Abstract
Background:
Variants of nasal septum and structures of nasal cavity are key in nasal surgeries, with some linked to certain pathologies. This study aims to determine their prevalence in the Nepali population at our hospital.
Method:
A retrospective, cross section study was conducted at a private hospital in Nepal with 342 adults (aged >13). Two radiologists assessed CT scans for variants of nasal septum, nasal septum deviation angles, and variants of the nasal turbinates and pneumatized uncinate process. Nasal septum deviations were graded from I to IV, and gender-specific prevalences and mean nasal septal deviation (NSD) angle were calculated. Statistical significance was tested using chi-squared test, t-tests, and ANOVA.
Results:
The prevalences were: nasal septum deviation (76.68%), septal spur (41.98%), septal pneumatization (40.23%), hypertrophied inferior turbinate (38.48%), lamellar concha (34.11%), concha bullosa (CB) (19.83%), supreme turbinate (9.33%), paradoxical middle turbinates (9.33%) and pneumatized uncinate process (8.45%). Nasal septum deviation was right-sided in 34.11%, left-sided in 34.40%, and S-shaped in 8.16%. The prevalences of nasal septum types were: type I (30.9%), type II (48.1%), type III (16.91%), and type IV (4.08%). The mean septal deviation angle was 6.77° (SD 4.52°).The mean septal deviation in deviated septum was 8.64° (SD 3.2°) Significant association were found between deviated septum and septal spur, CB, hypertrophied inferior turbinate, and paradoxical middle turbinate (P < 0.001, 0.012, 0.001, 0.016), as well as between variants of NSD and sides of CB, hypertrophied inferior turbinate, and septal spur (P = 0.006, <0.001, <0.001). The prevalence of CB was significantly high in female (P = 0.001). There was significant association of types of nasal septum with CB (P = 0.003). There was significant difference in deviation angle between variants of deviated nasal septum (P = 0.048), notably between septum deviated to left side and “S”-shaped nasal septum (P = 0.024).
Conclusion:
Recognizing variants of nasal septum and nasal cavities is crucial to prevent surgical complications.
Keywords: concha bullosa, hypertrophied inferior turbinate, nasal septum deviation, surgical complications
Introduction
Humans possess a pair of nasal cavities (NC) that serve as the entry point to the respiratory tract, separated by a nasal septum (NS). These cavities condition the air entering the respiratory system. The NS is typically straight until about age 7, after which it may deviate left or right or form an “S” shape due to heredity, trauma, or connective tissue disorders[1,2]. Variants of the nasal septum and nasal cavities such as a deviated nasal septum (DNS), septal spur (SS), septal pneumatization (SP), lamellar concha (LC), concha bullosa (CB), pneumatized uncinate process (PUP), hypertrophied inferior nasal turbinates (HINT), paradoxical middle turbinate (PMT), and supreme nasal turbinate (SNT) can narrow the nasal cavity, impinge on adjacent structures, and reduce sinus aeration, predisposing individuals to sinus and nasal infections[3]. These variants also hinder endoscopic procedures[4]. HINT often occurs on the side opposite to the deviated septum as a compensatory mechanism, though infection and inflammation can also contribute to this hypertrophy[5,6]. While numerous studies have examined the prevalence of nasal cavity variants in various populations, detailed research with adequate sample sizes is still lacking in Nepal. This study aims to fill this gap and enhance the understanding of nasal cavity variants in the Nepali population.
HIGHLIGHTS
The study emphasizes the importance of recognizing nasal septum and cavity variants to minimize surgical complications and optimize outcomes during nasal surgeries.
Nasal septum deviation (76.68%) was common in the Nepali population, along with septal spur (41.98%), septal pneumatization (40.23%), and hypertrophied inferior turbinate (38.48%).
Nasal septum deviations were mostly bilateral (34.11% right-sided, 34.40% left-sided), with a mean septal deviation angle of 6.77°.
Significant associations were found between nasal septum deviation and conditions like septal spur, concha bullosa, hypertrophied inferior turbinate, and paradoxical middle turbinate (P < 0.05).
Concha bullosa was notably more common in females (P = 0.001), with strong associations between septal deviation and the sides of concha bullosa and hypertrophied inferior turbinate.
Materials and methods
Study design
This is a retrospective, cross section study carried out in the department of radiology of a tertiary hospital in Kathmandu. The study is based on computed tomography of paranasal sinus conducted from December 2023 to August 2024. Ethical clearance was obtained from institutional review committee and registered in clinicaltrial.gov. Consent was waived by the institutional review committee because of retrospective nature of the study. The primary objective of our study was to find overall and gender wise prevalences of straight and deviated nasal septum, different variants of DNS, septal spur, septal pneumatization and variants of septal pneumatization, pneumatization of uncinate process, hypertrophied inferior nasal turbinate, lamellar concha, CB, supreme nasal turbinate and paradoxical middle turbinate. Another objective of our study was to determine the overall and gender wise mean nasal septal deviation (NSD) angle and classify the study population according to severity of deviation of the nasal septum.
