NeuroBites – Tail Avulsion


Every week, the BVNS neurologists, residents and interns convene to discuss a human or veterinary neurology/neurosurgery article.

NeuroBites is a digestible synopsis written by Dr. Bush of the article covered in journal club.

Welcome to NeuroBites.

Caraty J, Hassoun R, and Meheust P. Primary stabilisation for tail avulsion in 15 cats.
Journal of Small Animal Practice (2018) 59, 22–26. DOI: 10·1111/jsap.12773

Click HERE for full article.

Dr. Rivera recently did a very nice job discussing an article about the very end of the nervous system in cats – the nerves to the tail. Cats being the curious creatures that they are, can sometimes get into situations where they damage the nerves to the tail from traumatic avulsion of vertebrae.

What is this picture trying to show?
The first vertebrae of the tail is marked as Cd1 (caudal 1). There can be up to 23 vertebrae in the tail but only 5 are pictured here.  The beginning of the nerves to the tail starts at the end of the spinal cord (conus medullaris) and are located within the L6 vertebrae (number 6 above). From here, the nerves run all the way to the end of the tail within the vertebral canal of the tail. The nerves to the urinary and bladder start in L5 (not pictured) and exit the spinal cord in the sacrum (S).

What is a tail avulsion?
Detachment or tearing of a caudal vertebra from the adjacent caudal vertebra or sacrum.

How bad would a tail avulsion actually be?
Well, suddenly you have intense pain at your tail base and can’t urinate. Not to mention you cant move your tail for things like balance and signaling to other cats (and people) how you are feeling (imagine no Facebook).

Why would a tail pull injury result in an inability to urinate?
When the tail gets pulled there is damage to the nerve roots that run to the urinary bladder. The roots may just be stretched (reversibly damaged) or separated (permanently damaged).

What can be done for this problem?
There is a relatively simple surgery where suture is passed through a hole made in dorsal process (top fin) of the second sacral vertebrae and suture material passed around the lateral extensions of the avulsed caudal vertebrae.

Does this surgery work well?
If the patient has not experienced neurotmesis (complete cutting of the nerve) and the cat has surgery then:

15/15 (100%) – regain comfort in just 2 days
11/15 (73%) – regain ability to move their tail and feel their tail in 39 days on average (3-90 day range)
5/8 (63%) – regained ability to urinate even when they lose perianal reflexes

What did this article do for me?
Firstly, it made me aware that there is a surgery that can be applied in this situation that can improve outcome. Secondly, it made me think much more about what cats might do with their tails.

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