ABSTRACT
Background and Aims
Skeletal age estimation is as a transformative process, where the descriptive skeletal age indicator is translated into a chronological age. One of the limitations of the numerous methods used for examining age status is that as soon as the development sites have completed growth, which is relatively early, accurate age determination becomes challenging and more difficult. A synchondrosis is a joint cartilaginous in nature between two immovable bones that serves to allow growth until the hyaline cartilage is converted into bone before or during early adult life. The age of spheno‐occipital synchondrosis (SOS) ossification is relatively late, compared with other cranial base synchondroses. Hence, knowing the accurate age of SOS closure can have an important impact in the medical, forensic, and anthropological fields. The aim of our study is to evaluate the use of the SOS as a means of skeletal age estimation in Cameroon.
Methods
We carried out a cross‐sectional analytical study using CT scans. Our study period included patient radiological files from January 2022 to April 2024 at the radiological unit of the Yaoundé University Teaching Hospital (YUTH) and two radiological centers in Yaoundé. We used a five‐stage SOS closure classification going from Stage 1 where the SOS is completely open to Stage 5 where there is complete fusion of SOS and the scar obliterated.
Results
We retained 312 participants, 171 (54.8%) of which were males and 141 (45.2%) were females with a sex ratio of 1.2. The mean age in our study was 17.4 ± 11.9 years. The first decade was the most represented with 34.6%. The mean age of closure for Stage 1 was 4.8 ± 3.3 years and for Stage 5 was 28.6 ± 7.8 years and the differences were statistically significant. Comparing the SOS closure with sex, we observed no clear difference between males and females, with their mean ages also being similar. In Stage 1 the mean age for males was 5.1 years and the mean age for females was 4.1 years.
Conclusion
SOS closure in our study was as from the mean age of 23.5 years. SOS closure is linked to age in our study with a progressive increase in closure stage with age. SOS Stage 1 mean age of closure was at 4.8 years followed by 12.9 years then 19.9 years, 23.5 and finally 28.6 years at Stage 5, respectively. With respect to sex, there was no difference in SOS closure between males and females in all stages but Stage 1 in our study.
Keywords: age, sex, skeletal age determination, spheno‐occipital synchondrosis
1. Introduction
Skeletal age estimate is characterized as a transformative process in which the descriptive skeletal age indicator is converted into a chronological age. Unfortunately, this procedure is not error‐free due to the stages needed in assessing skeletal morphology and converting these data into a chronological age [1, 2]. There are various methods for determining a person's age, including dental and skeletal (hand/wrist) approaches, both of which have limits. Additionally, once these development sites have completed growth, precise age estimation becomes much more difficult [3].
A synchondrosis is a cartilaginous junction formed by two inflexible bones that allows for growth until the hyaline cartilage is transformed into bone before or during early adulthood [3].
Cranial base synchondroses are essential growth sites for the craniofacial skeleton [4].
The spheno‐occipital synchondrosis (SOS) is the junction of the occipital and sphenoid bones, located in the clivus area at the base of the skull, anterior to the foramen magnum and inferior to the pituitary fossa [3]. This synchondrosis, together with the intersphenoid synchondrosis and spheno‐ethmoidal synchondrosis, is one of three synchondroses found along the midline of the cranial base [4].
Until now, the SOS has been examined primarily in terms of cranial base growth and its link to dento‐alveolar development [3, 5]. There have been few forensic studies on its use for age assessment, and none in our context, in Cameroon.
SOS ossification occurs relatively late in comparison to other cranial base synchondroses that fuse prenatally (intersphenoid) or in early childhood (spheno‐ethmoidal) [6]. Hence, knowing the precise age of SOS closure has important applications in medicine, forensics, and anthropology [7].
Radiological investigations reveal that the fusion of the SOS starts from the endocranial surface and progresses to the ectocranial surface [3, 4]. According to Alhazmi et al. [6], in females, the SOS closes at a faster pace and at a younger age than males, although there is no significant difference in fusion progress between males and females at the age of 16 [3]. Bassed et al. [3] revealed that a scar at the location of fusion can last up to 25 years. Age determination is crucial in a number of professions, including anthropology, forensics, and medicine. There are various ways to determine age, including dental exams and carpal bone assessments. However, no research has been done in our local context about the comparatively late ossification age of SOS. Therefore, we planned to use computed tomography (CT) to radiologically assess the timing of closure of the SOS and assess this synchondrosis as a useful tool for age estimation.
