Sunday, July 15, 2012

Animal shelter surgery: autoligation

When I watched my first video on how to spay a dog, lo these many (two) years ago, I kept saying “what’s a pedicle?” Apparently it was very important to tie the suture around the pedicle very tightly. And from context it was clear that the pedicle was the bit of tissue connecting the ovary to the body wall. But what was it?

I finally figured it out. The pedicle is the bit of tissue connecting the ovary to the body wall. It isn’t really anything in particular, it isn’t any actual anatomical structure, it just holds the ovary in place. But blood vessels run through it, so when you cut it in order to remove the ovary from the animal, lots of bleeding can happen. Bleeding is bad, particularly if it continues after the animal is closed up. So one of the hardest and most important parts of spaying a dog or cat is to make sure that you wrap some suture really, really tightly around the pedicle and tie it in a really, really secure knot so that no blood can get out.

Or not.

In shelter spays, the goal is speed. Most importantly, the less time spent under anesthesia, the better. This is particularly true in the case of feral cat spays, in which the cat can’t receive optimal post-op care because she can’t be handled. Also, of course, shorter spays means you can move more animals through in a day, sometimes dozens of animals per surgeon. We are not keeping up with the cat population with surgical sterilization as it is, so the high volume spay/neuter operations really try to keep as many animals as possible moving through.

One way that shelter vets try to make surgery time shorter is with autoligation. Instead of tying suture around the pedicle before cutting it, the pedicle is actually tied to itself. It’s a lot faster once you learn to do it. There is no futzing with getting the suture around the little cat pedicle with all the big clamps around it (oops! I looped the suture around a clamp! Time to start over). Tie the pedicle to itself, cut, inspect, let it sink back into the abdomen and move on. This is a pedicle tie, also known as autoligation (in other words, ligating the pedicle with itself).

Why don’t all vets do this? I suspect some private practice vets do. However, the technique takes a little learning, so if you’re not doing at least a few spays a week, it’s not really worth the investment. One vet recently told me that his private practice only performed about one spay a month. The rest were done in shelters, and that was fine by them.

And that’s one of the ways in which shelter surgery is different from general surgery.

This post written in celebration of my first unsupervised pedicle tie.


  1. Congrats on your first unsupervised pedicle tie. ;) This reminds me of a video I watched of a cat neuter, where the testicle was kinda twisted off rather than cut off... The idea being speed and less 'bother', as the twist prevents most blood flow.

  2. After reading your post earlier this month, I done some research in to pedicle ties and I must say after trying it, I love it. Keep up the good work!