Forensic Age Estimation by Spheno-Occipital Synchondrosis Fusion Degree

Abstract

The analysis of ossification points plays a considerable role in forensic age estimation. Although traditional methods are still in use, researchers are working on different age estimation procedures especially within the development of radiologic methods. One of these methods is to define spheno-occipital synchondrosis fusion degree. Spheno-occipital synchondrosis, an important growth point on cranial base, provides noteworthy information about age estimation through its late stage ossification nature. This study aimed to investigate spheno-occipital synchondrosis fusion degree for age estimation in the Turkish population. In our study, 1-mm-sectioned computed tomography images of 638 (399 men and 139 women) subjects within the age of 10 to 25 years were retrospectively examined. It is stated in our study that spheno-occipital syncondrosis fusion begins superiorly and progresses inferiorly until it is completed. Spheno-occipital syncondrosis is known to be totally open at the mean (SD) age of 11.5 (1.5) years in men and 10.7 (0.8) years in women. In addition, fusion degree is known to be increased with age. Fusion starts approximately 2 years earlier in women than in men, and the process of fusion completes at the age of 17 years in both sexes. An analysis of fusion degree between sex groups showed significance at the age of 11 to 15 years, and Spearman rank correlations indicate a significant positive relationship between age and degree of spheno-occipital fusion (P < 0.001; men, ρ = 0.714; women, ρ = 0.698). Consequently, 5-staged analysis of spheno-occipital synchondrosis fusion degree in use with 1-mm computed tomography images will be helpful for age estimation between 11 and 17 years.

Timing and rate of spheno-occipital synchondrosis closure and its relationship to puberty

“…However, it is worth mentioning that the youngest and oldest ages are affected by sample compositions and age limits. Some studies have samples that include individual ages up to 25 years, and they reported Stage 3 closure age in both sexes around 20 years and above [ 18 , 30 ]. The same could be said when we calculate the mean age of oldest individuals with completely open SOS (Stage 0).…”

“…Early studies assert complete closure between 17 and 25 years in males and females [ 8 , 11 ]. Later, differences in closure age between males and females were reported with females beginning to fuse between 11 and 14 years and males between 13 and 16 years [ 12 – 18 ]. More recently, Computed Tomography (CT) and Cone Beam Computed Tomography (CBCT) have been used in SOS evaluation.…”

“…Due to superior visualization achieved using 3D radiographic scans, more recent studies have used it to evaluate the skull base, claiming it could result in more accuracy in determining SOS closure [ 15 , 19 ]. Recent studies using CT imaging reported age of closure would start around 11 years of age in female and around 13 years in males [ 15 , 17 , 18 ]. However, other studies that used CT scans reported closure could start as early as 4 years [ 4 , 20 – 22 ].…”

Spheno-Occipital Synchondrosis Fusion Correlates with Cervical Vertebrae Maturation

“…The spheno-occipital synchondrosis has gained importance for both age estimation and clinical applications, particularly because of its late ossification process [ 32 ]. Fusion of the spheno-occipital synchondrosis usually starts about 2 years earlier in females than in males [ 11 , 33 ], in a similar way than that observed during general growth at the beginning of puberty [ 34 ]; however, no significant differences seem to occur at the end of the process [ 12 , 32 ].…”

“…Age estimation of subjects by using the closure stage of spheno-occipital synchondrosis is widely variable among studies, which may be attributed to the different methodological approaches used, i.e. macroscopic [ 11 , 35 , 36 ], radiographic [ 37 ] or CBCT [ 12 – 14 , 32 ], different scoring systems, sex, or population variations.…”