large variation both in size and symptoms.

Now you say “They told me mine was 7mm but honestly I have no clue what that really means”
The 7mm is the length of the tonsil or the tonsillar herniation. It’s a measurement of how far the cerebellum has dropped. Here’s an image that may help explain it.


For some people the cerebellum herniation can restrict the flow of CSF (cerebral spinal fluid), the blue area in the images, and can cause a condition called hydrocephalus (aka water on the brain). It can alter the blood flow within the brain. It can put pressure on the spinal cord, sending weird/odd messages anywhere in the body. The cerebellum’s main role is to monitor and regulate motor behaviour ie movement, balance, posture without any need for conscious awareness.

It was formerly thought that these were the only roles the cerebellum played, but it has now been shown that the cerebellum plays a much bigger role in our body’s autonomic systems. This can also be why some medicos can be a little dismissive when we report symptoms, by saying things like “Well, that’s not related…” and for Patient ‘A’ that maybe correct, but that’s not to say that it’s not related for Patient ‘B’. We are all individual and so can our symptoms be very individual.

I hope this may help to resolve some of your questions.

Merl from the Modsupport Team

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I have 7mm protrusion. Diagnosed in 2005. No symptoms until high speed MVA 2021. Extensive ligament damage from C0-C7. Rotation of C1 to C2 of 27 degrees. Lots symptoms now.
Diagnosed as Cranial Cervical Instability CCI.
Saw Dr. Scott Rosa Upper Cervical Chiropractor in NY who did extensive MRI to show neck ligament damage. There was no change in herniation length after accident. Still 7mm.
Many CCI patients have old injuries that become symptomatic years later …often after another injury. If you search Dr. Scott Rosa and Dr. C Centeno. Centeno Schultz clinic this may provide clarification. This may not be your case but worth researching if you have had any type of head injury…whiplash, fall, sports injury, EDS connective tissue condition even if happened years ago.
Another avenue to consider

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I had an eight mm herniation traumatically caused when i was a volunteer EMT on duty in the rescue squad. I was in a broken swivel seat in the back which was vlbe broken by an accident about 5 months prior to the day my cerebellum was herniated. I was sitting in the swivel captain’s chair. The latch had not been repaired from the first accident. The centrifugal force of the seat spinning as well as we were hit by a 46,000 ton freight train hitting the rescue squad right by where I was sitting. This herniated my Cerebellum 8mm. Then two different physical therapists did mechanical traction. That made me severely worse. So much so i went downhill quickly with pain and more symptoms. I found out that I had Chiari from a psyc