We calculated the sample size using the following formula in www.openepi.com, Version 3.
Sample size (n) = [DEFF × Np(1−P)]/[(d2/Z21-α/2 × (N−1) + P × (1−P)].
Population size (for finite population correction factor or fpc) (N): 1 000 000.
Hypothesized % frequency of outcome factor in the population (P): 68.1%; anticipated prevalence of deviated nasal septum in Nepali population based on previous study by Shrestha et al[7].
Confidence limits as % of 100(absolute ± %) (d): 5%.
Design effect (for cluster surveys-DEFF): 1.
Considering confidence interval of 95%, 334 samples would be adequate. We obtained data from 343 CT scans which is more than adequate.
Inclusion and exclusion criteria: All computed tomography (CT) scan of paranasal sinuses (PNS) referred for evaluation of chronic rhinosinusitis and nasal polyposis and CT scan of head referred for evaluation of headache, dizziness, loss of consciousness in patients aged 13 years and more were included in the study. CT PNS and head done for evaluation of trauma, tumors, extensive polyposis and previous nasal surgery were excluded from the study. Additionally, CT scan of PNS and head of patients aged less than 13 years were excluded from our study since structures in nasal cavities fully develop by that age.
Radiological procedures
We analyzed the CT scans done in our department for investigation and treatment purpose. The CT scans were randomly selected and analyzed independently by two radiologists with experience of 4–5 years. In case of any confusion during reading the CT scan, help was sought from another senior radiologist with experience of 15 years in the field of general radiology. The CT scans were performed with a 160-slice Toshiba MDCT scanner in helical mode, using a slice thickness of 0.65 mm, a voltage of 120 kV, and automatic mAs settings. The volumetric data obtained from these scans were reformatted into axial, coronal, and sagittal planes for thorough analysis, which was conducted on a specialized Toshiba workstation. The interpretation was mainly done in coronal plane in bone window. No patient was exposed to radiation for the purpose of our study only. Average radiation exposure during the investigation was 1.5–3 mSv2.
The work has been reported in line with the revised Strengthening the Reporting of Cohort, Cross-sectional and case-control Studies in Surgery (revised STROCSS) criteria[8].
The objective criteria for interpretation of findings in CT scan were as specified in Table 1.
Figure 1.
(A) Nasal septum in the midline, representing a straight nasal septum. (B) Deviated nasal septum (DNS) to the right side. (C) DNS to the left side. (D) Nasal septum with the superior part deviated to the right of the midline and the inferior part deviated to the left of the midline, representing an “S”-shaped nasal septum.
Figure 2.
Straight nasal septum with septal spur towards right side (white arrow).
Figure 3.
(A) Anterior septal pneumatization (red star). Anterior septal pneumatization is extension of frontal sinus and crista galli pneumatization into the bony nasal septum. (B) Posterior septal pneumatization (yellow star). Posterior septal pneumatization is extension of sphenoid sinus pneumatization into the bony septum.
Figure 4.
Bilateral hypertrophied inferior nasal turbinates (HINT). The width of the thickest part of the inferior nasal turbinate was measured as shown in the figure. The inferior nasal turbinate was considered hypertrophied if the width was ≥12 mm.
Figure 5.
Pneumatization of the bulbous part and lamellae of the bilateral middle turbinate, indicative of concha bullosa. The concha bullosa on the left side is dominant. (B) Pneumatization of the vertical lamella of the right middle turbinate, while the bulbous part is not pneumatized, indicating a lamellar concha (yellow arrow). Concha bullosa is seen on the left side (red arrow).
Figure 6.
Pneumatization of left uncinate process (white arrow). The right uncinate process is not pneumatized.
Figure 7.
(A) Infero-medial curvature of the left middle turbinate (green arrow), indicative of a paradoxical middle turbinate. The right middle turbinate exhibits normal curvature, and the nasal septum is deviated to the right side. (B) Accessory turbinate located superior to the superior nasal turbinate on both sides, identified as supreme nasal turbinates.
Table 1.
