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195Kulak Burun Bogaz Ihtis Derg 2016;26(4):195-200
Original Article / Çalışma - Araştırma
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doi: 10.5606/kbbihtisas.2016.54280
Prevalence of pneumatized uncinate process and
accompanying neighboring variations
Pnömatize unsinat proses prevalansı ve komşu varyasyonlar ile birlikteliği
Alper Yenigün, MD.,1 Cihat Gün, MD.,2 İsmihan İlknur Uysal, MD.,2 Musa Kemal Keleş, MD.,2
Alaaddin Nayman, MD.,3 Ahmet Kağan Karabulut, MD.2
ABSTRACT
Objectives: This study aims to investigate the prevalence of uncinate process (UP) pneumatization and also to investigate the
association of UP pneumatization with concurrent morphological variations in neighboring structures and the presence of maxillary
sinusitis.
Patients and Methods: This was a retrospective study where coronal computed tomography scans of 1,500 UPs in 750 patients
(483 males, 267 females; mean age 36.3±14.7 years; range 7 to 84 years) were examined to determine the prevalence of UP
pneumatization and to assess any concurrent neighboring anatomical structures and the presence of maxillary sinusitis between
January 2013 and June 2013.
Results: Uncinate process pneumatization was identified in a total of 6.26% of our patients with 1.60% being bilateral, 2.53% on the
right only, and 2.13% on the left side only. Other than concurrent occurrences of right maxillary sinus septa (p=0.046), growth of the right
ethmoidal bulla (p=0.044) and presence of maxillary sinusitis (right side: p=0.046, left side: p=0.035) were seen.
Conclusion: We detected a 6.2% prevalence of UP pneumatization in our study group. An abnormally sized and over-pneumatized UP
can cause narrowing of the infundibulum and impaired sinus drainage. Such functional blockage can lead to recurrent maxillary sinusitis,
stuffiness, and decreased olfaction.
Keywords: Computed tomography; paranasal sinus; pneumatized; sinusitis; uncinate process.
1Department of Otorhinolaryngology, Bezmi Alem Vakıf University, Faculty of Medicine, İstanbul, Turkey
2Department of Anatomy, Selçuk University, Selçuklu Faculty of Medicine, Konya, Turkey
3Department of Radiology, Selçuk University, Selçuklu Faculty of Medicine, Konya, Turkey
Received /
Geliş tarihi:
June 18, 2015
Accepted /
Kabul tarihi:
June 29, 2016
Correspondence / İletişim adresi:
Alper Yenigün, MD. Bezmi Alem Vakıf Üniversitesi Tıp
Fakültesi Hastanesi Kulak Burun Boğaz Anabilim Dalı, 34093 Fatih, İstanbul, Turkey.
Tel: +90 505 - 504 06 96 e-mail
(e-posta):
alperyenigun@gmail.com
Available online at
www.kbbihtisas.org
doi: 10.5606/kbbihtisas.2016.54280
QR (Quick Response) Code
ÖZ
Amaç: Bu çalışmada pnömatizasyon unsinat proses (UP) prevalansı ve UP pnömatizasyonun komşu yapılarda eşzamanlı morfolojik
varyasyonları ve maksiller sinüzit varlığı ile ilişkisi araştırıldı.
Hastalar ve Yöntemler: Bu retrospektif çalışmada, Ocak 2013 - Haziran 2013 tarihleri arasında, 750 hastanın (483 erkek, 267 kadın;
ort. yaş 36.3±14.7 yıl; dağılım 7-84 yıl) 1500 UP koronal bilgisayarlı tomografi taramaları, UP pnömatizasyonu prevalansını belirlemek ve
herhangi bir eşzamanlı komşu anatomik yapıyı ve maksiller sinüzit varlığını değerlendirmek üzere incelendi.
Bulgular: Unsinat proses pnömatizasyonu, hastalarımızın %1.60’ında iki taraflı, %2.53’ünde yalnız sağ tarafta ve %2.13’ünde yalnız sol
tarafta olmak üzere toplam %6.26’sında tespit edildi. Sağ maksiller sinus septanın (p=0.046) eşzamanlı oluşumu dışında, sağ etmoidal
bulla büyümesi (p=0.044) ve maksiller sinüzit varlığı (sağ taraf: p=0.046, sol taraf: p=0.035) görüldü.