2. General Objective
Evaluate the use of the SOS as a means of skeletal age estimation in Cameroon.
3. Methodology
We carried out a cross‐sectional analytical study on patient radiological files from the period of January 2022 to April 2024. Our study was a multicentric study at the Yaoundé University Teaching Hospital (YUTH) and two radiological centers in Yaoundé. The study population included radiological files of the patients that had carried out a CT scan in our study sites.
Our study had a retrospective and prospective arm. The prospective arm consisted of radiological files that were collected from the start of our study in November 2023 till the end of April 2024 (our study duration). All radiological files from January 2022 to November 2023 were part of the retrospective arm.
We included radiological files of patients aged from 1 to 40 years who had carried out an exploitable head and neck CT scan. We excluded radiological images which had motion artifacts, CT scan of patients who had a mass or fracture at the maxilla, base of the skull and spheno‐occipital region, CT scans of patients who had systemic diseases or syndromic conditions with significant effects on bone density or cortex of maxillofacial bones, patients who had cranial anomalies and hydrocephalus, radiological files for which the indication of the CT scan was not available, as well as radiological files of patients who had trauma as an indication.
3.1. Procedure
The CT scan of the head and neck region was collected and stored using external hard disk drives. After the collection of data, we interpreted the different CT scans in team with a radiologist. All CT scans were assessed blindly using a computer dedicated to medical imaging at the YUTH. The CT scans were performed on three different CT machines and the images obtained were imported using three different softwares (AQUARIUS INTUITION Edition V 4.4 for YUTH, EVOLUCARE VIEW STD for la Clinique de la Cathedrale, and RADIANT DICOM for CERIMED), respectively.
The head and neck CT scans were read and analyzed in the following way: the head CT scans were without injection. The axial images were acquired in helicoidally with a fine section of 0.5 mm and all the images were reconstructed into sagittal section in a bone window.
The fusion of the SOS was assessed using a five‐stage system modified from that developed by Powell and Brodie [8]. The different stages include:
Stage 1 in which the SOS is completely open.
Stage 2 where the superior border of the SOS closed.
Stage 3 in which the superior half of the SOS fused.
Stage 4 where there is complete fusion of the SOS and the scar present.
Stage 5 where there is complete fusion of SOS and the scar obliterated.
We chose this classification because it is easy to use and it takes in consideration the presence of the scar.
In our results tables, all participants in a particular stage will be presented as “Yes” and the other participants in the study not part of this stage will be presented as “No.”
3.2. Ethical Consideration
Ethical clearance was obtained from the Institutional Review Board of the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé 1 (N°721/UY1/FMSB/VDRC/CSD). Authorization from the Director of YUTH and the radiological centers was solicited and obtained.
3.3. Data Management and Statistical Analysis
Data were entered using SPSS version 27.0. Pearson's χ 2 test was used for comparison between categorical data and Student's t–test for quantitative data. Descriptive data were summarized using percentages and frequencies.
We proceeded to carry out a simple binary logistic regression using Stata 18.0. The tests were two‐sided. For the tests, the significant threshold was set at 0.05 that is all p values < 0.05 were considered statistically significant. The results were presented in figures and tables.
4. Results
4.1. General Characteristics of the Study Participants
Our study enrolled 2290 participants who had a carried out a CT scan from our 3 study sites, 940 were included in the study on the basis of being head and neck CT scans of which 628 were excluded based on our exclusion criteria. We finally retained 312 of these participants which we used to investigate for skeletal age as shown in Figure 1.
Figure 1.
Workflow diagram of our study.
4.1.1. Age and Sex Distribution of the Study Participants
Of the 312 participants retained, 171 (54.8%) were males and 141(45.2%) were females with a sex ratio of 1.2. Our study participants had an age range with bottom and top extremities of 1 and 40 years old.
The mean age in our study was 17.4 ± 11.9 years. The first decade was the most represented with 34.6%, within which the 0–5 age group representing 22.8% of our study population. The other frequencies can be seen in Figure 2.
Figure 2.
Age groups in the study population (n = 312).
4.2. Timing of the Spheno‐Occipital Synchondrosis Closure
4.2.1. Stages of Closure
We classified the stages of the SOS closure according to Powell and Brodie which was simple and easy to use. Amongst our study participants, 108 (34.6%) were in Stage 1 as can be seen in Table 1.
