# Atlantoaxial Subluxation/Instability



## kpmc328 (Mar 13, 2015)

A couple months ago, our Havanese puppy, Zoe (5 months old at the time) ran into her crate to get a toy and on her way out, she fell on her side and started yelping in pain. We could not figure out what was wrong..we thought she may have injured her leg, because she wasn't walking right and didn't want to walk due to the pain. We took her to her vet, and our vet right away realized that whatever was wrong, it was neurological and recommended we go to the speciality emergency clinic nearby.

At the emergency clinic, the internist thought it might be meningitis, which is often fatal in dogs. We started treating with IV antibiotics and pain medicine and she stayed overnight. The next day, a neurologist saw her, and based on her x-ray, he diagnosed Zoe with Atlantoaxial Subluxation, as he could not see a dens or odontoid process on her imaging. She received an MRI and spinal tap to be confirm the diagnosis.

Atlantoaxial subluxation/instability (AAI) is a rare diagnosis that is either congenital or due to trauma. When congenital, it is often in toy breed dogs such as yorkies and toy poodles, but it can affect any toy dog usually less than 1 year old and from mild trauma, such as jumping off furniture. I have not found it be reported in a Havanese anywhere online. Dogs with congenital AAI have an absence or hypoplasia (smaller size) of the dens, which is a protruding thin piece of bone on the 2nd cervical vertebrae (axis of C2) that fits into the first cervical vertebrae (atlas or C1) and keeps C1 and C2 aligned. Without the dens, whenever Zoe would flex her neck or bend it forward, space would form between the two vertebrae at the back and C2 would slide behind C1 in the front, causing compression of her spinal cord.

Zoe was very fortunate that she was diagnosed quickly and has an outstanding neurologist. She wore a neck brace to remind her not to flex her neck for 3 months. After her initial episode, she started to walk again, but 2.5 months after, she had another scary episode where her back legs were paralyzed again. We immediately started her on a steroid taper and by the end of the week, she was walking, although still a bit ataxic (wobbly). We spoke with her neurologist, and he said since she could stand, we didn't need emergent surgery and could wait until the scheduled day, which was in two weeks.

At 8 months old, her bones were mature enough for her to undergo surgery, the only permanent treatment. On tuesday this week, she had her C1 and C2 vertebrae stabalized with screws and a bone cement. She is walking, and we expect a full recovery.

This was an extremely scary and emotional ride for my husband and I. Growing up with dogs, I never expected anything like this to happen. As Havanese are becoming more popular, I wanted to share our story, in case AAI would ever affect another Havanese. We did let our breeder know. It is a "congenital" condition, however it is rare and may have just been a random genetic mutation that only affected Zoe. So far, her litter mates have not had any health issues. We love Zoe so much, and we are so happy with how well she is doing. 

For more information, I found this link helpful:
https://www.acvs.org/small-animal/atlantoaxial-instability


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## krandall (Jun 11, 2009)

Wow. I'venever heard of this, but thank you for sharing your story. I'm glad that you were able to get such good treatment for Zoe and that the outlook for her is so bright!


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## Heather's (Jun 18, 2012)

Your so very fortunate to have great vets to properly diagnose the problem. It"s good to hear Zoe is recovering well after surgery!


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## whimsy (Apr 3, 2010)

Wow. ...so glad your baby is back on the road to recovery! Sounds like a very stressful time you all went through. (She's adorable  )


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## Zoe093014 (Jan 27, 2015)

She's adorable! I'm so glad Zoe will be fine! And again thank you for sharing that story. My Zoe has been diagnosed with MVD, a rare congenital liver disease which made anaesthesia difficult with her spay and dental. But so far she is symptom free from the MVD. 
Best to you and Zoe,

Linda


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## Ollie"s Mom (May 23, 2014)

Wow, scary, but what a happy ending. Thanks for the info and I hope Zoe is back to jumpin and playing soon.


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## Sassy's Mom (Feb 4, 2015)

Zoe keep getting better. Thanks for sharing like Karen I've never heard of it either.


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## kpmc328 (Mar 13, 2015)

Thank you all for the kind words! Zoe is recovering well, and she is starting to act like a puppy again


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## Dee Dee (Jul 24, 2015)

How terrifying your poor baby! (SO adorable BTW!!!).
I had not heard of this either. But I have had tons of horrible health issues with my last 3 babies, Great Dane and 2 longhaired Dachshunds. That is why I chose Havanese this time they seem like a very healthy breed (comparatively, over all) but I know they have their issues and like you said it's so good to educate others in the breed about the things like this that do crop up. So glad your Zoe should have a full recovery good on you for figuring it out so quickly.


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## Jackie from Concrete WA (Mar 23, 2015)

Wow, never heard of this before. Thanks for bringing it to our attention.


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