Anatomical variations of the nose and paranasal sinuses by C.T scan evaluation in patients undergo functional endoscopic sinus surgery for chronic ...
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ISSN: 0005-2523
Volume 62, Issue 03, May, 2022
Anatomical variations of the nose and paranasal sinuses
by C.T scan evaluation in patients undergo functional
endoscopic sinus surgery for chronic rhinosinusitis
Ali NEZAR HASAN1, FEJER ADNAN JASIM2, Sara Suhail Hussein3
Departmrnt of Otolaryngologist M.B.CH.B, F.I.B.M.S.(ENT) Alkarkh general hospital1,2,3
Keywords: ABSTRACT
CT scan, FESS, Anatomic Radiologic assessment of the nose and paranasal sinuses is vital in
variations.
identifying the site and extent of sinonasal disorders and in planning
surgical treatments. To assess the frequency of the anatomical variations
of the nose and paranasal sinuses in chronic rhinosinusitis and it's
importance in patients undergoing functional endoscopic sinus surgery.
This cross-sectional study consisted of 25 patients (17) males, (8)
females who were attending Otorhinolaryngology Department at Al-
Shaheed Ghazi Al-Hariri Hospital for Surgical Specialties / Medical City
Teaching Complex, from October 2019 to December 2020. A detailed
history, clinical examination, computerized tomographic imaging had
been done and taken to see the detailed anatomy of the nose and
paranasal sinuses and to evaluate the presence of anatomical variations
and soft tissue abnormality. C.T scan of 25 patients, age from (19-70)
years with chronic rhinosinusitis (CRS) has detected multiple types of
anatomic variations with septal deviation being the most frequent in 15
patients (60%), concha bullosa was detected in 11 patients (44%), agger
nasi cells in 10 patients (40%), bulla ethmoidalis in 4 patients (16%),
onodi cells in 3 patients (12%), haller cells in 2 patients (8%), frontal
cells type III and IV in 2 patients respectively (8%). Other anatomical
variations like aerated septum, aerated uncinate process, Keros class II
and III and hypoplastic frontal sinus also detected. Anatomical variations
in the nose and paranasal sinuses are not unusual. Computed tomography
is the gold standard method in radiological assessment of chronic
rhinosinusitis and in pre-surgical evaluation in every patient undergoing
functional endoscopic sinus surgery. Multiplanar scan is very important
to assess the paranasal sinuses in three-dimensional way before surgery.
This work is licensed under a Creative Commons Attribution Non-Commercial 4.0
International License.
1. Introduction
Radiological assessment of the nose and paranasal sinuses is vital for determining the location and extent of
sinonasal disorders and for surgical planning.
1053A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
CT scans are used to help in both the diagnosis and planning of chronic sinusitis surgery. However, a
considerable proportion of perfectly asymptomatic individuals have mucosal abnormalities. Before doing a
CT scan of the sinuses, it is vital that the patient has received proper medical therapy for the nose and sinus
problem. The main scan utilized to evaluate the anatomy of the sinuses is the coronal scan. These scans
should be sufficiently close together to enable the tracking of an identified cell from one slice to the next.
This enables the reconstruction of a three-dimensional picture of the anatomy from the images.
Despite the fact that nasal morphology varies considerably across people, some anatomical differences are
generally typical. Certain anatomic variants are associated with rhinosinusitis [1], [2].
Computed tomography is the preferred technique for defining the normal structure and anatomical
variations of the paranasal sinuses [3].
1.1 Aim of study
This study aimed to assess the frequency of anatomical variations of the nose and paranasal sinuses in
chronic rhinosinusitis and it's importance in patients undergoing functional endoscopic sinus surgery.
2. PATIENTS AND METHODS
2.1 Study design
The candidates of this cross-sectional study consisted of patients who were attending Otorhinolaryngology
Department Ghazi Al-Hariri Hospital for Surgical Specialties / Medical City Teaching Complex, from
October 2019 to December 2020.
Among 100 patients who underwent C.T scan evaluation for CRS, 25 of them included in the study for
having anatomical variations of nose and paranasal sinuses (17 males and 8 females) and 75 were excluded.
For every patient in the study; a detailed history, clinical examination, computerized tomographic imaging
had been done to see the detailed anatomy of nose and paranasal sinuses and to evaluate the presence of
anatomical variations and soft tissue abnormality.
