Sensory and Autonomic Fibers in Anterior Ethmoid, Posterior Nasal, Posterolateral Nasal Nerves.

BACKGROUND

Sensory and autonomic nerves supply the sinonasal mucosa and contribute to the pathophysiology of certain forms of chronic rhinitis, rhinosinusitis, and craniofacial pain. The compositions of these intranasal nerves have been incompletely studied. The purpose of this cadaveric study was to investigate the relative areas of sensory, parasympathetic, and sympathetic nerve fibers within different nasal nerves.

METHODS

Ten fresh cadaver heads were dissected, and anterior ethmoid (AEN), posterior nasal (PNN), and posterolateral (PLNN) sections were harvested unilaterally via endonasal and transorbital approaches. Specimens were formalin-fixed, sectioned, and stained with hematoxylin and eosin, as well as for neuropeptides (substance-P, calcitonin gene-related peptide [CGRP], neurokinins-A and B [NKA, NKB], vasointestinal peptide [VIP], neuropeptide Y [NPY]), and enzymes (choline acetyltransferase [ChAT] and tyrosine hydroxylase [TH]). Enzyme and neuropeptide nerve marker percent areas were calculated using brightfield analysis. Sensory and autonomic nerve marker percent areas were then compared within and between AENs, PNNs, and PLNNs.

RESULTS

In total, 10 PNNs and AENs and 8 PLNNs were available for analyses. Sensory, parasympathetic, and sympathetic nerve markers were identified in every PNN, PLNN, and AEN, and were mostly equivalent between nerves. Only neurokinin-A demonstrated a significantly greater percent area than other markers across different nasal nerves.

CONCLUSION

Sensory and autonomic nerve markers were present in all AENs, PNNs, and PLNNs, and were largely equivalent between nerves. NKA presented the greatest percent area consistently across each of the nerve types. Future studies should explore the relative contributions of sensory versus autonomic dysfunction in chronic rhinitis, rhinosinusitis, and craniofacial pain.

LEVEL OF EVIDENCE

Level 4.