Nasal physiology: improving our understanding in the health and disease
The erroneous concept that “bigger is better”
in terms of nasal airway size still surfaces in
otolaryngologic practice, and the importance
of laminar and transitional airﬂow for opti-
mal nasal function are sometimes forgotten,
as are the effects of the normal nasal cycle on
interpretation of computed tomography (CT)
and magnetic resonance (MR) imaging. Sev-
eral articles in this issue of the International
Forum of Allergy and Rhinology (IFAR) eval-
uate different aspects of nasal physiology and
nasal symptomatology in health and disease.
Computer ﬂow dynamic (CFD) simula-
tion has become popular in recent years as
a methodology for evaluating nasal airﬂow
and sinus air exchange. De Gabory et al.
use a highly re-
ﬁned CFD gridding model to evaluate the airﬂow during
the respiratory cycle, and the supplementary slow motion
videos available online from the IFAR website are deﬁ-
nitely worth review. The study nicely demonstrates how
the olfactory cleft is mainly ﬁlled from the posterior dur-
ing expiration and how particles remain in the posterior
portion of the olfactory cleft after the respiratory cycle has
been completed. They hypothesize that this may explain
why patients may ﬁrst recover a sense of taste before they
recover a sense of smell.
Nishijima et al.
use CFD models to evaluate the effects of
virtual polyps on olfaction. This study suggests that polyps
in the preolfactory region strongly decrease olfactory air-
ﬂow on inspiration, and that polyps in the middle meatus
might increase olfactory airﬂow, but they point out that
the anticipated increase in olfaction has not been observed
clinically, probably because clinical mucosal changes are
typically more diffuse and polyps may also result in medi-
alization of the middle turbinate.
Although the racial origin of the model utilized in the
de Gabory et al.
study is not denoted, the airﬂow pattern
would suggest a white nose and presumably the Nishijima
work utilized Asian models. Despite the publication
of a number of CFD airﬂow simulations, none to my knowl-
edge have yet evaluated individuals of African descent, who
in earlier airﬂow models were described as having airﬂow
patterns along the ﬂoor of the nose, thus creating an op-
portunity for future research.
View this article online at wileyonlinelibrary.com.
How to Cite this Article:
Kennedy DW. Nasal physiology: improving our understanding in the health and
disease. Int Forum Allergy Rhinol. 2018;8:666–667.
Hou et al.
evaluate symptoms of nasal ob-
struction, eosinophil cationic protein (ECP),
and nasal nitric oxide (NO) in allergic
rhinitis (AR) patients and healthy con-
trols. They show that nasal NO and ECP
were positively correlated in mild to moder-
ate nasal obstruction, but severe nasal ob-
struction resulted in a signiﬁcant decrease
in nasal NO, supporting a prior study
by Suojalehto et al.,
which showed that
nasal NO correlated with opaciﬁcation score
and eosinophil count in patients without
marked sinus ostial obstruction. However,
the Hou et al.
article is the ﬁrst study to
demonstrate loss of correlation between NO
and ECP with marked nasal obstruction.
At the other end of the nasal patency spectrum, empty
nose syndrome (ENS) is thought to arise as a result of
too patent nasal airways. Manji et al.
report on a cross-
sectional study evaluating the impact of ENS in 53 in-
dividuals by functional and psychological questionnaires.
They demonstrate a strong correlation between ENS and
depression, anxiety, overall daily pain and discomfort,
and impairment in activities of daily living. They recom-
mend addressing both the psychiatric components and the
physiologic issues in order to obtain optimal management
Brooks et al.,
in contradistinction to a number of prior
studies, demonstrate that there is a signiﬁcant correlation
between Lund-Mackay CT scores (LMCTS) and overall
22-item Sino-Nasal Outcome Test (SNOT-22) scores in a
large tertiary rhinology center cohort utilizing a longitudi-
nal linear mixed effects model. Many prior studies have not
demonstrated a correlation between CT scores and patient
symptomatology. When looking at individual symptom do-
mains, the effect relationship was only seen in the rhinologic
and extranasal domains—the domains reﬂecting the ma-
jority of symptoms used to diagnose chronic rhinosinusitis
(CRS). Additionally, patients with the most severe preop-
erative LMCTS had the largest postoperative improvement
at 12 months postoperation.
One of the major issues that we face in treating patients
with chronic sinusitis is maintaining medical therapy and
patient compliance once symptoms are resolved follow-
ing surgery. I have long felt that enabling the patient to
see the persistent but often asymptomatic mucosal inﬂam-
mation seen during video endoscopic examination (VEE)
may be beneﬁcial in improving medication compliance.
Bhalla et al.
report on a study demonstrating signiﬁcantly
higher general patient satisfaction and communication as
International Forum of Allergy & Rhinology, Vol. 8, No. 6, June 2018 666