Objective criteria for interpretation of variants on NC and NS
| Variants of nasal cavity | Objective definition |
|---|---|
| Straight nasal septum | The nasal septum (bony and cartilaginous part) is in midline (Figure 1A). |
| Deviated nasal septum (DNS) | Deviation of nasal septum (bony or cartilaginous part or both) from the midline (Figures 1B, 1C, 1D). |
| DNS to right | Deviation of nasal septum (bony or cartilaginous part or both) towards the right side (Figure 1B). |
| DNS to left | Deviation of nasal septum (bony or cartilaginous part or both) towards the left side (Figure 1C). |
| “S” shaped nasal septum | Deviation of some part of the nasal septum to one side and other part of the nasal septum to contralateral side providing cranio-caudal ‘S’ or reverse ‘S’ shaped configuration in coronal image (Figure 1D). |
| Septal spur | Projection of a bony spur at the junction of perpendicular plate of ethmoid and upper surface of vomer (Figure 2). |
| Septal pneumatization | Pneumatization (usually partial) of the bony nasal septum (Figure 3A, 3B). |
| Anterior SP | Extension of frontal sinus or pneumatized crista galli into the bony nasal septum (Figure 3A). |
| Posterior SP | Extension of sphenoid sinus pneumatization into bony nasal septum (Figure 3B) |
| Hypertrophied inferior nasal turbinate | Width of thickest part of inferior nasal turbinate was measured. Inferior nasal turbinate was considered hypertrophied if width was 12 mm or more (Figure 4). |
| Lamellar concha | Pneumatization of vertical plate that attaches nasal turbinate to lateral nasal wall (Figure 5A, 5B). |
| Concha bullosa | Pneumatization of bulbous portion or both bulbous and vertical plate of middle turbinate (Figure 5B). |
| Pneumatized uncinate process | Pneumatized air cell in uncinate process (Figure 6). |
| Paradoxical middle turbinate | Inferomedial curvature of middle turbinate (Figure 7A). |
| Supreme nasal turbinate | Accessory turbinate above the superior nasal turbinate and arising from medial surface of labyrinth of ethmoid (Figure:7B). |
NSD angle was measured in coronal plane using a protractor provided in the picture archiving and communication system (PACS) (PSP Insite pad Version1.3.7.2). NSD angle is the angle between a line drawn in midline and the line connecting most deviated point of nasal septum and crista galli (Fig 8). Midline was defined as a line connecting crista galli superiorly with the maxillary crest. In “S” shaped nasal septum, there is deviation of nasal septum to both sides. The angle between line joining the point with maximum deviation and crista galli and midline was considered as NSD angle. Type of nasal septum is based on severity of NSD angle. The nasal septum is of four types in shown in Table 2.
Figure 9.
Different types of nasal septum classified based on the nasal septal deviation (NSD) angle. (A) Type I nasal septum with an NSD angle of 4.6°. A Type I nasal septum has an NSD angle ≤5°. (B) Type II nasal septum with an NSD angle of 6.9°. A Type II nasal septum has an NSD angle between 5° and 10°. (C) Type III nasal septum with an NSD angle of 14.5°. A Type III nasal septum has an NSD angle between 10° and 15°. (D) Type IV nasal septum. A Type IV nasal septum has an NSD angle greater than 15°.
Figure 8.
Method of measuring the nasal septal deviation (NSD) angle. One line is drawn along the midline, connecting the crista galli to the maxillary crest. A second line is drawn from the crista galli to the most deviated point of the nasal septum. The angle between these two lines represents the NSD angle. It is important to note that the second line should connect the crista galli to the most deviated part of the nasal septum, not the tip of the septal spur.
Table 2.
Types of nasal septum based on severity of deviation
Statistical analysis
The collected data was entered in IBM SPSS statistics for windows (version 25.0 IBM Corp., Armonk, NY, USA) and analyzed. Chi squared test, independent sample t test, one-way ANOVA (analysis of variance) and post hoc tests were used to establish relationship between two variables and P values were obtained. Significant data was considered if P value is less than 0.05.
Result
In our evaluation of 343 plain CT scans of the paranasal sinuses (PNS), we found a sample comprising 155 males (45.19%) and 188 females (54.81%). The mean age of the study population was 39.16 years, with a standard deviation of 17.01 years, ranging from 13 to 91 years. When analyzed by gender, the mean age for males was 39.36 years (SD: 18.76 years; range: 15–89 years), while for females, it was 39.98 years (SD: 15.47 years; range: 13–91 years).
Table 3 presents the overall and gender-specific prevalence of various nasal cavity variants identified in our study.
Table 3.
Overall and gender-wise prevalence of different anatomical variants of nasal with standard deviation of cavity
| Anatomical variant | Prevalence in male (%) | Prevalence in female (%) | Overall prevalence (%) |
|---|---|---|---|
| Deviated nasal septum | 78.71 | 75.00 | 76.68 |
| Septal spur | 44.52 | 39.89 | 41.98 |
| Septal pneumatization | 38.10 | 42.02 | 40.23 |
| Hypertrophied inferior nasal turbinate | 41.29 | 36.17 | 38.48 |
| Lamellar concha | 32.90 | 35.11 | 34.11 |
| Concha bullosa | 12.26 | 26.10 | 19.83 |
| Supreme nasal turbinate | 10.97 | 7.98 | 9.33 |
| Paradoxical nasal turbinate | 9.68 | 9.04 | 9.33 |
| Pneumatized uncinate process | 9.68 | 7.45 | 8.45 |
The overall and gender wise prevalence of straight nasal septum and variants of deviated nasal septum (i.e., deviated to the right, deviated to the left, and “S”-shaped) are listed in Table 4.
Table 4.