Sonuç: Çalışma grubumuzda %6.2 UP pnömatizasyon prevalansı tespit edildi. Anormal büyüklükte ve aşırı pnömatize UP, infundibulum
daralmasına ve bozulmuş sinüs drenajına neden olabilir. Bu tür fonksiyonel blokaj tekrarlayan maksiller sinüzit, burun tıkanıklığı ve koku
alma duyusunun azalmasına yol açabilir.
Anahtar Sözcükler: Bilgisayarlı tomografi; paranazal sinüs; pnömatize; sinüzit; unsinat proses.
196 Kulak Burun Bogaz Ihtis Derg
The sickle- or boomerang-shaped uncinate
process (UP) was first identified by Johann
Friedrich Blumenbach in 1790. The structure
represents a thin, brittle, osseous lamella that
is orientated sagittally and has a dorsal concave
margin and an anterior convex one.[1] The UP is a
thin osseous structure, resembling a boomerang.
It extends from the ethmoid bone to the ethmoid
process of the inferior concha. During weeks
10-12 of intrauterine development, invagination
of the middle meatus becomes discernible and
the maxillary sinus is formed.[2] During this
phase, the UP and bulla ethmoidalis are seen as
a narrow groove (the hiatus semilunaris). The
UP plays an important role in the regulation of
ventilation of the paranasal sinus and, in normal
physiology, drainage of the sinuses. During
endoscopic sinus surgery, the UP is a significant
landmark on the lateral nasal wall.[3]
Several anatomical variants of UP have been
identified. Two are medial or lateral deviations
of the UP. Two others are the atelectatic or
hypertrophic UP which may originate from
pneumatization.[4] Diverse anatomical variations
of pneumatized maxillofacial osseous structures
have been frequently reported in the medical
literature. However, there still is no definite
explanation for why pneumatizations occur with
such anatomical variation.[3] Uncinate process
pneumatization (UPP) may cause narrowing of
the middle meatus, interfering with drainage
throughout the infundibulum.[5] Computed
tomography (CT) is considered the best method
of visualizing the paranasal sinuses and UP.[6]
The maxillary sinuses are cavities inside
the maxillary bone, inferior to the orbit in
the upper section of the cheek.[7] Sinusitis is
the inflammation of a sinus, generally caused
by bacterial, viral, or fungal infection, and
all types share common symptoms of fever,
blocked nose, and rhinorrhea, or runny nose.
Maxillary sinusitis is distinct in its presence of a
suborbital, which is increased when the patient
tilts his or her head forward. Typical treatment
for acute sinusitis is based on antibiotics and
nasal decongestants, sometimes accompanied by
corticosteroids.[7]
We aimed to investigate the frequency of UPP
and its concurrent presence of morphological
variations in neighboring anatomical structures.
PATIENTS AND METHODS
In this study we investigated the prevalence
of UPP and any concurrent occurrences of
morphological variations such as maxillary sinus
septa, agger nasi and Haller cells, pneumatization
of the middle concha, growth of ethmoidal
bulla, septal deviation in neighboring tissues
and presence of maxillary sinusitis.
Local institutional review board approved
the study. The study was conducted in
a c c or da nc e w it h t h e p r i nc ip le s o f t he D e cl a r at i o n
of Helsinki. We evaluated coronal paranasal
sinus CT (Brilliance 64-slice CT scanner,
Philips Medical Imaging, The Netherlands)
images, taken at 3 mm sections. The coronal CT
scann i ng was performed on patients positioned
supinely with the head position adjusted so
that the hard palate was parallel to, while
the sagittal plane was perpendicular to, the
floor. Uncinate process pneumatization was
defined as an UP in which there was an air gap
completely surrounded by tissue, as in concha
bullosa.
All paranasal CT images were ordered for
sinonasal, otologic, and maxillofacial inquiries,
between January 2013 and June 2013. Patients
with maxillofacial trauma, nasal polyposis or
sinus anomalies and those who had undergone
previous sinus surgery were excluded. Coronal
sectional CT scans of 1500 UPs in 750 patients
(483 males, 267 females; mean age 36.3±14.7
years; range 7 to 84 years) were evaluated for
the prevalence of UPP and for any concurrent
occurrences of morphological variants in
neighboring anatomical structures and presence
of maxillary sinusitis.
Statistical analysis
The data were evaluated statistically using the
chi square test. P values <0.05 and p<0.001 were
considered to indicate statistically significant
differences.
