Is septoplasty required in case of mild dns. i also have mild infection in bilateral maxillary sinuses. doctor also suggested fess.

Depends on symptoms: A mild deviation of the septum usually does not cause problems. The septoplasty would be indicated for certain nasal symtoms like persistent obstruction, runny nose, etc. The fact that you are aware of maxillary sinus infection suggests that a ct scan has been performed. If there is mild disease and your symptoms are minor, ask your doctor if further medical treatment is an option.

If med Rx fails: If medical therapy with antibiotics, decongestants, steroids and hygiene (neti pot) fails to produce improvement, surgery may be a good option.