Topical intranasal anesthesia impairs trigeminal function and airflow perception

Impairment of airflow perception by the intranasal trigeminal system may explain chronic nasal obstruction (CNO),especially in cases where no major deformity or mucosal inflammation can explain reduced airflow. We aim to characterize the effect of topical intranasal anesthesia on intranasal trigeminal sensitivity and consequently the sensation of nasal obstruction.

We performed a crossover study of 16 healthy subjects, randomised for either treatment (topical intranasal anesthesia with 10% Xylocaine) or placebo (saline solution). We used the Trigeminal Lateralization Task (TLT) with eucalyptol to assess trigeminal sensitivity. We measured nasal patency objectively with Peak Nasal Inspiratory Flow (PNIF), and subjectively with a Visual Analog Scale (VAS), the Empty Nose Syndrome 6-Item Questionnaire (ENS6Q), and the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire.

Topical intranasal anesthesia significantly reduced intranasal trigeminal sensitivity. Further, after topical intranasal anesthesia,reduced trigeminal sensitivity was associated with the subjectively reduced nasal patency, as highlighted by ENS6Q and NOSE scores.

Topical intranasal anesthesia reduces intranasal trigeminal function resulting in subjectively reduced nasal patency. In future studies, the relation of reduced intranasal trigeminal function and subjective nasal obstruction needs to be addressed to open an avenue for potential interventions for an important portion of ENT patients.