|Year : 2021 | Volume
| Issue : 3 | Page : 280-285
Evaluation of anatomical variations of sella turcica with age and gender using digital lateral cephalogram in Chennai city
Anandhi Sekar Arthisri, Subramaniyan Dhanapriya, A Niranjana, S Mehazabin, F Massillamani, S Kailasam
Department of Oral Medicine and Radiology, Ragas Dental College and Hospital, Chennai, Tamil Nadu, India
|Date of Submission||26-Jan-2021|
|Date of Decision||05-Jul-2021|
|Date of Acceptance||08-Aug-2021|
|Date of Web Publication||28-Sep-2021|
Dr. Anandhi Sekar Arthisri
Department of Oral Medicine and Radiology, Ragas Dental College and Hospital, Chennai - 600119, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Pituitary gland dysfunction might be predicted by examining the alteration of Sella turcica during the routine radiological examination of lateral cephalogram. Aim: The study aimed to analyze the variation in size and shape of sella turcica according to age and gender on lateral cephalogram among the people in the south zone of Chennai city. Materials and Method: A series of lateral cephalogram images from 200 patients comprising 94 males and 106 females were collected retrospectively from archives in the database. The shape and size of sella turcica were measured digitally. Statistical analysis was done using the Chi-square test and unpaired sample t-test. Results: The frequency of distribution of shapes of sella turcica among the people in Chennai city was 46% normal followed by 15.5% irregular dorsum sellae, 14.5% pyramidal shape, 11.5% bridging, 7% oblique anterior wall, 5.5% double contour. The length and depth of Sella turcica was greater in males when compared with that of the females which were statistically significant (P < 0.01). The depth and diameter were higher in the 10–20 years age group than the 20–30 year age group, which was statistically significant (P = 0.01). Conclusion: The size of Sella turcica alters between different age groups and gender. Variations in the shape of Sella turcica were present in nearly half of the individuals in the present study. Thus, the morphology of Sella turcica should be assessed as a part of routine radiographic examination.
Keywords: Age, cranial fossa, gender, pituitary gland, sella turcica
|How to cite this article:|
Arthisri AS, Dhanapriya S, Niranjana A, Mehazabin S, Massillamani F, Kailasam S. Evaluation of anatomical variations of sella turcica with age and gender using digital lateral cephalogram in Chennai city. J Indian Acad Oral Med Radiol 2021;33:280-5
|How to cite this URL:|
Arthisri AS, Dhanapriya S, Niranjana A, Mehazabin S, Massillamani F, Kailasam S. Evaluation of anatomical variations of sella turcica with age and gender using digital lateral cephalogram in Chennai city. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2021 Nov 29];33:280-5. Available from: https://www.jiaomr.in/text.asp?2021/33/3/280/326881
| Introduction|| |
The chief gland of the body that controls most of the endocrine functions is the Pituitary gland. The Sella turcica (also called hypophyseal fossa or pituitary fossa) is a saddle-shaped depression in the sphenoid bone lined by the dura mater. One of the main reasons for imaging the sella turcica is that it is a window to the pituitary, a pea-sized gland that is often called the master endocrine gland.
On Lateral radiographs, the sella turcica appears as a radiodense saddle-shaped outline of the fossa extending between the anterior and posterior clinoid processes. It is located in close vicinity to copious vital structures such as the sphenoid sinus, optic chiasm, cavernous sinus, and hypothalamus. The evolution of the sella turcica is allied to that of the pituitary gland. The normal surface area of the sella turcica varies from 18 to 115 mm2 in females and from 22 to 122 mm2 in males.
The functional matrix theory states that ''the origin, development and maintenance of all skeletal units are secondary, compensatory, and mechanically obligatory responses to temporally and operationally prior demands of related functional matrices.'' Therefore, according to this theory, it can be anticipated that the pituitary gland serves as the functional matrix of the sella turcica.
Moreover, the development of the pituitary gland is completed before cartilaginous sella turcica is formed and thus the deviation in the shape of sella turcica will reflect on the morphological functioning of the pituitary gland. An ample number of studies suggest that the size of the sella turcica can change correspondingly with an increase or decrease in the size of the pituitary gland., Cephalometric radiography plays a major role in diagnosis, treatment planning, and predicting the prognosis of endocrine disorders., The shape of the sella turcica can be classified into three types: Round, oval and flat.
As an oral radiologist, some of the incidental findings on the lateral cephalogram like alteration in size or shape of the sella turcica, would prompt the prime role of dentist in detection of skull lesions. Various studies have assessed the anatomical variation of the hypophyseal fossa in different populations of the world. Therefore, the prime objective of the study is to analyze the variation in size and shape of sella turcica according to age and gender on lateral cephalogram among the people in the Chennai city.
| Materials and Methods|| |
This study was approved by the Institutional Ethics Committee (Ref no: IEC/RDCH/20181245). The procedure is in accordance with the ethical standards as per the Helsinki Declaration of 1975 as revised in 2000.