Table 1.
Distribution of spheno‐occipital synchondrosis stages in the study population (n = 312).
| Stage | Frequency | Percentage (%) |
|---|---|---|
| Stage 1: completely open | 108 | 34.6 |
| Stage 2: superior border closed | 35 | 11.2 |
| Stage 3: superior half closed | 08 | 2.6 |
| Stage 4: complete fusion scar present | 57 | 18.3 |
| Stage 5: complete fusion scar obliterated | 104 | 33.3 |
4.2.1.1. Stages of Closure by Mean Age
The mean age of participants in Stage 1 was 4.8 ± 3.3 years and the difference was statistically significant. There is a progressive increase in mean ages of SOS closure as we progress with the stages in other words participants presented with a higher mean age for each stage progressively from Stages 1 to 5 as can be seen in Table 2.
Table 2.
Distribution of spheno‐occipital synchondrosis stages by mean age in the study population (n = 312).
| Stage | Mean age ± SD | p |
|---|---|---|
| Stage 1 | 0.000 | |
| Yes | 4.8 ± 3.3 | |
| No | 24.1 ± 9.1 | |
| Stage 2 | 0.017 | |
| Yes | 12.9 ± 3.6 | |
| No | 18.0 ± 12.5 | |
| Stage 3 | 0.560 | |
| Yes | 19.9 ± 7.9 | |
| No | 17.4 ± 12.1 | |
| Stage 4 | 0.000 | |
| Yes | 23.5 ± 7.6 | |
| No | 16.1 ± 12.4 | |
| Stage 5 | 0.000 | |
| Yes | 28.6 ± 7.8 | |
| No | 11.9 ± 9.6 |
Note: Bold values indicate statistically significant.
4.2.2. Maximum and Minimum Ages by Stages
We observed a progressive increase in age amongst our study participants as we moved from Stages 1 to 5 as shown in Table 3.
Table 3.
Minimum and maximum ages for spheno‐occipital synchondrosis stages in the study population (n = 312).
| Stages | Minimum age | Maximum age |
|---|---|---|
| Stage 1 | 1.0 | 13.0 |
| Stage 2 | 6.0 | 21.0 |
| Stage 3 | 14.0 | 34.0 |
| Stage 4 | 9.0 | 40.0 |
| Stage 5 | 13.0 | 40.0 |
4.2.3. Stratification by Age Groups
Amongst our study participants, when we stratified the five stages by age groups, we observed that 91% of participants in Stage 1 where in the 0–10 age group and the remaining 9% of participants were in the 10–15 age group as can be seen in Table 4. Furthermore, there was a statistical significance in 4 out of the 5 SOS closure stages when compared to the age groups as seen in Table 4.
Table 4.
Number of participants per age group and stage (n = 312).
| Stages | Age groups | p | |||||||
|---|---|---|---|---|---|---|---|---|---|
| [0–5] | [5–10] | [10–15] | [15‐20] | [20‐25] | [25‐30] | [30‐35] | [35‐40] | ||
|
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
Freq Per (%) |
||
| Stage 1 (n = 108) | 71 (65.8) | 28 (25.9) | 09 (8.3) | 00 (0.0) | 00 (0.0) | 00 (0.0) | 00 (0.0) | 00 (0.0) | 0.000 |
| Stage 2 (n = 35) | 00 (0.0) | 08 (22.8) | 17 (48.6) | 09 (25.7) | 01 (2.9) | 00 (0.0) | 00 (0.0) | 00 (0.0) | 0.000 |
| Stage 3 (n = 08) | 00 (0.0) | 00 (0.0) | 03 (37.5) | 03 (37.5) | 00 (0.0) | 00 (0.0) | 02 (25.0) | 00 (0.0) | 0.057 |
| Stage 4 (n = 57) | 00 (0.0) | 01 (1.7) | 05 (8.8) | 20 (35.1) | 11 (19.3) | 07 (12.3) | 08 (14.0) | 05 (8.8) | 0.000 |
| Stage 5 (n = 104) | 00 (0.0) | 00 (0.0) | 06 (5.7) | 14 (13.5) | 18 (17.3) | 20 (19.2) | 24 (23.1) | 22 (21.2) | 0.000 |
Note: Bold values indicate statistically significant.