Overall and gender-wise prevalence of straight nasal septum and variants of deviated nasal septum in the study population (abbreviation: pr stands for prevalence)
| Straight nasal septum | Deviated nasal septum (DNS) | |||||||
|---|---|---|---|---|---|---|---|---|
| DNS to right | DNS to left | ‘S’ shaped nasal septum | ||||||
| N | Prevalence (%) | N | Prevalence (%) | N | Prevalence (%) | N | Prevalence (%) | |
| Male | 33 | 21.29 | 56 | 36.12 | 56 | 36.12 | 10 | 6.45 |
| Female | 47 | 25.00 | 61 | 39.35 | 62 | 32.98 | 18 | 9.57 |
| Overall | 80 | 23.32 | 117 | 34.11 | 118 | 34.40 | 28 | 8.16 |
The overall and gender wise prevalence of non-pneumatized bony nasal septum, different variants of septal pneumatization and overall and gender wise prevalence of different sides of bony spur are enlisted in Table 5. The overall and gender wise prevalence of septal pneumatization and bony spur are listed in Table 3.
Table 5.
Overall and gender-wise prevalence of variants of septal pneumatization, sides of bony spur and pneumatized uncinate process in the study population
| Septal pneumatization | Bony spur | Uncinate process | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Present | Absent | Present | Absent | Present | Absent | |||||||||||||||||
| Anterior | Posterior | Both | Towards right | Towards left | Towards right | Towards left | Both sides | |||||||||||||||
| n | *Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | |
| Male | 4 | 2.58 | 54 | 34.84 | 1 | 0.65 | 96 | 61.94 | 31 | 20.0 | 38 | 24.52 | 86 | 55.48 | 7 | 4.52 | 6 | 3.87 | 2 | 1.29 | 140 | 90.32 |
| Female | 3 | 1.60 | 72 | 38.30 | 4 | 4.20 | 109 | 57.98 | 36 | 19.15 | 39 | 20.74 | 113 | 60.11 | 2 | 1.06 | 6 | 3.19 | 6 | 3.19 | 174 | 92.56 |
| Total | 7 | 2.04 | 126 | 36.73 | 5 | 1.46 | 205 | 59.77 | 67 | 19.53 | 77 | 22.45 | 199 | 58.02 | 9 | 2.62 | 12 | 3.5 | 8 | 2.33 | 314 | 91.55 |
*Pr is abbreviation for Prevalence.
Tables 3 and 6 show overall and gender-wise prevalence of CB, lamellar concha, hypertrophied inferior nasal turbinate, paradoxical nasal turbinate and supreme nasal turbinate and their variants in the study population.
Table 6.
Overall and gender-wise prevalence of variants of concha bullosa, lamellar concha, hypertrophied nasal turbinate, paradoxical nasal turbinate and supreme nasal turbinate in the study population
| Concha bullosa | Lamellar concha | Hypertrophied nasal turbinate | Paradoxical nasal turbinate | Supreme Nasal turbinate | |||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Present | Absent | Present | Absent | Present | Absent | Present | Absent | Present | Absent | ||||||||||||||||||||||||||||||||
| Towards Right | Towards Left | Both Sides | Towards right | Towards Left | Both Sides | Right Side | Left Side | Both sides | Right Sides | Left side | Both sides | Right side | Left side | Both sides | |||||||||||||||||||||||||||
| n | *Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | ||
| Male | 5 | 3.23 | 5 | 3.23 | 9 | 5.81 | 136 | 87.74 | 11 | 7.10 | 11 | 7.10 | 29 | 18.71 | 104 | 67.10 | 29 | 18.71 | 28 | 18.07 | 7 | 4.52 | 91 | 58.71 | 11 | 7.10 | 4 | 2.58 | 0 | 0 | 140 | 90.32 | 2 | 1.29 | 5 | 3.23 | 10 | 6.45 | 138 | 89.03 | |
| Female | 17 | 9.04 | 19 | 10.11 | 13 | 6.91 | 139 | 73.94 | 17 | 9.04 | 16 | 8.51 | 33 | 17.55 | 122 | 64.89 | 31 | 16.49 | 28 | 14.89 | 9 | 4.79 | 120 | 63.83 | 7 | 3.72 | 6 | 3.19 | 4 | 2.12 | 171 | 90.96 | 1 | 0.53 | 2 | 1.06 | 12 | 6.38 | 173 | 92.02 | |
| Total | 22 | 6.41 | 24 | 7.00 | 22 | 6.41 | 275 | 80.17 | 28 | 8.16 | 27 | 7.87 | 62 | 18.08 | 226 | 65.89 | 60 | 17.49 | 56 | 16.33 | 16 | 4.66 | 211 | 61.52 | 18 | 5.25 | 10 | 2.92 | 4 | 1.17` | 311 | 90.67 | 3 | 0.87 | 7 | 2.04 | 22 | 6.41 | 311 | 90.67 | |
*Pr is abbreviation for Prevalence.
Table 7 shows overall and gender-wise prevalence of different types of nasal septum.
Table 7.
Overall and gender-wise prevalence of different types of nasal septum in the study population
| Type I (normal to minimal) | Type II (mild) | Type III (moderate) | Type IV (severe) | |||||
|---|---|---|---|---|---|---|---|---|
| n | *Pr (%) | n | Pr (%) | n | Pr (%) | n | Pr (%) | |
| Male | 48 | 30.97 | 72 | 46.45 | 29 | 18.71 | 6 | 3.87 |
| Female | 58 | 30.85 | 93 | 49.47 | 29 | 15.43 | 8 | 4.26 |
| Total | 106 | 30.9 | 165 | 48.10 | 58 | 16.91 | 14 | 4.08 |
*Pr is abbreviation for Prevalence.
