I have my nasal septum deviated to the left for about the last 6 years. I somehow blame it on the sutra neti I used to do because I didnt have the deviation before it. I might be wrong in the cause. My deviation is not very severe. Only that if I have to breathe with only my left nose (not during natural shift of dominant nostril) by closing my right nostril I have a bit of a problem.
My question is, are there any caveats for people doing pranayama with septum deviations. Especially pranayama like anuloma viloma or nadi shodhana which require alternate nostril breathing. As of now I get around the problem by using my other hand (while one hand does the nostril closing and opening) to open my left nostril a bit.
I too had a deviated septum which interfered with my practice. Its been several years now since I've had the corrective surgery, and well, it was probably one of the best things I've done for my overall health and happiness.