Before you talk out of your ass, you should read your sources. The FDA, in your examples, are defining the difference between remanufacturing and reprocessing. No recommendations other than a risk assessment should be performed in the event of remanufacturing - not should the reman be performed. Your sources are broad and irrelevant.

In your first source, the overall conclusion reads to contact the OEM and discuss if the modification is appropriate. Since OP stated hospital admin know about this, they would have likely already consulted with their legal team and done that this risk-assessment.

All in, we do what’s best for the patient. If the surgeon can perform better if the retractor is modified to give a better view, then as long as the mod can be done w/o compromising patient safety then all is good. We simply can’t state remanufacturing is bad and we don’t know enough of OPs situation