Its primarily used to prevent large scab formation. If this occurs on opposing sides of a sinus cavity or can lead to fusion of that cavity. Conversely, keeping these scabs constantly moist could also lead to fusion.

Despite my use of this spray, I still had fusion occur post-FESS+sinoplasty. Also this was all in 2001, so the standard of care may have changed a lot since then.

An isotonic solution i.e. similar salt concentration to normal body tissue/fluid, is used post-surgery.

This is very different to a hypertonic solution i.e. higher salt concentration to normal body tissue/fluid, which is helpful for every day use to break-up thick mucus build-up. Importantly, a hypertonic solution should not be used post-surgery as this could be irritating if not damaging.