4.3. The Relationship Between the Spheno‐Occipital Synchondrosis Closure With Age and Sex
Comparing the SOS closure with sex we observed no clear difference between males and females apart from Stage 1 where 72 (66.7%) were males and 36 (33.3%) were females as can be seen in Table 5.
Table 5.
Spheno‐occipital synchondrosis stages by sex in the study population (n = 312).
| Stages | Sex | p | |
|---|---|---|---|
|
Male Percentage (%) |
Female Percentage (%) |
||
| Stage 1 (n = 108) |
72 (66.7) |
36 (33.3) |
0.002 |
| Stage 2 (n = 35) |
18 (51.4) |
17 (48.6) |
0.720 |
| Stage 3 (n = 08) |
03 (37.5) |
05 (62.5) |
0,475 |
| Stage 4 (n = 57) |
28 (49.1) |
29 (50.9) |
0.378 |
| Stage 5 (n = 104) |
50 (48.1) |
54 (51.9) |
0.117 |
Note: Bold values indicate statistically significant.
The mean ages between males and females were very similar amongst our study participants. In Stage 1 the mean age was 5.1 years and the mean age for females was 4.1 years as seen in Table 6.
Table 6.
Mean age ± SD of males and females in each stage (n = 312).
| Stages | Sex | |
|---|---|---|
| Male (n = 171) | Female (n = 141) | |
| Stage 1 | 5.1 ± 3.5 | 4.1 ± 2.9 |
| Stage 2 | 14.0 ± 3.7 | 11.7 ± 3.2 |
| Stage 3 | 15.0 ± 1.7 | 22.8 ± 9.0 |
| Stage 4 | 22.3 ± 7.7 | 24.6 ± 7.5 |
| Stage 5 | 28.9 ± 7.3 | 28.3 ± 8.2 |
We then proceeded to carry out a simple binary logistic regression as seen in Table 7.
Table 7.
Simple binary logistic regression.
| Variables | Odds ratio | 95% CI | p |
|---|---|---|---|
| Stage 1 | |||
| Age | 0.54 | 0.45–0.64 | p < 0.0001 |
| Sex | |||
| Male (ref) | 1 | ||
| Female | 0.47 | 0.29–0.77 | 0.002 |
| Stage 2 | |||
| Age | 0.96 | 0.93–0.99 | 0.020 |
| Sex | |||
| Male (ref) | 1 | ||
| Female | 1.17 | 0.58–2.36 | 0.670 |
| Stage 3 | |||
| Age | 1.02 | 0.96–1.08 | 0.560 |
| Sex | |||
| Male (ref) | 1 | ||
| Female | 2.06 | 0.48–8.77 | 0.329 |
| Stage 4 | |||
| Age | 1.05 | 1.03–1.08 | p < 0.0001 |
| Sex | |||
| Male (ref) | 1 | ||
| Female | 1.32 | 0.74–2.35 | 0.341 |
| Stage 5 | |||
| Age | 1.18 | 1.14–1.23 | p < 0.0001 |
| Sex | |||
| Male (ref) | 1 | ||
| Female | 1.50 | 0.94–2.41 | 0.092 |
Note: Bold values indicate statistically significant.
For every unit increase in age, the odds of being in Stage 1 reduced by 46% after adjusting for the effect of sex. There is strong evidence that this association is statistically significant (95% confidence interval (CI) (0.45–0.64), p < 0.0001).
Females compared to males are 53% lower odds of being in Stage 1 after adjusting for the effect of age. There is strong evidence to suggest that this association is statistically significant (95% CI (0.29–0.77), p = 0.002).
For every unit increase in age, the odds of being in Stage 2 reduced by 4% after adjusting for the effect of sex. There is some evidence that this association is statistically significant (95% CI (0.93–0.99), p = 0.02).
Females are at 1.17 higher odds of being in Stage 2 after adjusting for age. There is not enough evidence that this association is statistically significant (95% CI (0.58–2.36), p = 0.670).
For every unit increase in age the odds of being in Stage 3 increases by 1.02 after adjusting for the effect of sex. There is not enough evidence that this association is statistically significant (95% CI (0.96–1.08), p = 0.560).
Females are at 2.06 higher odds of being in Stage 3 after adjusting for age. There is not enough evidence that this association is statistically significant (95% CI (0.48–8.77), p = 0.329).
For every unit increase in age, the odds of being in Stage 4 increases by 1.05 after adjusting for the effect of sex and there is strong evidence to suggest statistically significance (95% CI (1.03–1.08), p < 0.0001).
