From what I understand, a surgery involves a doctor cutting into the body to modify something inside, yes?

Given that this is the case, I don’t think it would actually be possible for me to even have surgery, as my humanoid form is just a visible manifestation of the spirit occupying me. I mean, I’m not intangible, but if I were to sustain serious injury I could just disperse and reform, good as new.

I hope this has helped shed some light as to how tsukumogami bodies work!