Under normal conditions, the airflow through the nasal cavity for breathing enters in the form of laminar flow along the nasal septum. In patients with deviated septum, the nasal cavity is altered and deformed, and the airflow enters the nasal cavity forming a vortex, which disturbs the airflow and allows allergens to accumulate, increase in concentration and prolong the retention time. The protruding part of the deviated septum is more susceptible to the impact of airflow and the sensitivity of the sneezing reflex arc is increased. In addition, the onset of allergic rhinitis is related to the vegetative nervous system in addition to the antigen-antibody response. Long-term uneven stimulation of the bilateral nasal cavity easily leads to increased excitability of the nasal parasympathetic nerves. After correcting the anatomical abnormalities in the nasal anatomy and removing the factors of nasal septal deviation, the different degrees of nasal tract obstruction are lifted.
When the respiratory airflow is smooth, the inflammation of the nasal mucosa and the secretion of nasal mucosal glands and vascular nerve reactivity can be reduced, which reduces the secretion of eosinophils and basophils and relieves inflammatory nasal mucosal edema and vasodilatation, thus relieving clinical symptoms. Therefore, the efficacy of surgical treatment in patients with allergic rhinitis with deviated septum is significantly better than that in patients without surgical treatment; and the long-term efficacy of surgical treatment in patients with allergic rhinitis with deviated septum is better than that in patients with allergic rhinitis without deviated septum.
The destruction of the parasympathetic fibers of the anterior septal nerve and nasal mucosal nerve endings during surgery also reduces the reactivity of the nasal mucosa blocking the action of the overexcited parasympathetic nerve on blood vessels and glands, which has a certain effect on improving the outcome.