Females are at 1.32 higher odds of being in Stage 4 after adjusting for age but there is not enough evidence that this association is statistically significant (95% CI (0.74–2.35), p = 0.341).
For every unit increase in age, the odds of being in Stage 5 increases by 1.18 after adjusting for the effect of sex and there is strong evidence to suggest statistically significance (95% CI (1.14–1.23), p < 0.0001).
Females are at 1.5 higher odds of being in Stage 5 after adjusting for age but there is not enough evidence that this association is statistically significant (95% CI (0.94–2.41), p = 0.092).
The five‐stage classification of the SOS we used can be seen in detail below (Figures 3, 4, 5, 6, 7).
Figure 3.
Sagittal cut showing spheno‐occipital synchondrosis Stage 1 in which the synchondrosis is completely open.
Figure 4.
Sagittal cut showing spheno‐occipital synchondrosis Stage 2 in which the superior border of the synchondrosis closed.
Figure 5.
Sagittal cut showing spheno‐occipital synchondrosis Stage 3 in which the in which the superior half of the synchondrosis fused.
Figure 6.
Sagittal cut showing spheno‐occipital synchondrosis Stage 4 in which there is complete fusion of the synchondrosis and the scar present.
Figure 7.
Sagittal cut showing spheno‐occipital synchondrosis Stage 5 in which there is completely open complete fusion of the synchondrosis and the scar obliterated.
5. Discussion
5.1. General Characteristics of the Study Participants
We retained 312 participants in our study with a mean age in our study was 17.4 ± 11.9 years similar to Alhazmi and colleagues who had a mean age of 13.30 ± 2.85 years [6] and Al‐Gumaei and colleagues with a mean age of 13.89 ± 1.13 years [9] and Tashayyodi and colleagues with a mean age of 14.93 ± 4.16 years [10].
We also used an age interval in our study of 1–40 years, we used this wide range in our study because it was the first time the SOS closure was studied in our population and hence to maximize the chances of representing all the five closure groups in our studies. A study by Nayak and colleagues had a smaller age range of 7–15 years [11], also a study by Al‐Gumaei and colleagues had an age range 6–25 years [9]. This could be because these studies were carried out on previous local studies, hence, they had a background on which age groups to use.
In our study sample, the first decade was the most represented with 34.6%. This was similar to Tashayyodi and colleagues in which the first decade was also the most represented with 60% [10]. This similarity was in part because we used the same SOS closure classification, however, the difference in percentages could be due the difference in sample sizes with our sample size being much larger.
All participants in Stage 1 were under the age of 15, with the oldest being 13, similar to results by Tashayyodi et al. [10] who had all participants in Stage 1 under the age of 17.
For our study, we used head and neck CT scans taken previously for purposes not related to this study to avoid irradiating the patients unnecessarily.
5.2. Timing of the Spheno‐Occipital Synchondrosis Closure
There exist several classifications for the SOS closure, we used the five‐stage classification by Powell and Brodie, as we felt it was didactic and easy to use clinically.
To interpret our CT scan, we used sections of 0.5 mm similar to Bassed and colleagues who used 1 mm thickness [3]. These fine slices provide high‐resolution images that allow accurate and precise separation of anatomical structures and aids to clear view the growth stages.
It is widely acknowledged that cranial growth is mostly dependent on brain growth and so follows the neural growth pattern (extremely rapid growth in the first 2–3 years, rapid decline, and near completion by the age of 7–8 years). Facial growth, on the other hand, is independent of brain growth and follows the typical skeletal growth pattern of most bones and muscles, which grow fairly uniformly from birth to adulthood with a distinct surge during adolescence. The cranial base, which serves as the link between the cranium and the face, is projected to grow at a rate that is somewhere between neural and general skeletal rates [12].
There was a significant association between the SOS Stages 1 and 2 closure and the mean age, showing that participants in Stages 1 and 2 are generally younger, similar to results by Tashayyodi and colleagues who made the same observation [10]. Also, there was a significant association between participants in Stages 4 and 5 and the mean age. This shows participants with Stages 4 and 5 are generally older. Our results are similar to those of Tashayyodi et al. [10] in finding a significant association between Stage 5 and mean age. We also agree with these authors in not finding a significant association between Stage 3 and mean age. However, our results differ from Tashayyodi et al. [10] in that we did find a significant association between Stage 4 and mean age, whereas Tashayyodi and colleagues did not.