RE SULTS
Uncinate process pneumatization was detected
in a total of 47 patients ( 6.26%). In 2.53% (n=19)
of the patients UPP was located at the right side,
in 2.13% (n=16) of the patients on the left side,
and 1.60% (n=12) of the patients had bilateral
UPP. Of the patients with UPP, 34 (72.3%) were
males, 13 (27.7%) were females, and their ages
197
Prevalence of pneumatized uncinate process and accompanying neighboring variations
ranged between 16 and 75 years, with a mean
age of 31.1±13.9 years.
Maxillary sinusitis was detected in 22.8% of
the 47 UPP patients (94 sides): 21. 3% located on the
right and 24.3% at the left side. The simultaneous
occurrence of UPP and the presence of maxillary
sinusitis was found to be statistically significant
on the right and left sides (right side: p=0.046, left
side: p=0.035; Table 1).
Growth of the ethmoidal bulla was detected
in 1.06% of the 47 UPP patients (94 sides): 0.7%
located on the right and 2.1% located on the left
side. The simultaneous occurrence of UPP and
growth of the ethmoidal bulla was statistically
significant on the right but not significant on the
left side (right side: p=0.044, left side: p=0.405;
Table 1).
Maxillary sinus septa were detected in 12.8%
of the 47 UPP patients (94 sides), 21.3% located on
the right and 4.3% on the left side. Simultaneous
occurrence of UPP and maxillary sinus septa was
found to be statistically significant on the right
side, while no significance was found on the
left side (right side: p=0.046, left side: p=0.345;
Table 1). Agger nasi cells were detected in 85%
of the 47 UPP patients (94 sides), 95% located on
the right and 75% on the left. The simultaneous
occurrence of UPP and agger nasi cells showed
no statistical significance (right side: p=0.553,
left side: p=0.345; Table 1). Haller cells were
detected in 4.2% of the 47 UPP patients (94 sides):
2.1% located on the right and 6.3% located on the
left side. The simultaneous occurrence of UPP
and Haller cell was not statistically significant
on either side (right side: p=0.626, left side
p=0.140; Table 1). Pneumatization of the middle
concha was detected in 26.5% of the 47 UPP
patients (94 sides), 27.6% located on the right and
25.5% located on the left side. The simultaneous
occurrence of UPP and pneumatization of the
middle turbinate was not statistically significant
on either side (right side: p=0.905, left side:
p=0.959; Table 1). Septal deviation was detected
in 17.0% of the 47 UPP patients. The simultaneous
occurrence of UPP and septal deviation was not
statistically significant on either side (right side:
p=0.693, left side: p=0.865; Table 1).
One case of UPP on the right side originated
from the medial face of the orbit and the superior
wall of the maxillary sinus (Figure 4).
DISCUSSION
The UP is a thin, sickle-shaped osseous structure
located between the middle and inferior conchae.
In normal physiological conditions, the UP is
effective in the aeration of the sinuses and
their drainage.[5] The tip of the UP articulates
with the perpendicular lamina of the palatine
bone, the superior wall of maxillary sinus,
the basal lamella of ethmoid bone, and the
lamina papyracea.[8] The diversity of such joints
provides clues for analyzing the morphology
of the nasal fontanelles.[5] Little is known about
the morphology of the UP. In some cases,
an abnormally grown UP and its extensive
pneumatization can lead to narrowing of the
paranasal sinus drainage route.[9]
In sinus surgery, the UP is dissected first
during a middle meatal antrostomy.[10] Later, the
Table 1. Simultaneous occurrence of uncinate process
pneumatization and morphological variations of
neighboring structures
Variations UPP right UPP left
p p
Maxillary sinus septa 0.046* 0.345
Agger nasi cell 0.553 0.345
Haller cell 0.626 0.140
Pneumatization of middle concha 0.905 0.959
Growth of ethmoidal bulla 0.044* 0.405
Nasal septal deviation 0.693 0.865
Presences of sinusitis 0.046* 0.035*
UPP: Uncinate process pneumatization; Chi square test; * p<0.05; **
p<0.001.
Figure 1. Uncinate process pneumatization on the right with
bilateral middle concha pneumatization.
