What is a good way of wishing someone 'good luck' for an operation? The words 'good luck' don't sound right, especially because it is a very difficult operation with lots of severe risks.
I feel that I know what you mean by not wanting to add "luck" into the equation. It seems to me that calling luck into play would only serve to add more stress to an already stressful situation. Hoping for luck brings to my mind a feeling of more uncertainty, and questions the reliability of the surgeon and anesthesiologist. I would probably tend to want to stay as positive as possible, making a statement that is not a question as much as it is a foregone conclusion. Such as: "I will be so happy to see you in recovery after the operation" or "Things will be so much better after you're through this". Since I do not know the nature of the operation I can't give a specific answer to your question, however I do hope that you get my meaning. Best of luck to you in finding a suitable term that you're comfortable with. ☺
I happen to be a cardiologist and every week I see a lot of patients in their pre-op evaluation. After I have seen them and my job is finished, I hand them my report and wish them good-luck. I think what really matters is not exactly the words you use, but how it all sounds. A warm and sincere "good-luck" when shaking hands will certainly be appreciated.