However, in participants in Stage 3 there was no significant association with mean age hence we could differentiate between participants having SOS closure in this group versus those who did not. These results were also similar to Tashayyodi and colleagues who showed no significant association between participants in Stages 3 and 4 and mean age [10].
Moreover, when we stratified the mean ages by age groups as seen in Table 6, we observed a significant association with four out of five SOS closure stages. This shows the potential of the SOS as a skeletal age determinant in people among the age groups included in our study (1–40 years).
There is a progressive increase in mean ages of SOS closure as we progress from Stages 1 to 5 as seen in Table 3, showing the place of the SOS in skeletal age determination, even though in the latter stages there is no clear lower and upper age limit demarcation. However, with a larger sample size, this could help reduce and isolate this outlier values. Also, this high precision of age determination in Stage 1 which corresponds to young patients in more important in settings where the majority of populations are young like ours.
Our mean age of SOS closure for Stages 4 and 5 were 23.5 and 28.6 year‐olds, respectively. Our results are similar to Ford who reported the age of SOS closure of around 17 and 25 years [12] and Krogman et al. who had a mean age of around 18–23 years [4, 13].
On the other hand, Bassed and colleagues reported SOS closure by age 17 [3] and Okamoto et al. reported SOS closure by age 17 much lower than our results [14]. This difference could suggest interpopulation differences and show the need for more research to confirm or refute these differences and maybe lead to population‐specific data.
Interestingly, a previous study evaluating the cephalometric characteristics in Cameroon by Pierre et al. [15] described increased sagittal skeletal values compared to other population‐based studies and this can be explained by the late SOS closure permitting more growth as we observed in our study.
5.3. The Relationship Between the Spheno‐Occipital Synchondrosis Closure With Age and Sex
Biological studies are interested in SOS behavior because it occurs together with childhood and adolescent growth. It is one of the few bone structures that can be used to determine age during this stage of life [16].
The zygomaxillary suture (ZMS) is the longest and thickest circummaxillary suture, with the highest resistance to orthopedic pressures after rapid maxillary expansion (RME) and protrusion [17]. An interesting finding of a study carried out by Tashayyodi and colleagues showed the significant inverse correlation of SOS grade and MPS opening irrespective of age, and the direct correlation of SOS fusion and ZMS fusion [10]. This shows the importance of the SOS to the maxillofacial sphere and their close relation. Furthermore, the SOS closure stages could be used as a guide for RME in orthodontics as well as in craniofacial growth assessment.
We retained 312 participants in our study, we had 171 (54.8%) were males and 141(45.2%) with a male to female sex ratio of 1.2, hence we could compare males and females in our study on an equal footing to verify if there was a difference between SOS closure and sex.
We noticed no major difference between SOS closure and sex in our study amongst all five stages barring Stage I where we observed that 72 (66.7%) were males and 36 (33.3%) were females even though the mean age were identical. Our results are similar to Bassed and colleagues who had no statistical difference between males and females after the age of 16 [3]. Other studies have shown a difference between males and females [8, 16, 18, 19, 20, 21, 22] and they evoked a possible link between hormones and early SOS closure.
Scheuer and Black believed that SOS closure occurs during adolescence it could be related to significant maturation events such as sexual maturity [23]. In the same light, Alhazmi and colleagues observed an association between SOS closure and female puberty more specifically they found a significant association between menarche commencement in females and SOS closure and calculated the rate of SOS closure, which occurs at a faster rate in females and at an earlier age compared to males [6].
Regarding our simple binary regression, just like the association between stages of closure by mean age and the association between SOS stratification by age groups, four out of the five stages (Stages 1, 2, 4, and 5) showed a statistically significant association with age after adjusting for sex. This shows that the SOS closure can be used for age estimation with the odds per unit increase in age increasing by 1.18 of being in Stage 5 and lower (1.05) of being in Stage 4 and the lowest odds increase of 0.54 in Stage 1 confirming the progressive increase in mean ages of SOS closure as we progress with the stages.
In our study, we did not observe early female SOS closure which was also confirmed after the simple binary logistic regression with all stages except Stage 1 showing no statistical significance comparing females to males after adjusting for the effect age and this could further suggest interpopulation differences and show the need for more research to confirm or infirm these differences and maybe lead to population‐specific data.
5.4. Limits of the Study
-
1.
