|Year : 2021 | Volume
| Issue : 3 | Page : 220-223
Pneumatisation patterns of the frontal sinus in adult Nigerians
Beryl Shitandi Ominde, Patrick S Igbigbi
Department of Human Anatomy and Cell Biology, Delta State University, Abraka, Delta State, Nigeria
|Date of Submission||18-Feb-2021|
|Date of Decision||07-Mar-2021|
|Date of Acceptance||07-Mar-2021|
|Date of Web Publication||04-Sep-2021|
Beryl Shitandi Ominde
Department of Human Anatomy and Cell Biology, Delta State University, P.M.B. 1, Abraka
Source of Support: None, Conflict of Interest: None
Introduction: The varying pneumatisation patterns of the frontal sinus (FS) can be utilised in the forensic identification of human remains. This study aimed at determining the pneumatisation patterns of the FS of adult Nigerians. Materials and Methods: This descriptive cross-sectional retrospective study was carried out at the radiology department of a tertiary hospital in Nigeria following ethical approval. Brain computed tomography images of 336 patients (199 males and 137 females) aged ≥20 years were utilised. Images with facial and sinonasal pathologies were excluded from this study. The FS was evaluated and classified as either absent, bilateral or triple. The existence of complete or partial septa was noted, and the roof was categorised as either smooth or scalloped. Data were analysed using the Statistical Package for the Social Sciences version 23. The frequencies of each variant were presented in percentages. A Chi-square test was used to evaluate gender differences. P < 0.05 was considered statistically significant. Results: Bilateral FS was seen in 244 (72.6%) patients. This was followed by triple FS (48, 14.3%) and aplasia (44, 13.1%). The prevalence of partial septa was 197 (58.6%), with a significantly higher prevalence in males (149, 74.9%) than in females (48, 35.0%) (P = 0.017). The scalloped roof of the FS was more frequent (226, 67.3%) than the smooth FS roof (110, 32.7%), although both showed statistically significant gender differences (P = 0.021, 0.028). Conclusion: The scalloped roof and partial septa of the FS showed sexual dimorphism. Hence, their accuracy in sex prediction may be explored in our population.
Keywords: Aplasia, frontal sinus, pneumatisation, septum
|How to cite this article:|
Ominde BS, Igbigbi PS. Pneumatisation patterns of the frontal sinus in adult Nigerians. Adv Hum Biol 2021;11:220-3
| Introduction|| |
The frontal sinuses (FSs) are irregularly shaped, mucosal lined, pneumatic compartments between the internal and external cortical surfaces of the frontal bone. These asymmetric chambers develop independently of each other and are separated by a bony septum. The FS is not radiographically visible at birth. Its development begins at 2 years of age, and by 5–6 years, it becomes radiographically evident. During puberty, it grows slowly and later achieves its maximum size at 20 years.
Pneumatisation of the FS is influenced by craniofacial configuration, the thickness of the frontal bone and hormonal growth factors. The morphology of FS remains stable throughout adult life. However, it may continue to expand with age due to atrophic changes and mechanical stresses of mastication., The configuration of the FS may be altered by environmental factors, history of orthodontic treatment, developmental anomalies, chronic sinusitis and endocrine disorders such as acromegaly and Paget's disease. Hyperpneumatisation may be caused by sporting activities, tumours, trauma and post-mortem changes.
The analysis of the FS size, shape and patterns of pneumatisation has been largely accepted as a reliable technique for forensic identification of human remains in cases where soft tissue becomes putrid or charred., This is due to its stability throughout adult life, unique nature in each individual and great resistance against external traumatic forces and decomposition. Ante-mortem radiographs taken for clinical purposes are compared with post-mortem radiographs for positive identification using definitely individualised structures such as the shapes and contours of the FS. Computed tomography (CT) is more accurate for assessing the paranasal sinuses and for comparison of forensic data due to their high resolution and a three-dimensional display. This study, therefore, aimed at determining the pneumatisation patterns of the FS in adult Nigerians using CT.
| Materials and Methods|| |
This was a descriptive cross-sectional retrospective study which was conducted at the radiology department of a tertiary Delta State University Teaching Hospital in Nigeria. Three hundred and thirty-six brain CT images of 199 male and 137 female patients aged 20 years and above were retrieved from the Picture Archiving and Communications Systems after ethical approval by the hospital's Research and Ethics Committee, EREC/PAN/2020/030/0371. These were CT images taken between 1st June 2015 and 30th June 2020 using a 64-slice CT scanner. Images of patients aged below 20 years were excluded from this study since the paranasal sinuses are not yet fully developed before 20 years of age. Images with evidence of facial trauma, sinonasal tumours, skull congenital anomalies and evidence of previous sinus surgery were also excluded from this study.
The FSs were identified bilaterally by using coronal and axial sections. The patterns of pneumatisation of the FS were classified as either absent, bilateral (one septum) or triple (two septa). A partial septum was defined as a bony projection more than 1 mm extending from the bony wall into the sinus space but not dividing the cavity. A diverse continuity of the bony roof of the FS as inward or outward arc was categorised as a scalloped roof.