Inclusion criteria: Adult Patients who met the diagnostic criteria of CRS and not responding to medical
treatment after 2 to 3 months and have anatomical variations in their C.T scan.
Exclusion criteria
1. Patient with history of previous sinus surgery.
2. Patient with history of maxillofacial trauma.
3. Patient with head and neck tumors.
Patients were submitted our questionnaire formula that includes general history information plus primary
and additional symptoms for the diagnosis of chronic rhinosinusitis. So, if the patients met the criteria for
the diagnosis, they underwent physical examination started by general examination, then
• Examination of face as dark circles around eyes seen in allergic rhinitis and chronic rhinitis, and
scar.
• External nose examination regarding deviation, gross deformity, and any previous scar.
• Nasal Patency assessing by cotton piece test.
Then, an anterior rhinoscopy using a headlight and Killian nasal speculum with or without a topical
vasoconstrictor in search of the lateral nasal wall, septum (deviation and spur), mucosa, and discharge is
performed (amount, consistency, odor and color). Then using nasal endoscope 0-degree, 4 mm diameter,
and 175 mm length after application of decongestant and local anesthesia (xylometazoline drop 0.1% and
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xylocaine spray 10%) to look for;
Posterior septal deviation and enlarged middle turbinate
Mucopurulent discharge from (middle meatus)
Oedema/mucosal obstruction in the middle meatus
Nasal polyposis
After physical examination if the patients had positive findings, then they had been submitted for computed
tomography scanning.
All C.T scans were taken by Siemens AG definition AS unit, Computerized tomography department, Ghazi
Al-Hariri Hospital for Surgical Specialties.
Scanning parameters include;
Plane= coronal, axial and sagittal.
Slice thickness= 3 mm.
Window width=200-2000 Hounsfield unit.
Scanning direction was from anterior to posterior (frontal to sphenoid sinus).
Patients are in supine position.
Bony anomalies and soft tissue diseases are shown in images with the proper window width and height.
The severity of CRS was assessed using the Lund-Mackay criteria. The scores for complete opacification,
partial opacification, and normal mucosa were 2, 1, and 0 correspondingly. When osteomeatal complex is
open, it is given 0, when closed 2 points were counted. Anatomical variations were detected by C.T scan
evaluation.
Surgery:
Preoperative Patients Counselling: The patients involved in the current research were provided with
comprehensive information on alternative forms of therapy, the nature of surgery, the results of surgery,
including benefits and probable problems, and the type of surgery. Prior to FESS, written informed
permission was sought from each patient. They were also advised of the need of post-operative follow-up in
order to monitor recovery and prevent problems.
Investigations:
Routine preoperative investigations as hematological (C.B.C), biochemical (R.F.T), bleeding profile (PT.,
PTT. INR), viral screen, CXR was done.
Premedication: We gave the patients antibiotics (Augmentin tab (Amoxicillin /clavulanic acid) 625 mg*3 or
azithromycin tab 500mg 1*1). If there are signs of acute infection, oral steroid 20 to 30mg/day, topical
nasal steroid*2 and saline nasal wash*3 for 10 days to reduce inflammation.
• Instruments and procedures:
All the surgeries were done under general anesthesia with orotracheal tube.
Hypotensive technique and reverse Trendelenburg position and throat pack inserted, right sided head tilting
of the patient, patient’s head fixed using a head ring.
Endoscopic system consists of: 0,30,45,70-degree Hopkins rigid endoscope (4mm) connected to a camera
and display screen all manufactured by KAREL STORZ.
After sterilization and draping the surgery started with preparation of the nose with 0.1% xylometazoline
soaked packs left for 5 minutes to decongest the mucosa.
Different approaches of FESS (Messerklinger, Intact Bulla Technique) was followed according to the
condition of the patient, the surgical procedure consist of septoplasty, uncinectomy, anterior
ethmoidectomy, middle meatal antrostomy, posterior ethmoidectomy, partial middle turbinectomy,
sphenoidotomy and frontal sinus intervention as needed according to nature and extent of the disease.
1055A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
None of the patients had excessive intraoperative or postoperative bleeding, no ophthalmic complication,
one case had intraoperative CSF leak after injury to fovea ethmoidalis on the left side (patient has Keros
classification type 3) repaired immediately with facia lata, surgical and gel foam.