Sample size estimation
The power of the study is 80%. The sample size was calculated with a standard deviation of 12.39, the absolute error of 2% at a 95% confidence interval using the formula 4SD2/LD2. The study sample consisted of 200 lateral cephalograms of patients from the archives in the database of the Department of Oral Medicine and Radiology.
Inclusion and Exclusion Criteria
The age range in this study was 10–30 years. Lateral cephalograms with good visibility of all cephalometric structures including sella turcica were included. Patients with radiographic evidence of craniofacial abnormalities and maxillofacial surgery/trauma were excluded.
All lateral cephalograms were taken using X Mind Pano D+ Ceph (SOREDEX PaloDEx Group Oy, Nahkelantie 160 FI-04300 Tuusula, Finland) X- ray machine in a standardized manner with optimum exposure factors. All linear measurements were made with an inbuilt Scanora software (SOREDEX, Nahkelantie 160, Tuusula, Finland). Examination of lateral cephalogram was done by a single investigator. The consistency of the observer was confirmed by asking them to reassess the images of random subjects and compared them with the corresponding original data.
Size of sella turcica
For estimating the size of sella turcica three linear measurements, that is, length, diameter, and depth in the mid-sagittal plane was measured according toSilverman and Kisling method as shown in [Figure 1].
|Figure 1: Size of Sella turcica. DS -- TS = the length (l), APD--TS = Anterior posterior diameter (APD), L -- BPF = Depth of the Sella turcica D Area of the Sella turcica = Length × Depth, TS = Tuberculum Sellae, DS = Dorsum Sellae, BPF = Base of pituitary fossa|
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- Length – The distance between the tuberculum sella (TS) to the tip of the dorsum sella (DS).
- Depth – A line perpendicular to the line drawn above to the deepest point on the floor.
- Anteroposterior diameter – Line is drawn from the tuberculum sella to the most posterior point on the posterior inner wall of the fossa.
Shape of sella turcica
Axelsson et al. have classified the shapes of sella turcica into five variations in morphology despite the normal shape namely oblique anterior wall, sella turcica bridging, the double contour of the floor, irregularity in the posterior part of dorsum sellae (notching), pyramidal shape of the dorsum [Figure 2] and [Figure 3].
|Figure 2: Shapes of Sella turcica- Radiographic images. (a) Normal Sella turcica, (b) Oblique anterior wall, (c) Bridging of Sella turcica, (d) Double contour of floor of Sella turcica, (e) Irregular dorsum Sella, (f) Pyramidal Sella turcica|
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|Figure 3: Shapes of Sella Turcica- Line diagrams. (a) Normal Sella turcica, (b) Oblique anterior wall, (c) Bridging of Sella turcica, (d) Double contour of floor of Sella turcica, (e) Irregular dorsum Sella, (f) Pyramidal Sella turcica|
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The collected data were analyzed with IBM SPSS statistics software 23.0 Version (Statistical package for social science Inc., Chicago, Illinois, USA). To describe the data descriptive statistics frequency analysis, percentage analysis was used for categorical variables, and the mean and standard deviation (SD) were used for continuous variables. To find the significant difference between the bivariate samples in Independent groups the Unpaired sample t-test was used. To find the significance in categorical data Chi-Square test was used. In all the above statistical tools the probability value 0.05 was considered as a significant level.
| Results|| |
Among the 200 lateral cephalograms examined 106 were radiographs of female (53%) patients and 94 were radiographs of male (47%) patients. The distribution of shapes of sella turcica among the study group revealed that the most common shape was normal 46% followed by irregular dorsum sellae 15.5%, pyramidal shape 14.5%, bridging 11.5%, oblique anterior wall 7% and double. contour 5.5% in the decreasing order of frequencies [Table 1]
|Table 1: Distribution of demographic characteristics and shape among the study participants|
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On comparing the size of sella turcica with gender the length and diameter of the sella turcica using Mann–Whitney U test was statistically significant (P < 0.01), but the depth of sella turcica was not significant (P = 0.113) [Graph 1]
On comparing the size of sella turcica between the age groups, the depth and diameter of the sella turcica using Mann–Whitney U test was statistically significant (P < 0.01), but the length of sella turcica was not significant (P = 0.457) [Table 2] and [Table 3].
On comparing the shapes of sella turcica like normal, Oblique anterior wall, Sella turcica bridging, Double contour of the floor, Irregularity in the posterior part of dorsum sellae (notching), the Pyramidal shape of the dorsum with age and gender the results were not statistically significant (P < 0.05) [Graph 2].
Finally, on comparing the mean values of the linear measurements with different shapes of the sella turcica using the Kruskal–Wallis test, the length, depth, and diameter were statistically significant (P < 0.01) [Graph 3]. Post hoc analysis using Mann–Whitney U test for comparing the shape with length (P < 0.01), depth (P < 0.01) and diameter (P < 0.005) was statistically significant [Table 4].
| Discussion|| |
The sella turcica comprises the dorsum sellae, tuberculum sellae, hypophyseal fossa, and dwells the pituitary gland. The sella turcica reflects the pathological changes even before the emergence of symptoms related to pituitary dysfunction., The measurement taken from the radiographs directly correlate with the pathological measurement of sella turcica from the autopsy specimen with a higher sensitivity rate of 77%.