Data were analysed using the Statistical Package for the Social Sciences version 23. The frequencies of each variant were presented in percentages. A Chi-square test was used to evaluate for gender differences. P < 0.05 was considered statistically significant.
| Results|| |
The study analysed the FSs of 336 patients. This encompassed 199 males (59.2%) and 137 females (40.8%). The patients' age ranged between 20 years and 99 years, while the average age was 53.29 ± 18.18 years. A complete intersinus septum was seen in 244 (72.6%) patients, hence the bilateral occurrence of the FS in 146 (73.4%) and 98 (71.5%) males and females, respectively. This was the most common pneumatisation pattern of the FS [Figure 1]A. Two complete septa were seen in 14.3% (48) of the patients. This pattern of triple FS was more prevalent in males (31, 15.6%) than in females (17, 12.4%) [Figure 1]B. There was no statistically significant gender difference in the bilateral and triple presence of the FS (P = 0.241, 0.346). The presence of FS agenesis either unilaterally or bilaterally showed a prevalence of 44, 13.1%, with a slightly higher prevalence in females (22, 16.1%) than in males (22, 11.1%) (P = 0.746) [Table 1]. Partial septa were seen in 197 (58.6%) patients with a significantly higher prevalence in males (149, 74.9%) than in females (48, 35.0%) (P = 0.017) [Figure 1]C.
|Figure 1: Reformatted coronal computed tomography images showing frontal sinus septa. (a) Bilateral frontal sinus with a single complete septum. (b) Triple frontal sinus with two complete septa. (c) Presence of complete and partial septa.|
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The scalloped outline of the upper border of the FS was more predominant (226, 67.3%) than the smooth FS roof (110, 32.7%). Scalloping arcades were observed bilaterally with a higher preponderance in the males (151, 75.9%) than in females (75, 54.7%) [Figure 2]A and [Figure 2]B. On the other hand, female patients had a higher prevalence of smooth FS roof (62, 45.3%) than male patients (48, 24.1%). Furthermore, there was a statistically significant association between gender and the presence or absence of the arcades (P = 0.021, 0.028).
|Figure 2: Reformatted coronal computed tomography images showing variant roof of the frontal sinus. (a) Smooth roof. (b) Scalloped roof.|
Click here to view
| Discussion|| |
We report a preponderance of the bilateral FS separated by a complete intersinus septum in 72.6%. This was slightly lower than 75.1% documented by Acar et al. in Turkey. Triple FS with two complete intervening septa were observed in 14.3%, higher than 13.2% documented by Acar et al. The prevalence of FS aplasia was 13.1%, and this was higher than 3.7% reported amongst the Turkish. Lower frequencies of FS aplasia were also observed from CT studies carried out in Brazil (1%) and Saudi Arabia (7.3%)., Consistent with our findings, the CT study by Acar et al. documented no significant association between gender and these patterns of FS pneumatisation.
The prevalence of partial septa (58.6%) in our population was higher than 25.9% documented by Acar et al. Similarly, these scholars documented a significantly higher prevalence in males than in females, possibly due to differences in genetic factors. Contrary to our findings, Yoshino et al. observed no association between gender and the existence of partial septa. Using digital AP radiographs of 400 adults, Gadekar et al. documented the absence of partial septa in 55.2% of Indians. Benghiac et al. found out that the presence of multiple septa in the right FS and left FS may accurately predict Romanian males and females, respectively. The lack of intrasinusal septa in Iraq was reported as an essential parameter in sex determination. However, according to a Persian study by Akhlaghi et al., the number of FS septa is not a reliable parameter in sex determination. The discrepancies in the prevalence of the incomplete septa documented in literature could be attributed to genetics, race and ethnicity.
The configuration of the FS roof varies in each individual and different population groups. The prevalence of the scalloped roof (67.3%) was higher than the findings documented in Turkey (37.9%) by Acar et al. The variance is possibly due to differences in geographical and environmental factors as well as race. Akin to the findings of Acar et al., we observed a statistically significant higher prevalence of scalloped FS roof in males than in females. The frequency of the smooth FS roof was 32.7%, with a statistically significant higher prevalence in females than in males. These gender differences in the outline of the FS may perhaps be caused by the differences in the genetic, muscular, nutrition and hormonal factors. Yoshino et al. reported no significant association between sex and the outline of the FS roof.
The findings of this study and the comparison with other literature reports reveal the varying pneumatisation patterns of the FS in different populations. According to Gadekar et al., the irregular configuration of the FS contributes to its unique character in each individual. Positive forensic identification may be achieved by the comparison of these unique features on ante-mortem and post-mortem radiographs through superimposition. This method is simple, fast, reliable and requires minimal skill., However, it is limited by the inability to store the acquired data, the availability of both radiographs for comparison, the need for repeat evaluation for every case and the lack of exact replication of the ante-mortem radiograph with the same density and angulation post-mortem., The coding system was proposed to overcome these challenges though it is affected by many false positives. According to Yoshino et al., the partial septa and outline of the superior border of the FS were part of the seven discrete morphological variables, which are coded, and the numbers used to formulate a given pattern of the FS to aid in identification.
| Conclusion|| |
The scalloped roof and partial septa of the FS showed sexual dimorphism. Their accuracy in the prediction of sex may be investigated to aid in personal identification in our population.
Strength of study
The use of CT images enhanced the accuracy of our findings due to minimal superimposition as in radiographs.
Limitation of study
The sample size was small, hence the findings of this study may not be generalised. Despite establishing sexual dimorphism in the partial septa and scalloped roof of the FS, the study did not predict the accuracy of these patterns in sex determination.
Future result directions
The accuracy of using the pnematization patterns of the FS in the prediction of sex can be further evaluated in our studied population.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]