Postoperatively patients were prescribed I.V antibiotics (ceftriaxone 1 gm *1) for 2 days in all cases (7 days
in C.S.F leak case) followed by oral antibiotics (mostly cefixime tab 500mg *1) for 5 to 7 days, the nasal
pack was removed on 48 postoperative hours in all the cases except (with C.S.F leak, the pack was removed
after 7 days) followed by isotonic saline nasal wash *4 and steroid nasal spray (Budesonide nasal spray *2)
in different periods according to the pathology.
2.2 Statistical Analysis
Using the available SPSS-27 statistical software, data analysis was conducted (Statistical Packages for
Social Sciences- version 27). Simple measurements of frequency, percentage, mean, standard deviation, and
range were used to show the data (minimum-maximum values).
The significance of percentage differences (qualitative data) was evaluated using the Pearson Chi-square
test with Yate's adjustment or the Fisher Exact test, as appropriate. When the P value was less than or equal
to 0.05, statistical significance was evaluated.
Name: Age: Sex:
Residency: occupation:
Telephone number:
Diagnostic criteria
1. Primary symptoms:
A.Nasal blockage/obstruction/congestion
B.Nasal discharge (anterior/posterior)
2. Additional symptoms:
A.Facial pain/pressure/fullness
B.Hyposmia/anosmia
3. Systemic review:
4. PMH:
5. PSH:
6. Social H:
7. Family H:
8. Drug H:
Physical examination with anterior rhinoscopy or nasal endoscope
1-Purulent nasal discharge unilateral bilateral
2-Mucosal changes (color, edema, hypertrophy…)
3-Edema or mucopurulent discharge of middle meatus
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4- Endoscopic examination of nasopharynx
Anatomical variations by CT-scan examination
1-Concha bullosa unilateral bilateral
2 -Paradoxically bent middle turbinate unilateral bilateral
3 -Over pneumatized ethmoidal bulla unilateral bilateral
4 -Haller cells unilateral bilateral
5 –Agger nasi cells unilateral bilateral
6 –Septal deviation (moderate to severe)
7-Onodi Cells unilateral bilateral
8-Dehiscence of the Lamina Papyracea unilateral bilateral
9-Aerated Crista Galli
10-Asymmetry in Ethmoid Roof Height unilateral bilateral
11-Aerated uncinate process unilateral bilateral
12-Asymmetrical sphenoid sinus
13-Asymmetrical frontal sinus
14-Asymmetrical maxillary sinus
3. RESULTS
3.1 Age and gender distribution
A total of 25 patients with features of chronic rhinosinusitis underwent C.T scan evaluation and they were
submitted to functional endoscopic sinus surgery at Ghazi AL Hariri hospital in Baghdad Medical City. Of
these patients 17 (68%) were males and 8 (32%) were females, male to female ratio 2:1. Age distribution
varied from (19-70) years with a mean of 37.7±15.5 years as shown in (table 1)
Table (1) Age, gender, occupation distribution.
No %
Age (years) 19 --30 years 10 40.0
31---49 8 32.0
=>50 years 7 28.0
Mean±SD (Range) 37.7±15.5 (19-70)
Gender Male 17 68.0
Female 8 32.0
3.2 Chief complaint distribution
Among 25 patients, 12 had bilateral nasal obstruction while 13 had unilateral. 12 patients complained of
headache, 10 patients with facial and periorbital pain, 6 patients with nasal and postnasal discharge and 6
patients with hyposmia as shown in (table 2).
Table (2) Chief complaint distribution.
1057A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
Chief complaints No %
Nasal obstruction (12 bilateral & 13 unilateral) 25 100
Headache 12 48.0
Pain (Facial/Periorbital) 10 40.0
Discharge (Nasal/Postnasal) 6 24.0
Hyposmia/Anosmia 6 24.0
3.3 Mucosal thickening
Maxillary sinus was involved in 16 patients (64%) followed by ethmoidal sinus in 10 patients (40%),
sphenoid sinus was involved in 7 patients (28%) and finally the frontal sinus involvement in 5 patients with
a percentage of (20%) as shown in (table 3).
Table (3) mucosal thickening distribution.
