New method for quantification of the relative severity and (a)symmetry of isolated metopic synostosis

Abstract

Trigonocephaly is the result of premature fusion of the metopic suture and its severity can vary widely. However, there is no gold standard for quantification of the severity. This study was performed to quantify severity using the Utrecht Cranial Shape Quantifier (UCSQ) and to assess forehead symmetry. Nineteen preoperative non-syndromic trigonocephaly patients (age 1 year) were included for the analysis of severity and symmetry. Severity according to the UCSQ was based on the following combined variables: forehead width and relative skull elongation. The UCSQ was compared to the most established quantification methods. A high correlation was found between the UCSQ and visual score (r = 0.71). Moderate to negligible correlation was found between the UCSQ and frontal angle, binocular distance, inter-ocular distance, and frontal stenosis. Additionally, correlation between the visual score and these established quantification methods was negligible. Assessment of the frontal peak (a)symmetry (ratio of right to left triangle area in the curve) showed a mean right versus left triangle area ratio of 1.4 (range 0.9-2.4). The results suggest that the UCSQ is appropriate for the quantification of severity based on the high correlation with clinical judgement. Furthermore, a larger triangle area right than left was unexpectedly found, indicating forehead asymmetry.

Intracranial Volume Not Correlated With Severity in Trigonocephaly

“…Since little is known about the correlation between severity of trigonocephaly and its ICV, the present study correlated with the severity of the skull deformity according to UCSQ to ICV. In our previous study, we found high correlation between the UCSQ method and severity of trigonocephaly and is therefore proven to be eligible for quantification purposes in trigonocephaly patients (Kronig et al, 2021).…”

“…In our previous study, we combined ΔY peak and width of frontal peak at F-0.05. A high correlation was found between severity of trigonocephaly and these combined variables (Kronig et al, 2021).…”

“…The curves, generated by the UCSQ method (Figure 2), were analyzed for different variables. Trigonocephaly can be classified according to severity based on UCSQ for trigonocephaly and its severity calculation (Figure 2) (Kronig et al, 2021).…”

“…In our previous study, we combined DY peak and width of frontal peak at F-0.05. A high correlation was found between severity of trigonocephaly and these combined variables (Kronig et al, 2021). In order to differentiate between the different levels of severity of trigonocephaly, we will use the introduced severity calculation: (Width of frontal peak at F ¼ 0.05-66) Â À2.9 þ (DY peak À 0.26) Â 8300.…”

“…Severity of trigonocephaly can be established by using UCSQ (Utrecht Cranial Shape Quantifier) (Kronig et al, 2020a). Utrecht Cranial Shape Quantifier is an outline-based method of classification and quantification of skull shape deformities (Kronig et al, 2020, Kronig et al, 2021). This method has the advantage of capturing the actual skull shape variation with every 3D diagnostic system that captures the surface of the head.…”