Table 8 shows overall and gender-wise mean, range and standard deviation of NSD angle in the study population.
Table 8.
Overall and gender-wise mean, range and standard deviation of NSD angle in the study population
| Gender | Mean NSD (degrees) | Range | SD (degrees) |
|---|---|---|---|
| Male | 6.95 | 0–17.70 | 4.47 |
| Female | 6.63 | 0–17.87 | 4.56 |
| Overall | 6.77 | 0–17.87 | 4.52 |
Table 9 shows overall and DNS variant-wise mean, range and standard deviation of NSD angle in the study population.
Table 9.
Mean, range, and standard deviation of each variant of deviated nasal septum in the study population
| Mean NSD (degrees) | Range | SD (degrees) | |
|---|---|---|---|
| DNS to right | 8.86 | 2–17.87 | 3.45 |
| DNS to left | 8.17 | 2.9–16.8 | 2.86 |
| ‘S’ shaped nasal septum | 9.69 | 2.7–16.8 | 3.28 |
| Overall | 8.64 | 2–17.87 | 3.20 |
Discussion
Our study found that DNS and septal spur are the most and second most common nasal cavity variants in our population, with prevalences of 76.68% and 41.98%, respectively. Previous literatures report that the prevalence of DNS ranges from 19.4% to 92.7%, as shown in Table 10. Tiwari et al[9] reported a DNS prevalence of 53% in the Nepali population; however, this study was based on clinical examination rather than CT scans, which may underestimate the actual prevalence. In contrast, a CT-based study by Shrestha et al[7] reported a 68.1% prevalence of DNS in the Nepali population, which aligns closely with our findings. Similarly, another study by Pokharel et al[10] reported a DNS prevalence of 73.1% in a CT-based study, further supporting our results. The variation in DNS prevalence reported by different Nepali authors may be attributed to the ethnic diversity within the population.
Table 10.
Overall and gender wise prevalences of DNS and prevalences of variants of DNS in studies done by various authors
| Study | Population | Number of samples | Pr* of DNS | Pr of DNS in Male | Pr of DNS in Female | Pr of DNS to Right side | Pr DNS to Left Side | Pr of “S” shaped nasal septum |
|---|---|---|---|---|---|---|---|---|
| Karki S et al [11] | Nepali | 218 | 56.9% | – | – | 42.2% | 14.7% | – |
| Janovic et al [12] | Serbia | 386 | 92.7% | – | – | – | – | – |
| Devareddy et al [13] | Indian | 100 | 62% | – | – | 26.0% | 28.0% | 8.0% |
| Pérez-Piñas et al [14] | Spain | 110 | 55% | – | – | – | – | – |
| Ominde et al [15] | Nigerian | 336 | 40.5% | 36.7% | 46% | 47.1% | 52.9% | 0% |
| Madani et al [16] | Saudi Arabia | 681 | 75.2% | 74.7% | 67.4% | 33.0% | 34.5% | 7.6% |
| Taghiloo et al [17] | Iran | 100 | 75% | 74.5% | 75.5% | – | – | – |
| Smith et al [18] | USA | 883 | 19.4% | 18.9% | 19.9% | – | – | – |
| Al-Qudah [19] | Jordan | 110 | 43% | – | – | 23.6% | 19.1% | 0% |
| Alsubael and Hegazy [20] | Saudi Arabia | 100 | 78% | 76.0% | 80.0% | – | – | – |
| Earwaker [21] | Australia | 800 | 44% | 22% | 22% | – | – | 21.0% |
| Qureshi and Usmani [22] | Pakistan | 50 | 56.0% | – | – | – | – | – |
| Turna et al [23] | Turkey | 5832 | 59.1% | – | – | 26.5% | 25% | 7.5% |
| Stallman et al [24] | Portugal | 998 | 65% | – | – | 34.4% | 32.06% | 1.5% |
| Serifoglu et al [25] | Turkey | 250 | 81.2% | – | – | 52.7% | 47.3% | – |
| Bora et al [26] | Turkey | 1532 | 78.7% | – | – | – | – | – |
| Koo SK et al [27] | Korea | 594 | 98.8% | 36.4% | 43.9% | 18.5% | ||
| Shokri et al [28] | Iran | 250 | 90.4% | 44.2% | 55.8% | – | – | – |
*Pr is abbreviation for Prevalence.
