Recently published findings in the Journal of Sleep Research by Professor Eng Ooi
These findings indicate major improvements in upper-airway collapsibility during wakefulness and sleep, and reductions in loop gain following multi-level upper-airway surgery but no systematic changes in key OSA pathophysiology/severity measures following isolated nasal surgery, although the sample size for this comparison was small.
https://onlinelibrary.wiley.com/doi/10.1111/jsr.70416