How does a deviated septum affect the sinus enough to justify surgery?

Good question. Rhino-sinusitis is a viral/bacterial or rarely a fungal infection of the paranasal sinuses caused by obstruction of the very narrow entrances to the sinus cavities from the nose. As such, a deviated septum would have to be so severe as to obstruct those openings. However, your surgeon may opt to correct such a deviated septum, if access to the sinuses is obstructed by the septum.

Related Questions

What are some things I should know after having deviated septum and sinus surgery?

Irrigate/followup. Deviated septum and sinus surgery have come a long way over the past decade. Now most patients don't need packing and don't get bruised or swollen on the outside. But it important to follow instructions and not strain or do strenuous activities for a few weeks after surgery. Irrigate with saline regularly and keep your followup appointments so your surgeon can make sure you heal properly.

Should I be concerned that I am not able to smell after deviated septum and sinus surgery?

Time Heals Most. It is not unusual for your symptoms of nasal obstruction and inability to smell to get worse before they get better after surgery. This is often due to intranasal swelling & improves with time. That being said, some people have impaired smell before surgery and don't realize it. On the other hand, damage to your smell nerves during surgery & persistent sinusitis are known risks. See your surgeon.

Why do I still have sinus problems if I had deviated septum surgery;?

Not the only cause. A deviated septum is not always the cause of sinusitis. It may produce a nasal airway obstruction that contributes to sinusitis but there are many other possible explanations for the sinusitis. Testing the septum may relieve outflow o structuring but decongestants, drainage and antibiotics may still be needed.
Sinusitis? The deviated septum may have had nothing to do with your sinus problems. You need to be reevaluated to determine your diagnosis.
Sinus surgery. Maybe you need sinus surgery. Have you nose evaluated by a board certified otolaryngologist.
See an ENT. For evaluation, imaging and treatment options.