Susie, how old is your dog, and is she generally in good health?
In Switzerland, and generally in Europe, an ovariectomy - that is removal of ovaries only - is the preferred procedure for young, gynecologically healthy females and has been for 20 plus years now.
The rationale is that the surgery is simpler, shorter, the incision smaller (laser keyhole is one possible procedure if the vet has that equipment) hence less anesthetic and operative risk and a quicker recovery.
I understand your question and concerns if you come from a country where ovariohysterectomy is the norm, as I did. If it helps - when the ovaries are removed hormone production stops, thus the danger of pyometra is reduced. The incidence of post-ovariectomy pyo is very very low, about the same as post-ovariohysterectomy stump pyo, IIRC.
Studies have shown about the same low level of post operative concerns (later incontinence, etc.) with both surgeries. So on balance, the lesser surgical risk involved in an ovariectomy is generally the deciding factor for young healthy dogs.
However, in an older dog, or if the dog is suffering from/is prone to one of the reproductive system diseases, or if there is an anatomical anomaly then the full ovariohysterectomy (ovaries and uterus) might be recommended.
Which procedure is best for your dog is a discussion to be had with your vet.
Hooligan, the only young healthy female I've had since coming to Europe, had the ovariectomy at age 15 months. A quick surgery, no after effects, she was bouncing around again the same day. She's still a healthy active lady at almost 10 years old. (How can my baby be 10? Where does the time go?)
My older girls each had the ovariohysterectomy, decision based on individual medical necessity in each case.
Whichever option you choose, I'm glad to hear that you are getting this done.
I was told that my first sheltie should not have the op, or any elective surgery, when young due of a heart condition. However, at age 8 she developed pyometra, a truly awful and often fatal condition, and had to have an emergency ovariohysterectomy, taking the risks we had feared now at a time when she was already gravely ill. In hindsight, I wish I had had second, third and fourth opinions as to the risks of surgery when she was young. She survived the pyo, but it was a very near thing. That incident opened my eyes, to say the least. The incidence of pyometra is 30% in mature intact females - and pyo is something like 75% fatal.
So good for you for getting this done.
I've written about this before but coming from the US, I had assumed that an ovariohysterectomy was the norm. When speaking about Hooligan's sterilization to my vet here I used the euphemism 'spay', as did he. However, to the vet a spay naturally meant the ovariectomy, which is what he did. I was surprised, and not to say a bit freaked out, when I learned afterwards that Hooligan still had a uterus - but the vet pointed me to the research on the subject, and reading the studies I was convinced that this was indeed the right thing for Hooligan.
But the incident did teach me one thing: Never use euphemisms when having a medical discussion!
Enough of my rambling. Wishing you and your girl all the best with the surgery.