The inadequate archivage of patient files and CT scans limited our work sample and retarded our study because more time was needed to collect the necessary information.
-
2.
We could not obtain more information from the patient's files like region of origin which could have helped us evaluate more sociodemographic aspects of our study.
6. Conclusion
SOS closure in our study was as from the mean age of 23.5 years. SOS closure is linked to age in our study with a progressive increase in closure stage with age. SOS Stage 1 mean closure age was at 4.8 years followed by 12.9 years then 19.9 years, 23.5 and finally 28.6 years at Stage 5, respectively. With respect to sex, there was no difference in SOS closure between males and females in our study.
The SOS is linked to age in our study and hence can be used as a means of skeletal age determination in medical, forensic, and anthropological fields especially with its relative late closure.
Author Contributions
Conceptualization: Zilefac Brian Ngokwe, Bengondo Messanga Charles, and Mballa Amougou Jean Claude. Methodology: Sano Sylvie, Zilefac Brian Ngokwe, and Mballa Amougou Jean Claude. Data curation: Sano Sylvie. Investigation: Sano Sylvie, Zilefac Brian Ngokwe, and Mballa Amougou Jean Claude. Validation: Zilefac Brian Ngokwe, Bengondo Messanga Charles, and Mballa Amougou Jean Claude. Formal analysis: Sano Sylvie and Mballa Amougou Jean Claude. Supervision: Bengondo Messanga Charles and Mballa Amougou Jean Claude. Visualization: Zilefac Brian Ngokwe and Mballa Amougou Jean Claude. Project administration: Zilefac Brian Ngokwe, Bengondo Messanga Charles. Writing – original draft: Sano Sylvie, Zilefac Brian Ngokwe, and Mballa Amougou Jean Claude. Writing – review and editing: Zilefac Brian Ngokwe and Bengondo Messanga Charles. All authors have read and approved the final version of the manuscript. Zilefac Brian Ngokwe had full access to all of the data in this study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis.
Funding
The authors received no specific funding for this work.
Disclosure
The lead author Zilefac Brian Ngokwe affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
Ethics Statement
Ethical clearance was obtained from the Institutional Review Board of the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé 1 (N°721/UY1/FMSB/VDRC/CSD).
Consent
A waiver was obtained for informed consent after viewing our protocol and study type was obtained from the Institutional Review Board of the Faculty of Medicine and Biomedical Sciences of the University of Yaoundé 1 (N°721/UY1/FMSB/VDRC/CSD).
Conflicts of Interest
The authors declare no conflicts of interest.
Data Availability Statement
Data will be made available upon reasonable request from the authors.
References
- 1. Christensen A. M., Passalacqua N. V., and Bartelink E. J., “Age Estimation,” in Forensic Anthropology (Elsevier, 2014), 243–284. [Google Scholar]
- 2. Nawrocki S., “The Nature and Sources of Error in the Estimation of Age at Death From the Skeleton,” in Age Estimation From the Human Skeleton, ed. K. Latham and M. Finnegan (2010), 79–101, http://www.amazon.com/Age-Estimation-Human-Skeleton-Krista/dp/0398079501.