Mucosal thickening No %
Maxillary mucosal thickening 16 64.0
Ethmoidal mucosal thickening 10 40.0
Sphenoidal mucosal thickening 7 28.0
Frontal mucosal thickening 5 20.0
3.4 Anatomic variations distribution
C.T scan of 25 patients with CRS detect multiple types of anatomic variations with septal deviation being
the most frequent in 15 patients (60%), concha bullosa was detected in 11 patients (44%), agger nasi cells in
10 patients (40%), bulla ethmoidalis in 4 patients (16%), onodi cells in 3 patients (12%), haller cells in 2
patients (8%), frontal cells type III and IV in 2 patients respectively (8%). Other anatomical variations like
aerated septum, aerated uncinated process, Keros class II and III were detected in 2 patients respectively
(8%).
Finally, hypoplastic frontal sinus, asymmetrical sphenoid sinus, rudimentary frontal sinus, aerated crista
galli and paradoxical middle turbinate were detected in 1 patient respectively (4%) as shown in (figure 1).
The severity of CRS was graded using the Lund-Mackay criteria as illustrated in (figure 2).
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Type of anatomic CT variation findings Percentage
0 10 20 30 40 50 60 70
Septal deviation 60
Concha Bullosa 44
Aggar Nasi Cells 40
Bulla Ethemodalis 16
Aerated septum (bony parts) 8
Aerated uncinate process 8
Hypoplastic frontal sinus 4
Asymmetrical sphenoidal sinus 4
Paradoxical Middle turbinate 4
Frontal cell (Type III & Type IV) 8
Haller cells 8
kerosclass II 4
Kerosclass III 4
Onodi cells 12
Rudimentary frontal sinus 4
Aerated Crista galli 4
Figure (1) Anatomic variations distribution.
Figure (2) Lund-Mackay score distribution.
1059A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
3.5 Intraoperative complications distribution
There was one case with (Keros class 3) who developed left side injury to fovea ethmoidalis during surgery
and repaired immediately with facia lata, surgical and gel foam. Percentage (4%) as shown in table (4)
Table (4) Intraoperative complications distribution.
Intraoperative Complications NO. Percentage%
Orbital - 0
Skull base injury 1 4
Bleeding - 0
No postoperative complications regarding epistaxis, adhesions and mucocele formation after a follow up
period for 6 weeks.
4. DISCUSSION
The debut of head and neck CT imaging and the continuing expansion of its usage have unquestionably
benefited the doctor. In the examination of the paranasal sinuses, CT has become an indispensable
diagnostic tool and an important component of surgical planning. Additionally, it is utilized to generate
intraoperative road maps. CT is now the preferred radiological test for assessing the paranasal sinuses of a
patient with CRS [4].
4.1 Mucosal thickening variants
In this study, Maxillary sinus was the most commonly involved sinus (64%), followed by Ethmoid sinus
(40%), Sphenoid sinus (28%) and frontal sinus (20%).
Maxillary sinus was the most usually afflicted sinus in research by [5] (67.1%), followed by Anterior
Ethmoids (54.1%), Posterior Ethmoids (10%), Frontal (22.1%), and Sphenoid sinus (10%).
According to [4], the Maxillary sinus (99%) was the most often affected sinus, followed by the Anterior
Ethmoids (89%), Posterior Ethmoids (61%), Frontal (64%), and Sphenoid sinus (31%).
In [6] research, the Maxillary sinus was most often affected (72.9%), followed by the Ethmoids (65.8%),
Frontal sinus (55%) and Sphenoid sinus (35%).
4.2 Nasal septum variations
Nasal septal deviation (60%) was the most common anatomical variations observed in our study, there were
two cases with aerated septum (8%).
Almost similar prevalence was shown in articles by [7], [8]. who reported (65%) and (74.1%) respectively.
Lower incidence of septal deviation (20.9%) was observed in Onwuchekwa & Alazigha study with similar
incidence of septal aeration (8%) [1].
[9], [10] found prevalence of 44% and 38% in their study respectively. These differences may be explained
by variations in populations and samples sizes in each study.
4.3 Nasal turbinates variations
Pneumatization of conchae is one of most prevalent sinonasal anatomical changes.
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The middle turbinate is the most common location of pneumatization, whereas superior and inferior
turbinates are less common [1]. The incidence of middle turbinate pneumatization in our research was (44
percent). [11] reported a comparable incidence (42.6 percent). Higher prevalence was reported by [8], [12]
who got (53.7%) and (67%) respectively. Lower incidence range reported by (28%) [10] and (15%) [7].
