Hello I have gone through your question and understand your concern. Various factors can cause persistent infection despite of surgery including allergy, sub optimal surgery, removal of excess of tissue during surgery, fungal infection, immunodeficiency and many others. Smoking and alcohol consumption can also cause recurrent infections by causing paralysis of cilia lining the nasal tract and thereby causing mucosal secretions to pent up in the tract which promotes growth of microbes leading to infection. To find out the cause of infection the above mentioned factors must be ruled out firstly and secondly the cause have to be treated then with best possible approach. Sometimes surgery does not resolve the recurrent infection but only drain the obstruction which is the main goal of surgery. In such cases antibiotics can be taken to treat infection or alternative techniques of treating the condition is Somnoplasty where radiofrequency is used to treat the sinus or a papaya derivative formulation called as ClearEase have found to be helpful. Hope your concern is answered. Thank you.