Judy brings up a most important point - to make your own saline solutution.
There are packets you can get to make these too. But the key is that the On
the Shelf saline solutions contain preservatives such as benzalkonium that
can actually make the sinus condition worse. At least once a week we see a
patient whose ONLY problem is the reaction to the OTC saline spray and are
cured by using self made fresh solution.
   Hypertonic vs isotonic nasal solution: For whatever reason, all my
patients are given the choice of using isotonic and gradually trying
hypertonic. All prefer isotonic and I can't recall any that continued on
hypertonic. Perhaps using the balanced saline made a difference?
We see a lot of Empty Nose Syndrome and for them hypertonic is especially
contraindicated.
   
   Judy's reference to irrigation for cold prevention is important. There
is a product in your nose called ICAM-1. When this is removed by irrigation,
you remove the portal of entry of the cold virus. However this should be
used only when everyone at the office has a cold and you get very ill when
you do get a cold.
   One of the studies claimed that 20% of flight passengers got sick while
flying. I think that is a bit high, but I see the ones who always get sick
when they fly. Measures to improve nasal cilia activity has been a major
part of the solution.

The physics of pulsatile irrigation is most interesting as it applies to
removal of bacteria, pollen, etc. It has been used for mining too to remove
the silt and leave the coal.
Actually more research has been done in the field of orthopedics:

Using Pulsatile Pressure Saline/Antibiotic Irrigation, Betts N. et al.
Compendium Contin Educa Dent, 17(9): 871 1996.

Evaluation Of Wound Irrigation By Pulsatile Jet And Conventional Methods,
Brown LL; Shelton HT. Ann Surg. 1978 Feb, 187:2, 170-3

The Efficacy of Various Irrigation Solutions in Removing Slime Producing
Staphylococcus, Anglen, J. J., Orthop Trauma 1994 Oct;8(5):390-6.
Here pulsatile irrigation was reported 100x more effective in removing
bacteria from infected screws than regular irrigation.
.

Thanks for this !