In our study, there was no significant difference in the prevalence of DNS between males and females. Similarly, Shokri et al[28] and Taghiloo et al[17] found no significant gender difference in the prevalence of DNS in the Iranian population. However, Bora et al[26] and Madani et al[16] reported DNS was significantly more common in males in the Turkish and Saudi Arabian population respectively. In our study, the prevalence of straight nasal septum, DNS to the right, DNS to the left, and “S”-shaped septum was 23.32%, 34.11%, 34.40%, and 8.16%, respectively. The prevalence of these variants in different populations is compared in Table 11. There was no statistically significant gender difference in the prevalence of variants of DNS. Similar findings were reported in the Nepali population by Pokharel et al[10], with 26.9% having a straight septum, 38.5% with DNS to the right, and 34.6% with DNS to the left. Bagri et al[29] found left-sided DNS slightly more common in the Indian population. Similar to our finding, Madani et al[16] also reported no significant gender difference in variants of DNS in the Saudi Arabian population.
Table 11.
Overall and gender wise prevalences of septal spur, septal pneumatization, concha bullosa, paradoxical nasal turbinate and pneumatized uncinate process in studies done by various authors
| Study | Population | Number of samples | Pr* of septal spur | Pr of septal pneumatization | Pr of concha bullosa | Pr of PNT | Pr PUP |
|---|---|---|---|---|---|---|---|
| Karki S et al[11] | Nepali | 218 | – | – | 54.1% | 39.4% | 10.1% |
| Dasar U et al[30] | Turkish | 400 | 42.3 % | 2 % | 67.5% | 15.8% | 13.8% |
| Turna et al[23] | Turkish | 6224 | 19.9% | 34.8% | 57.2% | 9% | 7% |
| Stallman et al[24] | Portugal | 998 | – | – | 44% | – | – |
| Al-Qudah et al[19] | Jordan | 110 | – | 27% | 62% | 18% | 6% |
| Kalaiarasi et al[31] | India | 202 | – | – | 31.7% | – | – |
| Ominde et al[15] | Nigeria | 336 | 11.9% | 3% | |||
| Biswas et al[3] | India | 50 | 12% | 36% | 10% | 6% | |
| Bora et al[26] | Turkey | 1532 | – | 1.3% | 40.9% | 16.4% | – |
| Pokharel et al[10] | Nepal | 130 | – | – | 24.6% | 7.7% | 5.4% |
| Shokri et al[28] | Iran | 250 | 34.8% | 40% | 34.8% | 16.8% | 12.8% |
| Koo SK et al[27] | Korea | 594 | 1.2% | – | 53.7% | – | – |
*Pr is abbreviation for Prevalence.
The prevalence of septal spur in our study was 41.98%, slightly higher in males (44.52%) than in females (39.89%), but this difference was not statistically significant (P = 0.388). There was a highly significant association between DNS and septal spur (P < 0.001), with 93.5% of septal spurs coexisting with DNS, and only 6.5% occurring with a straight septum. Additionally, we found a highly significant correlation between the side of the DNS and the septal spur (P < 0.001), with 79.2% of spurs on the same side as the deviation, 5.6% on the opposite side, and the rest in “S”-shaped nasal septa. Madani et al[16] reported a higher prevalence of septal spur (69.2%) in the Saudi Arabian population, with a significant male predominance. However, they found no significant difference in the side of the spur between genders. Shokri et al[28] found a lower prevalence of septal spur in males (32.2%) compared to females (67.8%). In the Indian population, Bagri et al[29] observed septal spurs in 29% of patients. Ominde et al[15] found no statistically significant gender or side differences for septal spurs, with all cases being associated with DNS and occurring on the same side as the deviation.
In our study, the prevalence of septal pneumatization was 40.23%, with a higher rate in females (42.02%) than in males (38.10%), though the difference was not significant (P = 0.457). There was no significant association between DNS and septal pneumatization (P = 0.061), and DNS variants and septal pneumatization types (P = 0.648). Anterior pneumatization occurred in 2.04%, posterior in 36.73%, and both in 1.46%, with no gender difference in pneumatization types (P = 0.494). Shokri et al[28] reported similar findings, with no gender difference (P = 0.56), but a significant association between DNS and septal pneumatization (P = 0.03). Ominde et al[15] and Madani et al[16] also found no significant gender difference (P = 0.960 and 0.67), though Madani et al reported a lower frequency of septal pneumatization in DNS cases (P < 0.001).
The prevalence of CB in our study was 19.83%, with a higher prevalence in females (26.10%) compared to males (12.26%). Notably, 72.1% of individuals with CB were female, and the gender difference was statistically highly significant (P = 0.001). We found a significant association between DNS and CB (P = 0.012), with 88.2% of CB cases also exhibiting nasal septum deviation. There was a statistically significant association between variants of DNS and the side of CB (P = 0.006), as CB was typically found on the side opposite the nasal septum deviation. The prevalence of CB was 6.41% on the right side, 7.0% on the left side, and 6.41% bilaterally, with no significant difference in the side of CB between genders (P = 0.255). Pokharel et al[10] reported a 24.6% prevalence of CB in the Nepali population, with a bilateral predominance (10.8%), 7.7% on the left, and 6.2% on the right, which aligns with our findings. Karki et al[11] identified CB as the third most common variant of the paranasal sinuses and nasal cavities in the Nepali population. Bora et al[26] reported a higher prevalence of CB in males (P = 0.019) and found a statistically significant association between septum deviation and CB (P = 0.031). Stallman et al[24], Saraf et al[32], Koo et al[27], and Kucybała et al[33] reported a strong association between DNS and CB on the contralateral side.