There may also be an irregular curving of the middle turbinate towards midline, referred to as paradoxical
middle turbinates, which was identified in one instance (4 percent) in our investigation, which is virtually
identical to the figure published by (6.4 percent) [5].
The incidence is less in comparison to 12% by [10] and 15% by [13].
This may be related to geographic and racial features.
Rarely does the anatomy of the inferior turbinates vary. None of the documented abnormalities were seen in
this investigation, including pneumatization of the inferior turbinate, bifid inferior turbinates, and
hypertrophy or hypoplasia of the osseous or soft tissue of the inferior turbinates.
4.4 Ethmoidal sinus variations
Agger nasi cells: these cells were present in (40%) in our study, which is similar to (40%) [24] and nearly
similar to (48%) [10] and (49%) [14].
Higher incidence was reported by [11] (88.5%). These disparities may be explained by different definitions
assigned to this anatomical variant.
Over pneumatized ethmoid bulla was found in (16%) in this study which was similar to (18%) as found by
and less as found in study by (5%) [12], [15].
Haller's cells (infraorbital ethmoid cell) are ethmoidal cells that progress into medial floor of orbit nearby to
and above the maxillary sinus ostium and, if increased in size, can narrow the posterior aspect of the
ethmoidal infundibulum and superior medial part of the maxillary sinus ostium [16]. The percentage of
Haller’s cells in our study was (8%), reported (15%) [13], higher percentage was reported by (36%) [11]
and (28%) [10]. This is may be explained by using different radiological parameters.
Onodi cells (OC) are pneumatized ethmoid cells located posterior to the sphenoid sinus. It is possible that
the presence of OC during surgery raises the risk of optic nerve and internal carotid artery damage.
Recognition of OC before to surgery is crucial to avoiding these regrettable outcomes [16]. The percentage
of OC was found in (12%) in our study which is higher than (7%) in [14] and (7.27%) in study [17]. Almost
similar incidence (10.4%) found in [18] study. Higher prevalence ranging from (49.5%) to (60%) had been
recorded in two studies in Thailand [19], [20]. These differences may be explained by different samples
sizes.
Pneumatization of the crista galli was found in (4%) in this study.
Almost similar prevalence were found in [18] study (2.4%) and (8%) in study [17].
Higher prevalence (13%) was found in study [21].
1061A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
Aeriated uncinate process: the prevalence was (8%) in our study which is almost similar to [12] (6%) and
[16] (9%) in their studies.
Lower incidence (2.8%) reported by [5].
According to Keros classification of the roof of ethmoid, type II was found in (4%) and type III also in (4%)
in our study. [5] found (7.8%) type II and (1.4%) type III which is almost similar to our study. [22] found
higher prevalence of type II (17.9%) and lower incidence of type III (0.5%) in his study.
The observed discrepancy in the distribution of Keros type among patients in the previously cited research
may be attributable to differences in sample sizes. Ethnic differences among the cases may also contribute
to the distribution's variability.
4.5 Frontal sinus variations.
Hypoplasia of the frontal sinus was reported in (4%) in our study which is similar to (3.64%) in [17] study
and (4.64%) in [23] study.
Higher prevalence (9.6%) was found in [24] study.
These ethmoid cells, also known as frontal cells or Kuhn's cells, are closely linked to agger nasi cells. They
are divided into four distinct categories based on their pneumatization. In eight percent of patients, type III
and type IV frontal cells were detected. Similar prevalence (8.73%) was found in in [17] study. Lower
prevalence (3.1%) of frontal cells was observed in [25], [26] (5%) in their studies. Rudimentary frontal
sinus was observed in (4%) in our study which is similar to prevalence of (4.1%) in [27].
Higher prevalence (8.32%) was observed in [28].
Lower incidence (1.2%) was found in [29]. Ethnical and racial factors could explain the difference.
4.6 sphenoid sinus variations
The Sphenoid sinus is the most variable and inaccessible of the paranasal sinuses, with pneumatization
varying from modest to considerable. Changes in the size, pneumatization, and pattern of septations of the
Sphenoid sinus result in variations in the segmentation of the Sphenoid sinus. The pneumatization may
include the larger wing of the sphenoid, the pterygoid process, the clivus, and sometimes the anterior
clinoid process [30].
