Airflow and the Nasal Cycle: Nasal Patency Fluctuations after Laryngectomy

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Abstract
A periodic fluctuation in nasal patency or “nasal cycle” is observed in the majority of adults but has not hitherto been demonstrated in individuals after diversion of nasal airflow. Acoustic rhinometry, a highly sensitive technique which does not require airflow, provided the opportunity to evaluate this situation in patients who had undergone laryngectomy. We examined 21 postoperative individuals (mean postoperative time 4 years) and 14 control subjects matched for age (including 2 patients prelaryngectomy). Acoustic rhinometry was performed serially over 3–8 hours to determine minimum cross-sectional area and nasal cavity volume as indices of nasal patency. Fluctuations in nasal patency were observed in all laryngectomees and controls. These were classified as classical (reciprocal alternating), in concert (parallel) or irregular. The distribution of the control and laryngectomy subjects between the cycle categories was not statistically significant (Fisher's exact test: P > 0.05). The mean periodicity of the cycle was similar in the two groups (controls: 180 minutes, laryngectomees: 176 minutes), but the mean amplitude was significantly less in the laryngectomy group (68 versus 96 cm3; P < 0.07 Mann-Whitney U test). The nasal cycle can continue after cessation of airflow, but it is diminished in amplitude. Therefore, afferent input from nasal airflow receptors may continue to play a role in modulating the cycle's periodicity and amplitude, but are not responsible for generating the underlying cycle phenomenon.