The prevalence of lamellar concha (LC) in our study was 34.11%, with a slightly higher prevalence in females (35.11%) compared to males (32.9%). However, the gender difference was not statistically significant (P = 0.668). Additionally, we found no significant association between DNS and lamellar concha (P = 0.248), nor were DNS variants significantly associated with the side of lamellar concha (P = 0.105). Since lamellar concha occupies minimal space in the nasal cavity, it is not expected to significantly influence the deviation of the nasal septum. The prevalence of LC was 8.16% on the right side, 7.87% on the left, and 18.08% bilaterally, with no significant difference in LC side between genders (P = 0.757). In the Egyptian population, El Anwar et al[34] reported a lamellar concha prevalence of 11.6%, which is lower than our findings.
The prevalence of hypertrophied inferior nasal turbinate (HINT) in our study was 38.48%, with a higher prevalence in males (41.29%) compared to females (36.17%). However, this gender difference was not statistically significant (P = 0.332). We observed a significant association between DNS and HINT (P = 0.001), with 86.4% of HINT cases occurring in patients with DNS. Our study also shows a highly significant association between variants of DNS and the side of HINT (P < 0.001), with most patients showing HINT opposite the side of DNS, which aligns with the expectation of compensatory hypertrophy of the inferior turbinate. The prevalence of HINT was 17.49% on the right side, 16.33% on the left, and 4.66% bilaterally, with no significant difference in side of HINT between genders (P = 0.907). Bagri et al[29] reported that an increasing angle of septal deviation was associated with a higher incidence of contralateral turbinate hypertrophy. Similarly, Tomblinson et al[35] found a significant association between DNS and inferior turbinate hypertrophy on the contralateral side.
The prevalence of paradoxical middle turbinate (PMT) in our study was 9.33%, with a higher prevalence in males (9.68%) compared to females (9.04%), though this difference was not statistically significant (P = 0.841). Our study revealed a significant association between DNS and PMT (P = 0.016), with 93.75% of PMT cases coexisting with DNS. However, variants of DNS were not significantly associated with the side of PMT (P = 0.173). The prevalence of PMT was 5.25% on the right side, 2.92% on the left side, and 1.17% bilaterally, with no significant difference in side prevalence between genders (P = 0.075). Pokharel et al[10] reported PMT in 7.7% of the Nepali population, more frequently on the right side (3.1%) than the left (2.3%), without any statistically significant correlation with gender or side. In contrast, El Anwar et al[34] found that septal deviation did not affect the occurrence of PMT, which contradicts our findings.
The prevalence of supreme nasal turbinate (SNT) in our study was 9.33%, with a higher prevalence in males (10.97%) compared to females (7.98%), though this difference was not statistically significant (P = 0.344). Our study found no significant association between DNS and SNT (P = 0.52). There was no significant association between variants of DNS and the side of SNT (P = 0.091). The prevalence of SNT was 0.87% on the right side, 2.04% on the left side, and 6.41% bilaterally, with no significant difference in side prevalence between genders (P = 0.431). While we expected SNT to occupy additional space in the nasal cavity and deviate the septum to the opposite side, our findings did not support this expectation. In fact, 65% of cases exhibited bilateral SNT, which likely contributed little to the deviation of the septum. Additionally, the small size of SNT in nearly all cases would have minimal impact on nasal septum deviation.
The prevalence of pneumatized uncinate process (PUP) in our study was 8.45%, with a higher prevalence in males (9.68%) compared to females (7.45%). Specifically, PUP was found on the right side in 2.62%, on the left side in 3.5%, and bilaterally in 2.33%. There was no significant difference in PUP prevalence between genders (P = 0.46) or in the side of PUP (P = 0.093). Additionally, no significant association was found between DNS and PUP (P = 0.052). Khadka et al[36] reported a PUP prevalence of 1.04% in the Nepali population, which is lower than our findings. Baldea et al[37] studied uncinate process variations in the Romanian population, reporting a PUP prevalence of 3.4%, with higher rates in males than females. They noted bilateral PUP in 1.46% and unilateral PUP in 1.95%, with unilateral cases occurring exclusively on the left side. Fikir et al[38] reported a PUP prevalence of 8.05% in the Mexican population.
Among the different types of nasal septum, type II was the most prevalent, with a prevalence of 48.10%. Type I was the second most common, at 30.9%, while types III and IV had prevalences of 16.91% and 4.08%, respectively. There was no significant difference in the types of nasal septum between males and females (P = 0.865). However, a significant difference was observed in the types of nasal septum among cases with CB (P = 0.003), with type II being the most common (57.4%), followed by type III (19.1%). The types of nasal septum were not significantly different among the variants of DNS (P = 0.085). Lazim et al[39] reported that in the Malaysian population, 7.1% had normal septal angulation (<5°), 55.1% had mild angulation (5-10°), and 37.8% had moderate angulation (11-20°), with no cases of severe angulation (>20°). Bagri et al[29] classified Indian patients by NSD angle into three groups: group I (0-7°), group II (7.1-11°), and group III (>11°), with most patients in group II (35%), followed by group I (33%) and group III (31%). Serifoglu et al[25] found that in the Turkish population, 17.2% had mild deviation (<9%), 30.8% had moderate deviation (9-15%), and 33.2% had severe NSD (>15%). These findings are roughly consistent with ours, indicating that mild deviation is more common than severe deviations. We expect types III and IV nasal septum to be associated with more severe symptoms of nasal obstruction and sinonasal pathologies.