Extensive pneumatization of the right side of sphenoid sinus toward the greater wing of sphenoid is seen in
one case in our study (4%).
Lower prevalence (1.8%) was observed in [30] study of 500 patients in India. While higher incidence (12%)
of lateral extension of sphenoid sinus toward greater wing was found in Wang J et al. study of 100 patients
in China.
These disparities may be explained by individual variations in the population and different samples sizes.
There may be dehiscence in the bony wall between carotid arteries and sphenoid. With extensive
pneumatization, the bone topping the carotid arteries, optic nerves, maxillary nerves and vidian nerve can
be very thin or even absent, making these structures susceptible to iatrogenic trauma during surgery [17].
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5. Conclusions
This study shows that anatomical variations in nose and paranasal sinuses are not unusual.
Computed tomography is the gold standard method in the radiological investigation of chronic
rhinosinusitis and in pre-surgical evaluation in every patient undergoing functional endoscopic sinus
surgery. Multiplanar scan is very important to assess the paranasal sinuses in three-dimensional way before
surgery.
6. Recommendations
1. CT scan is always indicated in patients with CRS undergoing FESS, any anatomical variations
should be identified when evaluating CT scans.
2. Navigation system is very important especially in frontal and sphenoid sinus surgery.
3. Larger sample size of patients is recommended for future researches.
7. REFERENCES
[1] Papadopoulou A-M, Bakogiannis N, Skrapari I, Bakoyiannis C. Anatomical Variations of the
Sinonasal Area and their Clinical Impact on Sinus Pathology: A Systematic Review. International Archives
of Otorhinolaryngology. 2022.
[2] Al-Ataar ZI. The prevalence and antimicrobial resistance of Pseudomonas species in patients with
chronic suppurative otitis media. AL-Kindy College Medical Journal. 2015;11(1):49-52.
[3] Kirsch CFE. Imaging of Midfacial and Orbital Trauma. In: Patlas MN, Katz DS, Scaglione M,
editors. Atlas of Emergency Imaging from Head-to-Toe. Cham: Springer International Publishing; 2020. p.
1-14.
[4] Scaria S, Satheesh Kumar Bhandary RA, Bhat VS. Radiological evidence of the frequency of
involvement of paranasal sinuses in chronic rhinosinusitis. Website Rroij com taken on. 2018;25.
[5] Fadda GL, Rosso S, Aversa S, Petrelli A, Ondolo C, Succo G. Multiparametric statistical
correlations between paranasal sinus anatomic variations and chronic rhinosinusitis. Acta
Otorhinolaryngologica Italica. 2012;32(4):244.
[6] Nair S. Correlation between symptoms and radiological findings in patients of chronic
rhinosinusitis: a modified radiological typing system. Rhinology. 2009;47(2):181.
[7] Mamatha H, Shamasundar NM, Bharathi MB, Prasanna LC. Variations of ostiomeatal complex and
its applied anatomy: a CT scan study. Indian J Sci Technol. 2010;3(8):904-7.
[8] Aramani A, Karadi RN, Kumar S. A study of anatomical variations of osteomeatal complex in
chronic rhinosinusitis patients-CT findings. Journal of clinical and diagnostic research: JCDR.
2014;8(10):KC01.
[9] Dua K, Chopra H, Khurana AS, Munjal M. CT scan variations in chronic sinusitis. Indian Journal
of Radiology and Imaging. 2005;15(3).
[10] Yadav SP, Yadav RK, Singh J. Low dose CT in chronic sinusitis. Indian Journal of Otolaryngology
1063A. N. HASAN, F. A. JASIM and S. S. Hussein, 2022 Azerbaijan Medical Journal
and Head and Neck Surgery. 1999;52(1):17-22.
[11] Maru YK, Gupta V. Anatomic variations of the bone in sinonasal CT. Indian Journal of
Otolaryngology and Head and Neck Surgery. 2001;53(2):123-8.
[12] Scribano E, Ascenti G, Cascio F, Racchiusa S, Salamone I. Computerized tomography in the
evaluation of anatomic variations of the ostiomeatal complex. La Radiologia Medica. 1993;86(3):195-9.
[13] Lloyd GAS, Lund VJ, Scadding GK. CT of the paranasal sinuses and functional endoscopic
surgery: a critical analysis of 100 symptomatic patients. The Journal of Laryngology & Otology.