- 3. Bassed R. B., Briggs C., and Drummer O. H., “Analysis of Time of Closure of the Spheno‐Occipital Synchondrosis Using Computed Tomography,” Forensic Science International 200 (2010): 161–164. [DOI] [PubMed] [Google Scholar]
- 4. Kanchan T. and Krishan K., “Evaluation of Spheno‐Occipital Synchondrosis: A Review of Literature and Considerations From Forensic Anthropologic Point of View,” Journal of Forensic Dental Sciences 5 (2013): 72. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. Hoyte D. A. N., “The Cranial Base in Normal and Abnormal Skull Growth,” Neurosurgery Clinics of North America 2 (1991): 515–537. [PubMed] [Google Scholar]
- 6. Alhazmi A., Vargas E., Palomo J. M., Hans M., Latimer B., and Simpson S., “Timing and Rate of Spheno‐Occipital Synchondrosis Closure and Its Relationship to Puberty,” PLoS One 12 (2017): e0183305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Sinanoglu A., Kocasarac H. D., and Noujeim M., “Age Estimation by an Analysis of Spheno‐Occipital Synchondrosis Using Cone‐Beam Computed Tomography,” Legal Medicine 18 (2016): 13–19. [DOI] [PubMed] [Google Scholar]
- 8. Powell T. V. and Brodie A. G., “Closure of the Spheno‐Occipital Synchondrosis,” Anatomical Record 147 (1963): 15–23. [DOI] [PubMed] [Google Scholar]
- 9. Al‐Gumaei W. S., Long H., Al‐Attab R., et al., “Comparison of Three‐Dimensional Maxillary Growth Across Spheno‐Occipital Synchondrosis Maturation Stages,” BMC Oral Health 23 (2023): 100. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Tashayyodi N., Kajan Z. D., Ostovarrad F., and Khosravifard N., “Relationship of the Fusion Stage of Spheno‐Occipital Synchondrosis With Midpalatal and Zygomaticomaxillary Sutures on Cone‐Beam Computed Tomography Scans of Patients Aged Between 7 and 21 Years,” Turkish Journal of Orthodontics 36 (2023): 186–193. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11. Nayak R., Panakkal N. C., and T V., “Age Estimation by Spheno‐Occipital Synchondrosis Fusion in South Indian Population Using Computed Tomography,” Egyptian Journal of Forensic Sciences 13 (2023): 29. [Google Scholar]
- 12. Ford E. H. R., “Growth of the Human Cranial Base,” American Journal of Orthodontics 44 (1958): 498–506. [Google Scholar]
- 13. Krogman W. M., and Iscan Y. M., 1986. The Human Skeleton in Forensic Medicine, 2nd ed. (Charles C. Thomas Pub Ltd, 1986). [Google Scholar]
- 14. Okamoto K., Ito J., Tokiguchi S., and Furusawa T., “High‐Resolution CT Findings in the Development of the Sphenooccipital Synchondrosis,” AJNR American Journal of Neuroradiology 17, no. 1 (1996): 117–120. [PMC free article] [PubMed] [Google Scholar]
- 15. Pierre O.‐Z., Charles B., Catherine E., and Jules O., “Cephalometric Characteristics of Cameroonian Adults: Dimensional Analysis of 80 Cases,” Dentistry 9 (2019): 548, 10.35248/2161-1122.20.10.555. [DOI] [Google Scholar]
- 16. Hasani M., Mokhberi M., Karandish M., and Boroumand R., “Timing of Spheno‐Occipital Synchondrosis Closure in Cleft Lip and Palate Patients in Iranian Population,” Cleft Palate Craniofacial Journal 60 (2023): 1113–1117. [DOI] [PubMed] [Google Scholar]
- 17. Angelieri F., Franchi L., Cevidanes L. H. S., Hino C. T., Nguyen T., and McNamara J. A., “Zygomaticomaxillary Suture Maturation: A Predictor of Maxillary Protraction? Part I ‐ A Classification Method,” Orthodontics & Craniofacial Research 20 (2017): 85–94. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Can I. O., Ekizoglu O., Hocaoglu E., Inci E., Sayin I., and Kaya K. H., “Forensic Age Estimation by Spheno‐Occipital Synchondrosis Fusion Degree,” Journal of Craniofacial Surgery 25 (2014): 1212–1216. [DOI] [PubMed] [Google Scholar]
- 19. Franklin D. and Flavel A., “Brief Communication: Timing of Spheno‐Occipital Closure in Modern Western Australians,” American Journal of Physical Anthropology 153 (2014): 132–138. [DOI] [PubMed] [Google Scholar]
- 20. Sahni D., Jit I., Neelam, and Suri S., “Time of Fusion of the Basisphenoid With the Basilar Part of the Occipital Bone in Northwest Indian Subjects,” Forensic Science International 98 (1998): 41–45. [DOI] [PubMed] [Google Scholar]
- 21. Ingervall B. and Thilander B., “The Human Sphenooccipital Synchondrosis I. The Time of Closure Appraised Macroscopically,” Acta Odontologica Scandinavica 30 (1972): 349–356. [DOI] [PubMed] [Google Scholar]
- 22. Melsen B., “Time of Closure of the Spheno‐Occipital Synchondrosis Determined on Dry Skulls A Radiographic Craniometric Study,” Acta Odontologica Scandinavica 27 (1969): 73–90. [DOI] [PubMed] [Google Scholar]
- 23. Scheuer L. and Black S., The Juvenile Skeleton (Elsevier, 2004), https://onlinelibrary.wiley.com/doi/10.1002/ajhb.20454.
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data will be made available upon reasonable request from the authors.