I 'negotiated' with my surgeon ahead of time. Most of them do if you are using a private hospital. Also, your health insurance would list the surgeons who are signed up to the no gap fees.
The medication costs were high as these are now all 'outsourced' - good lurk for the hospitals.
My heaviest bill was the anesthetist (which had to be paid ahead of time) but as I went back for 2 additional surgeries they kindly did not charge fees after the 1st operation.
When I had knee surgery I did have to pay something for his assistant surgeon but cannot remember how much.
I'd suggest speak to him/her at your next appointment and he/she may negotiate.
Good luck.