1991;105(3):181-5.
[14] Al-Abri R, Bhargava D, Al-Bassam W, Al-Badaai Y, Sawhney S. Clinically significant anatomical
variants of the paranasal sinuses. Oman medical journal. 2014;29(2):110.
[15] Zinreich S, Albayram S, Benson M, Oliverio P. The ostiomeatal complex and functional
endoscopic surgery. Head and neck imaging 4th ed St Louis: Mosby. 2003:149-73.
[16] Kaygusuz A, Haksever M, Akduman D, Aslan S, Sayar Z. Sinonasal anatomical variations: their
relationship with chronic rhinosinusitis and effect on the severity of disease—a computerized tomography
assisted anatomical and clinical study. Indian Journal of Otolaryngology and Head & Neck Surgery.
2014;66(3):260-6.
[17] Onwuchekwa RC, Alazigha N. Computed tomography anatomy of the paranasal sinuses and
anatomical variants of clinical relevants in Nigerian adults. Egyptian Journal of Ear, Nose, Throat and
Allied Sciences. 2017;18(1):31-8.
[18] Bašić N, Bašić V, Jukić T, Bašić M, Jelić M, Hat J. Computed tomographic imaging to determine
the frequency of anatomical variations in pneumatization of the ethmoid bone. European archives of oto-
rhino-laryngology. 1999;256(2):69-71.
[19] Kasemsiri P, Thanaviratananich S, Puttharak W. The prevalence and pattern of pneumatization of
Onodi cell in Thai patients. Journal of the Medical Association of Thailand. 2011;94(9):1122.
[20] Thanaviratananich S, Chaisiwamongkol K, Kraitrakul S, Tangsawad W. The prevalence of an
Onodi cell in adult Thai cadavers. Ear, nose & throat journal. 2003;82(3):200-4.
[21] Som PM, Park EE, Naidich TP, Lawson W. Crista galli pneumatization is an extension of the
adjacent frontal sinuses. American Journal of Neuroradiology. 2009;30(1):31-3.
[22] Paber JELB, Cabato MSD, Villarta RL, Hernandez JG. Radiographic analysis of the ethmoid roof
based on Keros classification among Filipinos. Philippine Journal of Otolaryngology Head and Neck
Surgery. 2008;23(1):15-9.
[23] Nautiyal A, Narayanan A, Mitra D, Honnegowda TM. Computed tomographic study of remarkable
anatomic variations in paranasal sinus region and their clinical importance-A retrospective study. Annals of
Maxillofacial Surgery. 2020;10(2):422.
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[24] Ozcan KM, Hizli O, Sarisoy ZA, Ulusoy H, Yildirim G. Coexistence of frontal sinus hypoplasia
with maxillary sinus hypoplasia: a radiological study. European Archives of Oto-Rhino-Laryngology.
2018;275(4):931-5.
[25] Park S-S, Yoon B-N, Cho K-S, Roh H-J. Pneumatization pattern of the frontal recess: relationship
of the anterior-to-posterior length of frontal isthmus and/or frontal recess with the volume of agger nasi cell.
Clinical and experimental otorhinolaryngology. 2010;3(2):76.
[26] Woo H-J, Ye S-B, Bae C-H, Song S-Y, Kim Y-D. Anatomic variations of the frontal recess and
frontal sinusitis: Computed tomographic analysis. Journal of Rhinology. 2009:20-5.
[27] Yüksel Aslier NG, Karabay N, Zeybek G, Keskinoğlu P, Kiray A, Sütay S, et al. The classification
of frontal sinus pneumatization patterns by CT-based volumetry. Surgical and Radiologic Anatomy.
2016;38(8):923-30.
[28] Danesh-Sani SA, Bavandi R, Esmaili M. Frontal sinus agenesis using computed tomography.
Journal of Craniofacial Surgery. 2011;22(6):e48-e51.
[29] Çakur B, Sumbullu MA, Durna NB. Aplasia and agenesis of the frontal sinus in Turkish
individuals: a retrospective study using dental volumetric tomography. International journal of medical
sciences. 2011;8(3):278.
[30] Hiremath SB, Gautam AB, Sheeja K, Benjamin G. Assessment of variations in sphenoid sinus
pneumatization in Indian population: A multidetector computed tomography study. Indian Journal of
Radiology and Imaging. 2018;28(03):273-9.
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