In view of fostering the radiological interpretations of a lateral cephalogram, the current study was conducted to assess the morphological alteration of sella turcica, which has been found to have a clinical significance with the functioning of the pituitary gland. As the interpretation of the alterations of sella turcica in a younger age group would be helpful in scrutinizing the endocrinological problem at an earlier stage, the anatomy of sella turcica was evaluated in the lateral cephalogram, opted by the orthodontist as an increasing number of teenagers are considered about their aesthetic profile.
Of the 200 lateral cephalograms explored the predominant shape was found to be 46% normal followed by 15.5% irregular dorsum sellae, 14.5% pyramidal shape, 11.5% bridging, 7% oblique anterior wall, 5.5% double contour in decreasing of frequencies, and which was in accordance to previous studies conducted in a different study population of the same country., Whereas another study among the Turkish individuals revealed a slight variation in the frequency of shapes were the order of prevalence was normal morphology (39.0%), followed by pyramidal shape (15.5%), the double contour of the floor (14.6%), oblique anterior wall (14.4%), irregular dorsum sella (8.6%), and sella turcica bridge (8.0%). The discrepancy could probably be due to different ethnic backgrounds.
In our study, the most predominant shape was found to be normal (46%) and it was consistent with the studies conducted by Kumar et al. (27.3%), Chauhan et al. (28%) and Chaitanya et al. (20.6%) but the percentage of occurrence was lower than our study. The next common type in the present study was irregular dorsum sella (15.5%) which was following the study conducted by Kumar et al. (15.8%), Prarthna et al. (15.9%) and Chaitanya et al. (15%). The pyramidal shape of sella turcica was present in 14.5% of the individuals which was found to be consistent with the study conducted by Chaitanya et al. (14%) but higher than the study conducted by Kumar et al. (10.6%) and Prarthna et al. (4.5%). Bridging of Sella Turcica was found in 11.5% which was found to be less than the study conducted by Chaitanya et al. (16.3%) but higher than the study conducted by Kumar et al. (10%) and Axelsson et al. (10%). The oblique anterior wall was present in 7% which was in contrast to the study conducted by Kumar et al. (5.5%), Prarthna et al. (9.09%) and Chaitanya et al. (18.5%). Double contour was present in 5.5% of our study but 4.2% of the patients had double contour in the study conducted by Kumar et al. and 7% of the individuals had double contour in the study conducted by Chouhan et al. [Table 1].
The bridging of sella turcica (11.5%) has been said to be associated with Gorlin–Goltz syndrome, Rieger syndrome, and other disorders.,, Despite this there are copious pathological conditions analogous to freak development of sella turcica and pituitary gland. Consequently, we can endorse the patients with atypical sella turcica to prosecute with further diagnostic investigations succeeding an opinion of an endocrinologist, even though not all abnormalities could have a pathological correlation.
If the Sella turcica on a radiograph is enlarged it may indicate a hyper pituitary function in conditions such as adenomas, meningioma, primary hypothyroidism, and prolactinoma and syndromes such as empty sella syndrome, Nelson syndrome, Down's syndrome, William's syndrome, Seckel syndrome, and Axenfeld-Rieger syndrome., If diminished in size, it may indicate decreased pituitary function causing symptoms such as short stature and retarded skeletal growth.
The mean length, depth, and diameter of a normal sella turcica are 9.03, 7.34, and 10.91 mm which were in accordance to the previous studies.,, The length of the sella turcica seemed to be comparatively more in males than in females but it was vice versa in the case of diameter with a statistical significance of P < 0.0005. Similar results were found in studies conducted by Nagaraj et al. and Kumar et al. among the different study populations. In contrast to this, some studies conducted in different ethnic backgrounds namely Iraq, Pakistan, and Nigerian populations showed no statistical significance between the gender, due to differences in racial origin. The Depth of sella turcica was more in females than in males; however, the results were not statistically significant. The length and the diameter of sella turcica increased as the age progressed with a statistical significance of P < 0.0005. The results were in accordance to Chilton et al.,, and Kumar et al.,, [Graph 3].
Due to its diverse variations' clinicians must be eloquent with the morphological and radiographic variability of this region, to apprehend and investigate the abnormalities that may influence pathological situations well in advance before these become clinically evident.
Limitations and Future prospects
Lateral cephalogram being a two-dimensional image, patients with atypical sella turcica can be recommended for advanced radiographic imaging. Further research has to be done to find out the efficacy of diagnosing the endocrine disorders involving the pituitary gland, by periodic follow-up of patients with abnormal radiographic interpretations.
| Conclusion|| |
The size of the Sella turcica is significantly greater in the third decade of life than in the second decade. It is significantly larger in males compared to females which could be used for gender determination in forensic radiology. The altered shape of Sella turcica is found in approximately half of the individuals in the study population, this could be attributed to an underlying endocrine disorder. Further, longitudinal studies of patients with atypical sella turcica have to be carried out to confirm any occult pathologies.
The authors would like to appreciate the efforts of Dr. S. Venkatesan for assisting in statistical analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]