There was no significant difference in the NSD angle between males and females (P = 0.52). However, a significant difference was observed in the NSD angle among different variants of DNS (P = 0.048). Notably, the NSD angle between DNS to the left side and “S”-shaped nasal septum showed significant variation (P = 0.024). The presence of CB was associated with a higher mean NSD; the mean NSD in cases with CB was 8.82° ± 3.99°, compared to 6.27° ± 4.5° in cases without it, with a statistically highly significant difference (P < 0.001). Similar results were found by Madani et al[16], Serifoglu et al[25], and Lazim et al[25]. Serifoglu et al[25] reported mean deviation angles of 13.6 ± 5.29° for right deviation and 14.44 ± 6.08° for left deviation, with no significant difference between genders (P = 0.660). Ominde et al[15] reported an average NSD angle of 11.89 ± 2.82°, noting that males had a higher angle (12.55 ± 2.99°) than females (11.13 ± 2.41°), showing a significant difference (P = 0.003). They also found that the septum deviated more to the right (12.11 ± 2.55°) than to the left (11.54 ± 2.8°) (P = 0.027). Madani et al[16] found no significant differences in NSD angle between genders for right-sided and S-shaped NSD (9.6° vs. 10.4° and 9.1° vs. 8.7°, respectively; P = 0.163 and P = 0.751). However, left-sided NSD showed significantly higher deviation in males (14.1°) compared to females (10.6°) (P < 0.001). The differences between our study and these studies may be attributed to ethnic variations.
The findings of our study have important clinical implications in the diagnosis and management of nasal and sinus conditions. Knowing the prevalences of variants of different of nasal septum and nasal cavities can aid in preoperative planning for procedures such as endoscopic sinus surgeries and reduce the risk of complications. These anatomical insights enhance radiological interpretation and support tailored surgical approaches. Gender-wise analysis further contributes to personalized care. Additionally, the data provide a valuable reference for medical education and population-specific clinical guidelines.
The main strength of our study is its relatively big sample size and being the first focused study of nasal cavity on the Nepali population. Some earlier research covered nasal and paranasal sinus variants but did not focus solely on nasal cavities, some had smaller sample sizes or lacked sufficient detail. Another strength is the involvement of two experienced radiologists, ensuring accurate results. Extensive effort went into reviewing the literature and comparing our findings with studies from Nepal and other countries. A limitation of our study is that we did not include all minor nasal cavity variants, as doing so would complicate calculations and require a larger sample size. Additionally, since the Nepali population is heterogeneous, a larger, more geographically and ethnically diverse sample is needed to determine the true prevalence of nasal cavity variants. Our sample was limited and collected from a private hospital, which may not fully represent the Nepali population.
Conclusion
Understanding the prevalence of nasal cavity variants in a population is crucial for head and neck surgeons, as well as radiologists, when treating nasal cavity pathologies. The most common variants in our population include deviated nasal septum, bony spurs, and pneumatized septum. The prevalence of CB was significantly higher in females than in males, and Type 2 nasal septum was the most common. The average NSD angle measured 6.77 degrees.
Footnotes
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Contributor Information
Prajwal Dahal, Email: meprajwal7@gmail.com.
Sagar Poudel, Email: poudelsagar09@gmail.com.
Prajina Pradhan, Email: prajinapradhan@gmail.com.
Samjhana Ghimire, Email: samjhanaghimire@pahs.edu.np.
Sabina Parajuli, Email: parajulisabina48@gmail.com.
Natasha Dhakal, Email: d.19natasha@gmail.com.
Ethics approval
Ethical approval was obtained from Institutional Review Committee of Grande International Hospital.
Consent
The consent was waived by the institutional review committee since the study was retrospective in nature.
Sources of funding
No external funds were received for the research.
Author contributions
P.D.: conceptualization, manuscript writing; S.P., P.P.: statistical analysis; S.G., N.D.: data curation; S.P.: data curation, software.
Conflicts of interest disclosure
None.
Guarantor
The principal author Prajwal Dahal accepts full responsibility for the work and conduct of the study. I have access to the data and control the decision to publish.
Research registration unique identifying number (UIN)
Provenance and peer review
Paper was not invited.
Data availability statement
The data that support the findings of this study are openly available in clinicaltrials.gov at https://clinicaltrials.gov/study/NCT06434675, reference number NCT06434675.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are openly available in clinicaltrials.gov at https://clinicaltrials.gov/study/NCT06434675, reference number NCT06434675.