Surgeon in training here...
There is an sterile field composed by whats on the surgical Table (patient) and the drapes over him, The surgeon, OR Tech (The one that hands the instruments to the Surgeon), her table with instruments, the Overhead Light Handles (these are plastic pieces that are sterile for the Surgeons to handle) \
Everything else is non sterile... You would have to wear a surgical attire to enter the OR Suite: Scrubs (The green shirt and pants) Surgical Hat, and a mask.
You can bring your whole bag of gear. Besides what I mentioned, nothing else needs to be sanitized, Surgeons will call for you and they will move the Overhead lights away (Too Bright and Yellow for Photography), the Will also stop what they are doing and move away for you to take the shots.
You CAN NOT physically touch anything that is sterile, you can bend yourself, climb on a Steping stool (readily available in the ORs) if you need to.
Ive seen some pros doing it... They bring their camera with no neck strap, sometimes a hand strap (dont know how to call it) the Surgeon explains what he wants to show in the pic and he takes the shots and shows the surgeon the pics.
Sometimes the Surgeon Kindly ask this guy to stay during the Operation, so he can call for more shots at the appropriate time with no delay waiting for the guy to come.
That sounds like a very interesting way to earn a living as a photog. I wonder who owns the rights to the photos? I'd of course put some very fine print in the contract