198 Kulak Burun Bogaz Ihtis Derg
natural ostium is widened and nasal fontanelles
are opened. Measurements have been made
between UP and the nasolacrimal duct, the
sphenopalatine foramen, and other lateral
nasal wall structures, highlighting the UP’s
importance; however, they were not sufficient
for understanding the detailed morphology of
t h e U P.[10,11]
The UP constitutes the medial border of the
et h moid in f un dib u lu m . Thu s , whe n pne uma t iz ed
and in mucosal contact with the neighboring
ethmoid bulla and/or the middle concha, it
can interfere with sinus drainage throughout
the infundibulum and may cause obstruction
of the osteomeatal unit or recurrent maxillary
sinusitis.[12] Such a functional blockade is seen
at the contact point of the UP and the middle
concha.[12] Developmental pneumatization may
be seen most frequently at the anterosuperior
region, with the extension of an air cell inside
the UP.[5] In our study, we observed a statistically
significant correlation with the presence of
maxillary sinusitis (right side: p=0.046, left side:
p=0.035; Table 1).
Kennedy and Zinreich[13] found 1 UPP patient
in their series of 230 patients and reported a
prevalence of 0.4%. Bolger et al.[14] detected UPP
in eight patients in their series of 263 patients
and reported the prevalence of UPP as 2.5%. In
their cases, UPP was unilateral in four patients,
bilateral in one, with only slight pneumatization
in three patients. In the study by Cumberworth
et al.[15] of 250 patients, UPP was present in three
cases and the prevalence was calculated as 1.2%.
Kantarcı et al.[16] investigated 512 cases and
reported a 5% UPP prevalence. In one of their
Figure 2. Uncinate process pneumatization on the left with
bilateral middle concha pneumatization. Figure 3. Bilateral uncinate process pneumatization with
maxillary sinus septa on the right.
Table 2. Uncinate process pneumatization series in the medical literature
Authors Number of cases Date of publication Study type Prevalence
%
Kennedy et al.[13] 230 1988 Retrospective 0.4
Bolger et al.[14] 263 1990 Retrospective 2.5
Cumberworth et al.[15] 250 1993 Retrospective 1.2
Kantarci et al.[16] 512 2004 Retrospective 5
Christmas et al.[17] 1 2005 Case report -
Burrows.[3] 1 2011 Case report -
Lee and Kim[18] 1 2011 Case report -
Our study 750 2014 Retrospective 6.2
199
Prevalence of pneumatized uncinate process and accompanying neighboring variations
patients, UPP was accompanied by a Haller cell
on the same side. Christmas et al.[17] reported
their clinical approach in a case with UPP on the
right side. Burrows reported a case with UPP and
mucocele.[3] Lee and Kim[18] reported a case with
an UP pyocele.
In our study, we observed UPP in 47 (6.2%) of
our 750 patients, similar to other results in the
literature (Table 2). We have observed increased
prevalence of UPP in our study compared to
previous studies (Table 2). One reason for this
may be the development of imaging techniques
in recent years. Another reason may be the
heterogeneity of the patients studied, including
differences in age and ethnicity.
Our investigation of the simultaneous
occurrence of morphological variations of
neighboring structures such as maxillary sinus
septa, agger nasi cells, Haller cells, middle
concha pneumatization, growth of the ethmoidal
bulla, nasal septal deviation, and maxillary
sinusitis in our 47 patients with UPP did not
reveal any significant association between UPP
and morphological variants of neighboring
st ructures other than right max i l lar y sinu s sept a
(p=0.046) and growth of the ethmoidal bulla
(p=0.044). Although statistically significant, we
consider that these simultaneous occurrences
may not be clinically significant and may
prove to be insignificant in larger series. The
coexistence of UPP and maxillary sinusitis
was observed to be statistically significant on
the both sides (right side: p=0.046, left side:
p=0.035).
In all but one of our cases with UPP, the UP
was in the form of an extension of the medial wall
of the maxillary sinus or the inferior concha. In
one case, UPP on the right side originated from
the medial face of the orbit and the superior wall
of the maxillary sinus (Figure 4).
In this study, we did not investigate the
histological aspect of UPP for a relationship
between the UPP and maxillary sinus. In the
future, histologic study can be done on mucosa
of UP. This was a preliminary study; therefore,
future studies with more patients are needed to
confirm our findings.
In conclusion, this study may shows that in
a relationship between the UPP and maxillary
sinusitis at the first time. When planning a
surgical intervention for osteomeatal complex
problems, UPP has to be kept in mind in cases
with hypertrophic UP. We also concluded that
CT examinations play an important role in
the diagnosis of variations in both UP and
neighboring anatomical structures.
Declaration of conflicting interests
The authors declared no conflicts of interest with
respect to the authorship and/or publication of this
article.
Funding
The authors received no financial support for the
research and/or authorship of this article.
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